传感器安装对平板气动热测量精度的影响

Influence of sensor installation on accuracy of aerodynamic heating measurement on flat plate

对高超声速飞行器来说,气动热的准确预测是其合理选择防热材料及热结构设计的重要依据,但目前在激波风洞试验中气动热的高精度测量仍较为困难,热流的测量精度受到诸多非理想因素的影响,但传感器安装对热流测量精度的影响却鲜见研究。选取平板模型来研究传感器非理想安装对气动热测量精度的影响,针对不同的传感器安装偏差(凸出或凹入模型表面0.1~0.5 mm),分析不同雷诺数下传感器安装对气动热测量精度的影响规律及机理。研究结果表明:传感器安装对气动热测量精度有较大影响,凸出安装会导致热流测量结果偏大,而凹入安装则会导致测量结果偏小,热流偏差会随着安装偏差的增大而增大,且高来流雷诺数下传感器非理想安装所引起的热流误差更大;以边界层当地厚度对凹凸程度无量纲化,非理想安装带来的测量偏差只与该无量纲参数相关。研究结果能够为气动热测量的实验方案设计及测量误差分析提供一定的理论指导。

Accurate measurement of aerodynamic heating is an important issue for hypersonic vehicles to choose reasonable heat resistant materials and thermal structure design.However,it is still difficult to measure the heat flux accurately in shock tunnel experiments,and any slight deviation from ideal conditions may lead to inaccuracy.In-depth investigations are needed to carry out.In this study,the flat plate model is selected to study the influence of the non-ideal sensor installation on the accuracy of heat flux measurement.The sensors examined are protruding or recessed from the model surface in the order of 0.1 mm to 0.5 mm and different Reynolds numbers are considered.Related rules and mechanism of the influence of sensor installation on the accuracy of aerodynamic heating measurement are analyzed in detail.The results show that the sensor installation has great influence on the accuracy of the heat flux measurement.Protruding sensor installation results in larger deviation from actual heat transfer and recessed sensor installation results in smaller deviation compared to the results obtained with a smoothly installed sensor.The larger the protruding/recessed depth,the more severe the deviation,and this deviation will be larger under higher Reynolds number conditions.Using the non-dimensional form of protruding/recessed depth to the thickness of boundary layer,the level of deviation is only related to the non-dimensional value regardless of Reynolds number.In all,the results can provide theoretical guidance for the design and error analysis of aerodynamic heating measurement experiments.