一种屏蔽式总温探头设计及其测量误差估计

Design and measurement error estimation of a shielded total temperature probe

在忽略辐射误差的情况下,使用流固耦合传热数值模拟的方法预测了一种总温探头在不同工况下的速度误差和导热误差。结果表明:在马赫数为0.2~0.6的范围内,导热误差都保持在较小值;总误差的90%以上由速度误差贡献;最大测量误差为1.13 K,比结构A、结构B、结构C以及结构D分别低了331.6%、119.4%、61.6%以及59.5%;速度误差和导热误差存在互相影响的关系,存在最优解可使总误差最小;适用于等温来流和马赫数大于0.5的高速非等温来流的总温测量。最后探讨了热电偶节点位置对测量精度的影响,节点在从设计点远离支持体的过程中,测量误差遵循着先增大后减小的变化规律。

Ignoring the radiation error,the velocity error and heat conduction error of a shielded total temperature probe under different working conditions were predicted by using the conjugate heat transfer numerical simulation method.Results showed that the thermal conductivity error was kept at a small value in the range of Mach number from 0.2 to 0.6;more than 90%of the total error was contributed by velocity error;the maximum measurement error was 1.13 K,which was 331.62%,119.4%,61.6%and 59.5%lower than the common structure A,B,C and D,respectively;velocity error and conduction error affected each other,and there was an optimal solution to minimize the total error.It was applicable to the total temperature measurement of isothermal incoming flow and high-speed non-isothermal incoming flow with Mach number greater than 0.5.Finally,the influence of thermocouple junction position on measurement accuracy was discussed.When the junction was kept away from the support from the design point,the measurement error followed the change law of first increasing and then decreasing.