小型高温加热装置内部传热特性的模拟计算

Numerical Simulation of Heat transfer Characteristics in a High Temperature Heating Device for Experiment

以用于小型金属试样材料高温动态力学性能试验中的加热装置为研究对象,对与实验室现有小型压入测试试验机相匹配的加热装置进行传热特性研究。运用数值模拟方法得到并分析动态传热过程,以试样内能增加量一致时所需时间为衡量指标,讨论了总输入功率一定时,腔体几何参数对试样升温效率的影响。研究表明:随着传热过程进行,腔体对流热损失比重逐渐减小,辐射热损失比重逐渐上升并最终占据主导地位;在设计与优化加热装置腔体结构时,适当增大开口比有利于加快试样升温速度;开口比一定时适当增加高宽比或改变腔体形状也对改善试样升温效率有利。

The research object is the high temperature heating device used in the dynamic mechanical properties of materials under certain high temperature conditions in this paper.The device was designed according to the small-sized press-in material testing machine developed by our laboratory.Taking the time required for the increase of internal energy of the sample as a measure,the effect of cavity geometry on the heating efficiency of the sample is discussed when the total input power is constant based on numerical simulation.The results show that as the heat transfer process proceeds,the proportion of convective heat loss in the cavity gradually decreases,and the proportion of radiant heat loss gradually increases and eventually dominates;When designing and optimizing the cavity structure of the heating device,appropriately increasing the opening ratio is beneficial to speed up the heating rate of the sample;Appropriate increase of the aspect ratio or changing the shape of the cavity when the opening ratio is constant is also beneficial to improve the heating efficiency of the sample.