Comprehensive augmentation heat transfer from combustion gas of high temperature

摘要

The authors studied the combined augmentation and interaction of radiation and convection from combustion gas of high temperature, whose waste heat is often recovered in a shell-tube heat exchanger - an airpreheater. Focusing on its heat transfer mechanism, this paper studied three kinds of radiation elements with different shapes of their cross sections: plain plate, "+" and "gamma" shaped sections. Beside plain radiation plate, there are two kinds of radiation-disturbing elements designed to intensity the disturbance in flow field in addition to their augmentation of radiation heat transfer. In order to determine the effects of heat transfer augmentation, a model of radiation-convection interactionhas been established. Numerical and experimental studies have been carried out on these three kinds of radiation elements. The calculation shows that these radiation elements are quite effective in enhancing both the radiation and convection heat transfer. The experiments supported the results of numerical analysis with satisfactory accuracy.