Thermo-hydrodynamics of multiple drops impinging simultaneously on the grooved tubular surface and smooth cylindrical surface with different wettabilities

Abstract

This study used the VOF method to present the intrinsic thermo-hydrodynamics of multiple drops impinging on the grooved tubular surface and smooth cylindrical surface at the same time. Furthermore, the wall surface wettability was investigated for its influence on dynamics and heat transfer. The results show that for the hydrophilic surfaces, the non-dimensional liquid film contact area on the smooth cylindrical surface is approximately-four times as large as that on the grooved tubular surface. The height of the central uprising sheet on the smooth cylindrical surface outweighs that on the grooved tubular surface due to the corrugations’ inhibition and anisotropy of tubular surfaces. Moreover, the latter exhibits a significantly higher convective heat transfer coefficient, nearly-four times that of the smooth cylindrical surface initially. Compared with a stable liquid film on the grooved tubular surface, the variable liquid film on the smooth cylindrical surface affects the temperature distribution significantly. When the surface becomes hydrophobic, the corrugations’ inhibition is highlighted. As surface hydrophobicity increases, the difference in the liquid film contact area and global heat flow is smaller between two surfaces. In the stable stage, the enhancement of the convective heat transfer coefficient on the hydrophobic grooved tubular surface is strengthened.