Optimal Design and Research of Thermal Junction Parameters for Thin Film Thermocouples for Spacecraft

With the development of space missions, especially in the development of deep-space exploration and model missions for spacecraft, the spacecraft and its components will encounter high temperature and thermal environment. For example, the temperature measurement of the ablation material of the heaven and earth reciprocating aircraft and the supersonic aircraft surface requires that the high temperature sensor is small in size, does not damage the test piece or does not affect the environment to be tested. The temperature of the target being measured rises by a few hundred degrees (usually in the order of milliseconds or even microseconds), which requires the temperature sensor to have excellent dynamic response. Thin film thermocouples have low heat capacity and fast dynamic response for transient high temperature measurements. In this paper, the key factors affecting the dynamic response of NiCr/NiSi thin film thermocouples for spacecraft are discussed. Through theoretical analysis and simulation calculation, the key factor affecting the dynamic response of thin film thermocouples is the thickness of thermal junction. Experiments show that the thickness of the thermal junction has little effect on the static performance of the film thermocouple, but it has a great influence on the dynamic response performance.