Share

Transcritical leakage flow in CO2 expander.

Author(s) : FUKUTA M., ADACHI M., YANAGISAWA T., et al.

Summary

Carbon dioxide (CO2) is considered to be an alternative to HFC refrigerants due to its nonflammability, non-toxicity and small global warming potential. To improve the performance of the CO2 refrigeration cycle, using an expander as an expansion device to recover a throttling loss has been examined. Since an inlet condition of the expander is supercritical and an exit is subcritical, leakage through a narrow clearance in the expander flows from the supercritical to the subcritical and is called a transcritical flow. The transcritical leakage flow has serious influence on the expander performance. It is, therefore, necessary to clarify the characteristics of the transcritical leakage flow through the narrow clearance. In this study, the transcritical leakage flow is modelled analytically and the flow characteristic is examined by the model. The calculated mass flow rate agrees with the experimental one. It is found that frictional loss is predominant both in the supercritical and two phase region at any inlet temperature tested in this study. In addition, the sealing effect of oil on the transcritical leakage flow is shown to be little.

Details

  • Original title: Transcritical leakage flow in CO2 expander.
  • Record ID : 2011-0033
  • Languages: English
  • Source: Measures to address climate change. 2010 International Symposium on Next-generation Air Conditioning and Refrigeration Technology: February 17-19, Tokyo, Japan.
  • Publication date: 2010/02/17

Links


See other articles from the proceedings (75)
See the conference proceedings

Indexing