CN102252722B - Three-differential-pressure gas liquid two-phase fluid flow metering device - Google Patents

Abstract

The invention relates to a fluid flow metering device, in particular to a three-differential-pressure gas liquid two-phase fluid flow metering device capable of measuring gas liquid mixed fluid. The device comprises a horizontal pipe and a vertical pipe, wherein the horizontal pipe and the vertical pipe are connected with an inlet and an outlet of an elbow sensor respectively; pressure introducing ports on the inner side and the outer side of the elbow sensor are connected to a first pressure difference transmitter; two pressure introducing ports are arranged on the vertical pipe at intervals and are connected to a second pressure difference transmitter; two pressure introducing ports are arranged on the horizontal pipe at intervals and are connected to a third pressure difference transmitter; the space between the two pressure introducing ports of the second pressure difference transmitter is equal to the space between the two pressure introducing ports of the third pressure difference transmitter; and signal output ends of the first pressure difference transmitter, the second pressure difference transmitter and the third pressure difference transmitter are connected to an integrating meter. The three-differential-pressure gas liquid two-phase fluid flow metering device has a compact structure, does not additional pressure loss, has wear resistance and high pressure resistance and is difficult to block, wherein the precision of the device can be controlled to be within 1 percent completely; a new idea is provided for solving the metering problems of gas liquid two-phase fluid; and the applicability and the precision of measuring a high-pressure high-flow-velocity medium are more excellent than those of the traditional mass flowmeter.

Description

Three differential pressure gas-liquid two-phase flow metering apparatus

Technical field

The present invention relates to a kind of fluid flow rate measurement apparatus, the particularly a kind of three differential pressure gas-liquid two-phase flow metering apparatus that can measure gas, liquid fluid-mixing.

Background technology

Common flow measurement device is merely able to the gas of constant density or the capable metering of liquid usually.But often run into the gas-liquid two-phase flow measuring problem in some industry spot.

For example saturated vapour metering, at uniform temp, liquid under pressure composition ratio can be from 0% (dry saturated steam) to 100% (wet saturated steam), fluid density changes very greatly, and tradition is according to temperature, the accurate bulk density of method of pressing the definite density of compensation.But owing to do not find feasible method, can only suppose a steam moisture, this is very big to the flowmeter accuracy influence, and humidity is big more, and error is big more.

Again for example, in petrochemical industry, the measurement of high-pressure carbon dioxide gas well rate of discharge also runs into this type of problem.Operating mode 25-30 ℃, the 7.0Mpa condition is gas-liquid mixed phase district just, and under high pressure like this, the subtle change of fluid heat content can cause gaseous state to transform mutually with liquid, and classic method is not sure of liquid ratio at all.Once wanted to use mass flowmeter in early days, but the too high cisco unity malfunction of hydrodynamic pressure can only estimate because of can not find the desired flow meter for many years, give produce, management brings a lot of inconvenience.

Publication number is that the one Chinese patent application of CN1609563A discloses a kind of gas, liquid two-phase flowmeter device; Can measure gas, liquid mixing material flow; Its structure is that a pressure difference transmitter and a common discharge meter are set respectively in the different transportation sections of liquid conducting pipes, and the measurement result of pressure difference transmitter and flowmeter is sent into integrating instrument and carried out gas and the fluid flow that computing obtains standard state.Though the measurement mechanism of this structure can carry out flow metering to gas, liquid two-phase, its measuring accuracy is still lower, and its error in dipping can be difficult to satisfy the request for utilization of Trade Measures up to more than 15%.In addition, because the use of common quantifier restriction, the WT-MSR of said structure only can measure the lower fluid of pressure, can't satisfy the request for utilization under the condition of high voltage.

Summary of the invention

Technical matters to be solved by this invention is, a kind of three differential pressure gas-liquid two-phase flow metering apparatus that hydrodynamic pressure is big, measuring accuracy is high of measuring of allowing are provided.

Three differential pressure gas-liquid two-phase flow metering apparatus of the present invention include internal diameter orthogonal one section horizontal tube and the one section VERTICAL TUBE consistent with the inner wall surface roughness, and horizontal tube is connected with the entrance and exit of a Bending Tube Sensor respectively with VERTICAL TUBE; The medial and lateral impulse mouth of Bending Tube Sensor is connected to first pressure difference transmitter through pressure guiding pipe respectively; On VERTICAL TUBE, be arranged at intervals with two impulse mouths, these two impulse mouths are connected to second pressure difference transmitter through pressure guiding pipe respectively; On horizontal tube, also be arranged at intervals with two impulse mouths, these two impulse mouths are connected to the 3rd pressure difference transmitter through pressure guiding pipe respectively; Two impulse mouth spacings of said second pressure difference transmitter are suitable with two impulse mouth spacings of the 3rd pressure difference transmitter; The signal output part of first pressure difference transmitter, second pressure difference transmitter and the 3rd pressure difference transmitter all is connected on the integrating instrument, by integrating instrument the testing result of each several part is iterated computing, obtains the fluid mass flow.

Device of the present invention is ingenious to utilize outside pressure difference Δ P1 and Bending Tube Sensor two side VERTICAL TUBE and the differential pressure value Δ P2 of horizontal tube generation in the 90 degree Bending Tube Sensors, the quality that Δ P3 directly measures the gas-liquid two-phase fluid; Its compact conformation, the loss of no additonal pressure, wear-resistant, high pressure resistant, the difficult obstruction; Its precision can be controlled in 1% fully; Solution to the gas-liquid two-phase flow measuring problem provides a kind of new thinking again, especially all is superior to the traditional quality flowmeter in applicability and the degree of accuracy of measuring high pressure high flow rate medium.

Description of drawings

Fig. 1 is the structural representation of apparatus of the present invention.

Embodiment

The inventive system comprises internal diameter orthogonal one section horizontal tube 1 and the one section VERTICAL TUBE 2 consistent with the inner wall surface roughness, horizontal tube is connected with the entrance and exit of a Bending Tube Sensor 3 respectively with VERTICAL TUBE; The medial and lateral impulse mouth of Bending Tube Sensor 3 is connected to first pressure difference transmitter 4 through pressure guiding pipe respectively; On VERTICAL TUBE, be arranged at intervals with two impulse mouths, these two impulse mouths are connected to second pressure difference transmitter 5 through pressure guiding pipe respectively; On horizontal tube, also be arranged at intervals with two impulse mouths, these two impulse mouths are connected to the 3rd pressure difference transmitter 6 through pressure guiding pipe respectively; Two impulse mouth spacings of second pressure difference transmitter are suitable with two impulse mouth spacings of the 3rd pressure difference transmitter; The signal output part of first pressure difference transmitter, second pressure difference transmitter and the 3rd pressure difference transmitter all is connected on the integrating instrument, by integrating instrument two-part testing result is iterated computing, obtains the fluid mass flow.

The measuring principle of apparatus of the present invention is following:

1. the force value that is recorded by two impulse mouths of second pressure difference transmitter is P ₁, P ₂, according to Bernoulli equation

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="101025131128.png"\; state="\{\{state\}\}">P</figure-callout>}}_1+\frac{1}{2}{\mathrm{\&rho;<figure-callout\; id="1"\; label="V"\; filenames="101025131128.png"\; state="\{\{state\}\}">V</figure-callout>}}_1^2+{\mathrm{\&rho;<figure-callout\; id="1"\; label="gh"\; filenames="101025131128.png"\; state="\{\{state\}\}">gh</figure-callout>}}_1={\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="101025131128.png"\; state="\{\{state\}\}">P</figure-callout>}}_2+\frac{1}{2}{\mathrm{\&rho;<figure-callout\; id="2"\; label="V"\; filenames="101025131128.png"\; state="\{\{state\}\}">V</figure-callout>}}_2^2+{\mathrm{\&rho;<figure-callout\; id="2"\; label="gh"\; filenames="101025131128.png"\; state="\{\{state\}\}">gh</figure-callout>}}_2+\mathrm{\&delta;P}$

Wherein, V ₁≈ V ₂

Drag losses between δ P---two impulse mouths

Following formula can be reduced to

P ₁+ρgh ₁＝P ₂+ρgh ₂+δP

P ₁-P ₂＝ρg(h ₂-h ₁)+δP

ΔP ₂＝ρgh+δP (1)

2. ask 1-2 friction loss δ P

Classic method is wanted to ask the Reynolds number under the different in flow rate according to fluid mechanics earlier, confirms the friction loss coefficient again, and then obtains friction loss.This computation process more complicated, and along with the difference of flow, Reynolds number and friction loss coefficient constantly change, can not be simply all with a coefficient representative.Flow is big more, and this contradiction is outstanding more.For this reason, device of the present invention has increased by the 3rd pressure difference transmitter, and the spacing of its impulse mouth is the same with the impulse mouth spacing of second pressure difference transmitter, friction loss too, the pressure that does not just have action of gravity that difference in height causes to produce.

Δ P then ₃=δ P (2)

3. ask the two-phase fluid density p

(1), (2) simultaneous:

ΔP ₂＝ρgh+δP＝ρgh+ΔP ₃

Draw $\mathrm{\&rho;}=\frac{\mathrm{\&Delta;}{P}_2-\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="3"\; label="P"\; filenames="101025131128.png"\; state="\{\{state\}\}">P</figure-callout>}}_3}{\mathrm{Gh}}---\left(3\right)$

4. rate of flow of fluid

According to the mathematical model of Bending Tube Sensor, utilize the differential pressure value Δ P1 in the outside in the elbowmeter to calculate

$v=\mathrm{C\&alpha;}(\mathrm{Re},\mathrm{Fr},\mathrm{Ma},\frac{R}{D},\frac{L_1}{D},\frac{L_2}{D},\frac{{\mathrm{\&lambda;}}_1}{D},\frac{{\mathrm{\&lambda;}}_2}{D},\frac{{\mathrm{\&lambda;}}_3}{D},\frac{{\mathrm{\&lambda;}}_4}{D},\frac{\mathrm{\&Delta;}}{D},{\mathrm{\&beta;}}_1,{\mathrm{\&beta;}}_2)\sqrt{\frac{\mathrm{\&Delta;p}1}{\mathrm{\&rho;}}}---\left(4\right)$

Wherein:

V is a flow velocity,

C α is experiment correction factor (0.996≤C≤1.004),

Re is a Reynolds number, the ratio of expression viscous force and inertial force,

Fr is the Fu Lude number, the ratio of expression gravity and inertial force,

Ma is a Mach number, the ratio of expression elastic force and inertial force,

R/D, L1/D, L2/D, λ 1/D, λ 2/D, λ 3/D, λ 4/D, Δ/D are the elbowmeter geometric feature, Δ p1 is the pressure differential of Bending Tube Sensor medial and lateral impulse mouth.

5. ask mass rate

(3), (4) simultaneous:

$Q=0.9\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="101025131128.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\mathrm{\&alpha;}\sqrt{\frac{R}{D}}\sqrt{\frac{{\mathrm{\&Delta;P}}_1({\mathrm{\&Delta;P}}_2-\mathrm{\&Delta;}{P}_3)}{\mathrm{gh}}}(t/h)$

Claims (1)

1. differential pressure gas-liquid two-phase flow metering apparatus; It is characterized in that: it includes the internal diameter orthogonal one section horizontal tube (1) consistent with the inner wall surface roughness and one section VERTICAL TUBE (2), and horizontal tube is connected with the entrance and exit of a Bending Tube Sensor (3) respectively with VERTICAL TUBE; The medial and lateral impulse mouth of Bending Tube Sensor (3) is connected to first pressure difference transmitter (4) through pressure guiding pipe respectively; On VERTICAL TUBE, be arranged at intervals with two impulse mouths, these two impulse mouths are connected to second pressure difference transmitter (5) through pressure guiding pipe respectively; On horizontal tube, also be arranged at intervals with two impulse mouths, these two impulse mouths are connected to the 3rd pressure difference transmitter (6) through pressure guiding pipe respectively; Two impulse mouth spacings of second pressure difference transmitter are the same with two impulse mouth spacings of the 3rd pressure difference transmitter; The signal output part of first pressure difference transmitter, second pressure difference transmitter and the 3rd pressure difference transmitter all is connected on the integrating instrument.

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