Hydrodynamics and heat transfer of multiple droplets successively impacting on cylindrical surface

• Hydrodynamics and heat transfer of multi-droplet impact on cylindrical surface. • Multi-droplet interaction and anisotropy induced by cylindrical surface. • Liquid-vapor interface temperature caused by anisotropy and internal flow field. • The effect of vertical space between droplets on heat transfer performance. • The effect of cylinder diameter on heat transfer performance. Based on the sparseness of research on the multi-droplet impact coupled with the anisotropy induced by cylindrical surface, in this paper, the hydrodynamics and heat transfer of multiple droplets successively impacting on cylindrical surface are deeply studied with three dimensional numerical simulation method. The comparison of single, two and even three droplets impacting on the heated cylindrical surface is carried out, and the effect of vertical space between successive droplets is discussed. Moreover, the influence of cylinder diameter on the hydrodynamics and heat transfer of multi-droplet impact is analyzed in detail. The results show that, the combination of multi-droplet interaction and anisotropy induced by cylindrical surface greatly affects the global heat flow, heat transfer coefficient, temperature distribution of liquid-vapor interface. By decreasing the vertical space between successive droplets impacting on the heated cylindrical surface, the heat transfer performance is obviously improved. Increasing the cylinder diameter boosts the heat transfer performance, but once the cylinder diameter augments to a certain value, the change of cylinder diameter no longer has an effect on the heat transfer performance, which is very close to the flat surface situation.