镍基高温合金GH3536表面早期结霜特性实验分析

以镍基高温合金GH3536光滑表面和具有疏水性能的微孔结构表面为研究对象,对其表面的早期结霜特性进行研究。定量分析了表面温度、相对湿度和表面润湿性对霜晶形貌和生长速率的影响。研究结果表明:随着表面温度的降低,霜晶形成的初始时间缩短,生长速率加快,获得四种典型的霜晶形貌。相对湿度的增大导致霜晶数量的增加和形貌的改变,而液滴的凝结和冻结时间与相对湿度无关。对于相同的霜晶形貌,增大相对湿度对霜晶生长有一定的促进作用,而当霜晶形貌变化时,相对湿度的改变将导致霜晶高度和生长速率产生显著差异。由微孔结构构成的疏水表面能够通过增大成核势垒和接触热阻来有效地延迟霜晶的形成,但对随后霜晶生长和形貌的影响可以忽略。

Experimental analysis of early stage frosting characteristics on the surface of Ni-based GH3536 superalloy plate

Ni-based GH3536 superalloy smooth surface and microporous structured surface with hydrophobic properties were used as the object of study, and the early stage frosting characteristics of the surface were studied. The impact of surface temperature, relative humidity, and surface wettability on frost crystal shape and growth rate were investigated quantitatively. Results indicate that with the decrease of the surface temperature, the initial time of frost crystal formation is shortened, the growth rate of frost crystals is enlarged, and four types of frost crystal shapes are captured. The increase of relative humidity can increase the number of frost crystal and change frost crystal morphology, while the condensation and freezing time of droplets are independent of it. For the same frost crystal morphology, increasing the relative humidity has a certain promotion effect on the frost crystal growth, while when the frost crystal morphology changes, the change in relative humidity will result in significant differences in frost crystal height and growth rate. The hydrophobic surface made of micro-holes structures can evidently delay the formation of the crystal by increasing the nucleation barrier and contact thermal resistance. However, the impacts on frost crystal growth and shape are negligible.