CN1708674A - Apparatus and method for measuring parameters of a mixture having solid particles suspended in a fluid flowing in a pipe - Google Patents

Abstract

An apparatus 10 and method is provided that includes a spatial array of unsteady pressure sensors 15 - 18 placed at predetermined axial locations xl - xN disposed axiallyalong a pipe 14 for measuring at least one parameter of a solid particle/fluid mixture 12 flowing in the pipe 14. The pressure sensors 15 - 18 provide acoustic pressure signals P1(t) - PN(t) to a signal processing unit 30 which determines the speed of sound amix(omega) of the particle/fluid mixture 12 in the pipe 14 using acoustic spatial array signal processing techniques. The primary parameters to be measured include fluid/particle concentration, fluid/particle mixture volumetric flow, and particle size. Frequency based sound speed is determined utilizing a dispersion model to determine the parameters of interest. the calculating the at least one parameter uses an acoustic pressure to calculate.

Description

The apparatus and method of parameter of potpourri that have the solia particle of suspension in pipeline in the fluid that measurement is flowed

CROSS-REFERENCE TO RELATED PATENT

It on the application's part the continuation of the U.S. Patent application No.10/349716 (applicant's document code CC-0579) of submission on January 23rd, 2003, this application requires the U.S. Provisional Application No.60/351232 (applicant's document code CC-0410) of submission on January 23rd, 2002, the U.S. Provisional Application No.60/359785 (applicant's document code CC-0403) that on February 26th, 2002 submitted to, the U.S. Provisional Application No.60/375847 (applicant's document code CC-0468) that on April 24th, 2002 submitted to, the U.S. Provisional Application No.60/425436 (applicant's document code CC-0538) that on November 12nd, 2002 submitted to, and the right of priority of the U.S. Provisional Application No.60/426724 (applicant's document code CC-0554) that submitted on November 15th, 2002; Be the continuation of the U.S. Patent application No.10/376427 (applicant's document code CC-0596) of submission on February 26th, 2003 on the part, this application requires the right of priority of the U.S. Provisional Application No.60/359785 (applicant's document code CC-0403) of submission on February 26th, 2002; And be the extendible portion of the U.S. Patent application No.10/349716 (applicant's document code CC-0579) of submission on January 23rd, 2003, this application requires the U.S. Provisional Application No.60/351232 (applicant's document code CC-0410) of submission on January 23rd, 2002, the U.S. Provisional Application No.60/359785 (applicant's document code CC-0403) that on February 26th, 2002 submitted to, the U.S. Provisional Application No.60/375847 (applicant's document code CC-0468) that on April 24th, 2002 submitted to, the U.S. Provisional Application No.60/425436 (applicant's document code CC-0538) that on November 12nd, 2002 submitted to, and the right of priority of the U.S. Provisional Application No.60/426724 (applicant's document code CC-0554) of submission on November 15th, 2002, incorporate the whole of all these applications at this, for your guidance.

Technical field

The present invention relates to the device of the stream that passes through in a kind of measuring channel, thereby relate more particularly to a kind ofly utilize the velocity of sound that dynamic pressure measurement propagates in stream to determine the isoparametric apparatus and method of particulate/fluid ratio, particle size and volume flow rate that flow in the pipeline for example, described stream has the particulate that suspends in the fluid that continues.

Background technology

The invention provides the method for the parameter of the fluid/particle mixture in a kind of measuring channel, this method can be in many application, for example use in chemistry, pharmacy, oil and power generation industries.Especially, the invention provides a kind of measurement fine coal that uses and the method for air mixture in the pulverized fuel transfer system, this pulverized fuel transfer system is located in the coal-burning boiler that accounts for vast scale that uses in the power generation industries.

Current, in the U.S., the electricity above 50% produces with coal.Though in the U.S., coal is considered to save cost and rich in natural resources, mainly for the consideration of protection environment, the use of coal is restricted.In order to alleviate this influence, american energy department and electricity power enterprise have designed a large amount of plans and have come development process to reduce coal-fired environmental impact.These clean coal plans comprise and are designed to reducing pollutant, for example coal-fired, ash and oxides of nitrogen (NO _x) time improve the technology of combustion process to raise the efficiency.

The ability of measuring the composition of flow velocity in the coal pipeline and air/coal mixtures is the system of any performance that is designed to optimize the PF transfer system or an importance of strategy.Enterprise has recognized this point, and is therefore developing various technology to carry out this measurement always.These technology comprise the detector based on sampling apparatus, and based on the various technology real-time instrument of (comprising static charge, microwave, and ultrasound wave).

Summary of the invention

Thereby a kind of system of measuring the special parameter of definite this potpourri of propagating by ducted particulate/fluid mixture of the velocity of sound in industrial boiler system and relevant process, for example coal-burning boiler system that provides is provided purpose of the present invention.

According to the present invention, a kind of device that is used at least one parameter of measuring channel particulate/fluid mixture comprises the space array of being made up of at least two pressure transducers, described sensor along piping arrangement on different axial locations.Each pressure transducer is the transient pressure in the measuring channel on corresponding axial location.The pressure signal of transient pressure in the indication pipeline is provided on the described axial location of each described sensor corresponding sensor in described sensor.Signal processor provides the signal of at least one parameter of potpourri in the indication pipeline in response to described pressure signal.

According to the present invention, a kind of method that is used at least one parameter of particulate/fluid mixture in the measuring channel is included in along the transient pressure in the measuring channel on two of the pipeline predetermined axial measuring positions at least, thereby the pressure signal of transient pressure in the indication pipeline is provided on each position at least two predetermined axial measuring positions.In addition, described method comprises that also transient pressure that utilization is measured calculates at least one parameter of particulate/fluid mixture in the pipeline on axial measuring position.

Above-mentioned and other purpose of the present invention, feature and advantage will become more apparent according to following detailed description to its exemplary embodiment.

Description of drawings

Accompanying drawing 1 is the block scheme according to the flowmeter of the velocity of sound of the present invention, as to be used for measuring the fluid/particle mixture that flows at pipeline.

Accompanying drawing 2 is the synoptic diagram according to pulverized fuel (the PF)/air mixture parameter measurement system in coal-burning boiler system of the present invention.

Accompanying drawing 3 is photos of amplification of the particle size of expression attached system shown in Figure 2 distinctive coal.

Accompanying drawing 4 is according to the velocity of sound of of the present invention, potpourri and graph of relation according to the frequency of air/coal mass flow ratio.

Accompanying drawing 5 be according to of the present invention, as the real data of the velocity of sound of the function of air/coal mixtures frequency and the curve map of model.

Accompanying drawing 6 is that expression is according to the standard deviation of the velocity of sound of the different arrays that the present invention is directed to PF/ air mixture parameter measurement system and the graph of relation of frequency.

Accompanying drawing 7 be according to the present invention as the curve map of the velocity of sound of the function of frequency, this frequency is to have fixing particle size (50 millimeters) and the frequency of the air/coal mixtures of the air/fuel mass ratio that changes.

Accompanying drawing 8 be according to the present invention as the curve map of the velocity of sound of the function of frequency, this frequency is to have the particle size of variation and the air/fuel mass ratio equals the frequency of air/coal mixtures of 1.8.

Accompanying drawing 9 is the curve maps according to the velocity of sound of the function as air/coal ratio of the present invention.

Accompanying drawing 10 is to be used for according to the present invention determining that from analytical model and with the velocity of sound data of the definite dispersion of test method air/fuel compares and the process flow diagram of the optimizing process of particle size.

Accompanying drawing 11 is that the optimizing process with accompanying drawing 10 is applied to the curve map by the result of the data of sensor array record, and it is that 50 microns, airflow rate are that 100 feet per seconds, air/fuel are than the stream that is 1.8 that described sensor array is monitored in 6 inches circular ring pipes particle size.

Accompanying drawing 12 is curve maps of the result of the data set that is applied to a series of air/fuel ratios with variation of the optimizing process with accompanying drawing 10.

Accompanying drawing 13 is k ω curve maps of the data handled by array of pressure sensors according to the present invention, and described pressure transducer is used for measuring the velocity of sound of the coal/air mixture that flows at pipeline.

Accompanying drawing 14 is the side views according to a plurality of pressure transducers of the PVDF of having of the present invention, and described pressure transducer clips on the outside surface of pipeline.

Accompanying drawing 15 is fragmentary, perspective views of a pressure transducer of accompanying drawing 14.

Embodiment

With reference to accompanying drawing 1, provide a kind of enforcement flowmeter 10 of the present invention, a plurality of parameter/features of the potpourri 12 of this flowmeter survey solia particle, described solia particle is suspended in the lasting fluid that flows in pipeline or the conduit 14, wherein, fluid is defined as liquid and/or gas.This flowmeter can be configured to and be designed to measure the velocity of sound of propagating by potpourri.This flowmeter can be measured at least one in the following parameter of mixing logistics 12: fluid/particle concentration (volume phase mark volumetric phase fraction), volume flow rate, the size of solia particle, the mass rate of potpourri, and the speed of potpourri.In order to determine any one of these parameters, flowmeter 10 is measured the transient pressure that is produced by the velocity of sound of propagating by the potpourri that flows (SOS) in pipeline 14, and this will be described in more detail below.

The solia particle of potpourri 12 can be virtually any size, shape and material.For example, the size of this particulate may diminish to powder type, particle form, or size is bigger.Use in the application of the solia particle that flowmeter 10 can suspend in any fluid that is transmitted in by pipeline, for example in the application of chemistry, pharmacy, oil and generating, use.For example, the present invention is highly suitable for measuring the parameter (for example, air/coal ratio, particle size) of electricity generation system, and this electricity generation system uses fine coal to light the stove of steam boiler system.

As an example, the present invention will discuss at the context of the pulverized fuel that is used for generating electricity (PF) transfer system, but should be appreciated that this flowmeter also can be applied to the application of many as indicated above other.Typical PF transfer system 1 has been shown in the coal-burning boiler system 2 of accompanying drawing 2.Coal is pulverized and is entrained in the air in flour mill 3, thereby by the pipeline 12 that is used to transmit the PF/ air mixture is transferred to stove 6, and described air is by multiple device, as fan 4 generations.Typical stove has more than 50 coal pipelines, and the diameter of each coal pipeline is the 12-20 inch.Typically, the large-scale practical boiler greater than 300Mw can have the flour mill that the 4-11 platform is supplied with to stove.The PF transfer system with the fuel of right quantity and air jointly and be sent to the ability of stove respectively by these a plurality of coal pipelines has very strong influence to the performance and the discharging of this coal-burning boiler.

As everyone knows, the unevenness in the PF transfer system 1 can cause the variation of fuel/air mixture ratio, causes focus, high NO _xProduce zone and unburned fuel.Must be familiar with the contact between the performance of PF fuel delivery system 1 and steam generator system 2 fully.Comprised the particle size that flowmeter 10 of the present invention can be measured the fuel/air mixture ratio and offer the fine coal of stove, thereby provide feedback, so that the more effective burning of coal to be provided to the operator.

As mentioned above, flowmeter 10 of the present invention can be configured and be designed to measure and handle detected transient pressure P ₁(t)-P _N(t)), thus the parameter of determining to mix logistics 12, and this transient pressure is produced by the sound wave of propagating by potpourri.Accompanying drawing 1 has been represented such flowmeter 10, and this flowmeter survey is by the velocity of sound (SOS) of the one dimension sound wave of fluid/particle mixture propagation, thus definite the ingredients of a mixture, the just fluid of potpourri/particulate ratio.This flowmeter also can be determined the average-size of particulate, the speed of potpourri and the volume flow rate of potpourri.As everyone knows, in for example SONAR and RADAR field, sound is propagated with different speed by different media.The velocity of sound of the potpourri in the pipeline 14 can use multiple technique known to determine, for example the title of authorizing on March 12nd, 2002 is the U.S. Patent No. 6354147 of " Fluid ParameterMeasurement in Pipes Using Acoustic Pressures " and title those technology for stating among the U.S. Patent application No.10/007749 of " Fluid Parameter Measurement in Pipes Using AcousticPressures " of submitting to November 7 calendar year 2001, and these two patented claims are incorporated in this as a reference.The present invention utilizes at least one flowmeter 10 to determine the different parameters of fluid/particle mixture, and wherein, a parameter is the speed that sound is advanced in the mixture conduit system, and this speed will be described more fully below.

According to the present invention, measure the velocity of sound of propagating by potpourri 12 by using the transient pressure sensor array to monitor stream passively, thereby determine by being included in the one dimension compression wave propagation velocity of the fluid/particle mixture propagation in the pipeline 14.

As shown in Figure 1, flowmeter 10 comprises the array of at least three sound pressure sensors 15,16,17, and described sensor is positioned at along three axial position x of pipeline 14 ₁, x ₂, x ₃The place.Can recognize, as at position x _NShown in the pressure transducer 18 at place, this sensor array can comprise more than three pressure transducers.The pressure that is produced by sound wave can perhaps pass through other commercial measurement hereinafter described by the hole measurement that communicates with external pressure sensor 15-18 in the pipeline 14.Pressure transducer 15-18 is circuit 20,21, the time dependent pressure signal P on 22,23 ₁(t), P ₂(t), P ₃(t), P _N(t) offer signal processing unit 30, offer known fast Fourier transform (FFT) logical circuit 26,27,28,29 then respectively.This FFT logical circuit 26-29 calculates time-based input signal P ₁(t)-P _N(t) Fourier transform, and at circuit 32,33 provides complex frequency domain (or based on frequency) the signal P of the frequency content of expression input signal on 34,35 ₁(ω), P ₂(ω), P ₃ω), P _N(ω).Replace the FFT logical circuit, also can use any other to be used to obtain signal P ₁(t)-P _NThe technology of frequency domain character (t).For example, also can use cross-spectral density and power spectrum density formation frequency domain transfer function (or frequency response or ratio) hereinafter described.

With frequency signal P ₁(ω)-P _N(ω) deliver to a _Mix-Mx calculation logic circuit 38, this logical circuit 38 will be represented the signal a by the velocity of sound of potpourri propagation _Mix(ω) be fed to circuit 40, described signal is function frequency (in more back argumentation).With a _Mix(ω) signal is provided to mapping (or five equilibrium) logical circuit 42, and this logical circuit is with a _Mix(ω) be transformed into the number percent composition of PF/ air mixture, and will represent that the %Comp signal of described number percent composition (as mentioned below) is provided to circuit 44.Equally, if this Mach number Mx (ω) be can not ignore and be required, this calculation logic circuit 40 also can with the expression Mach number Mx (ω) signal Mx (ω) be provided to circuit 46, this signal Mx (ω) is the function of frequency.

Concerning ring duct shown in the accompanying drawing 1 or pipeline 12, when being lower than by (cut-on) frequency, frequency has only plane wave propagation (list of references Acoustics of Ducts and Mufflers, M.J.Munjal, JohnWiley﹠amp; Sons, New York, 1987):

$f<\frac{1.84}{\mathrm{\&pi;D}}a$

Concerning the potpourri of the velocity of sound that has 500 meter per seconds in 18 inches pipelines, this cutoff frequency is approximately 600Hz.Like this, in this example, only the one dimension sound wave is propagated below 600Hz.It should be noted that the very important point, one-dimensional wave still can be propagated on this frequency, but the pattern of the higher order of magnitude may exist or may not exist.

More particularly, the plane one dimension sound wave in homogenous mixts, known to sonic pressure field P (x along the x place, position of pipeline, t) can be expressed as the stack of right lateral afferent echo and left lateral afferent echo, wherein, the wavelength X of sound wave to be measured is compared with the diameter d of pipeline 12 long (that is, λ/d＞＞1), and described sonic pressure field is expressed as follows:

$P(x,t)=({\mathrm{Ae}}^{-i{k}_{r}x}+B{e}^{+i{k}_{l}x})e^{\mathrm{i\&omega;<figure-callout\; id="1"\; label="t\; Formula"\; filenames="A0381477000281.png,A0381477000322.png"\; state="\{\{state\}\}">t</figure-callout>}}$ Formula 1

Wherein, A, B are respectively the complex amplitudes based on frequency of right lateral afferent echo and left lateral afferent echo, and x is the pressure survey position along pipeline, and ω is frequency (unit: rad/sec, wherein ω=2 π f), and k _r, k _lBe respectively the wave number of right lateral afferent echo and left lateral afferent echo, they are defined as:

$k_r=\left[\frac{\mathrm{\&omega;}}{a_{\mathrm{mix}}\left(\mathrm{\&omega;}\right)}\right]\frac{1}{1+M_x\left(\mathrm{\&omega;}\right)}$ With ${\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A0381477000281.png,A0381477000322.png"\; state="\{\{state\}\}">k</figure-callout>}}_1\&equiv;\left[\frac{\mathrm{\&omega;}}{a_{\mathrm{mix}}\left(\mathrm{\&omega;}\right)}\right]\frac{1}{1-M_x\left(\mathrm{\&omega;}\right)}$ Formula 2

Wherein, a _Mix(ω) be the velocity of sound of potpourri in the pipeline, ω is a frequency (unit: rad/sec), and M _x(ω) be the axial Mach number that in pipeline, mixes logistics, wherein:

$M_x\left(\mathrm{\&omega;}\right)\&equiv;\frac{V_{\mathrm{mix}}}{a_{\mathrm{mix}}\left(\mathrm{\&omega;}\right)}$ Formula 3

Wherein, V _MixIt is the axial velocity of potpourri.Concerning the non-homogeneous potpourri, this axial Mach number is represented the average velocity of potpourri, and the low frequency sound field description remains unchanged basically.

(x, (x ω) is the e of formula 1 to frequency domain representation P t) to time-based sonic pressure field P in pipeline ^{I ω t}The coefficient of item, it is expressed as follows:

$P(x,\mathrm{\&omega;})=A{e}^{-i{k}_{r}x}+{\mathrm{Be}}^{+i{k}_{l}x}$ Formula 4

With reference to accompanying drawing 1, we find, at the pressure survey position x along three axial distribution of pipeline 12 ₁, x ₂, x ₃(x, ω) use formula 4 has produced a of conduct based on the function of the tonometric ratio of frequency to the P at place _MixEquation, this equation allows elimination factor A, B.Concerning optimum, A and B are essentially constant on Measuring Time, and in measure portion, do not have sound (or acoustic energy) to be produced or destroy basically.Acoustically-driven only enters part of detecting by the end of check part 51, can be independent of acoustic environment outside the check part like this and measure the velocity of sound within measure portion 51.Especially, respectively at three position x along pipeline 12 ₁, x ₂, x ₃The frequency domain pressure survey P at place ₁(ω), P ₂(ω), P ₃(ω) be expressed as follows, described frequency domain pressure survey is used for the formula 1 of right lateral afferent echo and left lateral afferent echo:

$P_1\left(\mathrm{\&omega;}\right)=P(x=x_1,\mathrm{\&omega;})={\mathrm{Ae}}^{-i{k}_r{x}_1}+{\mathrm{Be}}^{+i{k}_l{x}_1}$ Formula 5

$P_2\left(\mathrm{\&omega;}\right)=P(x=x_2,\mathrm{\&omega;})={\mathrm{Ae}}^{-i{k}_r{x}_2}+{\mathrm{Be}}^{+i{k}_l{x}_2}$ Formula 6

$P_3\left(\mathrm{\&omega;}\right)=P(x=x_3,\mathrm{\&omega;})={\mathrm{Ae}}^{-i{k}_r{x}_3}+{\mathrm{Be}}^{+i{k}_l{x}_3}$ Formula 7

Wherein, concerning given frequency, A and B describe sensor 14,16, the arbitrary constant of the sound field between 18.From formula 6,7, form P ₁(ω)/P ₂Ratio (ω), and obtain B/A, it provides following expression:

$R\&equiv;\frac{B}{A}=\frac{e^{-i{k}_r{x}_1}-\left[\frac{P_1\left(\mathrm{\&omega;}\right)}{P_2\left(\mathrm{\&omega;}\right)}\right]e^{-i{k}_r{x}_2}}{\left[\frac{P_1\left(\mathrm{\&omega;}\right)}{P_2\left(\mathrm{\&omega;}\right)}\right]e^{i{k}_l{x}_2}-e^{i{k}_l{x}_1}}$ Formula 8

Wherein, R is defined as reflection coefficient.

From formula 5 and 7, form P ₁(ω)/P ₃Ratio (ω), and obtain 0, obtain:

$\frac{e^{-i{k}_r{x}_1}+{\mathrm{Re}}^{i{k}_l{x}_1}}{e^{-i{k}_r{x}_3}+{\mathrm{Re}}^{i{k}_l{x}_3}}-\left[\frac{P_1\left(\mathrm{\&omega;}\right)}{P_3\left(\mathrm{\&omega;}\right)}\right]=0$ Formula 9

Wherein, R=B/A is by formula 8 definition, and k _rAnd k _lWith a by formula 2 definition _MixRelevant.Formula 9 can solve with the numerical value mode, and for example, by " error " or residual error item being defined as the amplitude in formula 9 left sides, and iteration is to minimize this error term.

$\mathrm{mag}[\frac{e^{-i{k}_r{x}_1}+{\mathrm{Re}}^{i{k}_l{x}_1}}{e^{-i{k}_r{x}_3}+{\mathrm{Re}}^{i{k}_l{x}_3}}-[\frac{P_1\left(\mathrm{\&omega;}\right)}{P_3\left(\mathrm{\&omega;}\right)}\left]\right]\&equiv;\mathrm{<figure-callout\; id="10"\; label="Error\; Formula"\; filenames="A0381477000272.png,A0381477000331.png"\; state="\{\{state\}\}">Error</figure-callout>}$ Formula 10

Data from sensor array can be handled in any territory, and described territory comprises frequency/spatial domain, time/spatial domain, time/wavenumber domain, perhaps wave number/frequency (k-ω) territory.Similarly, if desired, also can use any known ARRAY PROCESSING technology in the territory of being correlated with these or other.

Equally, also can use software (use microprocessor or computing machine) and/or firmware to realize some or all function in the signal processing unit 30, perhaps can utilize simulation and/or digital hardware to realize described function, described hardware has sufficient internal memory, interface, and can carry out function described here.

Acoustic pressure force transducer 15-18 detects sound pressure signal; measured sound pressure signal is a signal of comparing frequency lower (longer with wavelength) with the signal that is used for ultrasonic flowmeter of the prior art; therefore even be impossible place (roping) in protection or coal " viscous ", for example after bend; the present invention also more can tolerate the unevenness in the stream, as the viscous in stream and At All Other Times with the unevenness of spatial domain.Term " viscous " is known to one skilled in the art term, and the bad distribution form of serious room and time represented in this term, and described bad distribution form causes having the mixing logistics of extensively different composition density.Under this condition, most coal stream is positioned at along the zone of a side flow of pipeline 14.

In addition, the present invention determines the effective sound velocity of pipeline/PF/ air mixture system in conjunction with the flexibility of pipeline 14.By multiple non-discrete source, for example remote machine, flour mill, fan 4 (accompanying drawing 2), valve, bend pipe and PF/ air mixture flow itself, in the PF/ of pipeline 14 air mixture, produce sound pressure signal P ₁(t)-P _N(t).This last source, the PF/ air mixture 12 that promptly flows in pipeline 14 guarantee the minimum sound level of any PF/ air mixture piping system, distinct advantages of the present invention that Here it is, and described PF/ air mixture is common noise source.The sound that produces that flows increases with mean flow rate, and OA overall noise level (sound pressure level) is the function of generation mechanism and moist mechanism.Similarly, in the present invention, do not need outside discrete noise source, therefore can use passive monitoring to operate.When flowmeter 10 is monitored when mixing logistics 12 passively, the present invention attempts to increase sound source so that required sound wave is injected in the stream to be measured by for example compressing, vibrate and/or beaing method such as pipeline.

With pressure transducer, for example pipeline strain sensor, accelerometer, speed pickup or the displacement transducer of the particular type discussed, may need pipeline 14 to show the pipeline flexibility of specified quantitative to hereinafter.

Selectively, in order to minimize any error effects (and needs of respective alignment) that is caused by the pipeline flexibility, can make the axial check part 50 of pipeline 14 hard as much as possible, wherein, sensor 15-18 is along should axially checking part 50 location.In order to obtain required hardness, can make the thickness of the wall of check part 50 have preset thickness, perhaps this check part 50 can be made of stone material, and described material for example is a steel, titanium, Kevlar ^, pottery, perhaps other has the material of high mode.

Length (aperture) the Δ X of pressure transducer (15-18) array is at least one live part of the measurement wavelength of just measured sound wave.As will be in greater detail, wave length of sound to be measured be the function of the dispersing characteristic of potpourri 12 at least, and wherein, this dispersing characteristic is the size of particulate and the function of quality and fluid viscosity at least.The dispersion of potpourri big more (for example size and quality are big more and/or fluid viscosity more little), the length of required array is just long more.On the contrary, the dispersion of potpourri more little (for example size and quality are more little and/or fluid viscosity big more), the length of required array is just short more.

In addition, within the scope of the invention, if the location aware of sensor, then the spacing of pressure transducer can be known or arbitrarily.As hereinafter will be in greater detail, sensor 15-18 also can place (as shown in Figure 1) equally spacedly, the placement of perhaps any uneven or unequal-interval.Will be appreciated that,, then only need few to two sensors if known about the customizing messages of the sound characteristics of PF/ air mixture piping system.

As described, flowmeter 10 is measured the velocity of sound of the one dimension sound wave of propagating by fluid/particle mixture, thereby determines the ingredients of a mixture.Especially, directly the mass fraction with the particulate that flows is relevant for the velocity of sound of propagating by the solid/air mixture of dilution.Typical PF fuel delivery system 1 can be with the ratio work of air/coal of 1.5 to 2.5, wherein with 1.2kg/m under normal atmospheric environment ³Air is compared, and coal density is 1200 to 1400kg/m ³Like this, satisfy required mass ratio and can cause coal mixtures very rare on the volume basis, this is similar to 1/1000 the order of magnitude of volume.

Suppose that the coal particulate is enough little, and audio frequency and the interfering frequency relevant with sound are enough little, so that solia particle shows insignificant slip (stable with unsettled), can assumed speed of sound be nondispersive (being that frequency is constant) then, and can determine the volume phase mark of potpourri by the Wood equation:

${\mathrm{\&rho;}}_{\mathrm{mix}}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&phi;}}_i{\mathrm{\&rho;}}_i$

$\frac{1}{{\mathrm{\&rho;}}_{\mathrm{mix}}{a}_{\mathrm{<figure-callout\; id="2"\; label="mix"\; filenames="A0381477000281.png,A0381477000311.png"\; state="\{\{state\}\}">mix</figure-callout>}}^2}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{{\mathrm{\&phi;}}_i}{{\mathrm{\&rho;}}_i{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="A0381477000281.png,A0381477000311.png"\; state="\{\{state\}\}">i</figure-callout>}}^2}$

$\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&phi;}}_i=1$

Comprise the flexibility effect of introducing by conduit 12 (in this case, the modulus of ring pipe is E, and radius is R, and pipe thickness is t)

$\frac{1}{{\mathrm{\&rho;}}_{\mathrm{mix}}{a}_{\mathrm{measured}}^2}=\frac{1}{{\mathrm{\&rho;}}_{\mathrm{mix}}{a}_{\mathrm{<figure-callout\; id="2"\; label="mix"\; filenames="A0381477000281.png,A0381477000311.png"\; state="\{\{state\}\}">mix</figure-callout>}}^2}+\mathrm{\&sigma;}$ Wherein $\mathrm{\&sigma;}\&equiv;\frac{2R}{\mathrm{Et}}$

Utilize above-mentioned relation, accompanying drawing 4 is depicted as speed that sound the advances function as air/coal mass ratio in having the piping system of typical coal/air mixture.Concerning this example, suppose that pure air has the density of 1.2kg/m^3 and the velocity of sound of 365.9m/s, and the hypothesis coal have the density of 1400kg/m^3 and the velocity of sound of 2439m/s.As shown in the figure, increase the coal proportion, promptly reduce the air/result of coal ratio and reduced the velocity of sound.Physically, increase the quality that the coal particulate has loaded potpourri effectively, and can not change the compressibility of air fully.In the parameters of interest scope, the relation between the potpourri velocity of sound and air/coal ratio is showed well, and is monoatomic.

When the calibration curve based on first principle prediction when being inspirer, use the empirical data that is mapped to air/coal ratio from the velocity of sound can improve the accuracy of air/coal proportion that the present invention measures potpourri.

Yet, have been found that, the physical property of the coal/air mixture of powdery is generally: (be rated for the coal particulate of 50 μ m in for air except very low frequency, be similar to and all exist speed to slide on all frequencies outside the frequency＜1-2Hz), this situation and will be described in more detail below shown in Fig. 7 and 8.

Accompanying drawing 5 expressions are with the function of the measured velocity of sound as the frequency of the coal/air mixture 12 of reality.This velocity of sound utilizes passive monitoring technique of the present invention described here to measure.By on a plurality of narrow frequency scope between the 50-300Hz, using Capon ARRAY PROCESSING algorithm, determine the frequency dependence of this velocity of sound, thereby determine the frequency of specific acoustic propagation velocity.In this specific example, these data obtain when 100ft/sec flows to be nominally at coal/air mixture, and wherein, air/coal mass ratio equals 1.8.This coal particulate nominal size is 50 μ m, the typical fine coal that representative is used in generating and other commercial Application.Accompanying drawing 3 has represented to be used for the view of amplification of the coal particulate of this check.

In addition, as shown in Figure 5, the velocity of sound increases along with the frequency that increases, and with asymptotic line near steady state value.Velocity of sound asymptotic line at upper frequency is the airborne velocity of sound that only influences by the particulate that does not have to suspend basically.Equally, significantly, the velocity of sound of coal/air mixture does not reach the quasi-steady boundary of the low-limit frequency of measuring the velocity of sound.This velocity of sound will continue in lower frequency limit to reduce.Great discovery of the present invention is, disperses by the velocity of sound that the dilution particulate that suspends in the fluid that continues is propagated.As defined in this, the speed that sound wave is propagated by the potpourri that disperses changes with frequency.

Because total length (the Δ x of pressure transducer 15-18 array _Aperature) compare with the wavelength of sound and to diminish, thereby when frequency is more and more lower gradually, measure the degree of accuracy step-down inherently of the velocity of sound of potpourri 12, described total length (Δ x _Aperature) limit the aperture of this array.Usually, this aperture should be the live part of the wavelength of the velocity of sound interested at least.In specific embodiment, when total aperture is 3 feet, be the An arrayed recording velocity of sound data of four sensors of 12 inches by spacing.When 50Hz, the sound wave of 100ft/sec has the wavelength of 20ft.Like this, the aperture of this specific array (about 36 inches) only cross over 3/20 of wavelength, and slacken this array is accurately differentiated the velocity of sound under described aperture ability significantly.Importance of the present invention is that the ability of differentiating the velocity of sound when low frequency is directly relevant with the aperture of this array.Therefore, longer array is used for differentiate in more low-frequency velocity of sound.As shown in Figure 6, the standard deviation relevant with determining the airborne velocity of sound is expressed as have different apertures, be the function of frequency of three arrays of 15.ft, 3ft and 10ft.

Accurately measure the physical constraints of the velocity of sound when specifying in ultra-low frequency, these data propose, it may be problematic utilizing the relation of quasi-steady model explanation between the velocity of sound measured on the frequency that is higher than those frequencies that can use the quasi-steady model and air/fuel ratio, and in fact may be unpractical.Like this, understand by acoustic velocity measutement and the key of explaining the composition of coal/air mixture is the dispersing characteristic of this coal/air mixture.

According to the present invention, the dispersing characteristic of this system utilizes interactional first principle model between air and the particulate.This model is regarded as seeking illustrating the representative of the model I of dispersion effect.Under the situation of the purpose that does not change present disclosure, also other model (for example can be used to illustrate dispersion effect, referring to by R.L.Gibson, Jr. the title of being shown with M.N.Toks z is the article of " Viscous Attenuation of AcousticWaves in Suspensions "), it is incorporated in this as a reference.Slip between the local velocity of the lasting fluid phase of this model permission and the local velocity of particulate.By with the proportional power of difference of partial fluid speed and fluid fine particle speed to carrying out modeling by continuing the pulling force that fluid is applied on the particulate, described pulling force is by balance of shaking force:

$F_{\mathrm{drag}}=K(U_f-U_p)={\mathrm{\&rho;}}_p{v}_p\frac{{\&PartialD;U}_p}{\&PartialD;t}$

Wherein, K=proportionality constant, U _f=fluid velocity, U _p=particle speed, ρ _p=density of particle, and v _p=particulate volume.

Fluid fine particle is modeled as the power item of axial momentum equation in the effect that continues the acting force on the fluid phase.The CONTROL VOLUME of zone A and the axial momentum equation of length Δ x are provided by following formula:

$p_x-P_{x+\mathrm{\&Delta;x}}-K(U_f-U_p)\left\{\frac{{\mathrm{\&phi;}}_p\mathrm{\&Delta;x}}{v_p}\right\}=\frac{\&PartialD;}{\&PartialD;t}\left({\mathrm{\&rho;}}_f{U}_f\mathrm{\&Delta;x}\right)$

Wherein, P=is at the pressure at position x and Δ x place, φ _pThe volume fraction of=particulate, ρ _f=fluid density.

This particulate pulling force is provided by following formula:

$F_{\mathrm{drag}}=K(U_f-U_p)=C_d{A}_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="A0381477000281.png,A0381477000322.png"\; state="\{\{state\}\}">p</figure-callout>}}\frac{1}{2}{\mathrm{\&rho;}}_f{(U_f-U_p)}^2$

Wherein, C _d=tension coefficient, A _pThe front face area of=particulate, and ρ _f=fluid density.

Use stoke (Stokes) law at sphere upper pulling force when low Reynolds (Reynold) is counted, produce following tension coefficient:

$C_d=\frac{24}{\mathrm{Re}}=\frac{24\mathrm{\&mu;}}{{\mathrm{\&rho;}}_f(U_f-U_p)D_p}$

Wherein, D _p=mean particle dia, and μ=fluid viscosity.

In this model, find the solution K, produce:

K＝3πμD _p

Relation of plane and 1 dimension Acoustic Modeling technology in the use, the following relation of plane of dispersing characteristic that can derived ideal fluid fine particle potpourri.

In the superincumbent relation, fluid SOS, density (ρ) and viscosity (φ) all are pure phase bit stream bodies, v _pBe the volume of single particulate, and φ _pIt is the volume phase mark of particulate in the potpourri.

Primary interested two parameters are particle size and air/fuel mass ratio in fine coal is measured.For this reason, the interested dispersing characteristic that is check as the potpourri of the function of these two variablees.The dispersing characteristic of accompanying drawing 7 and 8 expression coal/air mixtures, its parameter are those parameters of often using in the fine coal transfer system.

Especially, accompanying drawing 7 expressions have the prediction characteristic of the coal of 50 microns nominal sizes in the air for the air/fuel ratio of certain limit.As shown in the figure, the influence of air/fuel ratio is limited in the low frequency boundary fully.Yet in higher frequency, the influence of air/fuel ratio becomes and is difficult to differentiate, and high frequency (be higher than～100Hz) time near the pure airborne velocity of sound.

Similarly, accompanying drawing 8 expression have 1.8 air/fuel than and the prediction characteristic of the coal/air mixture of different particle sizes.This accompanying drawing represents that particle size does not all have influence to the low frequency boundary (quasi-steady) of the velocity of sound or the high frequency boundary of the velocity of sound.Yet particle size has remarkable influence in zone of transition.

Accompanying drawing 7 and 8 expressions importance of the present invention.In other words, the dispersion property of the diluted mixture thing of the particulate that continues to suspend in the fluid can be divided into three frequency ranges roughly: low-frequency range, high-frequency range, and transition frequency scope.Preferably as shown in Figure 8, in low-frequency range, the velocity of sound of propagating by potpourri is identical basically, and irrelevant with particle size.In low-frequency range, this potpourri shows the quasi-steady model, or fricton-tight (non-dispersive) characteristic.As shown in the intermediate frequency range, the velocity of sound of propagating by potpourri depends on the size of particulate, and therefore shows dispersing characteristic.Concerning high-frequency range, be not subjected to the influence of particulate by the velocity of sound of potpourri propagation.In other words, the velocity of sound of propagating in the higher-frequency scope by potpourri is substantially equal to the velocity of sound propagated by fluid, and wherein particulate can not exert an influence, and this will be described in more detail below.

Known the aforesaid dispersion effect of passing through the velocity of sound of potpourri, will be appreciated that, preferably as shown in Figure 7, for the concentration of determining potpourri (for example, the air/fuel ratio), the frequency of tested sound wave should be in low-frequency range, and this low-frequency range shows small slip or fricton-tight (non-dispersive/quasi-stationary state).In addition, will be appreciated that as shown in Figure 8, in order to determine the particle size in the potpourri 12, the frequency of tested sound wave should be positioned at intermediate frequency range, this intermediate frequency range shows dispersing characteristic.

Though the influence of particle size is interrelated with the influence of air/fuel ratio,, the main influence of air-fuel ratio is a low frequency boundary of determining the velocity of sound to be measured, and the main influence of particle size is a frequency range of determining zone of transition.Along with particle size increases, the frequency that dispersion property occurs reduces.Concerning typical fine coal was used, this zone of transition began at quite low frequency place, was～2Hz for being of a size of 50 microns particulate.

In low-frequency range, this particulate shows inappreciable slip with respect to fluid.The approximate effective frequency range of fricton-tight, quasi-steady is the function of a plurality of parameters, and this parameter comprises particle size, continues phase place viscosity, particulate form, and density of particle.

Provide the velocity of sound of this quasi-steady (fricton-tight condition) by the low frequency boundary that concerns above, wherein, AFR is the air/fuel ratio:

Should be noted that particle size does not influence the low frequency boundary of the velocity of sound.With reference to accompanying drawing 9, at the air/coal mass ratio of certain limit, utilize embodiments of the present invention to measure the velocity of sound, this embodiment has and is spaced apart 20.5 inches, 8 sensors of average 20-40Hz.Express the velocity of sound of the coal/air mixture that uses the quasi-steady model prediction simultaneously.As shown in the figure, though caught trend substantially, promptly the velocity of sound reduces with the growth of coal loading amount, and error also is very significant, makes and explains abundant inadequately based on first principle of quasi-steady model.

In the high frequency boundary, dispersion relation has been predicted towards the asymptotic velocity of sound of pure fluid sound speed.

a _mix(ω∞)＝a _fluid

Enjoyably, this high frequency boundary is independent of particle size and air-fuel ratio.

The abundant low frequency of known measurement is to use the quasi-steady model and to recognize that the high frequency velocity of sound does not comprise the difficulty about the direct information of particle size or air/fuel ratio, obviously, should utilize the dispersing characteristic of coal/air mixture to determine particle size and air/fuel ratio based on acoustic velocity measutement.

As mentioned above, flowmeter 10 of the present invention comprises the average particle size of the coal in the PF/ air mixtures in accurately definite pipeline 14 and the ability of air/fuel ratio.If significantly do not slide between air and solid coal particulate, then the propagation of the one dimension sound wave by multiphase mixture will be subjected to the effective mass of potpourri and the effectively influence of compressibility.Concerning the air transfer system, the degree that fricton-tight hypothesis is used is the majorant of particle size and frequency.In small particle and low-frequency boundary, this fricton-tight hypothesis is effective.Along with the size increase of particulate, and the frequency gets higher of sound wave, this fricton-tight hypothesis little by little becomes invalid.Concerning given average coal particle size, the slip that increases with frequency gets higher causes dispersion, and perhaps in other words, the velocity of sound of potpourri changes with frequency change.By suitably calibration, the dispersing characteristic of potpourri will provide the measurement of average particle size, and the air/fuel of potpourri is than the measurement of (particulate/fluid ratio).

Equational above-mentioned model shown in below utilize producing, and with the velocity of sound as the function of frequency that experimental technique is determined the present invention includes the particle size determined simultaneously in coal/air mixture and the optimizing process of AFR:

With reference to accompanying drawing 10, represented according to optimizing process of the present invention, wherein, optimize analytical model free parameter so that error function minimize.For illustrative purposes, the error function that is utilized be analytical model and with experimental technique determine as the velocity of sound difference between the velocity of sound of the function of frequency and:

$\mathrm{err}=\underset{f=f_{\mathrm{low}}}{\overset{f=f_{\mathrm{high}}}{\mathrm{\&Sigma;}}}{(a{\left(f\right)}_{\mathrm{mode}l}-{a\left(f\right)}_{\mathrm{measured}})}^2$

Accompanying drawing 11 expression is applied to optimizing process the result after the data of sensor array record, and it is that 50 microns, airflow rate are that 100ft/sec, air/fuel are than the stream that is 1.8 that this sensor is monitored in 6 inches ring pipes particle size.Show measured and with the velocity of sound of Optimization Model prediction.As shown in the figure, this model has been caught the transition frequency scope preferably, and provide air/fuel than good assessment.

Accompanying drawing 12 expression is applied to optimizing process the result of the data set of a series of air/fuel ratios with variation.Should be noted that for this optimization particle size is retained as constant in the scope of this data set.

As mentioned above, the length of this array of pressure sensors should be the live part of the wavelength of the interested velocity of sound at least.The live part of this wavelength can be at least 30% of this wavelength, yet this part also can be less than 30%, and this depends on required measuring accuracy, measured wavelength, and/or the intensity of sound wave (for example, low signal-to-noise ratio).Therefore, the length of this array depends on the frequency of the interested velocity of sound (frequency and wavelength are inversely proportional to), and wherein, the frequency of the interested velocity of sound depends on the dispersing characteristic of measurement undetermined (for example, air/particulate ratio and particle size) and potpourri.For example, as shown in Figure 7, because the growth that potpourri disperses, the low-frequency range of the velocity of sound (quasi-stationary state) curve of measurement mixture concentration (as air/particulate ratio) is lower.As previously mentioned, the dispersing characteristic of this potpourri depends on many factors, and one of them is a particle size.When particle size becomes big, this disperses to become big, and reduces when particle size, and this disperses step-down.Therefore, the length of array is the function of particle size in the potpourri, and therefore, preferably as shown in Figure 8, along with particle size growth, the transition point between low-frequency range and the intermediate frequency (low-frequency cutoff) frequency reduces.

For example, when measuring the concentration of potpourri, along with the size growth of particulate, low-frequency cutoff reduces, and the therefore growth of interested wave length of sound, thereby needs the length of this array to become longer.On the contrary, along with the size of particulate reduces, low-frequency cutoff increases, and therefore the wavelength of interested sound wave reduces, thereby needs the length of this array to become shorter.Briefly, particulate is big more, and array is long more, and vice versa.During the size of particulate, identical more also is correct in determining potpourri.Yet, concerning the optimum performance of flowmeter, because the lower frequency (long wavelength) of intermediate frequency (short wavelength) that the measurement of concentration is positioned at than particle size is located, thereby the measurement of mixture concentration is compared with the measurement of particle size and may be needed longer array.

The actual low-limit frequency scope of surveying is approximately 10-25Hz, thereby the measurement of big particulate energy measurement quasi-steady model not perhaps, and described quasi-steady model in some cases can be less than 10Hz (that is, cutoff frequency be less than 10Hz).In these cases, interested velocity of sound frequency is positioned on this cutoff frequency.Yet, as shown in figure 10, by changing size and the ingredients of a mixture of particulate, making the disperal pattern curve fitting of the measured velocity of sound and potpourri, thereby determine the concentration of particle size and/or potpourri, this will be described in more detail below.

When the length of array depended on particle size, this length also can depend on other parameter that limits dispersion amount, the viscosity of for example quality of particulate, and potpourri inner fluid.

The factor of the length of another qualification (or influence) pressure transducer 15-18 array comprises the signal intensity of the sound wave that is received by processor.When signal intensity improved or be bigger, the length of this array must be shorter.This signal intensity depends on a plurality of factors, as the intensity of sound wave itself, and the signal to noise ratio (S/N ratio) of sensor, coupling of sensor or the like.

As shown in Figure 1, this spacing can be equally spaced, yet flowmeter of the present invention 10 is considered that this sensor can have and do not waited or uneven spacing.If the position of sensor or orientation are known, then this sensor can be with any required distance at interval.For the pressure transducer that communicates, minimum spacing is limited by the mechanical constraint of sensor.To bringing based on the sensor of strain, the PVDF that for example describes hereinafter, the flexibility of pipeline has limited the closeness at this interval.For example, pipeline is hard more, and the spacing of sensor must be big more, and on the contrary, the pipeline flexibility is big more, and sensor must be near more at interval.

The spacing of this pressure transducer also can be limited by the quantity of the sensor in the array that is arranged in given length.The sensor of arranging in the array of given length is many more, and then this spacing is near more.The quantity that is arranged in the sensor in the array depends on required or wants the degree of accuracy of the flowmeter 10 that obtains.The quantity of array inner sensor is many more, then can obtain the accurate more measurement of sonic pressure field.In other words, on given array length (or wavelength), the sampling of the acoustic pressure wave that provides or the quantity of measurement are many more, and the resolution that sensor can be realized in the measurement of the sound wave of to be measured or characterization is just big more.

Come the fluid/particulate ratio and particle size of the potpourri 12 in the measuring channel 14 except the velocity of sound that use records, flowmeter 10 further comprises by comparing the one dimension sound wave measures the ability of volume of mixture flow rate along with the speed difference that average flow is propagated and the one dimension sound wave is propagated against average flow.

Should determine that the method for the volume flow rate of particulate/fluid mixture 12 in the pipeline 14 depended on the interaction of this average flow and sonic pressure field.The sound wave that this interaction causes propagating along with average flow adds convection velocity with the velocity of sound (supposing that this particulate/fluid mixture does not flow) advances, and on the contrary, and the sound wave of advancing against average flow subtracts convection velocity with the velocity of sound and propagates.That is to say,

a _R＝a _mix+u

a _L＝a _mix-u

Wherein, a _RThe speed of=the sound wave of advancing to the right with respect to fixing observer's (being pipeline 14), a _LThe speed of=the sound wave of advancing left with respect to fixing observer, a _Mix=fluid sound speed (if fluid do not flow), and u=mean flow rate (in this case, suppose be flow from left to right).With the equation of these two equations in conjunction with generation average velocity,

$u=\frac{a_R-a_{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A0381477000281.png,A0381477000311.png"\; state="\{\{state\}\}">L</figure-callout>}}}{2}$

Therefore, as previously mentioned,, can multiply each other by area of section and calculate this mean flow rate mean flow rate and pipeline 14 by measuring the velocity of propagation of sound wave on respect to the both direction of fixed-piping.

Utilize this method to determine that the practicality of this average flow is based on fully accurately differentiating the velocity of sound to determine the ability of volume flow on both direction.Concerning typical fluid measurement, flow velocity typically is～10ff/sec, and the velocity of sound is～4000ft/sec.Like this, axially Mach number be approximately 0.0025 10/4000.Concerning flow velocity (+/-1ft/sec)+/-10% accuracy, the resolution of the velocity of sound of contrary trip and the ripple propagated along trip need for+/-0.5/4000 or 1/8000th.

Yet for the PF/ air mixture flow, axial flow velocity is nominally about 70ft/sec, and does not have～the stream velocity of sound of 700ft/sec.This has caused～0.1 Mach number, and this Mach number is approx than flow big two orders of magnitude of typical fluid.Concerning pulverized fuel stream, for flow velocity is differentiated 10% degree of accuracy (or+/-7ft/sec), have to the velocity of sound is differentiated+/-3.5ft/sec, or 3.5/700, or 1/200th.

Concerning acoustic velocity measutement, flowmeter 10 utilizes and the similar Processing Algorithm of employed those algorithms above.The time of the sound of propagating in handling pipeline 14 is relevant with dispersion relation with spatial frequency content.

ω＝ka _mix

Wave number is k, and this wave number is defined as k=2 π/λ, and ω is a temporal frequency, and unit is radian per second (rad/sec), and a _MixThe speed of in handling pipeline, propagating for sound.For this situation that sound is propagated on both direction, acoustical power is swelled (ridges) location along two sound, and one in the described sound protuberance is with a _Mix+ V _MixThe speed and the stream sound of advancing together, and another is with a _Mix-V _MixSpeed against the popular sound that advances.

K-w curve representation shown in the accompanying drawing 13 is supported just, can be used in combination axle pressure sensor array and sonar treatment technology and determine speed based on the ultimate principle of the flow measurement of sonar, in the pipeline naturally with this speed generation turbulent eddy convection current.The accompanying drawing 13 expression k-w curve that the sound field of coal/air mixture of pipeline produces of flowing through.Two sound protuberances are very obvious.Each gradient of shown two sound protuberance limits the velocity of sound of advancing along with average flow accordingly and carrying out against average flow respectively.Used parameter optimization method to determine " best " line of this of expression protuberance gradient.

In addition, accompanying drawing 13 expression the present invention determine the ability of fluid velocity mobile in pipeline.Wave number-the frequency curve (k-w curve) of accompanying drawing 14 expression transient pressures.The relative signal power of this contour representation in all combinations of frequency and wave number.The highest power " protuberance " uses the protuberance gradient that equates with velocity of propagation to represent sound wave.Dotted line is represented the maximization of two variablees of the best-fit of power, and described two variablees are the velocity of sound and flow velocity.The sound wave that the right side protuberance is represented and bulk flow is advanced in the same way, thereby its gradient is more precipitous than the left side protuberance, the sound wave that protuberance expression of described left side and bulk flow are reversed.This means that with respect to the fixation of sensor that is positioned on the pipeline, the acoustic ratio of advancing in the same way with bulk flow and the sound wave of the bulk flow negative line feed ground of advancing is faster.

Pressure transducer 15-18 described here can be the pressure transducer of any kind, piezo-electric pressure sensor for example, optical pressure sensor, capacitance pressure transducer,, resistive pressure sensor (for example Wheatstone bridge), accelerometer (or seismoreceiver), velocity measuring device, displacement measuring device etc., described pressure transducer can measuring channel instability (or exchange or dynamically) pressure in 14.If use optical pressure sensor, then sensor 15-18 can be based on the pressure transducer of Prague (Brgg) grating, and for example the title of submitting on September 8th, 1997 is the U.S. Patent application No.08/925598 of " High Sensitivity Fiber OpticPressure Sensor For Use In Harsh Environments ", the pressure transducer described in the present United States Patent (USP) 6016702 just.Selectively, sensor 14 can be strainometer electricity or optics, and described strainometer is attached to or embeds the outer wall or the inwall of pipeline, and measure the strain of tube wall, described sensor comprises microphone, nautical receiving set, perhaps other any can measuring channel the sensor of transient pressure in 14.In an embodiment of the invention, use optical fiber as pressure transducer 14, described optical fiber can connect individually, perhaps can use Wave division multiplexing (WDM), time division multiplexing (TDM) or other any optically multiplexed technology multiplexed along one or more optical fiber.

Concerning any embodiment described here, pressure transducer can be attached on the pipeline to guarantee suitable contact between sensor and the pipeline 14 by bonding agent, glue, epoxy resin, adhesive tape or other suitable setting tool, and described pressure transducer comprises electrical strain gauge described here, optical fiber and/or grating.Selectively, this sensor can removably or for good and all adhere to by known mechanical technique, for example machanical fastener, loading spring, clamp, clamp housing equipment, strapping or other equivalent technology.Selectively, this strainometer can be embedded in the complex pipe, and described strainometer comprises optical fiber and/or grating.If desired, concerning some was used, if desired, this grating can separate (or strain or sound isolation) with pipeline 14.

Within the scope of the invention, also can use the variation of strain in other any strain induction technology measuring channel, as highly sensitive piezoelectricity, electronics or electric strainometer, described strainometer is attached to or is embedded in the pipeline 14.

In some embodiments of the present invention, can use piezoelectron pressure transducer one or more as among the pressure transducer 15-18, described piezoelectron pressure transducer can come instability (or the dynamically or exchange) pressure in the measuring channel 14 to change by the pressure stage in the measuring channel.In an embodiment of the invention, this sensor 14 comprises the pressure transducer of being made by PCB Piezotronics.In a pressure transducer, have the sensor of integrated circuit piezoelectric voltage mode type, this sensor characteristics is embedded microelectronics amplifier, and the high impedance electric charge is transformed into low-impedance voltage output.Especially, use by PCB Piezotronics and make Model 106B, this device is an integrated circuit quartz pressure sensor highly sensitive, acceleration compensation, is suitable for measuring in hydraulic system and pneumatic system the low pressure voice phenomenon.Under the high static condition, it has the unique ability of measurement less than the little pressure variation of 0.001psi.106B has the sensitivity of 300mV/psi, and the resolution of 91dB (0.0001psi).

This pressure transducer comprises the MOSFET microelectronics amplifier of embedding, thereby the output of high impedance electric charge is transformed into voltage signal in low impedance.This sensor obtains power from constant current source, and can operate on long coaxial or flat cable, and does not have signal attenuation.Voltage signal in low impedance is not subjected to the influence of the cable noise or the insulation resistance degradation of contaminant of triboelectricity.The power supply of operating integrated circuit piezoelectric sensors takes cheaply usually, 24 to 27VDC, 2 to 20 milliamperes constant current source form.Data acquisition system (DAS) of the present invention can be incorporated constant current source into, so that power supply is provided directly for the integrated circuit piezoelectric sensor.

Most piezo-electric pressure sensor is made of compact model quartz crystal that is preloaded in stiff case or unconfined tourmaline crystal.These are designed to the resonant frequency that sensor provides microsecond response time and hundreds of KHz, and have minimum overshoot or ring.Small vibration film diameter has guaranteed the spatial resolution of narrow shock wave.

The output characteristics of piezoelectric pressure sensor systems is the output characteristics of AC coupling system just, wherein, the signal attenuation of repetition, up on original baseline and below have equal zone.Because the order of magnitude of the incident that is monitored can fluctuate, so output signal maintenance around baseline is stable, and the positive negative region of curve keeps equating.

And, as shown in figure 20, the present invention's imagination, each among the pressure transducer 15-18 of flowmeter 10,70 all comprises piezoelectric sensor 104-107, described piezoelectric sensor provides piezoelectric 110 to measure the transient pressure of fluid/particle mixture 12.The strain that the fluoropolymer of this piezoelectric, for example polymkeric substance, polarization, polyvinylidene fluoride measurements such as (PVDF) are inducted in handling pipeline 14, described strain is owing to the variation of handling transient pressure in the potpourri 12.Strain in the pipeline is transformed into output voltage or electric current by the piezoelectric sensor 104-107 that adheres to.

Preferably as shown in figure 21, PVDF material 110 is attached to the outside surface of steel band 112, and described steel band extends around the outside surface of pipeline 14, and clips on the described outside surface.The conformal typically of this piezoelectricity sensing element, thus allow measuring completely or near circumference completely of the strain of inducting.This sensor can be made of PVDF film, interpolymer film or flexible PZT sensor, and be similar to by Measurement Specialties, Inc., the sensor of describing in " Piezo Film Sensors technical Manual " is provided, and this sensor merges as a reference at this.The advantage of this technology is as follows:

1. non-intrusion type fluid-velocity survey

2. low-cost

3. measuring technique does not need driving source.The ambient flow moving noise is used as the source.

4. can flexible piezoelectric sensor be installed in the various configurations mode, thus the enhancing signal detection scheme.These configuration modes comprise a) sensor of colocated, b) has the segmentation sensor that opposite polarity disposes, c) wide sensor, thereby enhancing acoustic signal detection, and the detection that minimizes the vortex noise, d) Ding Zhi sensor geometry, thus minimize sensitivity to pipeline model, e) difference of sensor, thus from the vortex signal, eliminate noise.

5. higher temperature (140C) (interpolymer)

Though the present invention understands that for example array of pressure sensors comprises a plurality of similar sensors, the present invention's imagination also can be used any combination of different or similar pressure transducer in array.

Though the present invention can measure the solia particle that suspends in fluid, will be appreciated that, also can use sensor array to measure other leggy potpourri or stream, as steam flow.Should recognize further that the influence of the dispersion of big solia particle is similar to the big drop of the liquid that disperses in gas or the air in the convection cell, therefore when measuring quality of steam and drop size, should solve similar consideration.

Should be appreciated that also and can use, use, or it is merged in any other embodiment described here about the described any feature of specific implementations, characteristic, alternatives or modification.

Though describe according to exemplary embodiments and illustrated the present invention, under the situation that does not break away from the spirit and scope of the present invention, also can constitute aforesaid and multiple other interpolation and omission.

Claims (28)

1. the device of at least one parameter of particulate/fluid mixture in the measuring channel comprises:

The space array of at least two pressure transducers, described transducer arrangements is along on the different axial locations of pipeline, and each described sensor is the transient pressure in the measuring channel on corresponding axial location, and the pressure signal of the transient pressure in the indication pipeline is provided on the described axial location of each described sensor corresponding sensor in described sensor; And

Signal processor, described signal processor be in response to described pressure signal, and the signal of at least one parameter of potpourri in the indication pipeline is provided.

2. device as claimed in claim 1, wherein, each sensor measurement acoustic pressure, and the signal of noise in the indication pipeline is provided.

3. device as claimed in claim 1, wherein, signal processor responds described pressure signal, and the signal of an indication by the velocity of sound of potpourri propagation in the pipeline is provided.

4. device as claimed in claim 3, wherein, described signal processor comprises logical circuit, described logical circuit calculates the speed that sound is propagated along described space array.

5. device as claimed in claim 3, wherein, described signal processor comprises logical circuit, described logical circuit is that each described sound pressure signal calculates the signal based on frequency.

6. device as claimed in claim 4, wherein, each described sound pressure signal all comprises the signal based on frequency, and wherein, described signal processor comprises logical circuit, described logical circuit calculates the ratio of two described signals based on frequency.

7. device as claimed in claim 1 wherein, comprises at least three described sensors.

8. device as claimed in claim 3, wherein, signal processor comprises logical circuit, described logical circuit calculates the fluid composition of potpourri in the pipeline.

9. device as claimed in claim 1, wherein, at least one described pressure transducer is measured the circumference mean pressure on the described axial location of described sensor.

10. device as claimed in claim 9, wherein, at least one described pressure transducer comprises piezoelectricity sheet material.

11. device as claimed in claim 1, wherein, piezoelectricity sheet material is fluoropolymer, the polyvinylidene fluoride (PVDF) of polarization.

12. device as claimed in claim 1, wherein, the strain at least one described pressure transducer measuring channel.

13. device as claimed in claim 3 wherein, utilizes the definite velocity of sound based on frequency of disperal pattern, thereby determines at least one parameter of potpourri.

14. device as claimed in claim 3, wherein, acoustic sensor array is by spaced apart fully, so that the whole length of this array is the live part of the tested wavelength of just measured sound wave at least.

15. the method for at least one parameter of particulate/fluid mixture in the measuring channel, described method comprises:

Along transient pressure in the measuring channel at least two of the pipeline predetermined axial measuring positions, thereby provide the pressure signal of the transient pressure in the indication pipeline on each position at least two predetermined axial measuring positions; And

The transient pressure that use is measured on axial measuring position calculates at least one parameter of particulate/fluid mixture in the pipeline.

25. method as claimed in claim 24, wherein, measured transient pressure is an acoustic pressure, thereby the signal of noise in the indication pipeline is provided.

26. method as claimed in claim 25, wherein, at least one parameter of described calculating uses acoustic pressure to calculate the speed that sound is propagated in pipeline.

27. method as claimed in claim 26, wherein, at least one parameter of described calculating uses acoustic pressure to calculate the speed that sound is propagated along described space array.

28. method as claimed in claim 26, wherein, at least one parameter of described calculating uses acoustic pressure to come to be the signal of each described sound pressure signal calculating based on frequency.

29. method as claimed in claim 27, wherein, each described sound pressure signal comprises the signal based on frequency, and wherein, described signal processor comprises logical circuit, and described logical circuit calculates the ratio of two described signals based on frequency.

30. method as claimed in claim 24 wherein, is measured transient pressure at least three described sensor places.

31. method as claimed in claim 26, wherein, at least one parameter of described calculating uses acoustic pressure to calculate the fluid composition of potpourri in the pipeline.

32. method as claimed in claim 24 wherein, is measured at least one axial location that transient pressure is included in sensor and is measured the circumference mean pressure.

33. method as claimed in claim 32 wherein, is measured transient pressure and is used at least one the described pressure transducer that comprises piezoelectricity sheet material.

34. method as claimed in claim 24, wherein, this piezoelectricity sheet material is fluoropolymer, the polyvinylidene fluoride (PVDF) of polarization.

34. method as claimed in claim 24, wherein, the strain at least one described pressure transducer measuring channel.

35. method as claimed in claim 26 is utilized the definite velocity of sound based on frequency of disperal pattern, thereby determines at least one parameter of potpourri.

36. as method as described in the claim 26, acoustic sensor array is by spaced apart fully, so that the whole length of this array is the live part of the tested wavelength of just measured sound wave at least.

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