旋转封闭循环小通道内液态金属热驱动换热特性研究

高速旋转条件下,封闭循环小通道内的流体(热驱动介质)在浮升力的作用下会产生热驱动运动,将热量不断的从高温端携带至冷却端释放.本文通过数值模拟的方法,研究了离心力场下封闭循环小通道中,不同性质流体的流动和换热特性.重点分析了以液态金属锂、钠和钠钾合金为热驱动介质时,热驱动运动的换热特性Nu随Bu和Ro两个参数的变化规律.研究中发现在一定的Bu数变化范围内,以液态金属锂、钠以及钠钾合金为热驱动介质所得到的Nu均随Ro数的增大而减小;当Ro数相同时,Nu随Bu数的增加而变大.研究结果表明高转速,低加热量时,采用液态钠钾合金为热驱动介质可以得到最好的热驱动换热效果;在高转速,高加热量时以液态锂为热驱动介质时,热驱动换热能力最强.

Heat transfer characteristics of liquid metal thermal drive in rotating closed cyclic small channel

Using thermal drive in the small cyclic channel,heat can be efficiently transferred from the high temperature side to the cooled side.Numerical simulations were carried out to study the flow and heat transfer properties of different fluids under centrifugal force field.Three different liquid metals(Na,Li and alloy of Na-K) were applied as thermal drive medium(fluid inside the channel) and the average heat transfer coefficient Nu on the heated side varying with the Bu number and Ro number was studied.All the results show the average Nu number increases with Bu number and decreases with Ro number.Maximum heat transfer performance of thermal drive can be achieved in high rotating speed and lower heat flux if liquid Na-K was employed as thermal drive medium.When the rotating speed and heat flux both are high,the proper thermal drive medium is liquid Li which can result in maximum heat transfer performance.