已加工表面热源模型研究及磨削温度场数值模拟

摘要

The distributing shape of the heat source on machined surface is constructed to numerically simulate grinding temperature field with the shallow grinding model.Adopting the circular arc heat source model and the right triangular heat source on wheel/workpiece contact surface,the inverse heat transfer analysis is completed by the temperature matching method.The shape of the heat source on a machined surface is usually supposed as right triangle,triangle,parabola or ellipse.However,the above suppositions are based on specified grinding conditions,and are not generally applicable to all grinding conditions.Neglecting the above suppositions,the shape of the heat source on machined surface can be obtained with the proposed scheme according to specific grinding conditions.A shallow grinding model is established by finite element method to analyze the grinding temperature field of the workpiece,and a thermography camera is used to measure the real grinding temperature field.It is found that the shape of the heat source on machined surface varies with the change of grinding conditions.A comparison between the measured and simulated results indicates that the relative error of the maximum temperature on the machined surface in grinding zone ranges from 0.8％ to 9.5％,and the shallow grinding model can accurately simulate the grinding temperature field.%为了利用浅磨模型对磨削温度场进行数值模拟,基于圆弧热源模型、砂轮和工件接触表面直角三角形热源,采用温度匹配法进行了反传热分析,建立了已加工表面热源分布形状的计算方法.该方法不需预先假设已加工表面热源的分布形状,即可根据具体的磨削条件,获得相应的热源分布形状,解决了以往已加工表面热源的分布形状常被假设为直角三角形、三角形、抛物线和椭圆等形状,但上述假设都是基于特定的磨削条件,不能普遍适用于所有磨削工况的问题.采用有限元法建立了磨削温度场的数值仿真模型(浅磨模型),计算了工件的磨削温度场,采用热成像仪测量了磨削温度场,结果表明:已加工表面热源的分布形状随着磨削条件而改变,磨削温度场的模拟结果与测量结果具有很好的一致性,磨削区已加工表面最高温度的模拟值与测量值之间相对误差在0.8％～9.5％之间,建立的浅磨模型可以准确地模拟工件的磨削温度场.