Volume 63

Experimental Investigation of NaCl Salinity on Pool Boiling Heat Transfer Performance and Bubble Behavior Yanwei Zhao, Ruichao Shang, Yuxin Wu, Junfu Lyu

Abstract

The boiling heat transfer characteristics of saline solutions, exemplified by seawater, play a critical role in the operational safety of industrial equipment. A clear understanding of the influence of salt concentration on heat transfer performance is therefore essential. In this study, pool boiling experiments were conducted using deionized water and saline solutions with concentrations of 1%, 3.5%, and 6% over a heat flux range of 20–200 kW/m². Two types of heating surfaces were employed: a plain and a structured pin-fin stainless steel surface. The results demonstrate that heat transfer performance deteriorates in saline solutions on both surfaces compared to deionized water. However, when the salt concentration exceeds 3.5%, further increases have a negligible impact on heat transfer. The wall superheat required for the onset of nucleate boiling (ONB) was found to increase with salt concentration: recorded as 7.01 K for pure water and 18.45 K for the 6% saline solution at plain surface. Compared to the plain surface, the pin-fin surface featuring a width-depth-pitch configuration of 500 μm significantly alleviated heat transfer degradation and reduced the wall superheat required for nucleation.

Keywords NaCl solutions, pool boiling, heat transfer, bubble dynamic, plain surface, pin-fin surface