火星表面大气环境下热球风速仪的对流换热模型及试验验证

火星表面大气环境与一般轨道航天器所处的空间环境存在差异。为了实现极端环境下热模型修正、早期故障筛除、性能测试等目的，一般需要在模拟的低气压有风环境下对火星巡视器进行热试验，试验涉及在1400 Pa左右压力的环境下对0～15 m/s风速进行模拟和测量。文章针对极低气压下的风速测量问题，使用无量纲数分析方法建立恒热流式热球风速传感器表面的换热模型，对其在低气压下的输出、自然对流影响等进行分析，并与低气压下的测试结果进行对比。试验结果显示，在1400 Pa低气压下，热球风速探头表面仍以强制对流换热为主，探头灵敏度约为0.1～0.2 mV/(m·s-1)，可以用于极低压力下的风速测量。

The heat transfer model of hot-bulb anemometer in Martian atmospheric environment and corresponding test validation

In the Mars exploration missions, due to the low-pressure atmosphere, the heat transfer on the Mars surface is different from that in other in-orbit environment. It is necessary to test the Mars rover in a simulated low pressure and Martian atmospheric environment for the thermal model correction, the early failure screening, and the performance verification. One has to measure a wind speed of 0 to 15 m/s in the thermal test of the rover under a pressure of 1400 Pa . In this paper, the heat transfer model on the surface of a constant heat flow hot bulb probe is established by the dimensional number analysis method. The output signal and the natural convection influence under a low pressure are analyzed with the model, and the results are compared with the test results under the corresponding low pressure. It is shown that the forced convection plays a dominant role in the convection around the hot bulb probe under the pressure of 1400 Pa, and the sensitivity of the probe is about 0.1 to 0.2 mV/(m·s-1), which is adequate to be used in measuring the wind speed under a very low pressure.