CN105115550A - Online measurement device and online measurement method of double-pressure difference gas-liquid flow rate - Google Patents

Abstract

The invention discloses an online measurement device and an online measurement method of double-pressure difference gas-liquid flow rate. The online measurement device comprises a Venturi flowmeter; a gas-liquid pipe is arranged at one end of the Venturi flowmeter; the gas-liquid pipe is connected with a V-cone flowmeter through a connecting flange; a first pressure gauge is arranged at the front end of the Venturi flowmeter; a second pressure gauge is arranged at the throat part of the Venturi flowmeter; a fourth pressure gauge is arranged at the rear end of the V-cone flowmeter; a third pressure gauge is arranged at a position, between the fourth pressure gauge and the connecting flange, on the V-cone flowmeter. During an actual online gas-liquid flow rate measurement process, respective pressure differences of the Venturi flowmeter and the V-cone flowmeter in a pipeline are acquired and are transmitted into a processor; a gas-liquid two-phase flow rate measurement model is established in the processor; respective flow rates of a gas phase and a liquid phase are calculated and outputted according to the measured pressure differences and by combining the physical parameters of the pipeline and a fluid inputted through a human-computer interface; the online measurement device and the online measurement method have high measurement stabilities.

Description

A kind of two pressure reduction gas-liquid flow on-line measurement device and On-line Measuring Method

Technical field

The present invention relates to a kind of two pressure reduction gas-liquid flow on-line measurement device and On-line Measuring Method.

Background technology

The flowmeter existed in the market mostly is the flowmeter being applied to monophasic fluid and measuring, and the flowmeter kind of gas-liquid two-phase flow on-line measurement is few and expensive.Differential flowmeter stable performance and cost is lower, applies comparatively extensive, according to the pressure reduction of line size, physical properties of fluids and flowmeter, obtains current flow in monophasic fluid is measured.Two differential flowmeter combines primarily of former and later two differential flowmeters, and for measuring gas-liquid two-phase flow simultaneously, the pressure reduction etc. according to line size, gas-liquid two-phase physical property, two differential flowmeters obtains the flow of two-phase.Current existing pair of pressure reduction gas-liquid flow on-line measurement device has long throat Venturi meter to increase a pressure point at the larynx neck of venturi, this flowmeter, because of the similarity in flow field between upstream and downstream two pairs of pressure points, may affect the flow pattern accommodation of flowmeter.Also have complete symmetry V cone flow meter and two V to bore mix flow gauge, there is the problem that the similarity in fore-and-aft survey flow field is larger equally.Also have V cone flow meter in upstream, the combination of Venturi meter in downstream, V cone is comparatively large to the disturbance in flow field, downstream, has influence on the measurement performance of downstream Venturi meter.

Therefore, prior art awaits further must improving and develop.

Summary of the invention

In view of above-mentioned the deficiencies in the prior art, the two pressure reduction gas-liquid flow on-line measurement device of one provided by the invention and On-line Measuring Method, reduce the Flows drag losses that double-current gauge causes, and upstream flow meter is to the interference of downstream flow meter, improves the stability measured.

For solving the problems of the technologies described above, the present invention program comprises:

A kind of two pressure reduction gas-liquid flow on-line measurement device, wherein, it comprises Venturi meter, Venturi meter one end is provided with gas-liquid pipe, gas-liquid pipe is connected with a V cone flow meter by joint flange, Venturi meter front end is provided with the first pressure gauge, and the throat of Venturi meter is provided with the second pressure gauge; The rear end of V cone flow meter is provided with the 4th pressure gauge, and the 4th V cone flow meter between pressure gauge and joint flange is provided with the 3rd pressure gauge.

A kind of On-line Measuring Method using described pair of pressure reduction gas-liquid flow on-line measurement device, it comprises the following steps: gather Venturi meter and V cone flow meter pressure reduction parameter separately in pipeline by two pressure reduction gas-liquid flow on-line measurement device, then by pressure reduction Parameter transfer in processor, set up gas-liquid two-phase traffic measurement model in processor, calculate according to the pressure reduction parameter of input and export gas-liquid two-phase flow separately.

Described On-line Measuring Method, wherein, the above-mentioned step setting up gas-liquid two-phase traffic measurement model comprises:

Determine gas-liquid two-phase coefficient of flow C _mfor the total mass flow rate of two-phase mixture and the ratio of theory calculate flow;

$C_m=\frac{m_g+m_l}{m_{tpc}}---\left(1\right);$

Wherein, m _gfor gas phase mass flow, m _lliquid phase quality flow, unit is kg/s; m _tpcfor gas-liquid theoretical delivery;

Then obtain formula (2) according to Bernoulli equation and continuity equation, obtained by the pressure reduction measuring gas-liquid mixture;

$m_{tpc}=\frac{{\mathrm{\πD}}^2{\mathrm{\β}}^2\sqrt{2{\mathrm{\ρ}}_g{\mathrm{\ΔP}}_{tp}}}{4\×\sqrt{1-{\mathrm{\β}}^4}}---\left(2\right);$

Wherein, D is internal diameter of the pipeline, and unit is m; △ Ptp is the pressure reduction of the gas liquid two-phase flow that independent flowmeter records, and unit is Pa; β is the Throttling ratio of flowmeter;

Characterize the size of liquid content with XLM in gas-liquid:

$X_{LM}=\frac{m_l}{m_g}\sqrt{\frac{{\mathrm{\ρ}}_g}{{\mathrm{\ρ}}_l}}---\left(3\right);$

Wherein, ρ _gfor density of gas phase, ρ _lfor density of liquid phase, unit is kg/m ³;

Simultaneous formula (1), formula (2) obtain with formula (3):

$m_g=\frac{m_{tpc}\·C_m}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}---\left(4\right);$

Formula (4) is based on two phase flow coefficient C _mgas phase flow rate measure correlation; Wherein, m _tpcby the two-phase pressure reduction △ P recorded _tpcalculate, obtain two phase flow coefficient C _mwith X _lMfuntcional relationship; C _mwith X _lMbecome linear approximate relationship, the linear relation that different working condition pressures is corresponding different; This linear relation is:

C _m＝aX _LM+b(5)；

Wherein, a, b are relevant with the flow of pressure and gas, are constant; Formula (5) is brought into equation (4) to obtain:

$m_g=\frac{m_{tpc}({\mathrm{aX}}_{LM}+b)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}---\left(6\right);$

In the flow measurement process of two differential flowmeter, two different differential flowmeters obtain different gas phase flow rates and measure correlation;

$\begin{array}{c}{m}_g=\frac{m_{tpc1}\left(a_1{X}_{LM}+b_1\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\\ m_g=\frac{m_{tpc2}\left(a_2{X}_{LM}+b_2\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\end{array}---\left(7\right);$

Wherein, a ₁, b ₁, a ₂, b ₂by early stage, Venturi meter, V cone flow meter are carried out demarcation and obtained, m _tpc1and m _tpc2be the Theoretical Mass flow that two single current gauge calculate by formula (2), simultaneous formula (3), formula (4), formula (5), formula (6) and formula (7) solve, and obtain gas phase flow rate m _gwith liquid phase flow m _l.

The two pressure reduction gas-liquid flow on-line measurement device of one provided by the invention and On-line Measuring Method, combined by Venturi meter and V cone flow meter, in the gas-liquid flow on-line measurement process of reality, gather the pressure reduction between Venturi meter and V cone flow meter in pipeline, pressure reduction is transferred in processor, gas-liquid two-phase traffic measurement model is set up in processor, calculate according to the pressure reduction of input and export gas-liquid two-phase flow separately, the disturbance of venturi stream field is less, thus the impact reduced downstream V cone flow meter measurement performance, and V cone flow meter has good current stabilization and Ability of Resisting Disturbance, therefore V cone flow meter is placed on the combination unit in venturi downstream, there is good Measurement sensibility.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of two pressure reduction gas-liquid flow on-line measurement device in the present invention.

Embodiment

The invention provides a kind of two pressure reduction gas-liquid flow on-line measurement device and On-line Measuring Method, for making object of the present invention, technical scheme and effect clearly, clearly, the present invention is described in more detail below.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

The invention provides a kind of two pressure reduction gas-liquid flow on-line measurement device, as shown in Figure 1, it comprises Venturi meter 1, Venturi meter 1 one end is provided with gas-liquid pipe 2, gas-liquid pipe 2 is connected with a V cone flow meter 4 by joint flange 3, Venturi meter 1 front end is provided with the first pressure gauge 5, and the throat of Venturi meter 1 is provided with the second pressure gauge 6; The rear end of V cone flow meter 4 is provided with on the V cone flow meter 4 between the 4th pressure gauge the 7, four pressure gauge 7 and joint flange 3 and is provided with the 3rd pressure gauge 8.

Present invention also offers a kind of On-line Measuring Method using described pair of pressure reduction gas-liquid flow on-line measurement device, it comprises the following steps: gather Venturi meter and V cone flow meter pressure reduction parameter separately in pipeline by two pressure reduction gas-liquid flow on-line measurement device, then by pressure reduction Parameter transfer in processor, set up gas-liquid two-phase traffic measurement model in processor, calculate according to the pressure reduction parameter of input and export gas-liquid two-phase flow separately.

More specifically the above-mentioned step setting up gas-liquid two-phase traffic measurement model comprises:

Determine gas-liquid two-phase coefficient of flow C _mfor the total mass flow rate of two-phase mixture and the ratio of theory calculate flow;

$C_m=\frac{m_g+m_l}{m_{tpc}}---\left(1\right);$

Wherein, m _gfor gas phase mass flow, m _lliquid phase quality flow, unit is kg/s; m _tpcfor gas-liquid theoretical delivery;

Then obtain formula (2) according to Bernoulli equation and continuity equation, obtained by the pressure reduction measuring gas-liquid mixture;

$m_{tpc}=\frac{{\mathrm{\πD}}^2{\mathrm{\β}}^2\sqrt{2{\mathrm{\ρ}}_g{\mathrm{\ΔP}}_{tp}}}{4\×\sqrt{1-{\mathrm{\β}}^4}}---\left(2\right);$

Wherein, D is internal diameter of the pipeline, and unit is m; △ Ptp is the pressure reduction of the gas liquid two-phase flow that independent flowmeter records, and unit is Pa; β is the Throttling ratio of flowmeter;

Characterize the size of liquid content with XLM in gas-liquid:

$X_{LM}=\frac{m_l}{m_g}\sqrt{\frac{{\mathrm{\ρ}}_g}{{\mathrm{\ρ}}_l}}---\left(3\right);$

Wherein, ρ _gfor density of gas phase, ρ _lfor density of liquid phase, unit is kg/m ³;

Simultaneous formula (1), formula (2) obtain with formula (3):

$m_g=\frac{m_{tpc}\·C_m}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}---\left(4\right);$

Formula (4) is based on two phase flow coefficient C _mgas phase flow rate measure correlation; Wherein, m _tpcby the two-phase pressure reduction △ P recorded _tpcalculate, obtain two phase flow coefficient C _mwith X _lMfuntcional relationship; C _mwith X _lMbecome linear approximate relationship, the linear relation that different working condition pressures is corresponding different; This linear relation is:

C _m＝aX _LM+b(5)；

Wherein, a, b are relevant with the flow of pressure and gas, are constant; Formula (5) is brought into equation (4) to obtain:

$m_g=\frac{m_{tpc}({\mathrm{aX}}_{LM}+b)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}---\left(6\right);$

In the flow measurement process of two differential flowmeter, two different differential flowmeters obtain different gas phase flow rates and measure correlation;

$\begin{array}{c}{m}_g=\frac{m_{tpc1}\left(a_1{X}_{LM}+b_1\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\\ m_g=\frac{m_{tpc2}\left(a_2{X}_{LM}+b_2\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\end{array}---\left(7\right);$

Wherein, a ₁, b ₁, a ₂, b ₂by early stage, Venturi meter, V cone flow meter are carried out demarcation and obtained, m _tpc1and m _tpc2be the Theoretical Mass flow that two single current gauge calculate by formula (2), simultaneous formula (3), formula (4), formula (5), formula (6) and formula (7) solve, and obtain gas phase flow rate m _gwith liquid phase flow m _l.

In order to further describe the present invention, below enumerating more detailed embodiment and being described.

The Venturi meter and V cone flow meter that are combined into two differential flowmeter are individually demarcated, obtains the two phase flow coefficient C of each single current gauge _mwith X _lMrelational expression (5), namely obtain a in relational expression ₁, b ₁, a ₂, b ₂(wherein, subscript 1 represents Venturi meter, and subscript 2 represents V cone flow meter).

C _m＝aX _LM+b(5)；

$X_{LM}=\frac{m_l}{m_g}\sqrt{\frac{{\mathrm{\ρ}}_g}{{\mathrm{\ρ}}_l}}---\left(3\right);$

And then obtain the online flow measurement correlation (7) of concrete two pressure reduction mix flow gauge.

$\begin{array}{c}{m}_g=\frac{m_{tpc1}\left(a_1{X}_{LM}+b_1\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\\ m_g=\frac{m_{tpc2}\left(a_2{X}_{LM}+b_2\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\end{array}---\left(7\right);$

Wherein, m _tpccalculate according to formula (2), △ P _tptwo flowmeters pressure reduction separately during for measuring, m _tpcfor through type (2) calculates the gas-liquid theoretical delivery obtained.

$m_{tpc}=\frac{{\mathrm{\πD}}^2{\mathrm{\β}}^2\sqrt{2{\mathrm{\ρ}}_g{\mathrm{\ΔP}}_{tp}}}{4\×\sqrt{1-{\mathrm{\β}}^4}}---\left(2\right);$

Then in two differential flowmeter gas-liquid flow on-line measurement processes of reality, known line size and physical properties of fluids information, Venturi meter gathers former and later two force value, namely the pressure of the first pressure gauge 5 is the pressure of P1 and the second pressure gauge 6 is P2, obtain the pressure reduction of Venturi meter, be brought into the theoretical measuring flow obtaining Venturi meter in (2) formula.The pressure P 1 of venturi upstream is carried out the density of fluid as the pressure of pipeline, (3) formula that is brought into obtain gas-liquid flow process, X _lM.V cone flow meter gathers former and later two force value, and namely the pressure of the 3rd pressure gauge 8 is the pressure of P3 and the 4th pressure gauge 7 is P4, obtains the pressure reduction of V cone flow meter, is brought into the theoretical measuring flow obtaining V cone flow meter in (2) formula.By X _lMwith the m that two flowmeters obtain respectively _tpcbe updated in calibrated (7) formula, obtain the different gas-liquid flow equations corresponding from two flowmeters, simultaneous solution can obtain ducted gas phase flow rate m _gwith liquid phase flow m _l.

Concrete conversion process in above-mentioned steps all can be input in processor, has automatically been calculated by processor.In the flow meter calibration process of reality, by information such as simple man-machine interface operation input channel size, flowmeter structure size and physical properties of fluids, connect data-interface, can demarcation be completed by device automatically measuring and acquiring information.In gas-liquid flow on-line measurement process, direct automatically measuring and acquiring two differential pressure information, converting to solve by internal processor obtains gas-liquid two-phase flow separately.

Certainly; more than illustrate and be only preferred embodiment of the present invention; the present invention is not limited to enumerate above-described embodiment; should be noted that; any those of ordinary skill in the art are under the instruction of this instructions; made all equivalently to substitute, obvious form of distortion, within the essential scope all dropping on this instructions, protection of the present invention ought to be subject to.

Claims (3)

1. a two pressure reduction gas-liquid flow on-line measurement device, it is characterized in that, it comprises Venturi meter, Venturi meter one end is provided with gas-liquid pipe, gas-liquid pipe is connected with a V cone flow meter by joint flange, Venturi meter front end is provided with the first pressure gauge, and the throat of Venturi meter is provided with the second pressure gauge; The rear end of V cone flow meter is provided with the 4th pressure gauge, and the 4th V cone flow meter between pressure gauge and joint flange is provided with the 3rd pressure gauge.

2. one kind uses as right to want as described in 1 the On-line Measuring Method of two pressure reduction gas-liquid flow on-line measurement device, it comprises the following steps: gather Venturi meter and V cone flow meter pressure reduction parameter separately in pipeline by two pressure reduction gas-liquid flow on-line measurement device, then by pressure reduction Parameter transfer in processor, set up gas-liquid two-phase traffic measurement model in processor, calculate according to the pressure reduction parameter of input and export gas-liquid two-phase flow separately.

3. On-line Measuring Method according to claim 2, is characterized in that, the above-mentioned step setting up gas-liquid two-phase traffic measurement model comprises:

Determine gas-liquid two-phase coefficient of flow C _mfor the total mass flow rate of two-phase mixture and the ratio of theory calculate flow;

$C_m=\frac{m_g+m_l}{m_{tpc}}---\left(1\right);$

Wherein, m _gfor gas phase mass flow, m _lliquid phase quality flow, unit is kg/s; m _tpcfor gas-liquid theoretical delivery;

Then obtain formula (2) according to Bernoulli equation and continuity equation, obtained by the pressure reduction measuring gas-liquid mixture;

$m_{tpc}=\frac{{\mathrm{\πD}}^2{\mathrm{\β}}^2\sqrt{2{\mathrm{\ρ}}_g{\mathrm{\ΔP}}_{tp}}}{4\×\sqrt{1-{\mathrm{\β}}^4}}---\left(2\right);$

Wherein, D is internal diameter of the pipeline, and unit is m; △ Ptp is the pressure reduction of the gas liquid two-phase flow that independent flowmeter records, and unit is Pa; β is the Throttling ratio of flowmeter;

Characterize the size of liquid content with XLM in gas-liquid:

$X_{LM}=\frac{m_l}{m_g}\sqrt{\frac{{\mathrm{\ρ}}_g}{{\mathrm{\ρ}}_l}}---\left(3\right);$

Wherein, ρ _gfor density of gas phase, ρ _lfor density of liquid phase, unit is kg/m ³;

Simultaneous formula (1), formula (2) obtain with formula (3):

$m_g=\frac{m_{tpc}\·C_m}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}---\left(4\right);$

Formula (4) is based on two phase flow coefficient C _mgas phase flow rate measure correlation; Wherein, m _tpcby the two-phase pressure reduction △ P recorded _tpcalculate, obtain two phase flow coefficient C _mwith X _lMfuntcional relationship; C _mwith X _lMbecome linear approximate relationship, the linear relation that different working condition pressures is corresponding different; This linear relation is:

C _m＝aX _LM+b(5)；

Wherein, a, b are relevant with the flow of pressure and gas, are constant; Formula (5) is brought into equation (4) to obtain:

$m_g=\frac{m_{tpc}({\mathrm{aX}}_{LM}+b)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}---\left(6\right);$

In the flow measurement process of two differential flowmeter, two different differential flowmeters obtain different gas phase flow rates and measure correlation;

$\begin{array}{c}{m}_g=\frac{m_{tpc1}\left(a_1{X}_{LM}+b_1\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\\ m_g=\frac{m_{tpc2}\left(a_2{X}_{LM}+b_2\right)}{1+X_{LM}/\sqrt{{\mathrm{\ρ}}_g/{\mathrm{\ρ}}_l}}\end{array}---\left(7\right);$

Wherein, a ₁, b ₁, a ₂, b ₂by early stage, Venturi meter, V cone flow meter are carried out demarcation and obtained, m _tpc1and m _tpc2be the Theoretical Mass flow that two single current gauge calculate by formula (2), simultaneous formula (3), formula (4), formula (5), formula (6) and formula (7) solve, and obtain gas phase flow rate m _gwith liquid phase flow m _l.