Flow Distribution Characteristics in Microchannel Heat Sinks in Pumping Liquid Cooling System

Abstract

With the continuous improvement of pump-driven liquid cooling requirements for electronic devices, the cooling requirements for multiple dispersed units are inevitable, resulting in higher requirements of equal cooling capacity for parallel microchannel evaporators. Because of the existence of negative slope region in the characteristic curve of two phase flow in microchannel sink, the flow excursion will occur. The flow distribution in the parallel microchannel evaporator is simulated with ammonia as the working medium, and the effects of inlet subcooling degree, heat flux and length of connecting pipe on flow characteristic curve in a microchannel evaporator are studied. Besides, the influence of flow excursion on the overall temperature distribution of evaporator, and the influence of heat flux, inlet subcooling degree, and length of connecting pipe on the flow distribution of two parallel evaporators are investigated. The results show that the flow excursion between evaporators does not necessarily deteriorate the heat transfer capacity of the system, and the arrangement of heating flux, inlet and outlet connecting pipes has a great influence on the stability of the parallel evaporator system.

Keywords

• microchannel
• instability
• flow excursion
• two-phase flow
• numerical simulation