动态测量过程热电偶时间常数模型研究

Study on Time-constant Mathematics Model of Thermoelement in the Process of Dynamic Measurement

根据热电偶动态测温过程实际换热情况,运用对流、辐射和传导等传热学有关知识,建立了热电偶时间常数数学模型。以制作热电偶最常用的3种金属—镍、铂和钨为例进行的动态测量过程热电偶时间常数特性分析结果表明,动态测量过程中热电偶时间常数应该在不同的介质温度区间相应地选取不同的换热比重。应用结果表明,采用动态测量过程热电偶时间常数模型校正后,动态测量过程热电偶检定结果相对误差可减少4.0%。

Based on the actual condition of heat transfer in the process of thermoelement dynamic thermometric,a thermoelement time-constant mathematical model was built by applying heat transfer theory such as convection,radiation and conduction.The property analysis on dynamic measurement was carried out by taking three most commonly used metals in thermoelement-making as its example—nickel,platinum and tungsten.According to the results of analysis of thermoelement time-constant,time-constant of the thermoelement should choose different proportions of heat transfer at different medium temperature correspondingly.The application results indicate that the relative error of the thermoelement can reduce by 4.0% after dynamic measurement being revised by using of the thermoelement time-constant model in the process of dynamic thermometric.