Abstract: The onset of nucleate boiling(ONB)in the porous media with internal heat source was experimentally investigated.This paper adopted electromagnetic induction heating method to heat the pebble bed stacked with 8mm diameter steel balls.The inflexion of wall temperature was used to determine ONB.The influence factors of ONB were analyzed at the superficial velocity ranging from 0.025 m穝^-1 to 0.050 m穝^-1,heat flux ranging from 7.5 kW穖^-2 to 52 kW穖^-2.The temperature of wall had an inflexion clearly because of enhancement of heat transfer.The superheat of wall and heat flux required at ONB were smaller when the location was closer to the exit because temperature gradient decreased in the boundary layer.The superheat of wall and heat flux required at ONB were higher when velocity was higher because heat transfer was enhanced.

Key words: internal heat source, porous media, ONB

摘要： 对含内热源多孔介质通道内过冷沸腾起始点(ONB)的特性进行了实验研究,采用壁温拐点法确定了ONB。在表观流速为0.025~0.050 m·s^-1,热通量为7.5~52 kW·m^-2的范围内研究了各参数对ONB的影响规律。实验结果表明:出现ONB时壁温存在一个明显拐点;越靠近实验段出口,出现ONB所需壁面过热度越小,表面热通量越低;表观流速越高,出现ONB所需壁面过热度越大,表面热通量越高。

关键词: 内热源, 多孔介质, ONB