阶跃温度场在热电偶时间常数测试中的应用

The application of step temperature field in thermocouple time constant test

传统的采用机械方式将热电偶投掷到温度场热中测量电偶时间常数的方法,由于时间上的延迟,无法测量ms级、甚至μs级热电偶的时间常数,为此,提出了1种热电偶时间常数测试系统,该系统以大功率半导体激光器为阶跃温度场的激励信号对热电偶加热,利用红外探测器反馈控制模块实现加热过程温度场的控制。实验结果表明:提高激光器输出功率密度可以在50ms内产生1 126℃阶跃高温场;利用反馈控制模块可以在热电偶达到某一温度阶跃后,使热电偶吸收热量和散失热量达到动态平衡;测得某接点外露型热电偶在标况下阶跃温度为700℃时的时间常数为446ms。

Since the traditional thermocouple time constant measurements were required to throw the thermocouple into a temperature field by mechanical means,and the delay in time made it impossible to measure time constants of milliseconds,or even microseconds thermocouples.One kind test system of thermocouple time constant is proposed in this paper,which uses high-power semiconductor laser as an excitation signal of step temperature field to heat thermocouple,and uses infrared detector as feedback control module to realize the control of the temperature field in heating process.Experimental results show that a 1 126 ℃ step temperature field can be produced through improving the density of laser output power within 50 ms,and the feedback control module can make heat absorption and heat dissipation of thermocouple reach dynamic equilibrium after the thermocouple reaches a temperature step.When the step temperature is 700 ℃,an exposed junction thermocouple time constant is 446 ms,which is measured under standard conditions.