Szczepaniak Robert
Faculty of Aviation, Polish Air Force University, Dywizjonu 303 Street No 35, 08-521 Deblin, Poland.
Materials (Basel). 2022 Jul 7;15(14):4755. doi: 10.3390/ma15144755.
This paper deals with the problem of the influence of surface topography on the results of thermal diffusivity measurements when determined using the instantaneous surface heat source method, also called the pulse method. The analysis was based on numerical tests carried out using Comsol Multiphysics software. The results of experimental investigations on the actual material structure using an electron microscope, an optical microscope and a profilometer were used to develop a numerical model. The influence of the non-uniformity of the surface of the tested sample on the determined values of half-time of the thermal response of the sample's rough surface to the impulse forcing on the opposing flat surface was determined by developing the data for simulated measurements. The effect of the position of the response data reading area on the obtained simulation results was also analyzed. The obtained results can be used to improve the accuracy of experimental heat transfer studies performed on thin-film engineering structures depending on the uniformity and parallelism of the material applied to engineering structures. The difference in half-life determination error results for various analyzed models can be as high as 16.7%, depending on the surface from which the responses of the heating impulse are read. With an equivalent model in which 10% of the material volume corresponds to the rough part as a single inclusion, hemisphere, the error in determining thermal diffusivity was equal to 3.8%. An increase in the number of inclusions with smaller weight reduces an error in the determination of thermal diffusivity, as presented in the paper.
本文探讨了在使用瞬态表面热源法（也称为脉冲法）测定热扩散率时，表面形貌对测量结果的影响问题。分析基于使用Comsol Multiphysics软件进行的数值测试。利用电子显微镜、光学显微镜和轮廓仪对实际材料结构进行实验研究的结果来建立数值模型。通过对模拟测量数据的分析，确定了被测样品表面的不均匀性对样品粗糙表面对相对平面上脉冲激励的热响应半衰期测定值的影响。还分析了响应数据读取区域的位置对模拟结果的影响。所得结果可用于提高对薄膜工程结构进行的实验传热研究精度，这取决于应用于工程结构的材料的均匀性和平行度。根据读取加热脉冲响应的表面不同情况，各种分析模型的半衰期测定误差结果差异高达16.7%。在一个等效模型中，如果10%的材料体积对应于作为单个包含物的粗糙部分（半球体），热扩散率测定误差等于3.8%。如本文所述，增加重量较小包含物的数量可降低热扩散率测定误差。
