热线风速仪非标定工况下测试修正方法研究

Research on Reduction Method for Measurement by Hot Wire Anemometer on Non-Calibrated Conditions

关键词:  热线风速仪  温度  压力  修正方法  速度测量

Key words:  Hot wire anemometer  Temperature  Pressure  Reduction method  Velocity measurement

摘要:

为提高热线风速仪在非标定温度、压力流场下的测速精度以扩大其应用范围，对热线风速仪的换热理论模型进行了深入分析以及详细的理论推导。以热线的四种换热形式为基础，从理论上对热线探针热丝的换热进行了计算分析，在综合考虑强迫对流、自然对流、辐射换热、支架导热后，发现不同来流速度下的强迫对流占比是不同的。而在同一来流速度下，强迫对流占比几乎不随温度变化而变化，但随压力变化较大。以此为基础，综合考虑了温度、压力引起的物性参数变化对热丝换热的影响，以及由此导致的热丝电压值的变化，最终给出了一种新的适用于非标准工况的热线风速仪测试修正方法及修正公式。与公开文献数据进行了比对，平均误差0.68%，最大误差2.2%。证明该修正方法具有较高精度。

Abstract:

Aiming at expanding the application range by improving the accuracy of measurement using hot wire anemometer not calibrated over a range of temperatures and pressures， the heat transfer model of hot wire anemometer was analyzed theoretically and the derivations were carried out. Based on the four types of heat transfer， the heat transfer was calculated and analyzed. Considering forced convection， natural convection， heat radiation and heat conduction， it is found that the forced convection proportion is different under different flow velocities. In the same flow velocity， the forced convection proportion almost does not change with the temperatures， but changes a lot with the pressures. Based on this， a new reduction method and formula were put forward， which can be applied on non-calibrated conditions， considering the changes of the physical property parameters caused by temperature and pressure， as well as the voltage of hot wire. Public literature data were compared， the average error was 0.68%， the maximum error was 2.2%. It proved that the reduction method has high accuracy.