对流换热系数的瞬态测量技术

使用等热流法瞬态实验测量对流换热系数:基于流动稳定及热平衡条件下对测量表面突加一稳定热流,测出测量表面高低两种窄幅热色液晶的显色时间,根据窄幅液晶的显色温度及其时间通过求解一维半无限大平板非稳态导热方程得到对流换热系数.推导出此方法的误差传递公式,在此基础上分析如何得到准确的对流换热系数.最后给出热流法测对流换热系数的实验流程,并通过自由盘实验验证热流法测对流换热系数的可行性.

Transient measurement of heat transfer coefficient

A new method called constant heat flux method was talked about the calculation of the heat transfer coefficient, h . The way of calculating h for the transient experiment was from step-change solution by giving a constant heat flux suddenly. If the time at which the changes colour of thermochromic liquid crystal(TLC) is known, then h can be found from the solution of so-called semi-infinite plate problem. Uncertainties of h calculated using the so-called two point method were discussed later. On the basis of this discussion it were found out how the accurate h could be got. The procedure of calculating h using constant heat flux method were listed and the free plant experiment are used to prove the method-s accuracy.