石蜡相变材料在同心环隙管内的基本传热行为

Heat transfer performance of paraffin as a phase change material(PCM) in a concentric annulus

强调石蜡侧传热行为的强化作用,在自行搭建的传热装置上,以热媒侧为恒定温度热源,考察了石蜡相变材料蓄热过程的传热行为,研究了St(斯蒂芬数)、蓄热时间、石蜡温度、径向距离之间的变化规律。本工作发现,翅片在热传导控制的条件下的传热效果要优于对流传热控制时的效果。在热媒温度为65,70和75℃时,翅片管较光滑管,蓄热时间分别缩短77.5%,69.2%和56.3%,表明翅片对石蜡的传热强化效果显著。而且,蓄热时间和相界面推移速度均随St呈单调函数规律发展。

In order to the investigate heat transfer enhancement in paraffin side, a heat transfer experimental setup was constructed. Heat transfer performance of thermal storage processes of paraffin PCM was studied using a constant temperature heat source as the heating medium. The relationships between Stefan number, thermal storage time, paraffin temperature and radial distance were also investigated. The result shows that heat transfer effect with a finned tube under conditions of heat conduction is better than that under conditions of convection. With heating medium temperatures of 65℃, 70℃ and 75℃, when comparing the finned tube with the plain tube, thermal storage times are shortened by 77.5 %, 69.2 % and 56.3 % respectively, demonstrating the beneficial effect of the fins on the heat transfer enhancement in the paraffin. In addition, the thermal storage time and the lapse rate of phase interface vary monotonically with Stefan number.