NB/T 10301-2019Thermal balance experiment method for reciprocating internal combustion gas generating set (English PDF)

3.1 Thermal balance

In determining the calibration conditions within the system and within a specified time, the energy entering the system and the energy leaving the system are usually regarded as stable in value Balance, the fuel energy burned is equal to the sum of energy expenditures.

3.2 System

The object and boundary line of the heat balance test of the gas unit. In general, objects and substances passing through a part of the boundary line are called outside the system.

3.3 Test for thermal balance of gas generator set

In the gas-fired unit system, the distribution and use status of the burning fuel energy and energy conversion are tested and certain procedures are passed Method, quantitative measurement and calculation analysis.

3.4 Thermal efficiency of gas generator set

The gas-fired unit determines the system and the specified time within the calibration conditions, the output electric energy of the gas-fired unit accounts for the percentage of the fuel energy supplied.

3.5 High-temperature cooling water

Water used to cool the cylinder liner and (or) lubricating oil of a gas unit.

3.6 Low-temperature cooling water

Water used to cool the air and/or lubricating oil after pressurization of the gas unit.

6.1 Test space

6.1.1 The gas generator set manufacturer shall have a test site that meets the local environmental protection requirements and fire safety requirements, and the occupational safety and health protection Meet business requirements.

6.1.2 The test site is well ventilated, and has gas leakage detection and safety protection measures.

6.1.3 The safety design of gas-fired units meets the requirements of GB/T 33340.

6.1.4 According to the provisions of Table 1 in GB/T 21404-2008, the gas-fired unit shall be equipped with the necessary auxiliary devices and auxiliary equipment necessary to ensure its safe operation.

Safety protection devices, the performance indicators of each device meet the manufacturer's technical specifications for batch production.

6.1.5 The vibration and noise of the gas generating unit meet the technical conditions of the manufacturer.

6.1.6 The gas-fired unit should be run-in and tested for sufficient time, and the test load should be continuously adjustable.

6.1.7 The stability of test instruments, test equipment and system pipelines should be checked. A supply system and (or) that can ensure stable pressure should be adopted. Voltage stabilizing device.

6.1.8 The high temperature or low temperature cooling water can be cooled either through the engine radiator or through external circulation. Loop formed by external loop System, the pressure loss and water pump flow rate of the system are basically the same as the data of the engine's own cooling system.

6.1.9 It is advisable to install a heat exchanger on the exhaust pipe, and measure the exhaust heat energy by using the cooling water heat exchange method.

6.1.10 The fluid pipelines and (or) test equipment in the system should be insulated. After the heat preservation material is processed, the surface temperature of the exhaust pipe is not Above 120 °C, the surface temperature of the cooling water pipeline and (or) testing equipment should not exceed 45 °C.

6.2 Standard reference conditions and environmental conditions

6.2.1 For ease of use, the standard reference conditions specified in Chapter 5 of GB/T 21404-2008 are repeatedly listed.

6.2.2 In order to limit the uncertainty of the measurement results, the atmospheric conditions during the test should be within the following specified ranges.

1) Environmental dry gas pressure. 90 kPa<= <=110 kPa;

2) Absolute temperature of ambient air. 288 K<= <=308 K;

3) The relative humidity of the environment. 30%<= <=60%.

6.3 Cooling medium and fuel

6.3.1 The cooling water index used for the heat balance test of the gas-fired unit shall meet the requirements of Table 1.

6.3.2 When using cooling water that meets the requirements in Table 1, its specific heat capacity The value of C is 4.1868 kJ/kg·K;

6.3.3 When using coolant (glycol is used as an additive to water, the specific heat capacity of ethylene glycol is 2.28 kJ/kg·K, and the density is 1.128 kg/m³)

When, formula (1) can be used to calculate its specific heat capacity.

6.3.4 When the single fuel methane CH4 is used as fuel, the low calorific value is 35906 kJ/Nm 3.The density is 0.7174 kg/Nm3.

6.3.5 When using mixed gas as fuel, calculate the low calorific value and density according to the gas fuel classification and component analysis method specified in GB/T 33347.

6.4 Installation of measuring equipment and instruments

6.4.1 Instruments should be products approved by the national metrology department and used within the validity period of the metrology department's appraisal.

6.4.2 The instrumentation should be within the specified applicable range, and the measured value should not be less than 1/3 of the measurement full scale.

6.4.3 The installation of the flowmeter used for flow measurement shall meet the requirements of its instruction manual.

6.4.4 The sensor used to measure the temperature or pressure of the fluid outside the gas unit body. The length of the straight line before and after the measuring point should be greater than twice the length of the pipeline Diameter. When the measuring point position of the pressure sensor does not meet the requirements, a buffer tube should be installed.

6.4.5 A graphical visualized automatic collection system should be used to record the test data of the heat balance system. The visual display feature should characterize the heat balance model Attributes, visually display device shape, visualization results, graphs and other heat balance test object information on the screen.

6.5 Accuracy of measuring equipment and instruments

6.5.1 The temperature measuring device of the gas-fired unit should meet the accuracy of 6.3.2 in GB/T 21404-2008.

6.5.2 The power measuring device of the gas-fired unit should have an accuracy of 0.2%.

6.5.3 The cooling water flow measurement device for the thermal balance test should have an accuracy of 0.5%.

6.5.4 The cooling water pressure measuring device for the heat balance test should have an accuracy of 0.2%.

6.5.5 The results of the measurement parameters meet the tolerance range given in Table 4 of GB/T 21404-2008.

7.1 General inspection

According to the technical documents of the gas unit manufacturer, the general inspection of the test system should at least include the following.

1) The appearance of the gas unit is clean, the fixing parts are fastened without looseness, and there is no leakage of water, oil or gas.

2) The gas generator set is reliably connected with the external circulation system, exhaust pipe, etc.

3) Test equipment, meters, and instruments are working normally and operating well.

4) The gas generator set is reliably connected with test equipment and test instruments.

5) The performance indicators of the gas-fired unit should meet the requirements of the manufacturer, and the manufacturing and assembly records should be complete.

7.2 Basic steps

In order to ensure consistency with the specification, the gas-fired unit manufacturer should follow the following test procedures.

1) Determine the model and rated parameters of the gas unit participating in the heat balance test.

2) Establish a heat balance model and determine the control system for the heat balance test.

3) Obtain fuel low calorific value and composition data.

4) Measure gas consumption and output power according to the load point.

5) Take one or more measuring points to measure the ambient temperature, combustion exhaust temperature, temperature and flow rate of cooling water entering and exiting.

6) Calculate thermal efficiency and thermal balance based on test data.

7.3 Test method

7.3.1 Within the environmental conditions specified in 6.2.2, the gas-fired unit is started and adjusted to the rated frequency to ensure that the frequency is stable as required In the steady-state frequency band, perform a thermal balance test.

7.3.2 Gradually increase the load of the unit to reach 100% rated power, and determine the operating parameters of the thermal balance test control system. When high temperature water and low temperature When the fluctuation rate of the temperature difference between water inlet and outlet water should be less than 0.1 °C/min, the engine is considered to be in thermal equilibrium.

7.3.3 Measure at 0%, 25%, 50%, 75%, 100% stable conditions respectively, and ensure the monotonicity of load increase or decrease.

7.3.4 For the gas-fired unit, under the stable working conditions specified in 7.3.3, continuously measure the operating parameters of the heat balance test control system for three times, each time The measurement time is not less than 5 min.

7.3.5 A flow meter should be installed before the air-fuel ratio control system to measure the amount of fuel consumed.

7.3.6 According to the design features of the gas engine, measure the flow of high temperature cooling water and low temperature cooling water at the cooling water inlet or outlet. cold The flow velocity of the cooling water ranges from 1.5 m/s to 3 m/s, and the circulating water velocity by gravity is not more than 0.6 m/s.

7.3.7 Adjust the flow and flow rate of the heat exchanger on the exhaust pipe to keep the temperature of the exhaust leaving the heat exchanger not greater than 90 °C.

7.3.8 A platinum resistance (PT100 or PT1000) temperature sensor should be used to measure the temperature of high temperature cooling water and low temperature cooling water.

7.3.9 A thermocouple temperature sensor with K graduation should be used to measure the exhaust temperature.

7.3.10 After the measurement, calculate the thermal energy according to the calculation method given in Chapter 8, and enter the calculation result into the corresponding test report. For the test report, see Appendix B and Appendix C.

8.1 Heat balance of gas unit

8.1.1 In the heat balance system of a gas-fired unit, the fuel energy input is equal to the sum of various energy output.

8.1.2 The stable heat balance equation uses formula (2) to express the relationship between the various energies.

8.2 Fuel heat

The input fuel thermal energy (Q) is calculated by formula (3) and formula (4).

8.3 Air quality consumed by combustion

The air mass flow rate () is calculated by formula (5).

8.4 Enthalpy of combustion exhaust

8.5 Enthalpy of air required for combustion

8.6 Heat energy of exhaust

The heat energy of exhaust gas is calculated by formula (10).

8.9 Convection and radiant heat

8.10 Thermal efficiency