Intensification of heat transfer at propane pool boiling on single horizontal tubes

Abstract

A set of experiments was carried out with propane pool boiling on the smooth and porous surfaces of horizontal tubes in the saturation pressure ranges p = 3.45 to 13.8 bar ($\text{p}\text{p}{}_{\mathrm{c}}\text{= 0.081}\text{to}\text{0.323}$), temperature intervals − 10 to + 40 °C, and heat flux ranges 10² to 10⁵ W·m⁻². Three modes of heat transfer were determined: free convection, a transitional mode and developed boiling. Good correlation between the experimental data on smooth tubes and the data published in other references was observed. The dependence of boiling process on saturation pressure and the influence of porous coating parameters on heat transfer intensity were studied. Samples of smooth tubes, tubes with small roughness and tubes with gas-thermal metal sintering on the surface were used for the experiments. Remarkable heat transfer enhancement of up to 2.5–3 times was observed for propane pool boiling on porous horizontal tubes, in comparison with that on smooth and small roughness tubes over the heat flux intervals tested.