Influence of Stefan flow on the drag coefficient and heat transfer of a spherical particle in a supercritical water cross flow

The interaction between the fluid and particles is the key to obtain accurate flow and heat transfer rules. For a reactive particle, the Stefan flow will affect the mass, momentum, and energy transfer between the particle and the fluid. The Stefan flow on the coal particle surface cannot be neglected in supercritical water gasification technology. In this paper, the influence of different Stefan flow intensities on the drag coefficient (Cd) and the Nusselt number (Nu) of supercritical water (SCW) cross flowing around a fixed spherical particle with Re in the range of 10-200 is studied; at the same time, the velocity and temperature boundary layers and the flow field around the particle are analyzed. For the influence of the dramatic change of the thermophysical properties of SCW near the pseudo-critical point, simple analysis of the drag coefficient and heat transfer of the particle with Stefan flow is conducted. The results show that with the increase in Stefan flow intensity, Cd and Nu decrease and the thickness of velocity and temperature boundary layers increases. A model of the particle with Stefan flow is constructed, and the Cd and Nu correlation formulas of the particle with Stefan flow are obtained.

Automated summary

This study investigates the impact of varying Stefan flow intensity on the drag coefficient and Nusselt number of supercritical water flowing around a fixed spherical particle. Results show that with increasing Stefan flow intensity, both Cd and Nu decrease while the thickness of velocity and temperature boundary layers increases. Additionally, a model for particles with Stefan flow is constructed and correlation formulas for Cd and Nu are derived.