In this study, the RPI wall boiling model is developed to investigate the surface roughness effect in the subcooled flow boiling. The surface roughness is simulated by two different schemes. A novel scheme for studying the effect of microstructure surface roughness on subcooled flow boiling is developed. The results of this newly developed scheme are compared with the traditional method and a smooth surface. A randomly distributed roughness is generated and used to present Direct Roughness Simulation. The turbulence stresses are simulated by using the k-ε model. The results of both the Surface Roughness Model and the Direct Roughness Simulation method are compared with those of the smooth surface. The surface roughness model changes the wall function near the wall while Direct Roughness Simulation creates randomly distributed cavities of the wall. Results show that the wall surface temperature decreases, and the average vapor volume fraction and heat transfer coefficient are increased by considering the microstructure surface roughness. The effects of different operating conditions such as pressure, heat flux, mass flux, and subcooled temperature on the characteristics of heat transfer in subcooled flow boiling are studied by considering microstructure surface roughness and smooth surface.

在这项研究中，RPI壁沸腾模型被开发来研究过冷流沸腾中的表面粗糙度影响。表面粗糙度通过两种不同的方案进行模拟。提出了一种研究微观结构表面粗糙度对过冷沸腾影响的新方案。将该新开发的方案的结果与传统方法和光滑表面进行了比较。生成随机分布的粗糙度，并用于呈现直接粗糙度模拟。湍流应力通过使用k-ε模型进行模拟。将表面粗糙度模型和直接粗糙度模拟方法的结果与光滑表面的结果进行了比较。表面粗糙度模型会更改壁附近的壁函数，而直接粗糙度模拟会创建壁上随机分布的空腔。结果表明，考虑到微观结构表面粗糙度，壁表面温度降低，平均蒸气体积分数和传热系数增加。通过考虑微观结构表面粗糙度和光滑表面，研究了压力，热通量，质量通量和过冷温度等不同工况对过冷沸腾中传热特性的影响。