The Weak and Strong Oblique Shock Waves Appeared on the Carbon Dioxide Two-phase Flow in the Ejector Refrigeration Cycle

Abstract

After the Great East Japan Earthquake, the saving energy became the one of the most important issues. Especially, saving the electrical power for air-conditioning at summer time is a problem of great urgency. We have been developing the ejector refrigeration system which can improve coefficient of performance of refrigeration systems by converting exhausted expansion energy into useful pressure energy. The performance of the ejector is greatly affected by the pressure recovery at the mixing section in the ejector. It is elucidated by our recent research on the carbon dioxide refrigeration cycle that the pressure recovery at the ejector is performed by oblique shock waves appeared in the mixing section. The purpose of this research is to clarify the characteristics of the two-phase flow oblique shock waves in the supersonic carbon dioxide two-phase flow. It is shown by the theoretical analyses that the two types of oblique shock waves occur on the supersonic two-phase flow. One is the week shock wave behind of which the flow is still a subsonic state. The other is the strong oblique shock wave which has a large pressure recovery. And the experimental research also carried out by using the carbon dioxide two-phase flow channel. The theoretical results are compared with the experiment.