应变天平作为风洞试验的测量元件,保证天平的测量精度是相关领域的研究重点。但在连续式风洞中,由于风洞运行时间长及马赫数连续变换,天平体的温度会出现分布不均匀的情况,产生温度梯度。这种温度梯度对天平轴向力测量精度的影响尤为明显。为探究在连续式风洞中温度梯度对天平轴向力应变输出的影响,根据实际工况,总结出3种温度加载情况,利用ANSYS Workbench对80A天平进行热-固耦合分析。研究结果表明:在不考虑后支杆热传导的情况下,温度梯度基点的温度越高,温度输入越快,天平体的温度分布越不均匀,温度梯度越大,轴向力应变输出越大;在考虑后支杆热传导的情况下,天平体的温度分布相对均匀,温度梯度较小,轴向力热应变输出较小。

As a measuring element in wind tunnel test, it is important to ensure the measurement accuracy of strain balance.However, in the continuous wind tunnel, due to the long running time of the wind tunnel and the continuous transformation of Mach number, the temperature distribution of the balance body will be uneven, resulting in temperature gradient.This temperature gradient has an obvious influence on the measurement accuracy of the axial force of the balance.In order to explore the influence of temperature gradient on the axial force and strain output of the balance in the continuous wind tunnel, three temperature loading conditions are summarized according to the actual working conditions, and the thermal-solid coupling analysis of the 80A balance is carried out by ANSYS Workbench.The results show that the higher the temperature of the base point of the temperature gradient, the faster the temperature input, the more uneven the temperature distribution of the balance, and the larger the temperature gradient, the larger the axial force and strain output. Considering the heat conduction of the back support rod, the temperature distribution of the balance body is relatively uniform, the temperature gradient is small, and the output of axial force and strain is small.