CN101076710A - Multi-phase coriolis flowmeter - Google Patents

Abstract

A flowmeter is disclosed. The flowmeter includes a vibratable flowtube, and a driver connected to the flowtube that is operable to impart motion to the flowtube. A sensor is connected to the flowtube and is operable to sense the motion of the flowtube and generate a sensor signal. A controller is connected to receive the sensor signal. The controller is operable to determine a first flow rate of a first phase within a two-phase flow through the flowtube and determine a second flow rate of a second phase within the two-phase flow.

Description

Multi-phase coriolis flowmeter

Technical field

The present invention relates to flowmeter.

Background technology

Flowmeter can provide about the information of transmission through the material of conduit or stream pipe.For example, mass flowmeter can provide the quality reading of transmission through the material of conduit.Equally, the density flowmeter, perhaps densitometer can provide the density readings of the material of the conduit of flowing through.Mass flowmeter also can provide the density readings of material, therefore also can draw the reading of volume flow rate.

For example, brother's mass flowmeter measures based on this effect in brother's Leo, and the material of the conduit of wherein flowing through becomes the quality that radially flows and is subjected to the effect of coriolis force and therefore stands acceleration.Many Ge Shi formula mass flowmeters can bring out coriolis force by making a conduit around the pivotal axis that is orthogonal to catheter length carry out sine-wave oscillation.In this mass flowmeter, the flowing liquid quality stands the De Geshi reacting force and is delivered to conduit itself and shows the conduit amount of deflection on the coriolis force direction vector or skew in rotational plane.

Summary of the invention

According to an overall plan, a kind of flowmeter comprises vibratile stream pipe; Driver is connected in the stream pipe and is used for exciting the motion of flowing pipe; Sensor is connected in the senses flow pipe was managed and be used for to stream motion and generation sensor signal; And controller, through connecting with sensor-lodging second flow rate that this controller is used for determining first flow rate of first phase in the two-phase flow of flow tube and determines second phase in the two-phase flow.

Various embodiments can comprise one or more following characteristics.For example, first can comprise a gas mutually, and second can comprise a liquid mutually.

Controller be used to import by looking of the detected two-phase flow of flowmeter density and export the corrected density of this two-phase flow.Controller be used for according to look the theoretical relationship between density and the corrected density, perhaps according to look between density and the corrected density rule-of-thumb relation (such as, look to such an extent that the form between density and the corrected density stores relation) proofread and correct look density.

Controller be used to import by looking of the detected two-phase flow of flowmeter mass flowrate and export the correction mass flow rate of this two-phase flow.Controller can be used for according to look theory or the actual relationship between mass flowrate and the correction mass flow rate, form relation for example is to looking to such an extent that mass flowrate is proofreaied and correct.

Controller is used to import the phase fraction of winning of looking by the detected two-phase flow of flowmeter, and this looks the amount that the phase fraction of winning is determined first phase in the two-phase flow, and correction first phase fraction of output two-phase flow.Controller can be used for importing by the phase fraction sensor of flowmeter outside to first phase fraction of two-phase flow.

Controller can be used for determining first flow rate and second flow rate according to the corrected value that detects density and detection mass flowrate in the two-phase flow.Controller can be used for determining first flow rate and second flow rate according to the corrected value of determining detection first phase fraction of the amount of first phase in the two-phase flow.Controller can be used for according to first mutually and second mutually definite respectively first flow rate of density and second flow rate.

Controller can be used for determining first mutually the first surface speed and second mutually the second surface speed respectively according to first flow rate and second flow rate.Controller can be used for determining according to first surface speed and second surface speed the flow state of two-phase flow.Controller can be used for according to the average velocity of the average velocity of first phase and second phase determine first with second the sliding velocity between mutually.Controller can be used for according to first and second superficial velocities, determined flow state, or sliding velocity proofreaies and correct first flow rate and second flow rate, obtains to proofread and correct first flow rate thus and proofreaies and correct second flow rate.

According to another overall plan, a kind of method comprises the global density of determining through the two-phase flow of flow tube, this two-phase flow comprise first mutually with second mutually; Determine the bulk mass flow rate of two-phase flow; And determine first mutually first mass flowrate according to global density and bulk mass flow rate.

Various embodiments can comprise one or more following characteristics.For example, second mass flowrate of second phase can be determined according to global density and bulk mass flow rate.When determining global density, can determine looking of two-phase flow global density, and look to such an extent that global density can be calibrated to obtain global density.

When correction look during global density, look to such an extent that global density can be input to one and will look to such an extent that global density closes to lie in the theoretical relationship of proofreading and correct global density and goes, perhaps can be input to one and will look to such an extent that global density closes to lie in the rule-of-thumb relation of proofreading and correct global density and goes.

When correction look during global density, can import first density of first phase.Can determine first phase fraction of two-phase flow according to first density of global density, first phase and second mutually second density.When determining first mass flowrate of first phase, first mass flowrate can be determined according to first phase fraction and first density.

The first surface speed of first phase can be determined respectively according to first mass flowrate and second mass flowrate with second mutually the second surface speed.The flow state of two-phase flow can be determined according to first surface speed and second surface speed.First can determine according to the average velocity of first phase and the average velocity of second phase with second the sliding velocity between mutually.Can proofread and correct first flow rate and second flow rate according to first and second superficial velocities, determined flow state or sliding velocity.

First can comprise a gas mutually, and second can comprise a fluid mutually.

According to another overall plan, the flowmeter controller comprises density correction system, this system be used to import looking of two-phase flow density and export the corrected density of this two-phase flow, this two to stream comprise first mutually with second mutually; Mass flow rate correction system, be used to import looking of this two-phase flow mass flowrate and export the correction mass flow rate of this two-phase flow; And liquid stream constituent mass flow rate determines system, is used for determining first mutually first mass flowrate according to corrected density and correction mass flow rate.

Various embodiments can comprise one or more following characteristics.For example, liquid stream constituent mass flow rate determines that system is used for determining second mutually second mass flowrate according to corrected density and correction mass flow rate.

First can comprise a liquid mutually, and second can comprise a gas mutually.This scheme can comprise that a kind of phase fraction determines system, and this system is used for determining the correction phase fraction of two-phase flow, and wherein liquid stream constituent mass flow rate determines that system is used for determining first flow rate and second flow rate according to proofreading and correct phase fraction.This phase fraction determines that system can determine that the hole rate of gas flow is determined system in the two-phase flow.

This scheme can comprise that superficial velocity determines system, the first surface speed that this system is used for determining first phase and second mutually the second surface speed.The flowmeter controller can comprise that flow state determines system, and this system is used for determining the flow state of two-phase flow.

Flow state determines that system can be further used for determining phase slip speed according to the average velocity of first phase with second mutually the average velocity.Liquid stream constituent mass flow rate determines that system is used for improving determining that first mass velocity and second mass velocity are carried out according to first and second superficial velocities, flow state or phase slip speed.

The details of one or more embodiments will be set forth at accompanying drawing and following stating in the instructions.Other features can clearly obtain from instructions, accompanying drawing and claim.

Description of drawings

Figure 1A is the synoptic diagram that utilizes a kind of coriolis flowmeter of bent flowtube;

Figure 1B is the synoptic diagram that utilizes a kind of coriolis flowmeter of straight flowtube;

Fig. 2 is a kind of block scheme of coriolis flowmeter;

Fig. 3 shows the process flow diagram of coriolis flowmeter running among Fig. 2;

Fig. 4 shows the process flow diagram of the method that is used for definite two-phase flow liquids and gases flow rate;

Fig. 5 A and 5B are the curve maps that shows percentage error in the measurement of hole rate and liquid fraction respectively;

Fig. 6 shows for having specific orientation and spreading all over the curve map as the mass flow errors of the function of density drop-out value of a kind of Guan Eryan of stream of selected flow range;

Fig. 7 shows the process flow diagram of the method for corrected density measurement result.

Fig. 8 show looking of two-phase flow the density drop-out value and look the form that concerns between the mass flowrate;

Fig. 9 shows the process flow diagram of the method that is used for definite hole rate measurement result;

Figure 10 shows the process flow diagram of the method that is used for definite measurement of mass flow rate result who has proofreaied and correct;

Figure 11 show two-phase flow look the form that concerns between mass flowrate and the corrected density drop-out value;

Figure 12-the 14th, expression is used for flowing in a large number the curve map of example of the density correction of pipe;

Figure 15-the 20th, expression is used for flowing in a large number the curve map of example of the mass flowrate corrected value of pipe.

Embodiment

The type of flowmeter comprises digital flowmeter.For example, United States Patent (USP) 6,311,136 is included in as a reference at this, discloses a kind of digital flowmeter and has comprised signal Processing and the correlation technique of measuring method.The measurement result of this digital flowmeter can be very accurate, and noise is close to maybe can not ignore, and can make the positive and negative gain that has wide range at the exciting circuit that is used for encouraging conduit.This digital flowmeter thereby be very beneficial in multiple structure.For example, the common United States Patent (USP) of transferring the possession of 6,505,519, include in as a reference at this, disclose and utilized wide gain margin, and/or utilize negative gain, prevent burbling (stalling) and more accurately convection tube control, even under the hard situation such, also be like this such as two-phase flow a kind of liquid of liquid vapour mixture (for example comprise stream).

Though specifically describe digital flowmeter with reference to for example Fig. 1 and 2 below, should be appreciated that also to exist some analogue flow rate meters.Though these analogue flow rate meters may tend to have some exemplary shortcomings of mimic channel, for example precision is hanged down and the higher measurement result of noise with respect to digital flowmeter, and they also can be compatible mutually with the whole bag of tricks and device in this explanation.Thereby, in the following discussion, " flowmeter " or " gauge " speech is used in reference to device and/or the system that acts as what type, and wherein the coriolis flowmeter system adopts various control system and related device measurement to flow through to manage or the mass flowrate of certain or multiple material of other conduits, density and/or other parameters.

Figure 1A is the synoptic diagram that adopts a kind of digital flowmeter of bent flowtube 102.Specifically, bent flowtube 102 can be in order to measure one or more physical features amounts of for example a certain (flowing) fluid, and one is as indicated above.In Figure 1A, digital transmitter 104 and bent flowtube 102 switching sensors and two kinds of signals of excitation, thereby correspondingly both vibrations of sensing bent flowtube 102 encourage the vibration of bent flowtube again.By determining sensor and these two kinds of signals of excitation rapidly and accurately, digital transmitter 104 as mentioned above, has guaranteed the quick and accurate running of bent flowtube 102.With some case histories of the common digital transmitter of using 104 of bent flowtube in the common United States Patent (USP) of transferring the possession of 6,311,136 for example.

Figure 1B is the synoptic diagram that utilizes a kind of digital flowmeter of straight flowtube 106.Say that more specifically in Figure 1B, straight flowtube 106 interacts with digital transmitter 104.A kind of like this running of straight flowtube is similar to bent flowtube 102 on the notion aspect, and has multiple advantages/disadvantages with respect to bent flowtube 102.For example, just owing to the geometry situation of its structure, straight flowtube 106 is easier to (fully) filling and clearancen compared with bent flowtube 102.In running, bent flowtube 102 can operate under the frequency of for example 50-110Hz, and straight flowtube 106 can operate under the frequency of for example 300-1000Hz.The stream pipe that bent flowtube 102 representatives have multiple diameter, and can on multiple orientation, operate, such as on horizontal or vertical orientation.

With reference to Fig. 2, digital mass flowmeter 200 comprises that digital transmitter 104, one or more motion sensor 205, one or more driver 210, stream pipe 215 (are also referred to as conduit, and can represent or bent flowtube 102, straight flowtube 106, and temperature sensor 220 the perhaps stream pipe of any other type).Digital transmitter 104 can adopt one or more for example following devices to be achieved, for example processor, digital signal processor (DSP), field programmable gate array (FPGA), ASIC and other FPGA (Field Programmable Gate Array) or gate array perhaps have the FPGA (Field Programmable Gate Array) circuit of processor core.Should be appreciated that as 6,311 136 is described, be used for the running of driver 210 in the digital-analog convertor that is associated can be included in, and analogue-to-digital converters can be used for the usefulness of the sensor signal of conversion sensor 205 for digital transmitter 104.

Digital transmitter 104, at least according to the signal that receives from each motion sensor 205, producing for example flows through manages the density of 215 material and/or the measurement result of mass flowrate.Digital transmitter 104 also may command driver 210 flows the motion of managing in 215 to excite.This motion is carried out sensing by motion sensor 205.

Flow through pipe material the density measurements homogeneous phase about, for example, the frequency of the stream pipe motion that the exciting force that is applied by driver 210 produces in stream pipe 215, and/or be relevant to the temperature of stream pipe 215.Equally, the mass flowrate of the pipe 215 of flowing through is relevant to the phase place and the frequency of stream pipe 215 motions, and the temperature of stream pipe 215.

Temperature in the stream pipe 215 can utilize temperature sensor 220 to be measured, and this temperature can influence some character of stream pipe, such as its rigidity and size.Digital transmitter 104 can compensate these temperature effects.In Fig. 2, pressure transducer 225 is communicated in forwarder 104 equally, and is connected in stream pipe 215 for use in the pressure of senses flow through the material of stream pipe 215.

Should be appreciated that the hydrodynamic pressure of inflow pipe 215 into and on flow tube relevant points pressure drop these two all be the index of some flox condition.In addition, though can use outside temperature sensor measurement fluid temperature (F.T.), these sensors also can be used for convection tube and proofread and correct outside inner stream flow flowmeter sensor (design is used for measuring representative temperature).In addition, some stream pipes adopt a plurality of temperature sensors, and purpose is the measurement result of the altitude temperature difference effect between process fluid and the environment (for example flowing the surface temperature of pipe shell) is proofreaied and correct.As hereinafter illustrating in more detail, possible a kind of purposes of two kinds of measurement results of inlet fluid temperature and pressure is to calculate the actual density of liquids and gases in the two-phase flow according to predetermined formula.

Liquid fraction detector 230 refers to a kind of device, be used for liquid at stream pipe 215 comprise water and another fluid-such as oil-in, measure the water of liquid-for example-volume share.Certainly, if measurement result is preferentially selected, if perhaps this liquid does not comprise water, so this detector, or class likelihood detector can be used for measuring the volume share of certain fluid that is not water.In following explanation, measured liquid generally is assumed to water, and this paper water is as illustration, and liquid fraction detector 230 is commonly referred to as moisture content volume detector 230, or the water yield (water-cut) detector 230.

Void fraction sensor 235 is measured the number percent that is in the material of gaseous form in the stream pipe 215.For example, pipe 215 the water of flowing through can comprise the air that may be shaped as bubble.This situation, the material of the pipe 215 of promptly wherein flowing through comprises more than one materials, is commonly referred to as " two-phase flow ".Specifically, term " two-phase flow " can refer to a kind of liquid and a kind of gas; But, " two-phase flow " also can refer to other combinations of material, such as two kinds of liquid (for example oil and water).

Exist several different methods at present, in Fig. 2,, be used to measure the gas void fraction among a kind of liquid-gas two-phase flow generally by void fraction sensor 235 expression.For example, exist multiple sensors or detector, can inject in the two-phase flow to determine gas void fraction.As another example, Venturi tube (promptly, the pipe that has a narrowed throat, determine hydrodynamic pressure and speed by when certain fluid flows through pipe, measuring the pressure reduction that produces at the throat place), gas can be used for determining pressure gradient and can determining gas void fraction thus with this fact of moving greater than the speed of (respectively) liquid when passing restriction.Utilize the measurement result that also can obtain gas void fraction fully at the outside equipment of stream pipe.For example, can adopt the sonar measurement result to determine gas void fraction.Instantiation as a kind of like this system based on sonar can adopt CiDRA company (CiRDA Corporation of wallingford, connecticut) the SQNAR tracTM gas void fraction monitoring system of Sheng Chaning by health alunite Dick state Wo Lingfu.

In this instructions, by void fraction sensor measure or the streaming flow otherwise determined in gas flow be called void fraction, and be defined as α=gas volume/cumulative volume=gas volume/(liquid volume+gas volume).Therefore, be defined as 1-α in this amount that is called liquid fraction.

In many application that require the measurement of mass flow rate result, the hole rate in the liquid stream can be up to 20,30,40% or more.But, even under 0.5% minimum hole rate, the basic theory of coriolis flowmeter will become little available.

And the gas that exists in the liquid stream can also have influence on the measurement of liquid current density, can cause the density measurements reading lower usually.That is, should be appreciated that since in two-phase flow gas (for example, air) density can be lower than liquid () density for example, water, the density of liquid ρ of pipe so itself flows through usually _LiquidThe actual density ρ that will be higher than the two-phase flow that comprises this liquid and a certain gas _TrulyIn other words, when gas is added into the liquid stream that originally only comprises liquid, density can occurs and reduce.

Outside this physical phenomenon, measure the exportable density readings ρ of two-phase liquid stream De Geshi flowmeter of air inclusion _Look, that is the apparent measurement result of two-phase flow (for example combining by water and air) global density.This original measurement is ρ as a result _LookGeneral different (low) is in the actual global density ρ of two-phase flow _TrulyFor example, because due to the relative motion of gas in liquid stream, the resonant frequency that flowmeter adopted may virtual height and cause the density measurements reading lower.Should be appreciated that since most of this coriolis flowmeters in addition the hole rate of minor amount under all can't continuous service (for example defluidization or export coarse measurement result), so the flowmeter of the prior art of many routines is all never handled this problem.

U.S. Patent No. 6,505,519 is more than included in as a reference, discloses ρ _LookOriginal or the global density reading of sign of the two-phase flow of coriolis flowmeter output (that is, by) and ρ _TrulyThe difference of (that is actual original the or global density of two-phase flow) can be characterized by several different methods.As a result, the ρ that records _LookCan be proofreaied and correct to obtain actual global density ρ _{Proofread and correct}, the density of this correction equals ρ at least haply _Truly

Have slightly similarly, by the original or bulk mass flow rate MF of sign of brother's formula flowmeter survey gained _LookThe mass flowrate of two-phase flows (that is, all) can with the bulk mass flow rate MF of reality _TrulyDiffer a predictable amount that maybe can characterize.Should be appreciated that the bulk mass flow rate MF that is used for having proofreaied and correct _TrulyBearing calibration can be different from the bearing calibration that is used for density.For example, the MF that is used for correcting measuring _LookTo obtain actual MF _Truly(perhaps, at least, MF _{Proofread and correct}) several different methods be recorded in U.S. Patent No. 6,505, in 519.

To illustrate in further detail below and be used to proofread and correct ρ _LookAnd MF _LookThe example of various detailed method.Though in general, with regard to Fig. 2, digital transmitter is depicted as and comprises density correction system 240, and this system can be connected in density correction database 245, and mass flow rate correction system 250, and this system can be connected in mass flowrate correction database 255.Just like following described in more detail, database 245 and 255 for example can comprise that derive or that obtained in theory various correcting algorithms on experience, and/or provide the density of having proofreaied and correct or the various correction forms of mass rate numerical value at given one group of input parameter.What database 245 and 255 also can store multiple other types can be used for realizing information in density or the mass flow corrections.For example, density correction database can store many density p corresponding to particular fluid (for example water or oil) _Liquid

Secondly, in Fig. 2, hole rate determines/corrective system 260 can be used for determining comprising the hole rate of the two-phase flow of a certain liquid and a certain gas.An embodiment, for example, hole rate determines/corrective system 260 can be from the density p of having proofreaied and correct _TrulyIn determine actual void fraction α _TrulyIn another embodiment, hole rate determines/corrective system 260 can import the sign that obtains by void fraction sensor 235 or look the hole rate measurement result, and can proofread and correct this measurement result according to a kind of error character that is similar to above mentioned density and mass rate method.In another embodiment, void fraction sensor 235 can be used for directly measuring actual void fraction α _Truly, in the case, hole rate determines/corrective system 260 can import this measurement result fully.

In case factor ρ _Truly, MF _TrulyAnd α _TrulyDetermine, and perhaps be incorporated into other known or unknown quantitys that liquid stream constituent mass flow rate determines that system 265 is used for determining simultaneously the mass flowrate of liquid phase component and the mass flowrate of gaseous component so.Just, forwarder 104 can be used for determining the MF of flow rate separately of liquid stream component _LiquidAnd MF _Gas, this and the whole flow rate MF that just determines combination or total two-phase flow _TrulySituation opposite.Though, as just and mention, this measurement result can be determined and/or be exported simultaneously, they also can be determined individually or independently of one another.

In case component flow rate MF _LiquidAnd MF _TrulyDetermine in the mode summarized above that these determine that tentatively results just can be improved according to the superficial velocity (superficial velocity) of liquid stream component, sliding velocity between the component and/or the process through discerning flow state of liquid stream by a kind of so.Like this, can obtain improved flow rate MF _LiquidAnd MF _GasNumerical value, perhaps can be obtain at any time along with the change of these flow rates.

If superficial velocity referred to herein as a certain the flowing through with same mass flowrate to phasing of single phase and manages the sort of speed that will occur at 215 o'clock.Superficial velocity determines/corrective system 270 is included in the forwarder 104, for example be used for determining looking of a certain gas of two-phase flow or liquid or the superficial velocity of having proofreaied and correct.

Sliding velocity refers to a kind of state, and the gas-liquid two-phase under this state in the two-phase flow has different average velocity.Just, the average velocity AV of a certain gas _GasThe average velocity AV that is different from liquid _LiquidSo, phase slip S (phase slip) can be defined as S=AV _Gas/ AV _Liquid

Flow state (flow regime) speech refers to two-phase wherein toward each other and/or with respect to stream pipe 215 feature of mode of pipe 215 of flowing through, and can use definite just now superficial velocity to be explained at least in part.For example, a kind of flow state is known as " bubble state ", and wherein gas is entrained within a certain liquid as bubble.As another example, " plug core state " refers to a series of many liquid " plug " or liquid " core " that separated by bigger air bag.For example, in perpendicular flow, it is long-pending that the gas in the plug core flow state can occupy the entire cross section that almost flows pipe 215, so that final flowing alternately changes between high liquid and high gas composition.Knownly there is some other flow state and has feature that some is determined, comprise for example annularly flow state, disperse flow state and foam flow state, and other states.

Existing a certain particular flow state has been notified and has been subjected to influence of various factors, comprise the gas void fraction during for example liquid flows, the diameter of the orientation (for example horizontal or vertical) of stream pipe 215, stream pipe 215, be included in two materials within stream, and two in stream the speed (and relative velocity) of material.According to these and other factors, a certain particular fluid flow can be in given period internal conversion between some flow states.

Information about phase slip can be determined from flow regime knowledge at least in part.For example, in bubble flow regime, suppose that bubble is equally distributed, between each phase, have less relative motion so.In bubble coalescence and combine and form the place that distributes not too uniformly of gas phase, certain slippage may appear at each between mutually, and this moment, gas trended towards running through liquid phase.

In Fig. 2, in flow state determined that system 275 is comprised in, this system can be connected in the database 280 with flow state image.Like this, the information about existing flow state comprises phase slip information, can obtain, stores and read and write to be used for determining simultaneously two-phase flow liquids and gases mass flowrate separately.

In Fig. 2, should be appreciated that the various parts of digital transmitter 104 are got in touch each other, although for clarity, various contact circuits obviously do not draw.And, should be appreciated that the conventional components of digital transmitter 104 is not illustrated among Fig. 2, but be considered to be present in the digital transmitter 104 or can read and write therein.For example, digital transmitter 104 generally comprises the measuring system of (integral body) density and mass flowrate, and the exciting circuit system that is used to encourage described driver 210.

Fig. 3 shows the process flow diagram 300 of coriolis flowmeter 200 runnings among Fig. 2.Specifically, Fig. 3 shows the liquids and gases flow rate MF that flowmeter 200 among Fig. 2 is determined two-phase flow simultaneously _LiquidAnd MF _GasEmployed method.

In Fig. 3, can determine that a certain gas/liquid two-phase flow is present in the stream pipe 215 (302).This point can for example be finished during the mass flowmeter/densitometric configuration that is used for gas/liquid stream by operating personnel.As another example, this affirmation can detect the condition that has the two-phase gas-liquid flow by a specific character of utilizing coriolis flowmeter and automatically finish.Under one situation of back, this technology is than being recorded in for example United States Patent (USP) NO.6 in more detail, and in 311,136 and United States Patent (USP) NO.6,505,519, described patent is included in as a reference at this.

In case determined the existence of two-phase flow, the density correction database 245 that so just can utilize forwarder 104 is by density correction system 240 definite global density ρ through overcorrect _Truly(304).Just, the density p of sign _LookThrough overcorrect to obtain ρ _TrulyCarry out hereinafter will being described in more detail under the method for this correction.

In case determined ρ _Truly, so just can determine/corrective system 260 definite gas void fraction α through overcorrect by hole rate _Truly(306).In addition, the bulk mass flow rate MF that determines through overcorrect by mass flow rate correction system 250 _Truly(308).About density, be used to obtain calibrated void fraction _TrulyWith mass flowrate MF _TrulyThe whole bag of tricks will be described in more detail hereinafter.

In Fig. 3, from process flow diagram 300, should be appreciated that ρ _Truly, α _TrulyAnd MF _TrulyDetermine and can be undertaken by many orders.For example, in one embodiment, through the void fraction of overcorrect _TrulyBe based on the corrected density ρ that had before calculated _TrulyAnd determine, then, correction mass flow rate MF _TrulyAccording to α _TrulyDetermined.In another embodiment, α _TrulyAnd ρ _TrulyCan be calculated independently of one another, and/or ρ _TrulyAnd MF _TrulyCan be calculated independently of one another.

In case corrected density ρ _Truly, corrected void fraction _TrulyWith correction mass flow rate MR _TrulyKnown, the mass flowrate separately of gas and liquid component just can flow the constituent mass flow rate by liquid and determines that system 265 is determined (310) so.Be used for determining that the whole bag of tricks of liquid/gas component flow rate will be described in more detail with reference to Fig. 4 hereinafter.

In case determine, liquid/gas component flow rate separately is exportable or show (312) usefulness for the flowmeter operating personnel.Like this, operating personnel may obtain the mass flowrate MF about two-phase flow liquid simultaneously _LiquidWith gaseous mass flow rate MF _GasThe information of the two.

In some cases, thisly determine it may is very sufficient (314), at this moment, the output of liquid/gas component flow rate had been finished and had been crossed range of flow.But, in some other embodiment, the definite of each constituent mass flow rate can improve by considering following factor, for example (respectively) flow state of the superficial velocity separately of gas/liquid two components, liquid stream, and the phase slip between each component (if present).

Specifically, gas and liquid superficial velocity SV separately _GasAnd SV _LiquidDetermine as follows.Gas meter face velocity SV _GasBe defined as:

SV _Gas=MF _Gas/ (ρ _Gas* A _T) equation 1

Wherein measure A _TThe cross-sectional area of expression stream pipe 215, this xsect can flow some places that hole rate measures at liquid and obtain.Equally, liquid surface speed SV _LiquidBe defined as:

SV _Liquid=MF _Liquid/ (ρ _Liquid* A _T) equation 2

As shown in figs. 1 and 2, hereinbefore each superficial velocity determine it is the MF that determines according to previous _GasAnd MF _LiquidFrom the above description and should be appreciated that among Fig. 3 since these factors be according to ρ _Truly, α _TrulyAnd MF _TrulyCalculate, so MF _GasAnd MF _LiquidExpression is through mass flowrate MF overcorrect or real ^Truly _GasAnd MF ^Truly _LiquidAs a result, superficial velocity SV _GasAnd SV _LiquidExpression is through the numerical value SV of overcorrect ^Truly _GasAnd SV ^Truly _LiquidSecondly, as mentioned above, density values ρ _GasAnd ρ _LiquidRefer to the known density of the liquids and gases that remain to be discussed, this density can be stored in the density correction database 245.Following about calculating density p through overcorrect _TrulyThe whole bag of tricks described, density values ρ _GasAnd ρ _LiquidCan be called is the function of existing temperature or pressure, is detected by temperature sensor 220 and pressure transducer 225.

Utilize each superficial velocity and other known or calculate factors (some of them can be stored in the flow state graph table database 280), relevant flow state and/or phase slip can/corrective system 275 definite by flow state be determined (318).In case superficial velocity, flow state and phase slip are known, then can be to proofreading and correct global density ρ _Truly, correction mass flow rate MF _Truly, and/or proofread and correct hole rate ρ _TrulyFurther proofread and correct.Like this, as shown in Figure 3, can determine component flow rate MF _GasAnd MF _Liquid

(respectively) flow state in the two-phase liquid/gas flow can be drawn with one has the level line on the curve that concerns between liquid surface speed and the gas meter face velocity to be described.As described in just now, ρ _Truly, α _TrulyAnd/or MF _TrulyDetermine and can improve as follows, promptly at first determine the liquids and gases approximate value of flow rate separately, set up comparatively detailed model for the flow state that identifies then.For example, have a kind of flow state with relative high flow place at relatively low GVP, under this state, aerated fluid as a kind of at the homogeneous fluid that all has seldom or do not have error aspect density and the mass flowrate two at all.As flowing without any need for the homogeneous of proofreading and correct, it can utilize the observed result of excitation gain fully and detect, and this shows in a kind of setting the like this, although significant decline is being arranged aspect the density that observes, does not increase few or at all.

Fig. 4 shows the liquids and gases flow rate MF that is used for determining two-phase flow _LiquidAnd MF _GasThe process flow diagram 400 of the whole bag of tricks.Just, process flow diagram 400 ordinary representations are used for an example (310) of the whole bag of tricks of definite liquids and gases flow rate, and are as described above with reference to Figure 3.

In Fig. 4, determine (310) of liquids and gases flow rate start from input corrected density, hole rate and mass flowrate factor ρ _Truly, α _TrulyAnd MF _Truly(402).Under first situation (404), the liquids and gases flow rate is to utilize equation 3 and 4 (406) determined:

MF _Gas=α _Truly(ρ _Gas/ ρ _Truly) (MF _Truly) equation 3

MF _Liquid=(1-α _Truly) (ρ _Liquid/ ρ _Truly) (MF _Truly) equation 4

Fig. 3 and Fig. 4 supposition do not have sliding velocity (that is average velocity AV of gas phase, between liquid and gas two-phase _GasAverage velocity AV with liquid phase _LiquidEquate).This supposition is consistent with the fact that under first situation superficial velocity and flow state (also therefore, phase slip) are not determined.

Under second situation, reach (404) hereinafter, may/corrective system 275 definite determine whether there are (408) about phase slip by flow state.If there is no, reuse so equation 3 and 4 (406) or process finish.

If above be defined as S=AV _Gas/ AV _LiquidPhase slip have (408), MF so really _GasAnd MF _LiquidTwo can be utilized the stream pipe cross-sectional area A that is used to calculate each superficial velocity equally in equation 1 and 2 _TCalculated (410).Utilize the definition of given just now slippage S.

MF _Gas=ρ _Gas(α _TrulyA _T) (AV _Gas)=ρ _Gas(α _TrulyA _T) (S) (AV _Liquid) equation 5

MF _Liquid=ρ _Liquid((1-α _Truly) A _T) (AV _Liquid) equation 6

Because MF _Truly=MF _Gas+ MF _Liquid, equation 5 and 6 can be found the solution AV _LiquidTo obtain equation 7:

AV _Liquid=MF _Truly/ (A _T(ρ _Gasα _TrulyS+ ρ _Liquid(1-α _Truly))) equation 7

As a result, the liquids and gases flow rate utilizes equation 8 and 9 to be determined (406):

MF _Liquid=[ρ _Liquid(1-α _Truly)/(ρ _Gasα _TrulyS+ ρ _Liquid(1-α _Truly))] [MF _Truly] equation 8

MF _Gas=MF _Truly-MF _LiquidEquation 9

As mentioned above, the gas that is entrained in the liquid forms two-phase flow.The measurement of using coriolis flowmeter that this two-phase flow is carried out can draw and indicate parameter ρ _Look, α _LookAnd MF _LookBe respectively applied for the density of two-phase flow, hole rate and mass velocity.Because due to the relation of the essence of two-phase flow and coriolis flowmeter operation, these sign numerical value are incorrect and differ a foreseeable factor.As a result, indicating parameter can be calibrated to obtain actual parameter ρ _Truly, α _TrulyAnd MF _TrulyConversely, actual, the flow rate separately that can be used for determining simultaneously two (gas and liquid) components through the numerical value of overcorrect.

Fig. 5 A and 5B are the curves that the percentage error in hole rate and the liquid fraction measurement is shown respectively.In Fig. 5 A, percentage error is the density percent error that depends on multiple design and operating parameter, and generally refer to look the deviation of (sign) density and true combined density, this deviation provides with the form of the percentage (%) of gas in the liquid.

In Fig. 5 B, show the relation between real liguid rate and the sign liquid fraction.Fig. 5 B represents the result of some line size and flow rate for relevant flowmeter design.More broadly, funtcional relationship may be more complicated and depends on line size and two factors of flow rate.In Fig. 5 B, show a simple fitting of a polynomial, be used for proofreading and correct look liquid fraction.

Can adopt other method for drafting: for example, true void fraction can make with respect to indicating the hole rate plotting.For example, Fig. 6 is expression for a kind of mass flow errors as the density decreasing function that flows the pipe that has specific orientation and spread all over selected flow range.

Fig. 7 shows the process flow diagram 700 (Fig. 3 304) of the whole bag of tricks that is used for the corrected density measurement result.In Fig. 7, process starts from importing the type (702) of the stream pipe 215 that is adopted, and for example can comprise, stream pipe 215 is that bend or straight, and some other relevant fact, such as the size and the orientation of stream pipe 215.

Next, to not containing the fluid density ρ of gas _LiquidDetermine (704).This amount can be used for following (respectively) calculating, is used to simultaneously guarantee to influence density measurements ρ _LookOther factors, such as temperature, can not be misinterpreted as void fraction effects.In an embodiment, the user can directly import fluid density ρ together with the temperature dependency degree of density _LiquidIn another embodiment, some known fluids (and their temperature dependency degree) can be stored in the density correction database 245, and the user can inquire about fluid by name in this storehouse.In yet another embodiment, flowmeter 200 can be determined single phase fluid density, the fluid flow in period, and stores the usefulness of this value for future.

Can read sign mass flowrate MF from coriolis flowmeter _Look(706), read the sign density p from coriolis flowmeter then _Look(708).Next, density correction system 240 utility theory algorithms (710) or put into practice the real density ρ that the gas/liquid potpourri is determined in form correction method (712) _TrulyNumerical value ρ _TrulyCan be used as corrected density then and exported (714).

Algorithm density correction (710) can be determined according to following understanding, promptly when coriolis flowmeter is used to density measurement, if two-phase flow is not subjected to the influence of flowmeter normal operation, indicate the density value that can descend so, this value can be gone out by the equation inference of describing hole rate, and this correction repeats expression above using volumetric flow rate to be explained in this density according to equation 10:

α (%)=[(ρ _Look-ρ _Liquid)/(ρ _Gas-ρ _Liquid)] * 100 equations 10

This equation can be used for definition value " density drop-out value " or Δ ρ, shown in equation 11:

Δ ρ=(ρ _Look-ρ _Liquid)=α _(%)* (ρ _Gas-ρ _Liquid)/100 equation 11

Notice that equation 11 shows that numerical value Δ ρ is positive; But, this numerical value can be expressed as negative drop-out value by the right side of equation be multiply by-1 simply, thereby obtains equation 12:

Δ ρ=(ρ _Liquid-ρ _Look)=α _(%)* (ρ _Liquid-ρ _Gas)/100 equation 12

Numerical value ρ _GasCan be less than ρ _Liquid, this moment, equation 12 can be reduced to equation 13:

Δ ρ=(ρ _Liquid-ρ _Look)=α _(%)* ρ _Liquid/ 100 equations 13

As above extensively described, with the density measurements that coriolis flowmeter or arbitrary vibration densitometer are made, generally underestimated and need to proofread and correct by gauge.Therefore, under the two-phase flow situation, equation 12 or 13 thereby can be used for determining following two numerical value: through density drop-out value Δ ρ that correct or real _TrulyWith indicate or look density drop-out value Δ ρ _LookUtilize equation 13 as an example, can obtain equation 14 and 15:

Δ ρ _Truly=(ρ _Liquid-ρ _Truly)=α _(%)* ρ _Liquid/ 100 equations 14

Δ ρ _Look=(ρ _Liquid-ρ _Look)=α _(%)* ρ _Liquid/ 100 equations 15

Can derive or definite by rule of thumb Δ ρ _TrulyWith Δ ρ _LookWith look mass flowrate MF _LookAnd some other parameter-such as excitation gain, sensor compensation, temperature, phase state, or the like-between relation.This relation can be expressed as Δ ρ _Truly=f (MF _Look, excitation gain, compensation in the sensing, temperature, phase state and/or some other factor).

As a result, for every kind of every kind of setting stream pipe, all can derive usually or this relation of susceptible of proof at least.Manage for a model stream, be known as and be called Foxboro/Invensys CFS10 model stream at this and manage, determine from experience that under some conditions, above-mentioned funtcional relationship can be reduced to just function Δ ρ _LookAnd have a form that is shown among the equation 16:

Equation 16

In order not look to such an extent that to force equation 16 conditions on both sides during density be zero, the drop-out value relational expression obtains equation 17:

Equation 17

M generally depends on the complexity of rule-of-thumb relation, but can be as small as 2 in many cases (square) or 3 (cube).

In case determine real density drop-out value, return so by above-mentioned equation and just can directly derive real mixture density ρ _Truly, and real liquids and gases (hole) rates (latter is discussed in more detail with reference to Fig. 9).

When for example too complicated or inconvenience is used when functional relation, can adopt sheet format density correction (712).In these cases, known numerical value Δ ρ _LookWith Δ MF _LookCan determine ρ in order to the form that has Fig. 8 table 800 form by employing _Truly

Form 800 can be a sheet format question blank for example, can for example be stored in the database 245, perhaps in another storer, so that form is used for various application occasions.In addition, this form can be filled in initialization procedure, thereby is stored in the database 245 so that the independent application of form.

Should be appreciated that in algorithm and the form one or two all can expand to comprise many aspects, such as analogy gain, temperature, compensation or flow state.Algorithm or sheet format are proofreaied and correct also can be through expansion to comprise some other surface fitting method, such as neutral framework, rational basic function, wavelet analysis, perhaps principal component analysis (PCA).

As a result, should be appreciated that these expansions can be achieved in the scope of Fig. 3 and during the described therein processing.For example, during first situation, density can be determined as mentioned above.Then, during second situation, after identifying flow state, density can utilize flow regime information further to proofread and correct.

Fig. 9 shows the process flow diagram 900 (Fig. 3 306) of the whole bag of tricks that is used for definite hole rate measurement result.In Fig. 9, process starts from determining previous liquid and integral body (the having proofreaied and correct) density p of determining of system's 240 inputs by hole rate _LiquidAnd ρ _Truly(902).

Gas density ρ then _GasCan be determined (904).With fluid density ρ _LiquidIdentical, there are some definite ρ _GasMethod.For example, ρ _GasCan be assumed to the atmospheric density that generally is under the known pressure fully, perhaps can be the actual known density of the specific gas that remains to be discussed.As another example, this known density ρ _GasCan be in one of the reality that detects under reality that detects by pressure transducer 225 or the calculating pressure and/or by temperature sensor 220 or above each factor under the accounting temperature (that is, the known air or the density of specific gas).Temperature and pressure can utilize external unit to be monitored, and as shown in Figure 2, comprises temperature sensor 220 and/or pressure transducer 225.

Secondly, can learn that gas has in some concrete features that comprise aspect each factor of pressure, temperature or intensity of compression.These features can be imported and are used for determining current gas density ρ together with the identification information of gas _GasWith (respectively) liquid phase with, multiple gases can be stored in the storer, also can be together with described each feature just now, thereby make the user can be simply by selected gas and the density feature of access specific gas from tabular by name.

In case factor ρ _Liquid, ρ _GasAnd ρ _TrulyKnown, should be understood that from Figure 10 so, can easily determine void fraction _Truly(906).Then, if desired, so can be only by calculating 1-α _TrulyDetermine liquid fraction (908).

Though providing according to density, above-mentioned explanation determines void fraction _TrulyThe whole bag of tricks, but should be appreciated that the also available additive method of hole rate is determined.For example, indicate void fraction _LookCan be determined by coriolis flowmeter directly that perhaps determine system's (by void fraction sensor 235 expressions of Fig. 2) in conjunction with other hole rates, equation experiential then or that derive is proofreaied and correct to obtain α _TrulyIn some other embodiment, this external cavity rate determines that system can be used for providing α _TrulyDirect measurement result.

Figure 10 is that expression is used for definite process flow diagram 1000 (Fig. 3 308) of proofreading and correct flow-rate measurement result's method.In Figure 10, mass flow rate correction system 250 is at first imported the corrected density drop-out value Δ ρ that had before calculated _Truly(1002), then looking of coming out of input measurement mass flowrate MF _Look(1004).

Mass flow rate correction system 250 application table forms (1006) or algorithms are proofreaied and correct (1008) to determine the true mass flow rate MF of gas/liquid mixture _TrulyNumerical value MF _TrulyCan be used as the correction mass flow rate then and exported (1010).

At the sheet format timing (1006) of application quality flow rate, known numerical value Δ ρ _TrulyWith Δ MF _LookThe form that can be used for having by employing form 1100 forms among Figure 11 is determined MF _Truly

Form 1100 as described in table 900, can for example be the sheet format question blank, for example can be stored in the database 245, or in another storer, so that use it for various application occasions.In addition, this form can be filled during initialization procedure, is used to be stored in the database 245 so that form is used separately.

Standardized data M F _{Standard _ look}And M _{F standard _ true}Can be used for replacing above-described actual numerical value, so that comprise the above De Geshi stream of a specification pipe.In addition, every numerical value can be proofreaied and correct, and wherein proofreaies and correct by equation 18 and determines:

Δ MF=MF _Truly-MF _LookEquation 18

Value in the equation 18 is interpreted as representing actual or standardized numerical value.

In a kind of algorithmic approach, identical with density, the correction of mass flowrate can be by means of funtcional relationship theory or experience, is generally understood as to have Δ MF=f (MF _Look, hole rate, excitation gain, sensor compensation, temperature, phase state and/or other factors) form, be achieved.

For certain situation, this function can be reduced to polynomial expression, such as the polynomial expression that is illustrated in the equation 19:

Equation 19

For a set condition, functional relation can be the combination of polynomial expression and exponential form, shown in equation 20:

$\mathrm{\&Delta;MF}=a_{1}d{e}^{(a_2{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">d</figure-callout>}}^2+a_{3}d+a_4{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">m</figure-callout>}}^2+a_{5}m)}+a_6{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">d</figure-callout>}}^2+a_{7}d+a_8{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">m</figure-callout>}}^2+a_9\mathrm{<figure-callout\; id="20"\; label="m\; Equation"\; filenames="A20048000856400302.png,A20048000856400311.png"\; state="\{\{state\}\}">m</figure-callout>}$ Equation 20

In equation 20, d=Δ ρ _Truly, m=f (MF _Look)

In an embodiment, the m in the equation 20 can use look surface liquid speed SV _LiquidReplace, the latter is given SV by equation 2 as mentioned above _Liquid=MF _Liquid/ (ρ _Liquid* A _T).In this case, ρ _LiquidWith stream pipe cross-sectional area A _TBe parameter known or input, and can adopt the one-board temperature measuring equipment 220 of digitial controller/forwarder 104 for example temperature to be proofreaied and correct with real-time mode.

Should be appreciated that identically with above-mentioned density correction, a kind of in two kinds of forms of algorithms and sheet format or all can comprise many aspects through expansion is such as gain, temperature, compensation or flow state.Algorithms or sheet format are proofreaied and correct also can be through expansion to comprise some other surface fitting method, such as neutral framework, reasonably basic function, wavelet analysis or principal component analysis (PCA).

As a result, should be appreciated that these expansions can be achieved in the scope of Fig. 3 and during the described therein processing.For example, during first situation, mass flowrate can be determined as mentioned above.Then, during second situation, after identifying flow state, mass flowrate can utilize flow regime information further to proofread and correct.

All above functional relations about mass flowrate can, as reflect in Figure 11 form 1100, employing gas rate (α) or liquid fraction (100-α) thus replace the density drop-out value to explain again.In addition, though above-mentioned the whole bag of tricks depends on that known corrected density drop-out value Δ ρ is true, should be appreciated that some other method also can be used for proofreading and correct the mass flowrate of sign.For example, the several different methods that is used to proofread and correct the measurement of mass flow rate of two-phase flow is recorded in United States Patent (USP) 6,505, and in 519, the latter above is being included into as a reference.

More than the correction of density, hole rate and mass flowrate is being described in general sense, in order to realize for example side by side calculating the purpose of each liquid stream component (phase place) in two-phase flow, following explanation and respective drawings provide the instantiation of implementing these methods.

Figure 12-the 14th, the curve figure line of the density correction example of manifold tube is permitted in expression.Particularly, these examples are based on the data that obtain from three kinds of vertical water flowtubes, and each flows pipe is diameter 1/2 ", 3/4 " and 1 ".

More specifically say 1/2 " data take from the situation of 0.15kg/s flow rate and 0.30kg/s flow rate; 3/4 " data are taken from the situation of 0.50kg/s flow rate and 1.00kg/s flow rate; 1 " data are taken from the situation of 0.50kg/s flow rate, 0.90kg/s flow rate and 1.20kg/s flow rate.Figure 12 show liquid-gas mixture (two-phase flow) look the error e of density _dTrue drop-out value Δ ρ with liquid-gas mixture density _TrulyBetween relation:

Equation 21

Equation 22

Wherein, as mentioned above, ρ _LiquidBe the fluid density that does not contain gas, ρ _TrulyBe the real density of liquid-gas mixture, ρ _LookBe looking of liquid-gas mixture or indicate density.

In Figure 12, proofread and correct according to looking in the mixture density drop-out value Δ ρ _LookCarried out, shown in equation 23

Equation 23

In Figure 12, when fitting data, mixture density look and true drop-out value all once be standardized as numerical value between 0 and 1 divided by 100, wherein this standardization purpose is to guarantee the numerical stability of optimized Algorithm.In other words, the process of mixture density standardized look and true drop-out value be to be defined as fluid density ρ _LiquidRatio rather than the mixture density of its percentage in look and real density, shown in equation 24:

Equation 24

Model formation based on equation 17 provides equation 25:

Δ ρ _{Standardized true}=a ₁(Δ ρ _{Standardized look}) ³+ a ₂(Δ ρ _{Standardized look}) ²+ a ₃(Δ ρ _{Standardized look})

Equation 25

In this case, coefficient is a ₁=-0.51097664273685, a ₂=1.26939674868129, and a ₃=0.24072693119420.Figure 13 A and 13B represent to have the model of experimental data and remainder error.Figure 14 A and 14B provide same information, but each flow rate all draws separately.

In sum, the correction of density drop-out value be utilize look density value ρ _LookWith fluid density ρ _Liquid, by calculating look density drop-out value Δ ρ _LookIn forwarder 104, be achieved.Look the numerical value of density drop-out value through standardization to obtain Δ ρ _{Standardized look}=Δ ρ _Look/ 100, thus as mentioned above, the density drop-out value is calculated as ratio rather than percentage.(respectively) density correction model can be used for obtaining standardized mixture density drop-out value Δ ρ through overcorrect then _{Standardized true}At last, the density drop-out value Δ ρ of this numerical value not standardized to obtain to proofread and correct _{True peace}=100 Δ ρ _{Standardized true}Certainly, if through the mixture density drop-out value Δ ρ of overcorrect _TrulyBe defined as the ratio rather than the percentage of actual value, so last calculating has not just needed.

Figure 15-the 20th, expression is the curve map of the example of the mass flowrate correction of manifold tube perhaps.Particularly, these examples are that these diameters that flow pipes are: 1/2 based on the data that obtain from three kinds of vertical water flowtubes ", 3/4 " and 1 ".More specifically say 1/2 " data take from the situation of 0.15kg/s flow rate and 0.30kg/s flow rate; 3/4 " data are taken from the situation of 0.50kg/s flow rate and 1.00kg/s flow rate; 1 " data are taken from the situation of 18 kinds of flow rates between 0.30kg/s and the 3.0kg/s, and maximum density drop-out value is approximately 30%.

Figure 15 A and 15B show the data that are used for model of fit with respect to proofreading and correct mixture density drop-out value Δ ρ _TrulyWith looking of standardization real surface fluid velocity mass flow errors; That is, every flow line look the mass flow errors curve, and this look mass flow errors with respect to corrected density drop-out value Δ ρ _TrulyWith standardization real surface fluid velocity V _TnScatter diagram, shown in equation 26:

Equation 26

M wherein _tBe real fluid mass flow rate, i.e. the mass flowrate value of independent measurement, ρ _LiquidBe fluid density, A _TBe stream pipe cross-sectional area, and v _MaxBe the maximal value (thinking 12) of superficial fluid velocity, thereby make V at this _TnProvided the ratio of the real surface fluid velocity of the gamut that comes gravity line 215.In these examples, mixture density drop-out value and superficial fluid velocity before this model of match between 0 and 1 by standardization, thereby guarantee the numerical stability of model priority algorithm.

Figure 16 represent to look mass flow errors with proofread and correct mixture density drop-out value and standardization look the relation of superficial fluid velocity, and have the secure border of calibration model.Just, Figure 16 provided look mass flow errors with respect to the scatter diagram of corrected density drop-out value and normalization surface liquid velocity, and this moment the normalization surface liquid velocity $v_n=\frac{v}{v_{\max }}=\frac{m}{v_{\max }\&CenterDot;\mathrm{\&rho;}\&CenterDot;A},$ Wherein m be look fluid mass flow rate (that is, measured) as forwarder 104.Being overlapped on the curve map is the safety zone that limits model-promptly, the precision of this model and fitting data precision be similarly regional-a plurality of borders.Adopt this symbol, look mass flow errors e by $e=100\&CenterDot;\frac{m-m_t}{m_t}$ Provide.

Model formation in this case is shown in equation 27:

$e_n=a_{1}d{d}_{\mathrm{cn}}\&CenterDot;e^{a_2\mathrm{<figure-callout\; id="2"\; label="d\; d\; cn"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">d</figure-callout>}{d}_{\mathrm{cn}}^{}{}_2^{}+a_3{\mathrm{dd}}_{\mathrm{cn}}+a_4{\mathrm{<figure-callout\; id="2"\; label="v\; n"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">v</figure-callout>}}_n^{}+a_5{v}_n}+a_6{\mathrm{<figure-callout\; id="2"\; label="dd\; cn"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">dd</figure-callout>}}_{\mathrm{cn}}^{}+a_7{\mathrm{dd}}_{\mathrm{cn}}+a_8{\mathrm{<figure-callout\; id="2"\; label="v\; n"\; filenames="A20048000856400382.png,A20048000856400391.png"\; state="\{\{state\}\}">v</figure-callout>}}_n^{}+a_9{v}_n$ Equation 27

Wherein

$e=\frac{e}{100}=\frac{m-m_t}{m_t}$ Equation 28

Wherein, in equation 27 and 28, dd _CnBe the mixture density drop-out value of standardized correction, and V _nBe liquid standardized look superficial velocity.

In this case, coefficient is: a ₁=-4.78998578570465, a ₂=4.20395000016874, a ₃=-5.93683498873342, a ₄=12.03484566235777, a ₅=-7.70049487145105, a ₆=0.69537907794202, a ₇=-0.52153213037389, a ₈=0.36423791515369, and a ₉=-0.16674339233364.

The scatter diagram of Figure 17 representation model residual volume, and have model formation and coefficient; Promptly show the relation between model residual quantity and correction mixture density drop-out value and the standardization real fluid speed.Figure 18 A-18D and Figure 19 A-19D provide the independent real data of model residual error amount sum of errors of the whole data acquisition that is used for model of fit respectively.At last, Figure 20 A and 20B represent not only interpolation but also the outer model surface that inserts in safe fitted area outside.From Figure 16,20A and 20B, should recognize look the drop-out value of mass flowrate (surface liquid speed) and density boundary.

In sum, the mass flowrate of forwarder 104 is proofreaied and correct and is achieved in the following way in this example, promptly calculate look the density drop-out value, utilize above-mentioned (respectively) method to be proofreaied and correct and by it is made the data normalization (perhaps utilizing from the standardization corrected density drop-out value of density model acquisition) that draws divided by 100.Then, calculate standardized superficial fluid velocity V _n, and use this model to obtain standardization mass flow errors e _nEstimated value, wherein this value will look mass flow errors as the ratio of true mass flow rate.The numerical value that obtains can give nonstandardized technique by it be multiply by 100, and obtains the mass flow errors as the percentage of true mass flow rate thus.At last, look to such an extent that mass flowrate can be used the mass flow errors of nonstandardized technique:

$m_c=\frac{m}{e_n+1}$ Proofread and correct.

Be appreciated that above-mentioned explanation has big range of application, can under the two-phase flow condition, improve the measurement and the correction accuracy of coriolis flowmeter.Specifically, must be measured and/or proofread and correct under the multiple measurement application scenario of matter high level of accuracy in liquid phase mass flowrate and gas phase mass flowrate be useful especially to said method.An exemplary application is to measure the liquid phase mass flowrate and measure gas phase under the production of hydrocarbons environment.

Above-mentioned explanation is to carry out in the environment of the digital flowmeter of Fig. 2.But, should be appreciated that any oscillatory type or oscillatory type densitometer or flowmeter, simulation or numberical density meter or flowmeter, as long as can measure the polyphasic flow that comprises a certain percentage gas phase, all can adopt.Just, a very little percentage of whole process fluid-such as less than 5%-the time, some flowmeters are merely able to measure the process fluid that comprises a certain gas phase when this gas phase is limited to.Other flowmeters, such as above-mentioned (respectively) digital flowmeter, even gas void fraction reach 40% or higher in also can operate.

Many above-mentioned equations and calculating are all illustrated by density, mass flowrate and/or hole rate.But, should be appreciated that the various variations that utilize these parameters also can reach identical or similar result.For example, can adopt volume flow rate to replace mass flowrate.In addition, can adopt liquid fraction to replace hole rate.

This paper is illustrated many embodiments.Yet, should be appreciated that, can carry out multiple modification.Therefore, other embodiment all is in the scope of following claim.

Claims (40)

1. flowmeter comprises:

Vibratile stream pipe;

Driver is connected in described stream pipe and is used for exciting the motion of described stream pipe;

Sensor is connected in described stream pipe and is used for the motion of the described stream pipe of sensing and generates sensor signal; And

Controller, through connecting receiving described sensor signal, described controller is used for determining through first flow rate of first phase of the two-phase flow of described stream pipe and determines second flow rate of second phase in the described two-phase flow.

2. according to the described flowmeter of claim 1, the wherein said first phase air inclusion, described second comprises liquid mutually.

3. according to the described flowmeter of claim 1, wherein said controller be used to import by looking of the detected two-phase flow of described flowmeter density and export the corrected density of described two-phase flow.

4. according to the described flowmeter of claim 3, wherein said controller be used for according to described look the theory relation between density and the described corrected density proofread and correct described look density.

5. according to the described flowmeter of claim 3, wherein said controller be used for according to described look the empirical relationship between density and the described corrected density proofread and correct described look density.

6. according to the described flowmeter of claim 3, wherein said controller be used for according to described look the form between density and the described corrected density store relation proofread and correct described look density.

7. according to the described flowmeter of claim 1, wherein said controller be used to import by looking of the detected two-phase flow of described flowmeter mass flowrate and export the correction mass flow rate of described two-phase flow.

8. according to the described flowmeter of claim 7, wherein said controller be used for according to described look the theory relation between mass flowrate and the described correction mass flow rate proofread and correct described look mass flowrate.

9. according to the described flowmeter of claim 7, wherein said controller be used for according to described look the empirical relationship between mass flowrate and the described correction mass flow rate proofread and correct described look mass flowrate.

10. according to the described flowmeter of claim 1, wherein said controller is used to import the phase fraction of winning of looking by the detected two-phase flow of described flowmeter, described share has defined the amount of first phase in the described two-phase flow, and exports correction first phase fraction of described two-phase flow.

11. according to the described flowmeter of claim 1, wherein said controller be used to import by the phase fraction sensor to first phase fraction of described two-phase flow, described sensor is positioned at the outside of described flowmeter.

12. according to the described flowmeter of claim 1, wherein said controller is used for determining described first flow rate and described second flow rate according to the numerical value through overcorrect of the detection density of described two-phase flow and detection mass flowrate.

13. according to the described flowmeter of claim 12, wherein said controller is used for determining described first flow rate and described second flow rate according to detection first phase fraction that defines the amount of described two-phase flow first phase.

14. according to the described flowmeter of claim 1, wherein said controller is used for according to described first mutually and described second mutually definite respectively described first flow rate of density and described second flow rate.

15. according to the described flowmeter of claim 1, wherein said controller is used for coming respectively to determine described first mutually the first surface speed and described second mutually the second surface speed according to described first flow rate and described second flow rate.

16. according to the described flowmeter of claim 15, wherein said controller is used for determining according to described first surface speed and described second surface speed the flow state of described two-phase flow.

17. according to the described flowmeter of claim 16, wherein said controller be used for according to the average velocity of the average velocity of described first phase and described second phase determine described first with described second the sliding velocity between mutually.

18. according to the described flowmeter of claim 17, wherein said controller is used for according to described first and second superficial velocities, fixed flow state or sliding velocity described first flow rate and described second flow rate being proofreaied and correct, and obtains to proofread and correct first flow rate thus and proofreaies and correct second flow rate.

19. a method comprises:

Determine global density through the two-phase flow of flow tube, described two-phase flow comprise first mutually with second mutually;

Determine the bulk mass flow rate of described two-phase flow; And

Determine described first mutually first mass flowrate according to described global density and described bulk mass flow rate.

20. in accordance with the method for claim 19, comprise according to described global density and described bulk mass flow rate and determine described second mutually second mass flowrate.

21. in accordance with the method for claim 19, determine that wherein described global density comprises:

Determine looking of described two-phase flow global density; And

Proofread and correct described look global density to obtain described global density.

22. in accordance with the method for claim 21, wherein look to such an extent that global density is proofreaied and correct and comprised and look to such an extent that global density inputs to make and describedly looks to such an extent that global density closes and to lie in one and proofread and correct in the theory relation of global density with described to described.

23. in accordance with the method for claim 21, wherein look to such an extent that global density is proofreaied and correct and comprised and look to such an extent that global density inputs to make and describedly looks to such an extent that global density closes and to lie in one and proofread and correct in the empirical relationship of global density with described to described.

24. in accordance with the method for claim 21, wherein look to such an extent that global density is proofreaied and correct and comprised first density of importing described first phase to described.

25. in accordance with the method for claim 24, comprise first phase fraction of determining described two-phase flow according to first density of described global density, described first phase and described second mutually second density.

26. determine wherein in accordance with the method for claim 25, that first mass flowrate of described first phase comprises according to described first phase fraction and described first density and determine described first mass flowrate.

27. in accordance with the method for claim 20, comprise according to described first mass flowrate and described second mass flowrate and determine described first mutually the first surface speed and described second mutually the second surface speed respectively.

28. in accordance with the method for claim 27, comprise the flow state of determining described two-phase flow according to described first surface speed and described second surface speed.

29. in accordance with the method for claim 28, comprise according to the average velocity of the average velocity of described first phase and described second phase determine described first with described second the sliding velocity between mutually.

30. in accordance with the method for claim 29, comprise according to described first and second superficial velocities, determined flow state or sliding velocity described first flow rate and described second flow rate proofreaied and correct.

31. in accordance with the method for claim 20, wherein said first comprises gas mutually, and described second comprises liquid mutually.

32. a flowmeter controller comprises:

Density correction system, be used to import looking of two-phase flow density and export the corrected density of described two-phase flow, described two-phase flow comprise first mutually with second mutually;

Mass flow rate correction system, be used to import looking of described two-phase flow mass flowrate and export the correction mass flow rate of described two-phase flow; And

Liquid stream constituent mass flow rate is determined system, is used for determining described first mutually first mass flowrate according to described corrected density and described correction mass flow rate.

33. according to the described flowmeter controller of claim 32, wherein said liquid stream constituent mass flow rate determines that system is used for determining described second mutually second mass flowrate according to described corrected density and described correction mass flow rate.

34. according to the described flowmeter controller of claim 33, wherein said first comprises liquid mutually, the described second phase air inclusion.

35. according to the described flowmeter controller of claim 34, comprise that phase fraction determines system, this system is used for determining the correction phase fraction of described two-phase flow, and wherein said liquid stream constituent mass flow rate determines that system is used for determining described first flow rate and second flow rate according to described correction phase fraction.

36. according to the described flowmeter controller of claim 35, wherein said phase fraction determines that system is that the hole rate of determining gas flow in the described two-phase flow is determined system.

37. according to the described flowmeter controller of claim 34, comprise that superficial velocity determines system, the first surface speed that this system is used for determining described first phase and described second mutually the second surface speed.

38. according to the described flowmeter controller of claim 37, wherein said flowmeter controller comprises that flow state determines system, this system is used for determining the flow state of described two-phase flow.

39. according to the described flowmeter controller of claim 38, wherein said flow state determines that system also is used for determining phase slip speed according to described first phase average speed and the described second phase average speed.

40. according to the described flowmeter controller of claim 39, wherein said liquid stream constituent mass flow rate determines that system is used for improving determining that described first mass flowrate and described second mass flowrate are carried out according to described first and second superficial velocities, described flow state or described phase slip speed.

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