全玻璃真空太阳能热水器强化换热机理分析

本文应用Ansys Fluent软件对加装导流板全玻璃真空太阳能热水器内自然对流流场进行三维数值模拟计算,并与实验进行对比分析,通过改变导流板长度和位置改善热水器内的流动和换热。结果表明,与无导流板结构相比较,加装导流板后管内涡流消失,流体流动稳定,有利于管内自然对流,增强了换热效果,水箱内温度分层效果明显,有助于提高换热效率;同时得出导流板长度最佳选择范围为1.4～1.6 m,导流板加装在玻璃管中间位置与距管中间位置偏下1/2之间范围内更有助于换热。

Mechanism Analysis for the Heat Transfer Enhancement With All-Glass Vacuum Tube Solar Water Heaters

Three-dimensional numerical simulation calculates has been done by Ansys Fluent software for the all-glass vacuum tube solar water heaters with guiding plate in this paper,and comparative analysis is carried on with the experiment.It is aimed at improving water heater inner flow and heat transfer by changing the guiding plate of different lengths and upper and lower position. Compared with no guiding plate structure,It shows that,with a guiding plate,the vortex flow inside the tube disappears and the flow becomes steady,which is helpful to enhance the fluid flow and heat transfer.The temperature layering effect in the water tank is obvious which contributes to improving the water heaters efficiency.Meanwhile,It shows that the optimum selection range of the guiding plate length can be limited within 1.4-1.6 m and it help to the heat exchange if the guide plate is installed between the intermediate position and 1/2 below the intermediate position of the glass tube.