Numerical Simulation Of Fluid-solid Coupled Heat Transfer Process In Microchannel Cooler

Thermal effect caused by accumulation of waste heat in the solid-state laser is the key issue of hindering improving the laser’s output power. Microchannel Cooler has advantages of simple structure, small volume and high thermal efficiency. It can effectively decrease the accumulation of heat inside the laser. At the same time, it is benefit to realize the miniaturization of laser. So the microchannel cooler becomes one of the hot spots in the laser cooling technology now. However, the miniaturization of microchannel scale makes that small differences of experimental conditions or operation can cause the diversity of the experimental results. So the study of flow and heat transfer characteristics in the microchannel has not formed a unanimous conclusion.This article takes common conventional microchannel without contraction and microchannel with contraction in the literature as the research objects, establishes the corresponding two-dimensional flow model based on the study of CFD. The flow from laminar to turbulent range is simulated with the help of CFD software, FLUENT. It’s found that the contraction considered or not is a significant reason leading to a difference between the simulation results and the experimental results. It determines the influence factor and rule of the microchannel flow characteristics, investigate the effect of contraction structure to transition Reynolds number, find that the size of the contraction ratio has an important influence on the Reynolds number. The study determines the maximum transition Reynolds number Rec=3000and lay a foundation for the design and simulation of the microchannel cooler using for solid-state lasers of laboratory.Then this article takes the microchannel cooler using for solid-state lasers of laboratory as the research object. The two-dimensional model of the flow and heat transfer in the microchannel is established. The influence factors and rules of the heat transfer coefficient in microchannel cooler are discussed. Through the comparative study of different sizes of the microchannel, it was found that:under the same Reynolds number, the smaller diameter of the microchannel, the greater heat transfer coefficient and the better cooling effect it has. However, the decrease of the microchannel diameter will also lead to the rapid increase of flow resistance. The result also shows that the relationship of temperature properties has little effect on heat transfer characteristics. The results of this article have great significance on the study of the flow and h eat transfer characteristics in the microchannel, and provide a theoretical basis for the research and development of the microchannel cooler using for solid-state lasers of lab oratory and the acquisition of high-average-power laser at the same time.