高温流化床与浸入水平管束表面换热特性的实验研究

AN EXPERIMENTAL STUDY OF HEAT TRANSFER FROM TUBE ARRAYS IN THE HIGH-TEMPERATURE FLUIDIZED BED

本文研制出一种适用于高温流化床与埋入管表面间换热系数的测试元件,在水平单管或错排管束的条件下,用此元件对沿管周向的局部时均传热系数进行了实验测定.测出了流化床与埋入水平单管和管束的传热系数及其周向分布随流化速度、管间距的变化规律,得出适于本试验条件的管束平均换热系数经验公式。恰当安排管束的间距,不仅能改善管周向换热系数分布的均匀性,而且能提高整个床层与浸入表面间的换热能力。

A high-temperature heat transfer probe has been designed for measuring the local heat transfer coefficients between immersed tube surface and fluidized bed. By using this probe, the time averaged local heat transfer coefficients around a single or a central tube in an array were investigated. The Variation of heat transfer coefficients and its peripheral distribution between the bed and the tube with superficial velocity and the pitch in arrays were described here and the correllation of peripheral averaged heat transfer coefficients suited to this experiment conditions was obtained. It has been found that the suitable spaced tube array not only improve the uniformity of heat transfer around the tube, but also increase the heat transfer ability between the whole bed and immersed surfaces.