Natural convective boiling in vertical annular tubes filled with porous medium

Abstract

Experimental and theoretical studies were carried out on the natural convective boiling heat transfer and critical heat flux (CHF) in uniformly heated vertical annular tubes filled with a porous medium and submerged in saturated water and R11 liquid. The heat transfer experimental results were compared with the case without a porous medium. It was shown that heat transfer is greatly enhanced by the porous medium in the region of low heat flux. By adopting a simple mixing flow model, a generalized approximate relationship was derived for predicting the CHF. The prediction agrees relatively well with the CHF experimental data.