5.6 Testing and Verification
187
should be managed easy to calculate the heat leakage. Due to the large number of
temperature measuring points, thermocouples and other sensors with a small wire
diameter should be used to reduce the effect of temperature leakage of the temperature
measuring units.
The test conditions of VCHP should be determined according to the type of heat
pipe and test objectives. In order to study the performance of the heat pipe under
different conditions, special tests could be conducted to test the sensitivity of some
parameters.
5.6.3 Vacuum Thermal Insulation Testing
of High-Temperature Heat Shield
The high-temperature thermal shield was designed to protect structure and instruments of the lunar lander during when the landing engine was firing. Because of
the large size of the engine and the large amount of plume generated during firing,
the thermal insulation performance of the high-temperature heat shield could not be
verified directly with the actual engine firing. A test article of the high-temperature
heat shield with certain area was selected to conduct heat insulation performance test
alone.
1. Test Objectives
The major test objectives of the vacuum thermal insulation performance test of the
high temperature heat shield are as follows:
(1) To validate the design of high-temperature heat shield;
(2) To obtain the temperature distribution inside the heat shield when the engine
was firing and to provide test data for correction of the thermal analysis model.
2. Simulation Method of High Temperature Boundary
Because the performance of high-temperature heat shield could not be directly tested
by the engine firing and the boundary temperature was high (the highest temperature
of the nozzle was higher than 1300 °C), the challenge in the performance test of
high-temperature thermal shield was to accurately simulate the high temperature
boundary of the engine when the pressure was lower than 10
−2 Pa.
When the engine was ignited, the temperature of the nozzle would be stable after
a few seconds. Then after several minutes to over ten minutes of stable firing of
the engine, the temperature of the surface on the high-temperature thermal shield
which was opposite to the engine nozzle was generally stable in 60 s to 100 s with
the highest temperature 1000 °C. Two heating methods including high-power quartz
lamp and wind tunnel could achieve such a high temperature in a short period of time
up to date. It was longer (about tens of seconds) for the high-power quartz lamp to
heat to the specific temperature. However, the system of high-power quartz lamp was
relatively simple and easy to be integrated with available space environment simulator
187
should be managed easy to calculate the heat leakage. Due to the large number of
temperature measuring points, thermocouples and other sensors with a small wire
diameter should be used to reduce the effect of temperature leakage of the temperature
measuring units.
The test conditions of VCHP should be determined according to the type of heat
pipe and test objectives. In order to study the performance of the heat pipe under
different conditions, special tests could be conducted to test the sensitivity of some
parameters.
5.6.3 Vacuum Thermal Insulation Testing
of High-Temperature Heat Shield
The high-temperature thermal shield was designed to protect structure and instruments of the lunar lander during when the landing engine was firing. Because of
the large size of the engine and the large amount of plume generated during firing,
the thermal insulation performance of the high-temperature heat shield could not be
verified directly with the actual engine firing. A test article of the high-temperature
heat shield with certain area was selected to conduct heat insulation performance test
alone.
1. Test Objectives
The major test objectives of the vacuum thermal insulation performance test of the
high temperature heat shield are as follows:
(1) To validate the design of high-temperature heat shield;
(2) To obtain the temperature distribution inside the heat shield when the engine
was firing and to provide test data for correction of the thermal analysis model.
2. Simulation Method of High Temperature Boundary
Because the performance of high-temperature heat shield could not be directly tested
by the engine firing and the boundary temperature was high (the highest temperature
of the nozzle was higher than 1300 °C), the challenge in the performance test of
high-temperature thermal shield was to accurately simulate the high temperature
boundary of the engine when the pressure was lower than 10
−2 Pa.
When the engine was ignited, the temperature of the nozzle would be stable after
a few seconds. Then after several minutes to over ten minutes of stable firing of
the engine, the temperature of the surface on the high-temperature thermal shield
which was opposite to the engine nozzle was generally stable in 60 s to 100 s with
the highest temperature 1000 °C. Two heating methods including high-power quartz
lamp and wind tunnel could achieve such a high temperature in a short period of time
up to date. It was longer (about tens of seconds) for the high-power quartz lamp to
heat to the specific temperature. However, the system of high-power quartz lamp was
relatively simple and easy to be integrated with available space environment simulator