常温流化床局部瞬态热流测量中的若干问题

Some Aspects of the Measurement of Instantaneous Heat Transfer Coefficients in Fluidized Beds at Room Temperature

分析了在采用瞬态表面温度法测量常温鼓泡和循环流化床局部瞬态换热系数时所必须注意的若干问题 ,主要有 :A/D板、放大倍数、采样频率和探头材料的选取 。

Some important aspects including the choices of the probe materials, A/D board, gain and sampling rate are analyzed for the measurement of transient heat flux in room tempeature gas solid bubbling or circulating fluidized beds using the method of transient surface temperature method. The corresponding rules are proposed for the choices. Numerical modeling demonstrates the following: a. 12?bit A/D board employed in some previous literatures is not very suitable. It is better to choose 16?bit A/D board; b. The sampling rate should be at least 200?Hz; c. The gain should be chosen in such a way that the wavy component of the probe surface temperature signal is about 100～200 counters after A/D transform; d. It is best to choose such a metal as the probe material that its thermal conductivity is as low as possible and its thermal diffusivity is as high as possible.