Investigation on oblique shock waves occurred in the supersonic carbon dioxide two-phase flow

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.

In the refrigeration systems using the two-phase flow ejector, it is important to understand expansion waves and shock waves which are generated at the outlet of the nozzle. The theoretical oblique shock wave relations are derived for extreme conditions. Numerical analysis of the oblique twophase flow is also presented. Two types of two dimensional convergent-divergent nozzles with and without the inclined wall are used to measure pressure profiles along the nozzles wall. The two-phase flow in the divergent section of the nozzle obviously exhibits the supersonic decompression behavior. Numerical results can represent the experimental results with fairly good precision, but the reflections of the oblique shock wave cannot be predicted. The diameter of the droplet in twophase flow in the nozzle is guessed by this experiment to be the order of 5 [μm] and momentum frozen phenomenon occurs in this situation. The experimental oblique shock wave has the particular character of the two-phase flow, which is never seen in single phase flow explained by gas dynamics. The observation of the present study reveals the intrinsic feature that appears only in the supersonic two-phase flow.