工质回流式微通道圆盘热沉的热有效性构形研究

Constructal optimization based on thermal effectivity for circular disc heat sinks with reverting microchannels

建立了圆心回流式微通道圆盘热沉的三维模型,基于构形理论,考虑粘性耗散,研究了在层流流动范围内质量流率、热流密度和微通道分支数对圆心回流式微通道圆盘热沉压降、最高温度和热有效性的影响。数值计算结果表明:随着质量流率的增大,热沉压降逐渐增大,且增大幅度逐渐加大,最高温度和热有效性逐渐减小,但减小趋势逐渐趋缓;随着热流密度的增大,热沉压降基本保持不变,最高温度和热有效性近似呈线性增长;不同质量流率和不同热流密度条件下,均是微通道分支数越多,热沉压降和最高温度越小,热有效性越高,热沉整体传热性能越好。所得结果可为工质回流式微通道圆盘热沉的实际热设计提供理论支撑。

The 3-D model of circular disc heat sink with central reverting microchannels is established. Based on theconstructal theory,considering the viscous dissipation,the influences of mass flow rate,heat flux and the number ofmicrochannel branches on pressure drop,maximum temperature and thermal effectivity of the circular disc heat sinkwith central reverting microchannels in the laminar flow range are investigated. The numerical results show that,with the increase of mass flow rate,the pressure drop of heat sink increases gradually,and the increasing amplitudeincreases.The maximum temperature and the thermal effectivity decrease,but the decreasing trend gradually slowsdown.With the increase of the heat flux,the pressure drop of the heat sink almost remains unchanged,and the maximumtemperature and the thermal effectivity approximately increase linearly. Under the conditions of different massflow rates and different heat fluxes,the more the number of microchannel branches,the smaller the heat sink pressuredrop and the maximum temperature,the higher the thermal effectivity,the better the overall heat transfer performance.The results obtained here can give some theoretic supports for the practical thermal design of circular discheat sink with reverting microchannels.