采用将有限体积法求解三维层流传热方程获得的温度场耦合到ANSYS进行热变形分析的方法，研究了流道截面形状和尺寸对微通道水冷镜内传热现象和镜面热畸变的影响。计算了矩形、梯形、圆形3种截面形状以及3种不同水力直径(百微米量级)下微通道水冷镜的平均换热系数、温升和镜面热变形。结果表明，同一条流道，各壁面温度并不随激光辐照面和镜面呈对称分布，最高温度偏向下游；侧壁的换热系数最大，且沿水流方向逐步减小；流道距进水口距离越大，其换热系数越小。在3种截面形状微通道中，减小截面尺寸可获得较大换热系数，且梯形截面微通道水冷镜能获得最小的镜面热变形量，在热流密度为14730 W/m2，水力直径为239 μm，入口速度为2.54 m/s的条件下，其镜面热变形仅为0.016 μm。

The effect of cross-section shape and geometrical parameters of the channel on heat transfer and thermal deformation of the microchannel water-cooled mirror is studied by analyzing the temperature field obtained by using finite volume method to solve the three-dimensional steady laminar flow and heat transfer equations, and the deformation obtained by coupling the temperature field to ANSYS software. Three different cross-section shapes of microchannel, i.e., rectangle, trapezoid and circle, are investigated in this paper. Average heat transfer coefficient, temperature inereasing and thermal deformation of mirror of each shape examined with three geometrical dimensions, are simulated. It is found that for the same channel, temperature distribution is not symmetrical, the highest temperature moves to the downstream, the heat transfer coefficient of each interface is also different, the heat transfer coefficient of side wall is the biggest, heat transfer coefficient of other walls decreases along the water flow direction. For the mirror using the same shape microchannel and hydraulic diameter, the heat transfer coefficient decreases as the distance of the channel from water inlet increases. The average heat transfer coefficient and thermal deformation are related to hydraulic diameter and channel shape. Reducing hydraulic diameter may help to induce high heat transfer coefficient. The trapezoid channel mirror has the smallest thermal deformation among the three shapes channel mirrors. At the condition of heat flux of 14730 W/m2, hydraulic diameter of 239 μm and water inlet velocity of 2.54 m/s, the thermal deformation of the mirror with trapezoid channel is only 0.016 μm.