Share

Experimental study of a vapor-liquid ejector performance for compressor oil pumping.

Number: 2387

Author(s) : ALAM M., MILJKOVIC N., ELBEL S.

Summary

During the vapor-compression refrigeration system operation, some amount of the compressor lubricating oil is inevitably discharged from the compressor, and this oil gradually accumulates in other system components. Oil retention in the system becomes crucial if this deposited oil does not eventually return to the compressor. The heat exchangers’ effectiveness and the compressor reliability are reduced due to the larger oil retention volume in the heat exchangers. A potential solution to this oil retention problem could be utilizing a two-phase ejector in an HVAC&R system to pump the accumulated compressor oil from the system components, for example, the evaporator, and ensure sufficient oil return to the compressor. So far, refrigerant ejectors are used in vapor-compression systems mainly for expansion work recovery and evaporator liquid overfeed. In this paper, a novel method aimed at pumping the accumulated oil using an ejector is introduced, and the performance of a vapor-liquid ejector for the oil pumping application is experimentally investigated. An experimental test facility consisting of an oil separator and a dedicated ejector for oil pumping is built and integrated with a standard two-phase ejector system using R744 (CO2) as the refrigerant with PAG 46 oil. A portion of the high-pressure R744 vapor stream at the compressor outlet is bypassed and used as the motive fluid for the ejector, and the PAG 46 oil is entrained through the ejector suction chamber. For the initial experimental study, a standard two-phase R744 ejector geometry is used to gain insights into the oil entrainment capability and other ejector performance metrics. Experiments are conducted for a wide range of motive inlet pressures and flow rates. The vapor-liquid ejector performance is characterized by different parameters such as bypass ratio, entrainment ratio, pressure lift, and compression efficiency. Experimental results reveal valuable insights regarding the oil entrainment capability through the vapor-liquid ejector for the considered test conditions and ejector geometries.

Available documents

Format PDF

Pages: 10 p.

Available

Free

Download

Details

  • Original title: Experimental study of a vapor-liquid ejector performance for compressor oil pumping.
  • Record ID : 30033150
  • Languages: English
  • Subject: Technology
  • Source: 2024 Purdue Conferences. 20th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2024/07/17

Links


See other articles from the proceedings (104)
See the conference proceedings

Indexing