Author:
Haider Syed Angkan,Wang Xin,Elbel Stefan
Abstract
<div class="section abstract"><div class="htmlview paragraph">The oil circulation rate (OCR) is a deciding factor for the performance of automotive air conditioning systems at both the system and component levels. OCR is defined as the percentage by mass of oil present in a representative sample of oil-refrigerant mixture drawn from the system at steady state. In recent years, many industries are opting for low-OCR compressors, and so the OCR values are getting smaller, making it even more important to be able to accurately measure the OCR in the system. All the different OCR measurement techniques rely on the ASHRAE Standard 41.4 for proper calibration. This standard describes OCR measurement using a sampling technique which involves connecting an evacuated sampling cylinder at the liquid line of the system at steady state to draw a sample containing the liquid mixture of refrigerant and oil. However, several factors such as orientation of sampling cylinder and valve opening speed can affect the OCR results. The flow entering the sampling cylinder initially consists of both liquid refrigerant and liquid oil. As the valve on the sampling cylinder is opened, the refrigerant undergoes flashing followed by recompression and re-condensation of vapor refrigerant, and simultaneous filling up with liquid mixture until pressure equalization between the system supply line and evacuated sampling cylinder is achieved. This two-phase, two-component, phase changing flow is complex, and for the present study, flow visualization using a high-speed camera and analytical tools are used to study the flashing flow of pure refrigerant entering an evacuated sampling cylinder. The obtained results are used to compare with those obtained with oil-refrigerant mixture to shed light on how parameters such as sampling cylinder orientation and valve opening speed can affect the measured OCR values.</div></div>
Reference17 articles.
1. Radermacher , R. ,
Cremaschi , L. , and
Schwentker , R.A.
Modeling of Oil Retention in the Suction Line and Evaporator of Air-Conditioning Systems HVAC&R Research 12 1 2006 35 56 10.1080/10789669.2006.10391166
2. Youbi-Idrissi , M. and
Bonjour , J.
The Effect of Oil in Refrigeration: Current Research Issues and Critical Review of Thermodynamic Aspects International Journal of Refrigeration 31 2 2008 165 179 10.1016/j.ijrefrig.2007.09.006
3. Shen , B. and
Groll , E.A.
A Critical Review of the Influence of Lubricants on the Heat Transfer and Pressure Drop of Refrigerants, Part 1: Lubricant Influence on Pool and Flow Boiling HVAC&R Research 11 3 2005 341 359 10.1080/10789669.2005.10391142
4. Liu , X. and
Hrnjak , P.
Oil Effects on Performance of Automobile A/C System Proceedings of the International Refrigeration and Air Conditioning Conference West Lafayette, IN, USA 2016
5. Wang , X. ,
Haider , S.A. ,
Hrnjak , P. , and
Elbel , S.
Transient Migration of Oil at Compressor Discharge and Suction during Startup Proceedings of the International Refrigeration and Air Conditioning Conference West Lafayette, IN, USA 2022
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献