Effect of Stefan flow on the flow field and heat transfer near wall of supercritical carbon dioxide flowing over a stationary spherical particle

Abstract

In industrial applications, the phenomenon of scCO2 (supercritical carbon dioxide) flowing over particles is quite common. Considering that the scCO2 is chemically inactive but has high solubility, the pure Stefan flow will present without the related diffusion of a chemical reaction component and reaction heat, during the process of a spherical particle in the solid phase dissolved in a system of scCO2. To this, particle resolve-direct numerical simulation without considering the role of gravity and buoyancy is employed in this paper to investigate the high-temperature scCO2 flowing over a low-temperature stationary sphere with the uniformly, normally, and outward distributed Stefan flow on its surface, with the above cases conducted in the process of small variations on physical properties of scCO2. We present a series of variables in the flow field and temperature field near the sphere surface to study the effects of Stefan flow on them compared with cases without Stefan flow. Related distribution details of the velocity boundary layer and the temperature boundary layer near the sphere surface under conditions with or without the Stefan flow are also presented and analyzed. Different from other similar studies, our study also pays more attention to variables of the local fluid field as well as temperature field near the surface of the spherical particle. The results show that the presence of Stefan flow will reduce flow resistance of the freestream but inhibits heat transfer performance. Simpler correlations in form compared with previous well-established correlations are presented and are used to describe the operating conditions proposed herein.