基于连续激光加热法测量金属材料的比热容

提出了一种基于连续激光加热测量金属材料比热容的方法。建立有限尺寸试样在连续加热条件下的传热和准稳态测量模型,使用COMSOL Multiphysics仿真软件进行数值模拟验证。考虑实际测量过程中金属试样存热损失,对模型进行了热损失修正,仿真验证了在试样表面综合传热系数小于80W/(m2·K)的情况下,修正后的测量模型偏差小于±0.81%。使用532nm连续激光器作为加热源,加工了TC4钛合金、316L不锈钢、45钢、7075铝合金和T2紫铜等金属试样并在试样上打微孔,对受热面喷涂石墨,使用极细K型热电偶对试样内部温升进行测量,并使用T2紫铜的参考值对系统参数进行标定。实验结果表明,在常温下实验装置的测量重复性优于0.91%,各金属试样测量结果平均值与数据手册参考值的相对偏差均小于±3.1%。测量结果相对扩展不确定度为U=3.66%(k=2)。

Measurement of Specific Heat Capacity of Metal Materials by CW Laser Heating Method

A method for measuring the specific heat capacity of metal samples by CW laser heating was proposed. Heat transfer model of finite size specimen and the quasi-steady state measurement model under continuous heating were established and verified by numerical simulation with COMSOL Multiphysics software. Considering the heat loss of contact heat transfer, convection heat transfer and heat radiation in the actual measurement process, the heat loss of the measurement model was modified. The simulation results show that the deviation of the modified model is less than ±0.81% when the comprehensive surface heat transfer coefficient is less than 80W/(m2·K). The experimental measurement device was set up, 532nm CW laser was used as heating source. Titanium alloy TC4, stainless steel 316L, steel 45, aluminum alloy 7075 and copper T2 samples were processed and drilled micropore on each sample. The heated surfaces of the samples were coated with graphite and the temperature rise inside the samples was measured by using a very fine K-type thermocouple. The specific heat capacity of copper T2 was used to calibrate the system parameters. The experiment results show that the repeatability of measurement is better than 0.91%, the relative deviation between the average value of the measurement results of each metal sample and the reference value of the data manual is less than ±3.1%. The relative expanded uncertainty is evaluated to be U=3.66%(k=2).