Subcooled pool boiling performance on conical micro-pillars structures surfaces

Abstract

Experimental investigation to evaluate the pool boiling performance and mechanisms for liquid subcooling of 0 K, 5 K, 10 K and 20 K on four conical micro-pillars structured surfaces is conducted in this study. The critical heat flux and bubble behaviors on different conical micro-pillars structured surfaces are studied specifically. The results prove that higher critical heat flux can be obtained on conical micro-pillars structured surfaces, compared to the flat surface. S500 surface exhibits the highest heat flux among different conical micro-pillars structures surfaces under saturated condition owing to the increased bubbles. Bubble diameter is clearly decreased and the intensity of agitation is reduced with the degree of subcooling increasing. Thus, more nucleation sites can be activated under subcooled condition. The CHF increases with the increasing subcooling on micro-pillars structures surface due to the enhancement effect on natural convection as well as the inhibition effect on bubble growth and coalescence.