JB/T 3596-2001 Water jet vacuum pump performance test procedure

This standard specifies the performance test method of water jet vacuum pumps for condensing equipment to remove air and other non-condensable gases. It is used to determine the relationship between the dry air flow rate and the suction side pressure under different working water pressures and temperatures, and the power consumption of the vacuum pump. JB/T 3596-2001 Performance test procedures for water jet vacuum pumps JB/T3596-2001 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T3596
惰稀·無
2001-05-23
2001-10-01小
JB/T3596
This standard is based on the provisions of GB/T1.1-1993 Standardization Work Guide Unit 1: Rules for Drafting and Presentation of Standards Part 1: Basic Provisions for Standard Writing. It amends the format of the original standard JB/T3596-1984, confirms the content, and converts the relevant formulas using legal units. From the date of implementation, this standard will replace JBT3596-1984. This standard is proposed and managed by the National Steam Turbine Standardization Technical Committee. This standard is under the responsibility of Shanghai Power Generation Equipment Complete Design Institute, and Beijing Heavy Duty Automatic Machinery Factory participated in the drafting. The main drafters of this standard are: Liu Chen, Teng Wei. This standard was first issued in March 1984:
JB/T35962001
JB/T35961984
This standard specifies the performance test method of water jet vacuum pump (hereinafter referred to as vacuum pump) for extracting air and other non-condensable gases from condensing equipment, which is used to determine the relationship between the dry air flow rate and the suction side output H under different working water pressures and temperatures, and the power consumption of the vacuum pump.
This standard is applicable to the vacuum pump of the steam turbine condensing equipment of thermal power stations. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. Parties using this standard should discuss the possibility of using the latest versions of the following standards. GB/T1800.3-1998 Limits and fits Part 3 Standard norms and basic deviations (eg VIS0 2861: 1998) Flow measurement Throttling devices use orifice plates, nozzles and vents to measure the flow of fluids filling a circular tube GB/T 2624-1993 Flow (eq IS0 5167: 1991) 3 Definitions This standard adopts the following definitions: 3.1 Capacity The mass of dry air sucked from the water jet aerator suction space per unit time under design conditions. 3.21 Working wafer pressure The static pressure of the working water before the nozzle in the water chamber of the water jet aerator, expressed in absolute units. 3.3TworkingwaterterriperatureThe working water temperature at the inlet of the water jet exhauster water chamber. 3.4Suction pressuresuctionpressure
The pressure of the gas being pumped at the suction port of the water jet exhauster (D in front of the inlet pipe flange, or 610mm), expressed in absolute units.
3. 5Suction temperature
suction temperature.
The temperature of the gas being pumped at the suction port of the water jet exhauster. 3.6Discharge pressuredischargepressureThe static pressure of the discharge at the exhauster outlet (100mm below the outlet flange of the diffuser), expressed in absolute units. 4.1 The service parties participating in the test shall reach an agreement on the following matters of the test: a) Responsible for providing and installing instruments and equipment that comply with this regulation; b) The vacuum pump performance test can be carried out in the power plant (or manufacturer). If the vacuum pump configured by the power plant is used, the vacuum pump must be disconnected from the unit during the test, and the test conditions should meet the requirements of the manufacturer: e) Test purpose and required measurements:
d) Determination of test instruments:
e) Measurement method of vacuum capacity and working water flow:} The time interval between the commissioning and acceptance test of the vacuum pump; g) Error calculation of test results and the maximum allowable error, 4. 2 Preparation before the test is as follows:
a) Determine the layout of the test measurement points and install various instruments according to the location of the measurement points; b) All instruments should be calibrated before the test and can only be used after passing the test. Instruments that have a great influence on the test results must be recalibrated after the test:
) After the various instruments and related equipment are installed, the vacuum system of the entire test device is put into a tightness test. The water pressure test method can be used to check the leakage of each interface. The general test water pressure is 1.5 times the positive working pressure, and the vacuum system is 0.2MPa. The test can be carried out only after confirming that the interface is tight and leak-free. 4.3 The parties participating in the test should determine an arbitrator to command the test and make observations or the reliability of the operation method. 4.4 During the test period, representatives of any party can be on site to ensure that the test is carried out in accordance with this procedure and previous agreements. 4.5 The test system and instruments can be checked through preliminary tests to confirm that they are suitable for the test state. 4.6 If it meets the requirements of this test procedure and is agreed by all parties to the test, the preliminary test can be used as a formal test. 4.7 Before the test, the operation should be stable and the operating state should be as close to the design requirements as possible. 4.8 When doing the dry air suction performance test, each time the air measurement nozzle is replaced, it must be stable for 5min before measurement. 4.9 The readings of each test condition should be recorded at the same time. 4.10 Before the test, a unified test record sheet shall be used for each test condition and each test item, and the test record sheet shall be numbered, with the date, time and test item indicated.
4.11 During the test, if any abnormal phenomenon is found, it shall be reported to the test leader immediately and recorded in the remarks. 4.12 When collating and calculating the data, the reliability and consistency of each measured value shall be checked first. When the data is found to have a problem, this part of the data shall be partially or completely invalidated, and the test shall be repeated if necessary. 4.13 Error calculations shall be made for various measured values ​​and explained in the test report. 5 Measuring instruments and measurement methods
5.1 Pressure measurement
5.1.1 Measurement of suction pressure of the vacuum pump and discharge pressure at the outlet of the diffuser 5.1.1.1 When measuring the suction limit pressure, there shall be no less than 2 measuring points, located on the same cross section and at a 90-degree angle to each other, and installed near the inlet of the vacuum pump, as shown in Figure 1. The diameter of the pressure hole on the pipe is 6mm~8mm, and the inner wall of the pipe at the pressure hole should be free of burrs.
5.1 1.2 The meter can use a U-type mercury differential meter, and the instrument should have a scale with a reading of 1 mm. Or a pressure sensor or other pressure gauge with equivalent accuracy level 2
JB/T35962001
5.1,1.3 The pressure measuring point of the diffuser outlet can be determined according to the test needs. The pressure hole is the same as 5.1.1.1, and the gauge is 5.1.1.2. 5.1.2 Working water pressure measurement
The working water pressure is measured in reverse at the water pressure measuring point. The gauge is a 0.4-level spring pressure gauge: 5.1.3 Air pressure measurement
Use a precision barometer such as a mercury barometer or other barometers certified as correct and applicable by the metrology department to measure the atmospheric pressure value on site
5.2 Temperature measurement
The working water temperature, atmospheric temperature and the ambient temperature at the dry air intake point are all measured using a 0.1-scale glass mercury thermometer or a platinum resistance thermometer or thermocouple with equivalent accuracy level. a) The measuring point of working water temperature should be set on the pipe near the water chamber inlet: b) For atmospheric temperature measurement, the thermometer should be placed near the atmospheric pressure gauge: ) For ambient temperature measurement at the dry air intake, the thermometer should be installed near the inlet of the air measuring device. 5.3 Flow measurement
5.3.1 Air flow measurement
5.3.1.1 Requirements for air flow measuring device a) Standard air measuring nozzle is generally used to measure single air flow. Before testing, the vacuum pump is disconnected from the unit, the connecting pipe is removed, and the device of the cabinet 2 is installed:
b The diameter D of the air intake pipe should not be less than the diameter of the air intake port of the vacuum pump, and the minimum length L is 5 times the pipe diameter D.
Earn pressure, spread pressure
Thank you point one should be 97%
See Figure 2 Air measuring device
JB/T35962001
D,-610
D-Water pipe diameter: P.-Working water pressure: 1-Working water temperature: P~-Air flow rate Air pressure after spraying (suction pressure): P,-Discharge pressure: D--Air measuring device pipe connection pipe diameter: 1-Water chamber: 2-Working end: 3.-Water suction chamber: 4-Condensation part: 5-Expansion pipe: 6-Water tank: 7 Water jet pump: 8-Air measuring device cover Figure 1 Schematic diagram of the system and measurement point arrangement of the water jet vacuum pump test device Air measurement nozzle
Air intensity point
5.3.1.2 Requirements for air measuring nozzles
JB/T35962001
Positive spray force, two remaining points with the same weakness 50u-
Figure 2 Air flow measurement device
To the air heater
5. 3. 1. 2.1 The air measuring nozzle with a throat diameter of d-1.6 nm~2.5 mm shall be designed and manufactured according to Figure 3 and shall comply with the following regulations:
a) The nozzle material shall be selected with high wear resistance and corrosion resistance, stainless steel or phosphorus blue is recommended: b) The nozzle profile is shown in Figure 3, the outlet section shall remain cylindrical, there shall be no contraction section or diffusion section, and the outlet end shall remain sharp. The inlet section should smoothly transition with the cylindrical part, and the maximum value of the inner hole surface roughness R is 0.8uⅢ; c) The difference value of the nozzle throat diameter d shall be in accordance with the tolerance grade [T7 of GB/T1800.3-19984I3.2 (Table 1). The basic deviation value of the hole during processing is H7:
JB/T35962001
Figure 3 Dimensions of air measuring nozzles with a diameter of 1.6 to 25 mm d) The round line of the nozzle should be made accurate, and the sample knife should be used for processing: e) After the nozzle is manufactured, its actual diameter should be measured and printed. 5.3.1.2.2 Air measuring nozzles with a throat diameter of 3 mm to 66 mm (as shown in Figure 4) can also be ordered from the special manufacturing department.
Figure 4 Dimensions of air measuring nozzles with diameters of 3mm~66m 5.3.1.3 Calculation of air measuring nozzles
a) When the nozzle front-to-back pressure ratio is equal to or less than the critical pressure ratio (rF/P≤0.528), the nozzle diameter α is calculated using the following dry air flow g (kg/h) formula.
q=0.001935ad2/P./V
Where: 8--Flow coefficient (±1.6cL~25mm) is obtained from Figure 5. The Murnow number Re in Figure 5 is calculated as follows:
is the absolute viscosity of air (Pa·s) obtained from Figure 6 or obtained by the following approximate formula. ×106-17.21-4.67 (t/100) -0.217(t/100)2 (where 1 is the air temperature, 20°C for one stream) (2)
d nozzle throat diameter, mm
P. Absolute air pressure before the nozzle, Pa:
Y-specific volume of air before the nozzle, m/kg.
JB/T35962001
b) If the pressure ratio before and after the nozzle is equal to the critical pressure ratio, the nozzle diameter d is calculated according to the following dry air flow rate (kg/h) formula:
9-0. 003998a d2/P -P)/V -.
- expansion coefficient, which can be found according to Figure 7 or calculated by the following approximate formula; where
=0.271+0.932r-0.203
P——absolute pressure of air outside the nozzle, Pa
5.3.2 Working water flow measurement
Ding The working water flow rate can be determined by one of the following methods: (3)
a) Throttling flow measurement device of standard orifice plate or nozzle. The construction principle and calculation of the throttling device shall comply with the provisions of GB 2624;
Turbine flowmeter:
c) Pitot tube:
d) Superluper flowmeter.
5.4 Measurement of power consumption of the aspirator and the water pump a) The power consumption of the aspirator can be calculated based on the working water flow and pressure measured in the test; b) The power consumption of the water pump is measured with a 0.5-level three-phase power meter. 5.6 Noise measurement
a) Noise measurement can be measured by sound level, generally measuring A sound pressure level. When measuring, the sound level meter is placed 1m away from the aspirator:
b) The noise measurement point should be at the largest part of the sound source section of the aspirator; c) When measuring noise, attention should be paid to the influence of background (or background) noise, and repair should be made at the same time. 8
JB/T35962001
25681u
Figure 5 Nozzle flow coefficient
34568105
Reynolds number P
Select u formula, 106 17.21 +4.67(1d
- G.217 (-
Absolute viscosity of air
Air viscosity
JB/T35962001
Output temporary part
5:0 yuan
6 Arrangement and calculation of test data
JB/T35962001
6. 1 When calculating the test data, all test data should be sorted out first. If any abnormality is found in the data, the recorder should be consulted before analysis and judgment.
6.2 When calculating the test data, all measured values ​​should be corrected. 6.3 When calculating the test data, the table of thermodynamic properties of water vapor should use the chart or updated version based on the 1967 positive C formula approved by the Seventh International Conference on the Properties of Water Vapor in 1968 as much as possible. This should be explained in the test report. 6.4 Dry air flow 4 (kg/h)
To facilitate the calculation of test data, when the pressure before and after the nozzle When the pressure is equal to or less than the critical pressure ratio, the dry air flow can also be calculated by the formula (4) obtained by converting the formula (1).
Where: α-
9=0.03671
Flow coefficient is based on the actual calibration value:
Nozzle throat diameter, cm:
/10.288(t+273)
Local atmospheric pressure after temperature correction, Pa (absolute): PA
Ambient temperature at the inhaled air during the test, °C. 6.5 When using a mercury gas pressure gauge, the corrected local atmospheric pressure, P, (Pa) P, -133.32Bu[1- (c}-) tm]
Where: B
Local atmospheric pressure at temperature, mmHg:
Expansion coefficient of mercury, 0.000815/℃: -Linear expansion coefficient of brass ruler, 0.000019/℃ (preferably steel ruler, =0.000012/℃): Local atmospheric vortex during the test, ℃.
6.6 When using a mercury differential pressure gauge, the aerator suction pressure P, (Pa)P, =P--133.32[H(I-aitH+0.0735 (h,-h,)1Wu Zhong: H
The difference of mercury columns of mercury differential pressure gauge at temperature t, mmHg: —The height of water column on vacuum side of U-tube mercury differential pressure gauge, mmH,O:,
hThe quotient of water column on atmosphere side of U-tube mercury differential pressure gauge, mmH,O: The air temperature during test, ℃.
If only one water temperature test is carried out: For design water temperature or other water temperature, the following formula can be used to convert the suction side pressure P (Pa) P%=Pt-(PP)
Where: —
The suction pressure of test water temperature, Pa (absolute); Pr
The saturation pressure corresponding to the test water temperature, Pa (absolute); P\set —The saturation pressure corresponding to the design water temperature, Pa (absolute). 6.7 Working water volume of vacuum pump g
If the test equipment is a standard orifice plate, nozzle or Pitot tube, the working water volume of vacuum pump shall be calculated according to the flow calculation formula of the test equipment selected in the design.
6.8 Power consumption of the vacuum pump (kw)
Calculate the power consumption of the vacuum pump according to the measured working water volume and pressure of the vacuum pump. N,-g[ (P.-P.) ×10-+9.8Hr1-*Where: 9——Working water volume flow, m2/sP. Working water pressure, Pa528), the nozzle diameter α is calculated by the following dry air flow g (kg/h) formula.
q=0.001935ad2/P./V
Wherein: 8--Flow coefficient (±1.6cL～25mm) is obtained from Figure 5. The Murnow number Re in Figure 5 is calculated as follows:
is the absolute viscosity of air (Pa·s) is obtained from Figure 6 or calculated by the following approximate formula. ×106-17.21-4.67 (t/100) -0.217(t/100)2 (where 1 is the air temperature, one stream is taken as 20°℃) (2)
d nozzle throat diameter, mm
P. Absolute air pressure before the nozzle, Pa:
Y-specific volume of air before the nozzle, m/kg.
JB/T35962001
b) If the pressure ratio before and after the nozzle is equal to the critical pressure ratio, the nozzle diameter d is calculated according to the following dry air flow rate (kg/h) formula:
9-0. 003998a d2/P -P)/V -.
- expansion coefficient, which can be found according to Figure 7 or calculated by the following approximate formula; where
=0.271+0.932r-0.203
P——absolute pressure of air outside the nozzle, Pa
5.3.2 Working water flow measurement
Ding The working water flow rate can be determined by one of the following methods: (3)
a) Throttling flow measurement device of standard orifice plate or nozzle. The construction principle and calculation of the throttling device shall comply with the provisions of GB 2624;
Turbine flowmeter:
c) Pitot tube:
d) Superluper flowmeter.
5.4 Measurement of power consumption of the aspirator and the water pump a) The power consumption of the aspirator can be calculated based on the working water flow and pressure measured in the test; b) The power consumption of the water pump is measured with a 0.5-level three-phase power meter. 5.6 Noise measurement
a) Noise measurement can be measured by sound level, generally measuring A sound pressure level. When measuring, the sound level meter is placed 1m away from the aspirator:
b) The noise measurement point should be at the largest part of the sound source section of the aspirator; c) When measuring noise, attention should be paid to the influence of background (or background) noise, and repair should be made at the same time. 8
JB/T35962001
25681u
Figure 5 Nozzle flow coefficient
34568105
Reynolds number P
Select u formula, 106 17.21 +4.67(1d
- G.217 (-
Absolute viscosity of air
Air viscosity
JB/T35962001
Output temporary part
5:0 yuan
6 Arrangement and calculation of test data
JB/T35962001
6. 1 When calculating the test data, all test data should be sorted out first. If any abnormality is found in the data, the recorder should be consulted before analysis and judgment.
6.2 When calculating the test data, all measured values ​​should be corrected. 6.3 When calculating the test data, the table of thermodynamic properties of water vapor should use the chart or updated version based on the 1967 positive C formula approved by the Seventh International Conference on the Properties of Water Vapor in 1968 as much as possible. This should be explained in the test report. 6.4 Dry air flow 4 (kg/h)
To facilitate the calculation of test data, when the pressure before and after the nozzle When the pressure is equal to or less than the critical pressure ratio, the dry air flow can also be calculated by the formula (4) obtained by converting the formula (1).
Where: α-
9=0.03671
Flow coefficient is based on the actual calibration value: bzxZ.net
Nozzle throat diameter, cm:
/10.288(t+273)
Local atmospheric pressure after temperature correction, Pa (absolute): PA
Ambient temperature at the inhaled air during the test, °C. 6.5 When using a mercury gas pressure gauge, the corrected local atmospheric pressure, P, (Pa) P, -133.32Bu[1- (c}-) tm]
Where: B
Local atmospheric pressure at temperature, mmHg:
Expansion coefficient of mercury, 0.000815/℃: -Linear expansion coefficient of brass ruler, 0.000019/℃ (preferably steel ruler, =0.000012/℃): Local atmospheric vortex during the test, ℃.
6.6 When using a mercury differential pressure gauge, the aerator suction pressure P, (Pa)P, =P--133.32[H(I-aitH+0.0735 (h,-h,)1Wu Zhong: H
The difference of mercury columns of mercury differential pressure gauge at temperature t, mmHg: —The height of water column on vacuum side of U-tube mercury differential pressure gauge, mmH,O:,
hThe quotient of water column on atmosphere side of U-tube mercury differential pressure gauge, mmH,O: The air temperature during test, ℃.
If only one water temperature test is carried out: For design water temperature or other water temperature, the following formula can be used to convert the suction side pressure P (Pa) P%=Pt-(PP)
Where: —
The suction pressure of test water temperature, Pa (absolute); Pr
The saturation pressure corresponding to the test water temperature, Pa (absolute); P\set —The saturation pressure corresponding to the design water temperature, Pa (absolute). 6.7 Working water volume of vacuum pump g
If the test equipment is a standard orifice plate, nozzle or Pitot tube, the working water volume of vacuum pump shall be calculated according to the flow calculation formula of the test equipment selected in the design.
6.8 Power consumption of the vacuum pump (kw)
Calculate the power consumption of the vacuum pump according to the measured working water volume and pressure of the vacuum pump. N,-g[ (P.-P.) ×10-+9.8Hr1-*Where: 9——Working water volume flow, m2/sP. Working water pressure, Pa528), the nozzle diameter α is calculated by the following dry air flow g (kg/h) formula.
q=0.001935ad2/P./V
Wherein: 8--Flow coefficient (±1.6cL～25mm) is obtained from Figure 5. The Murnow number Re in Figure 5 is calculated as follows:
is the absolute viscosity of air (Pa·s) is obtained from Figure 6 or calculated by the following approximate formula. ×106-17.21-4.67 (t/100) -0.217(t/100)2 (where 1 is the air temperature, one stream is taken as 20°℃) (2)
d nozzle throat diameter, mm
P. Absolute air pressure before the nozzle, Pa:
Y-specific volume of air before the nozzle, m/kg.
JB/T35962001
b) If the pressure ratio before and after the nozzle is equal to the critical pressure ratio, the nozzle diameter d is calculated according to the following dry air flow rate (kg/h) formula:
9-0. 003998a d2/P -P)/V -.
- expansion coefficient, which can be found according to Figure 7 or calculated by the following approximate formula; where
=0.271+0.932r-0.203
P——absolute pressure of air outside the nozzle, Pa
5.3.2 Working water flow measurement
Ding The working water flow rate can be determined by one of the following methods: (3)
a) Throttling flow measurement device of standard orifice plate or nozzle. The construction principle and calculation of the throttling device shall comply with the provisions of GB 2624;
Turbine flowmeter:
c) Pitot tube:
d) Superluper flowmeter.
5.4 Measurement of power consumption of the aspirator and the water pump a) The power consumption of the aspirator can be calculated based on the working water flow and pressure measured in the test; b) The power consumption of the water pump is measured with a 0.5-level three-phase power meter. 5.6 Noise measurement
a) Noise measurement can be measured by sound level, generally measuring A sound pressure level. When measuring, the sound level meter is placed 1m away from the aspirator:
b) The noise measurement point should be at the largest part of the sound source section of the aspirator; c) When measuring noise, attention should be paid to the influence of background (or background) noise, and repair should be made at the same time. 8
JB/T35962001
25681u
Figure 5 Nozzle flow coefficient
34568105
Reynolds number P
Select u formula, 106 17.21 +4.67(1d
- G.217 (-
Absolute viscosity of air
Air viscosity
JB/T35962001
Output temporary part
5:0 yuan
6 Arrangement and calculation of test data
JB/T35962001
6. 1 When calculating the test data, all test data should be sorted out first. If any abnormality is found in the data, the recorder should be consulted before analysis and judgment.
6.2 When calculating the test data, all measured values ​​should be corrected. 6.3 When calculating the test data, the table of thermodynamic properties of water vapor should use the chart or updated version based on the 1967 positive C formula approved by the Seventh International Conference on the Properties of Water Vapor in 1968 as much as possible. This should be explained in the test report. 6.4 Dry air flow 4 (kg/h)
To facilitate the calculation of test data, when the pressure before and after the nozzle When the pressure is equal to or less than the critical pressure ratio, the dry air flow can also be calculated by the formula (4) obtained by converting the formula (1).
Where: α-
9=0.03671
Flow coefficient is based on the actual calibration value:
Nozzle throat diameter, cm:
/10.288(t+273)
Local atmospheric pressure after temperature correction, Pa (absolute): PA
Ambient temperature at the inhaled air during the test, °C. 6.5 When using a mercury gas pressure gauge, the corrected local atmospheric pressure, P, (Pa) P, -133.32Bu[1- (c}-) tm]
Where: B
Local atmospheric pressure at temperature, mmHg:
Expansion coefficient of mercury, 0.000815/℃: -Linear expansion coefficient of brass ruler, 0.000019/℃ (preferably steel ruler, =0.000012/℃): Local atmospheric vortex during the test, ℃.
6.6 When using a mercury differential pressure gauge, the aerator suction pressure P, (Pa)P, =P--133.32[H(I-aitH+0.0735 (h,-h,)1Wu Zhong: H
The difference of mercury columns of mercury differential pressure gauge at temperature t, mmHg: —The height of water column on vacuum side of U-tube mercury differential pressure gauge, mmH,O:,
hThe quotient of water column on atmosphere side of U-tube mercury differential pressure gauge, mmH,O: The air temperature during test, ℃.
If only one water temperature test is carried out: For design water temperature or other water temperature, the following formula can be used to convert the suction side pressure P (Pa) P%=Pt-(PP)
Where: —
The suction pressure of test water temperature, Pa (absolute); Pr
The saturation pressure corresponding to the test water temperature, Pa (absolute); P\set —The saturation pressure corresponding to the design water temperature, Pa (absolute). 6.7 Working water volume of vacuum pump g
If the test equipment is a standard orifice plate, nozzle or Pitot tube, the working water volume of vacuum pump shall be calculated according to the flow calculation formula of the test equipment selected in the design.
6.8 Power consumption of the vacuum pump (kw)
Calculate the power consumption of the vacuum pump according to the measured working water volume and pressure of the vacuum pump. N,-g[ (P.-P.) ×10-+9.8Hr1-*Where: 9——Working water volume flow, m2/sP. Working water pressure, Pa2 When calculating the test data, all measured values ​​shall be corrected. 6.3 When calculating the test data, the table of thermodynamic properties of water vapor shall be based on the 1967 formula for industrial use approved by the Seventh International Conference on the Properties of Water Vapor in 1968 or a newer version as far as possible. This shall be explained in the test report. 6.4 Dry air flow rate 4 (kg/h)
For the convenience of test data calculation, when the pressure before and after the nozzle is equal to or less than the critical pressure ratio, the dry air flow rate can also be calculated by formula (4) converted from formula (1).
In the formula: α-
9=0.03671
Flow coefficient according to the actual calibration value:
Nozzle throat diameter, cm:
/10.288(t+273)
Temperature correction store local atmospheric pressure, Pa (absolute): PA
Ambient temperature at the inhaled air during the test, °C. 6.5 When using a mercury pressure gauge, the corrected local atmospheric pressure, P, (Pa) P, -133.32Bu[1- (c}-) tm]
Where: B
Local atmospheric pressure at temperature, mmHg:
Coefficient of expansion of mercury, 0.000815/℃: -Linear expansion coefficient of brass scale, 0.000019/℃ (preferably steel scale, =0.000012/℃): Local atmospheric vortex during the test, ℃.
6.6 When using a mercury differential pressure gauge, the aerator suction pressure, P, (Pa) P, = P--133.32[H(I-aitH+0.0735 (h,-h,)1Wu Zhong: H
The difference of mercury column of mercury differential pressure gauge at temperature t, mmHg: - Height of water column on vacuum side of U-tube mercury differential pressure gauge, mmH,O:,
hThe quotient of water column on gas side of U-tube mercury differential pressure gauge, mmH,O: Air temperature during test, ℃.
If only one water temperature test is conducted: For design water temperature or other water temperature, the following formula can be used to convert the suction side pressure P (Pa) P%=Pt-(PP)
Where: -
The suction side pressure of test water temperature Inlet pressure, Pa (absolute); Pr
Saturated pressure corresponding to the test water temperature, Pa (absolute); P\set—saturated pressure corresponding to the design water temperature, Pa (absolute). 6.7 Aspirator working water volume g
If the test equipment is a standard orifice plate, nozzle or Pitot tube, calculate the aspirator working water volume according to the flow calculation formula of the test equipment selected in the design.
6.8 Vacuum insert power consumption (kw)
Calculate the aspirator power consumption based on the measured aspirator working water volume and pressure. N,-g[ (P.-P.) ×10-+9.8Hr1-*Where: 9——Working water volume flow, m2/sP. Working water pressure, Pa2 When calculating the test data, all measured values ​​shall be corrected. 6.3 When calculating the test data, the table of thermodynamic properties of water vapor shall be based on the 1967 formula for industrial use approved by the Seventh International Conference on the Properties of Water Vapor in 1968 or a newer version as far as possible. This shall be explained in the test report. 6.4 Dry air flow rate 4 (kg/h)
For the convenience of test data calculation, when the pressure before and after the nozzle is equal to or less than the critical pressure ratio, the dry air flow rate can also be calculated by formula (4) converted from formula (1).
In the formula: α-
9=0.03671
Flow coefficient according to the actual calibration value:
Nozzle throat diameter, cm:
/10.288(t+273)
Temperature correction store local atmospheric pressure, Pa (absolute): PA
Ambient temperature at the inhaled air during the test, °C. 6.5 When using a mercury pressure gauge, the corrected local atmospheric pressure, P, (Pa) P, -133.32Bu[1- (c}-) tm]
Where: B
Local atmospheric pressure at temperature, mmHg:
Coefficient of expansion of mercury, 0.000815/℃: -Linear expansion coefficient of brass scale, 0.000019/℃ (preferably steel scale, =0.000012/℃): Local atmospheric vortex during the test, ℃.
6.6 When using a mercury differential pressure gauge, the aerator suction pressure, P, (Pa) P, = P--133.32[H(I-aitH+0.0735 (h,-h,)1Wu Zhong: H
The difference of mercury column of mercury differential pressure gauge at temperature t, mmHg: - Height of water column on vacuum side of U-tube mercury differential pressure gauge, mmH,O:,
hThe quotient of water column on gas side of U-tube mercury differential pressure gauge, mmH,O: Air temperature during test, ℃.
If only one water temperature test is conducted: For design water temperature or other water temperature, the following formula can be used to convert the suction side pressure P (Pa) P%=Pt-(PP)
Where: -
The suction side pressure of test water temperature Inlet pressure, Pa (absolute); Pr
Saturated pressure corresponding to the test water temperature, Pa (absolute); P\set—saturated pressure corresponding to the design water temperature, Pa (absolute). 6.7 Aspirator working water volume g
If the test equipment is a standard orifice plate, nozzle or Pitot tube, calculate the aspirator working water volume according to the flow calculation formula of the test equipment selected in the design.
6.8 Vacuum insert power consumption (kw)
Calculate the aspirator power consumption based on the measured aspirator working water volume and pressure. N,-g[ (P.-P.) ×10-+9.8Hr1-*Where: 9——Working water volume flow, m2/sP. Working water pressure, Pa
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