CN104390679A

CN104390679A - Device for calibrating quality flow exceeding allowable temperature of reference flowmeter and method adopting device

Info

Publication number: CN104390679A
Application number: CN201410584523.5A
Authority: CN
Inventors: 程迪; 孟令瑾; 范学军
Original assignee: Institute of Mechanics of CAS
Current assignee: Institute of Mechanics of CAS
Priority date: 2014-10-27
Filing date: 2014-10-27
Publication date: 2015-03-04
Anticipated expiration: 2034-10-27
Also published as: CN104390679B

Abstract

The invention discloses a device for calibrating quality flow exceeding allowable temperature of a reference flowmeter. The device comprises a high-temperature working medium supply unit, a cooling working medium supply measuring unit, a mixer and a medium-temperature working medium measuring unit, wherein a high-temperature working medium provided by the high-temperature working medium supply unit and a cooling working medium provided by the cooling working medium supply measuring unit are mutually soluble in the mixer and then the mixture reaches the medium-temperature working medium measuring unit; the high-temperature working medium supply unit comprises a first pressure gauge, a first thermometer and a to-be-calibrated quality flowmeter; the cooling working medium supply measuring unit comprises a second pressure gauge, a second thermometer and a first standard quality flowmeter; the medium-temperature working medium measuring unit comprises a third pressure gauge, a third thermometer and a second standard quality flowmeter. The invention also provides a method adopting the device.

Description

A kind of mass rate caliberating device and method exceeding reference stream gauge allowable temperature

Technical field

The invention belongs to the technical field of automation equipment and equipment, relate to a kind of mass rate caliberating device exceeding reference stream gauge allowable temperature particularly, and adopt the method for this device.

Background technology

In Aero-Space and petrochemical industry, often need to measure the mass rate under hot conditions, and traditional M-t method, its measuring accuracy depends critically upon the accurate measurement of t, and when carrying out high temperature large discharge mass flowmeter calibration, because the normal flow source working time is limited and high temperature valve shut-in time measuring accuracy is limited, bring exceptional hardship to demarcation.

And carrying out transmission timing signal, when particularly exceeding the operating temperature range of existing standard mass flow meter, need heat working medium between two flowmeters or cool, larger heat exchange power and larger heat interchanger internal volume is needed when large discharge, the former can increase calibration cost, and the latter can improve to the stability requirement of traffic sources with to the requirement of demarcating T.T. (i.e. total flow).

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, and provide a kind of mass rate caliberating device exceeding reference stream gauge allowable temperature, it is simple to operate, efficiency is high and cost is low.

Technical solution of the present invention is: this mass rate caliberating device exceeding reference stream gauge allowable temperature, this device comprises high temperature refrigerant feeding unit, cooling working medium supply measuring unit, mixer, middle temperature working medium measuring unit, middle temperature working medium measuring unit is reached after the high temperature refrigerant provided by high temperature refrigerant feeding unit and the cooling working medium supplied measuring unit provided by cooling working medium dissolve each other in a mixer, high temperature refrigerant feeding unit comprises the first tensimeter, first thermometer, mass flowmeter to be calibrated, cooling working medium supply measuring unit comprises the second tensimeter, second thermometer, first standard mass flow meter, middle temperature working medium measuring unit comprises the 3rd tensimeter, 3rd thermometer, second standard mass flow meter.

Additionally provide and adopt the above method exceeding the mass rate caliberating device of reference stream gauge allowable temperature, comprise the following steps:

(1) close high temperature refrigerant supply measuring unit, open cooling working medium supply measuring unit and middle temperature working medium measuring unit, first and second standard mass flow meter is returned to zero;

(2) according to the high temperature refrigerant flow of expection, select suitable cooling working medium flow, ensure that the high temperature refrigerant flow demarcated has minimum relative error, guarantee that the second tensimeter numerical value and the 3rd tensimeter numerical value are all lower than the first tensimeter numerical value simultaneously;

(3) open high temperature refrigerant supply measuring unit, monitor that the 3rd thermometer numerical value is to ensure that the second standard mass flow is not damaged, if the 3rd thermometer numerical value exceedes specify limit value, cut off high temperature refrigerant supply measuring unit; If do not exceed, stable state to be achieved, records the reading of the first tensimeter numerical value, the first thermometer numerical value and first and second standard mass flow meter;

(4) close high temperature refrigerant supply measuring unit, after the fixed time of interval, close cooling working medium supply measuring unit and middle temperature working medium measuring unit;

(5) deducted the reading of the first standard mass flow meter by the reading of the second standard mass flow meter, obtain the numerical value of mass flowmeter to be calibrated.

According to conservation of energy principle, the fluid utilizing low temperature to dissolve each other and high temperature fluid blending to be calibrated obtain can the middle temperature fluid of direct measurement quality flow, wherein T ₁> T _limit> T ₃> T ₂, wherein T ₁for the temperature of high temperature refrigerant, T _limitfor the rated temperature of mass flowmeter to be calibrated, T ₃for the temperature of middle temperature working medium, T ₂for the temperature of cooling working medium.So the temperature of middle temperature working medium of the present invention can not exceed the rated temperature of mass flowmeter to be calibrated, so just ensure that the present invention can realize.By the present invention, cooling working medium is mixed mutually with high temperature refrigerant, obtain middle temperature working medium, adopt the flow of standard mass flow measurement amount cooling working medium, middle temperature working medium again, just obtain the flow of high temperature refrigerant to be measured after subtracting each other, operate more simply relative to existing apparatus and method, efficiency is higher and cost is lower.

Accompanying drawing explanation

Fig. 1 shows according to the structural representation exceeding the mass rate caliberating device of reference stream gauge allowable temperature of the present invention;

Fig. 2 is the minimum relative error line of cooling working medium flow;

Fig. 3 shows according to the schematic diagram exceeding the mass rate scaling method of reference stream gauge allowable temperature of the present invention;

Fig. 4 shows according to the structural representation exceeding a mass rate caliberating device preferred embodiment of reference stream gauge allowable temperature of the present invention.

Embodiment

Fig. 1 shows according to the structural representation exceeding the mass rate caliberating device of reference stream gauge allowable temperature of the present invention.As can be seen from Figure 1, this mass rate caliberating device exceeding reference stream gauge allowable temperature, this device comprises high temperature refrigerant feeding unit, cooling working medium supply measuring unit, mixer, middle temperature working medium measuring unit, middle temperature working medium measuring unit is reached after the high temperature refrigerant provided by high temperature refrigerant feeding unit and the cooling working medium supplied measuring unit provided by cooling working medium dissolve each other in a mixer, high temperature refrigerant feeding unit comprises the first tensimeter P1, first thermometer T1, mass flowmeter to be calibrated, cooling working medium supply measuring unit comprises the second tensimeter P2, second thermometer T2, first standard mass flow meter, middle temperature working medium measuring unit comprises the 3rd tensimeter P3, 3rd thermometer T3, second standard mass flow meter.

In addition, in order to enable cooling working medium dissolve each other under demarcation ratio with high temperature refrigerant better, high temperature refrigerant and cooling working medium are same substances.

In addition, mixer comprises a threeway, and first, second and third mouth of pipe of threeway connects high temperature refrigerant feeding unit, cooling working medium supply measuring unit, middle temperature working medium measuring unit respectively; The caliber of second mouth of pipe is little, to make the cooling working medium entered in threeway remain on turbulence state.

In addition, cooling working medium supply measuring unit is connected to described second mouth of pipe by a straight tube, and the length of straight tube is 10 times of the caliber of straight tube.Can ensure to enter cooling working medium in threeway like this at turbulence state.

In addition, this device also comprises working medium collector unit, and it is connected with middle temperature working medium measuring unit.If the potpourri after such cooling meets the demands can be re-used as cryogenic fluid use, can be cost-saving, and environmental protection.

(2) according to the high temperature refrigerant flow of expection, select suitable cooling working medium flow (can select according to Fig. 2), ensure that the high temperature refrigerant flow demarcated has minimum relative error, guarantee that the second tensimeter numerical value and the 3rd tensimeter numerical value are all lower than the first tensimeter numerical value simultaneously;

(5) according to the principle of mass conservation, deducted the reading of the first standard mass flow meter by the reading of the second standard mass flow meter, obtain the numerical value of mass flowmeter to be calibrated.

In addition, cooling working medium flow is selected according to the minimum relative error line of Fig. 2, the relative error of calibrational capacity can be made to minimize, in step (2), select suitable cooling working medium flow, to minimize the relative error of the mass rate to be calibrated calculated according to formula (1)

e_{1} = \frac{Δ {\overset{\cdot}{m}}_{1}}{{\overset{\cdot}{m}}_{1}} = \frac{\sqrt{e_{2}^{2} {\overset{\cdot}{m}}_{2}^{2} + e_{3}^{2} {({\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2})}^{2}}}{{\overset{\cdot}{m}}_{1}} - - - (1)

Wherein e represents relative error, represent mass rate, represent the measured deviation of mass rate, subscript 1,2,3 represents high-temperature medium, cryogenic media and mixed middle temperature medium respectively, and requiredly when carrying out littleization most satisfied is constrained to formula (2):

\{\begin{matrix} {\overset{\cdot}{m}}_{3} = {\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2} \\ Δ {\overset{\cdot}{m}}_{1} = \sqrt{Δ {\overset{\cdot}{m}}_{2}^{2} + Δ {\overset{\cdot}{m}}_{3}^{2}} \\ Δ {\overset{\cdot}{m}}_{2} = e_{2} {\overset{\cdot}{m}}_{2} \\ Δ {\overset{\cdot}{m}}_{3} = e_{3} {\overset{\cdot}{m}}_{3} \\ {\overset{\cdot}{m}}_{1} h_{1} + {\overset{\cdot}{m}}_{2} h_{2} = {\overset{\cdot}{m}}_{3} h_{3} (T_{3}) \\ {\overset{\cdot}{m}}_{1} > 0 \\ {\overset{\cdot}{m}}_{2, \min} < {\overset{\cdot}{m}}_{2} < {\overset{\cdot}{m}}_{2, \max} \\ {\overset{\cdot}{m}}_{3, \min} < {\overset{\cdot}{m}}_{3} < {\overset{\cdot}{m}}_{3, \max} \\ T_{3} < T_{3, \max} \end{matrix} - - - (2)

Wherein h represents the specific enthalpy of fluid, and T represents the temperature of fluid, subscript _{min, max}represent lower limit and the upper limit respectively.Its feasible zone as shown in Figure 2, and to e ₁differentiate and can obtain:

\frac{&PartialD; e_{1}}{&PartialD; {\overset{\cdot}{m}}_{1}} = - \frac{{\overset{\cdot}{m}}_{2} (e_{2}^{2} {\overset{\cdot}{m}}_{2} + e_{3}^{2} ({\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2}))}{{\overset{\cdot}{m}}_{1}^{2} \sqrt{e_{2}^{2} {\overset{\cdot}{m}}_{2}^{2} + e_{3}^{2} {({\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2})}^{2}}} < 0

\frac{&PartialD; e_{1}}{&PartialD; {\overset{\cdot}{m}}_{2}} = \frac{e_{2}^{2} {\overset{\cdot}{m}}_{2} + e_{3}^{2} ({\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2})}{{\overset{\cdot}{m}}_{1} \sqrt{e_{2}^{2} {\overset{\cdot}{m}}_{2}^{2} + e_{3}^{2} {({\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2})}^{2}}} > 0

So in high-temperature medium flow one timing, the cryogenic media flow mixed with it is less, and the relative error of the demarcation of this kind of method is less, considering the inequality constrain in formula (2), can obtain the minimum relative error line in Fig. 2.

According to conservation of energy principle, the fluid utilizing low temperature to dissolve each other and high temperature fluid blending to be calibrated obtain can the middle temperature fluid of direct measurement quality flow, wherein T ₁> T _limit> T ₃> T ₂, wherein T ₁for the temperature of high temperature refrigerant, T _limitfor the rated temperature of mass flowmeter to be calibrated, T ₃for the temperature of middle temperature working medium, T ₂for the temperature of cooling working medium.So the temperature of middle temperature working medium of the present invention can not exceed the rated temperature of mass flowmeter to be calibrated, so just ensure that the present invention can realize.Fig. 3 shows according to the schematic diagram exceeding the mass rate scaling method of mass flow meter temperature scope of the present invention.By the present invention, cooling working medium is mixed into high temperature refrigerant, obtain middle temperature working medium, adopt the flow of standard mass flow measurement amount cooling working medium, middle temperature working medium again, just obtain the flow of high temperature refrigerant to be measured after subtracting each other, operate more simply relative to existing apparatus and method, efficiency is higher and cost is lower.

Fig. 4 shows according to the structural representation exceeding mass rate caliberating device preferred embodiment (caliberating device of supercritical kerosene sonic nozzle flowmeter) of mass flow meter temperature scope of the present invention.This device is made up of high temperature refrigerant feeding unit, cooling working medium supply measuring unit, mixer, middle temperature working medium measuring unit, working medium collector unit.

Concrete operation step is as follows:

1. close high temperature oil valve V1, open cold oil valve V2 and miscella valve V3, open cold oil ram pump, first fill cold oil by pipeline, then close cold oil ram pump, and V2 and V3 is closed, mass flowmeter MF2 and MF3 is returned to zero;

2. then open V2, V3, open cold oil ram pump, according to the deep fat flow of expection, select suitable cold oil flow according to Fig. 2, ensure that demarcation has minimum relative error, guarantee that P2 and P3 is lower than P1 simultaneously;

3. pass into deep fat from deep fat entrance, open V1, pass into deep fat, monitor that T3 ensures that MF3 is not damaged, if T3 transfinites cut off V1 immediately, stable state to be achieved, records P1, T1 and MF3, MF2 reading;

4. close V1, treat that ducted heat taken away by cold oil, close cold oil ram pump, close V2, V3;

5. repeat said process, obtain the supercritical kerosene sonic nozzle flowmeter flow MF1=MF3-MF2 in different P1, T1 situation.

The above; it is only preferred embodiment of the present invention; not any pro forma restriction is done to the present invention, every above embodiment is done according to technical spirit of the present invention any simple modification, equivalent variations and modification, all still belong to the protection domain of technical solution of the present invention.

Claims

1. one kind exceeds the mass rate caliberating device of reference stream gauge allowable temperature, it is characterized in that: this device comprises high temperature refrigerant feeding unit, cooling working medium supply measuring unit, mixer, middle temperature working medium measuring unit, middle temperature working medium measuring unit is reached after the high temperature refrigerant provided by high temperature refrigerant feeding unit and the cooling working medium supplied measuring unit provided by cooling working medium dissolve each other in a mixer, high temperature refrigerant feeding unit comprises the first tensimeter, first thermometer, mass flowmeter to be calibrated, cooling working medium supply measuring unit comprises the second tensimeter, second thermometer, first standard mass flow meter, middle temperature working medium measuring unit comprises the 3rd tensimeter, 3rd thermometer, second standard mass flow meter.

2. the mass rate caliberating device exceeding reference stream gauge allowable temperature according to claim 1, is characterized in that: described high temperature refrigerant and described cooling working medium are the materials that can dissolve each other completely.

3. the mass rate caliberating device exceeding reference stream gauge allowable temperature according to claim 2, it is characterized in that: described mixer comprises a threeway, first, second and third mouth of pipe of threeway connects high temperature refrigerant feeding unit, cooling working medium supply measuring unit, middle temperature working medium measuring unit respectively; The caliber of second mouth of pipe is little, to make the cooling working medium entered in threeway remain on turbulence state.

4. the mass rate caliberating device exceeding reference stream gauge allowable temperature according to claim 3, is characterized in that: cooling working medium supply measuring unit is connected to described second mouth of pipe by a straight tube, and the length of straight tube is 10 times of the caliber of straight tube.

5. the mass rate caliberating device exceeding reference stream gauge allowable temperature according to claim 1, is characterized in that: this device also comprises working medium collector unit, and it is connected with middle temperature working medium measuring unit.

6. adopt the method exceeding the mass rate caliberating device of reference stream gauge allowable temperature according to claim 1, it is characterized in that: comprise the following steps:

7. method according to claim 6, is characterized in that: in step (2), selects suitable cooling working medium flow, to minimize the relative error of the mass rate to be calibrated calculated according to formula (1),

e_{1} = \frac{Δ {\overset{\cdot}{m}}_{1}}{{\overset{\cdot}{m}}_{1}} = \frac{\sqrt{e_{2}^{2} {\overset{\cdot}{m}}_{2}^{2} + e_{3}^{2} {({\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2})}^{2}}}{{\overset{\cdot}{m}}_{1}} - - - (1)

\{\begin{matrix} {\overset{\cdot}{m}}_{3} = {\overset{\cdot}{m}}_{1} + {\overset{\cdot}{m}}_{2} \\ Δ {\overset{\cdot}{m}}_{1} = \sqrt{Δ {\overset{\cdot}{m}}_{2}^{2} + Δ {\overset{\cdot}{m}}_{3}^{2}} \\ Δ {\overset{\cdot}{m}}_{2} = e_{2} {\overset{\cdot}{m}}_{2} \\ Δ {\overset{\cdot}{m}}_{3} = e_{3} {\overset{\cdot}{m}}_{3} \\ {\overset{\cdot}{m}}_{1} h_{1} + {\overset{\cdot}{m}}_{2} h_{2} = {\overset{\cdot}{m}}_{3} h_{3} (T_{3}) \\ {\overset{\cdot}{m}}_{1} > 0 \\ {\overset{\cdot}{m}}_{2, \min} < {\overset{\cdot}{m}}_{2} < {\overset{\cdot}{m}}_{2, \max} \\ {\overset{\cdot}{m}}_{3, \min} < {\overset{\cdot}{m}}_{3} < {\overset{\cdot}{m}}_{3, \max} \\ T_{3} < T_{3, \max} \end{matrix} - - - (2)

Wherein h represents the specific enthalpy of fluid, and T represents the temperature of fluid, subscript _{min, max}represent lower limit and the upper limit respectively.