CN105864019A - Accurate pump efficiency measuring method used in pump thermal performance test efficiency measurement - Google Patents

Abstract

The invention relates to an accurate pump efficiency measuring method used in pump thermal performance test efficiency measurement. At present, pump efficiency result accuracy greatly depends on the pressure and temperature accuracy of a pump inlet/outlet in pump thermal performance test efficiency measurement. The method includes the following steps that only a thermocouple A, a pressure gage A, a thermocouple B and a pressure gage B verified to be qualified are used for measurement; the thermocouple A and the pressure gage A are installed at the water inlet of a pump at first, and the thermocouple B and the pressure gage B are installed at the water outlet of the pump for measurement; then the thermocouple B and the pressure gage B are arranged at the water inlet of the same pump, and the thermocouple A and the pressure gage A are arranged at the water outlet of the same pump for measurement; and the pressure average value P1 serves as inlet pressure of the pump efficiency test at this time, the pressure average value P2 serves as outlet water pressure of the pump efficiency test at this time, and the values are substituted into a formula to calculate pump efficiency. The method is easy to operate, and capable of ensuring that the measured pump efficiency is more accurate.

Description

Efficiency of pump accurate measurement method in pump thermal performance test efficiency measurement

Technical field

The present invention relates to a kind of efficiency of pump accurate measurement method, especially relate in a kind of pump thermal performance test efficiency measurement Efficiency of pump accurate measurement method.

Background technology

Prior art is in pump thermal performance test efficiency measurement, and the import and export coolant-temperature gage pressure measurement method of pump generally uses two The import and export coolant-temperature gage (pressure) of thermocouple (Pressure gauge) independent measurement pump, finally takes every thermocouple (pressure in process of the test Power table) meansigma methods of measured value, owing to the import and export coolant-temperature gage (pressure) of pump is relatively big to efficiency of pump result of the test weighing factor, Make the accuracy of efficiency of pump result in pump thermal performance test efficiency measurement to pump inlet and outlet pressure temperature accuracy according to lazyness Relatively higher, in other test links accurately, in the case of other experimental conditions meet, other auxiliary flow measure accurately, give The measurement accuracy of the out temperature of feed pump is relied on higher by the efficiency measurement result of water pump, and the turnover of water circulating pump The measurement result of Circulating Water Pump Efficiency is affected bigger by the measurement accuracy of mouth pressure." North China Electric Power University's journal " is 2000 Thermodynamics method disclosed in the 88-92 page of the 4th phase of volume 27 October year is measured in the progress of the efficiency of pump, although note Carry the formula of the relatively good calculating efficiency of pump, but this computing formula has still been imported and exported the shadow of coolant-temperature gage (pressure) by pump Ring relatively big, if using existing measuring method to measure the import and export coolant-temperature gage (pressure) of pump, the certainty of measurement to thermocouple Require the highest, not only considerably increase the cost of investment of equipment, and considerably increase the cost that thermocouple is safeguarded, also Efficiency of pump measured deviation can be caused relatively big, and be difficult to get rid of test random error and instrument error.

Summary of the invention

It is an object of the invention to overcome above-mentioned deficiency present in prior art, and provide a kind of simple to operate, it is ensured that Efficiency of pump accurate measurement method in the efficiency more accurate pump thermal performance test efficiency measurement of survey calculation pump out.

The present invention solves the efficiency of pump essence that the problems referred to above be the technical scheme is that in this pump thermal performance test efficiency measurement Really measuring method, it is characterised in that: the step of described method is as follows: with and only with the qualified thermocouple A of verification, Pressure gauge A, Thermocouple B and Pressure gauge B measures, and thermocouple A and Pressure gauge A is first installed on the water inlet of pump, and by thermoelectricity Even B and Pressure gauge B is installed on the outlet of pump, with thermocouple A and Pressure gauge A measure respectively pump water inlet temperature Xl and Water inlet pressure R1, measures delivery side of pump coolant-temperature gage Yl and water outlet pressure Q1 respectively with thermocouple B and Pressure gauge B；Deng Stable conditions on-test laggard row DATA REASONING, thermocouple A, Pressure gauge A, thermocouple B and Pressure gauge B measure respectively To water inlet temperature X1, water inlet pressure R1, water outlet temperature Yl and the water outlet pressure Q1 of pump, and carry out number for the first time According to collection, gather the Pass Test requirement of initial data time；Etc. then after data acquisition for the first time terminates, by thermocouple B and Pressure gauge B is placed in the water inlet of same pump, and thermocouple A and Pressure gauge A is placed in the outlet of same pump, etc. Stable conditions on-test laggard row DATA REASONING, thermocouple B and Pressure gauge B measures water inlet temperature X2 obtaining pump respectively Measure respectively with water inlet pressure R2, thermocouple A and Pressure gauge A and obtain delivery side of pump coolant-temperature gage Y2 and water outlet pressure Q2, And carry out second time data acquisition, gather the Pass Test requirement of initial data time；After data acquisition terminates, be calculated into The temperature averages T1 of mouth of a river temperature Xl and water inlet temperature X2, the pressure of water inlet pressure R1 and water inlet pressure R2 is put down Average P1, the temperature averages T2 of water outlet temperature Yl and water outlet temperature Y2, and water outlet pressure Q1 and water outlet Pressure mean values P2 of pressure Q2, then using temperature averages T1 as the Inlet water temperature of the efficiency test of this pump, will press Power average value P 1 is as the inlet pressure of the efficiency test of this pump, using temperature averages T2 as the efficiency test of this pump Water outlet temperature, using pressure mean values P2 as the water outlet pressure of the efficiency test of this pump, substitute into formula and calculate pump efficiency Rate.

As preferably, the formula that the present invention calculates the efficiency of pump is as follows:

$H=\frac{P_2-P_1}{\mathrm{\ρ}\×g}+\frac{V_2^2-V_1^2}{2\×g}+Z_2-Z_1$

In formula: H lift, [m]；

P₁Inlet pressure, [Pa]；

P₂Outlet pressure, [Pa]；

ρ average density, [kg/m³]；

G acceleration of gravity, [9.81m/s²]；

V₁Inlet velocity, [m/s]；

V₂Exit velocity, [m/s]；

Z₁Inlet pressure gauge center absolute altitude, [m]；

Z₂Delivery gauge center absolute altitude, [m].

$P_u=\frac{G\×H\×g}{3600}$

In formula: P_uEffective power, [kW]；

G rate of discharge, [t/h].

$P_a=\frac{G_2(h_2-h_1)+G_x(h_1-h_x)}{3.6}+\mathrm{\Δ}E$

In formula: P_aFeed pump shaft power, [kW]；

h₂Feed pump water outlet specific enthalpy, [kJ/kg]；

h₁Feed pump Inlet water specific enthalpy, [kJ/kg]；

h_xSealing Water for Feedwater Pump water inlet specific enthalpy, [kJ/kg]；

G_xSeal water and enter the flow of the pump housing, [t/h]；

The heat radiation of Δ E feed pump bearing, the pump housing and mechanical loss etc., [kW].

Under the experimental condition of feed pump scene, Δ E can approximate the G taking (0.01～0.03) again₂(h₂-h₁), commerical test C class precision and whole can be met The requirement that body optimizes, takes

$\mathrm{\Δ}E=0.02\frac{G_2(h_2-h_1)}{3.6}$

Δ E more Method for Accurate Calculation:

Δ E=Δ E_m+E_x

$E_x=\frac{G_{mi}{c}_{ph}(t_{2i}-t_{1i})}{3600}$

In formula: E_xThe energy that cooling water or oil absorb, [kW]；

G_miCooling water or oil quality flow, [t/h]；

c_phCooling water or the specific heat capacity of oil, [J/ (kg. DEG C)]；

t_1i、t_2iCooling water or the out temperature of oil, [DEG C].

ΔE_m=Δ E_m1+ΔE_m2

${\mathrm{\ΔE}}_{m1}=\frac{G_{xo}(h_{xo}-h_x)}{3.6}$

In formula: Δ E_m1Sealing device leakage flow loses, [kW]；

G_xoSeal water circling water flow rate, [t/h]；

h_xoSeal water backwater enthalpy, [kJ/kg].

ΔE_m2=P_exA(t_e-t_a)

In formula: Δ E_m2The energy of pump housing radiation loss, [kW]；

P_exThe radiation loss power of the pump housing, rule of thumb can take 0.01 [kW/ (m²·℃)]；

A heat exchange area, [m²]；

t_e、t_aWater temperature, ambient temperature, [m in pump²]。

$\mathrm{\η}=\frac{P_u}{P_a}\×100\%$

In formula: η feed pump efficiency.

As preferably, meansigma methods of the present invention is arithmetic mean of instantaneous value.

As preferably, experimental condition of the present invention and program meet test requirements document.

The present invention compared with prior art, has the following advantages and effect: principle is simple, easily realizes, and measures accurately, can Lean on, stable, general idea is unique, only needs two to verify qualified thermocouples and the qualified Pressure gauge of two verifications, fits With wide, advantageously reduce equipment cost.The present invention is using very simple method and without additionally increasing the situation of equipment The degree of accuracy of the lower efficiency of pump that just can improve measurement result, simply, practical, effectively.The present invention reduces measurement pump in test The test random error of temperature and pressure of turnover saliva and instrument error, the measurement accuracy of the efficiencies of pump can be improved.

Detailed description of the invention

Below by embodiment, the present invention is described in further detail, and following example are explanation of the invention and this Bright it is not limited to following example.

Embodiment.

The step of the efficiency of pump accurate measurement method in the present embodiment pump thermal performance test efficiency measurement is as follows: with and only use school Test qualified thermocouple A, Pressure gauge A, thermocouple B and Pressure gauge B to measure, first thermocouple A and Pressure gauge A is pacified It is loaded on the water inlet of pump, and thermocouple B and Pressure gauge B is installed on the outlet of pump, with thermocouple A and Pressure gauge A Measure water inlet temperature Xl and the water inlet pressure R1 of pump respectively, measure delivery side of pump water respectively with thermocouple B and Pressure gauge B Temperature Yl and water outlet pressure Q1；Deng stable conditions on-test laggard row DATA REASONING, thermocouple A, Pressure gauge A, heat Galvanic couple B and Pressure gauge B measures respectively and obtains water inlet temperature X1 of pump, water inlet pressure R1, water outlet temperature Yl and go out Water pressure Q1, and carry out data acquisition for the first time, gather the Pass Test requirement of initial data time；Then first number is waited After terminating according to collection, thermocouple B and Pressure gauge B is placed in the water inlet of same pump, and by thermocouple A and Pressure gauge A It is placed in the outlet of same pump, waits stable conditions on-test laggard row DATA REASONING, thermocouple B and Pressure gauge B respectively Measure and obtain water inlet temperature X2 of pump and water inlet pressure R2, thermocouple A and Pressure gauge A measure respectively and obtain delivery side of pump Coolant-temperature gage Y2 and water outlet pressure Q2, and carry out second time data acquisition, gather the Pass Test requirement of initial data time；Number After terminating according to collection, it is calculated the temperature averages T1 of water inlet temperature Xl and water inlet temperature X2, water inlet pressure R1 With pressure mean values P1 of water inlet pressure R2, the temperature averages T2 of water outlet temperature Yl and water outlet temperature Y2, with And water outlet pressure Q1 and pressure mean values P2 of water outlet pressure Q2, then using temperature averages T1 as the efficiency of this pump The Inlet water temperature of test, using pressure mean values P1 as the inlet pressure of the efficiency test of this pump, by temperature averages T2 As the water outlet temperature of the efficiency test of this pump, using pressure mean values P2 as the outlet hydraulic pressure of the efficiency test of this pump Power, the substitution equation below calculating efficiency of pump:

$H=\frac{P_2-P_1}{\mathrm{\ρ}\×g}+\frac{V_2^2-V_1^2}{2\×g}+Z_2-Z_1$

In formula: H lift, [m]；

P₁Inlet pressure, [Pa]；

P₂Outlet pressure, [Pa]；

ρ average density, [kg/m³]；

G acceleration of gravity, [9.81m/s²]；

V₁Inlet velocity, [m/s]；

V₂Exit velocity, [m/s]；

Z₁Inlet pressure gauge center absolute altitude, [m]；

Z₂Delivery gauge center absolute altitude, [m].

$P_u=\frac{G\×H\×g}{3600}$

In formula: P_uEffective power, [kW]；

G rate of discharge, [t/h].

$P_a=\frac{G_2(h_2-h_1)+G_x(h_1-h_x)}{3.6}+\mathrm{\Δ}E$

In formula: P_aFeed pump shaft power, [kW]；

h₂Feed pump water outlet specific enthalpy, [kJ/kg]；

h₁Feed pump Inlet water specific enthalpy, [kJ/kg]；

h_xSealing Water for Feedwater Pump water inlet specific enthalpy, [kJ/kg]；

G_xSeal water and enter the flow of the pump housing, [t/h]；

The heat radiation of Δ E feed pump bearing, the pump housing and mechanical loss etc., [kW].

Under the experimental condition of feed pump scene, Δ E can approximate the G taking (0.01～0.03) again₂(h₂-h₁), commerical test C class precision and whole can be met The requirement that body optimizes, takes

$\mathrm{\Δ}E=0.02\frac{G_2(h_2-h_1)}{3.6}$

Δ E more Method for Accurate Calculation:

Δ E=Δ E_m+E_x

$E_x=\frac{G_{mi}{c}_{ph}(t_{2i}-t_{1i})}{3600}$

In formula: E_xThe energy that cooling water or oil absorb, [kW]；

G_miCooling water or oil quality flow, [t/h]；

c_phCooling water or the specific heat capacity of oil, [J/ (kg. DEG C)]；

t_1i、t_2iCooling water or the out temperature of oil, [DEG C].

ΔE_m=Δ E_m1+ΔE_m2

${\mathrm{\ΔE}}_{m1}=\frac{G_{xo}(h_{xo}-h_x)}{3.6}$

In formula: Δ E_m1Sealing device leakage flow loses, [kW]；

G_xoSeal water circling water flow rate, [t/h]；

h_xoSeal water backwater enthalpy, [kJ/kg].

ΔE_m2=P_exA(t_e-t_a)

In formula: Δ E_m2The energy of pump housing radiation loss, [kW]；

P_exThe radiation loss power of the pump housing, rule of thumb can take 0.01 [kW/ (m²·℃)]；

A heat exchange area, [m²]；

t_e、t_aWater temperature, ambient temperature, [m in pump²]。

$\mathrm{\η}=\frac{P_u}{P_a}\×100\%$

In formula: η feed pump efficiency.

Meansigma methods in the present embodiment is arithmetic mean of instantaneous value.What measurement for the first time and second time measurement were exchanged both includes thermocouple, Also include Pressure gauge.Experimental condition and program meet test requirements document.

Such as during certain power station pump thermal performance efficiency measuring tests, first verify qualified thermocouple with two and record the turnover of pump Saliva temperature is respectively 165.05 DEG C and 169.18 DEG C, secondly these two thermocouple measurement location swaps, records the turnover of pump Saliva temperature is respectively 164.80 DEG C and 169.36 DEG C；By data above it can be seen that due to the existence of thermocouple system error The import and export coolant-temperature gage error making single measurement pump is relatively big, and uses the measuring method of the present invention, then eliminate two thermoelectricity Systematic error between idol, measures the efficiency of pump for thermal performance test and provides data the most accurate, real.In like manner, originally Invention also eliminates the systematic error between two Pressure gauges.

Following table is to use the method calculated efficiency of pump result in the present invention.

Furthermore, it is necessary to explanation, the specific embodiment described in this specification, the shape of its parts and components, it is named Titles etc. can be different, and the above content described in this specification is only to present configuration example explanation.All depend on The equivalence change done according to structure, feature and the principle described in inventional idea of the present invention or simple change, be all included in this In the protection domain of bright patent.Described specific embodiment can be done various by those skilled in the art The amendment of various kinds or supplement or use similar mode to substitute, without departing from the structure of the present invention or surmount present claims Scope defined in book, all should belong to protection scope of the present invention.

Claims (4)

1. the efficiency of pump accurate measurement method in a pump thermal performance test efficiency measurement, it is characterised in that: described method Step is as follows: uses and only measures with qualified thermocouple A, Pressure gauge A, thermocouple B and the Pressure gauge B of verification, first will Thermocouple A and Pressure gauge A is installed on the water inlet of pump, and thermocouple B and Pressure gauge B is installed on the outlet of pump, Water inlet temperature Xl and the water inlet pressure R1 of pump is measured respectively, with thermocouple B and Pressure gauge with thermocouple A and Pressure gauge A B measures delivery side of pump coolant-temperature gage Yl and water outlet pressure Q1 respectively；Deng stable conditions on-test laggard row DATA REASONING, heat Galvanic couple A, Pressure gauge A, thermocouple B and Pressure gauge B measure respectively obtain water inlet temperature X1 of pump, water inlet pressure R1, Water outlet temperature Yl and water outlet pressure Q1, and carry out data acquisition for the first time, gather the Pass Test requirement of initial data time； Etc. then, after data acquisition for the first time terminates, thermocouple B and Pressure gauge B is placed in the water inlet of same pump, and by heat Galvanic couple A and Pressure gauge A is placed in the outlet of same pump, waits stable conditions on-test laggard row DATA REASONING, thermocouple B Measure respectively with Pressure gauge B and obtain water inlet temperature X2 of pump and water inlet pressure R2, thermocouple A and Pressure gauge A survey respectively Measure delivery side of pump coolant-temperature gage Y2 and water outlet pressure Q2, and carry out second time data acquisition, gather initial data time symbol Close test requirements document；After data acquisition terminates, it is calculated the temperature averages T1 of water inlet temperature Xl and water inlet temperature X2, Water inlet pressure R1 and pressure mean values P1 of water inlet pressure R2, water outlet temperature Yl and the temperature of water outlet temperature Y2 Meansigma methods T2, and water outlet pressure Q1 and pressure mean values P2 of water outlet pressure Q2, then temperature averages T1 is made For the Inlet water temperature of the efficiency test of this pump, using pressure mean values P1 as the inlet pressure of the efficiency test of this pump, Using temperature averages T2 as the water outlet temperature of the efficiency test of this pump, using pressure mean values P2 as the effect of this pump The water outlet pressure of rate test, substitutes into formula and calculates the efficiency of pump.

Efficiency of pump accurate measurement method in pump thermal performance test efficiency measurement the most according to claim 1, its feature It is: the formula calculating the efficiency of pump is as follows:

$H=\frac{P_2-P_1}{\mathrm{\ρ}\×g}+\frac{V_2^2-V_1^2}{2\×g}+Z_2-Z_1$

In formula: H lift, [m]；

P₁Inlet pressure, [Pa]；

P₂Outlet pressure, [Pa]；

ρ average density, [kg/m³]；

G acceleration of gravity, [9.81m/s²]；

V₁Inlet velocity, [m/s]；

V₂Exit velocity, [m/s]；

Z₁Inlet pressure gauge center absolute altitude, [m]；

Z₂Delivery gauge center absolute altitude, [m]；

$P_u=\frac{G\×H\×g}{3600}$

In formula: P_uEffective power, [kW]；

G rate of discharge, [t/h]；

$P_a=\frac{G_2(h_2-h_1)+G_x(h_1-h_x)}{3.6}+\mathrm{\Δ}E$

In formula: P_aFeed pump shaft power, [kW]；

h₂Feed pump water outlet specific enthalpy, [kJ/kg]；

h₁Feed pump Inlet water specific enthalpy, [kJ/kg]；

h_xSealing Water for Feedwater Pump water inlet specific enthalpy, [kJ/kg]；

G_xSeal water and enter the flow of the pump housing, [t/h]；

The heat radiation of Δ E feed pump bearing, the pump housing and mechanical loss etc., [kW]；

Under the experimental condition of feed pump scene, Δ E takes (0.01～0.03) G again₂(h₂-h₁), commerical test C class precision and global optimization can be met Requirement, take

$\mathrm{\Δ}E=0.02\frac{G_2(h_2-h_1)}{3.6}$

Or employing Δ E more Method for Accurate Calculation:

Δ E=Δ E_m+E_x

$E_x=\frac{G_{mi}{c}_{ph}(t_{2i}-t_{1i})}{3600}$

In formula: E_xThe energy that cooling water or oil absorb, [kW]；

G_miCooling water or oil quality flow, [t/h]；

c_phCooling water or the specific heat capacity of oil, [J/ (kg. DEG C)]；

t_1i、t_2iCooling water or the out temperature of oil, [DEG C]；

ΔE_m=Δ E_m1+ΔE_m2

${\mathrm{\ΔE}}_{m1}=\frac{G_{xo}(h_{xo}-h_x)}{3.6}$

In formula: Δ E_m1Sealing device leakage flow loses, [kW]；

G_xoSeal water circling water flow rate, [t/h]；

h_xoSeal water backwater enthalpy, [kJ/kg]；

ΔE_m2=P_exA(t_e-t_a)

In formula: Δ E_m2The energy of pump housing radiation loss, [kW]；

P_exThe radiation loss power of the pump housing, rule of thumb can take 0.01 [kW/ (m²·℃)]；

A heat exchange area, [m²]；

t_e、t_aWater temperature, ambient temperature, [m in pump²]；

$\mathrm{\η}=\frac{P_u}{P_a}\×100\%$

In formula: η feed pump efficiency.

Efficiency of pump accurate measurement method in pump thermal performance test efficiency measurement the most according to claim 1, its feature It is: described meansigma methods is arithmetic mean of instantaneous value.

Efficiency of pump accurate measurement method in pump thermal performance test efficiency measurement the most according to claim 1, its feature It is: experimental condition and program meet test requirements document.