EVAPORATION HEAT TRANSFER CHARACTERISTICS

AND CORRELATION FOR R410A-OIL FLOW BOILING

 IN 7 mm C-SHAPE HORIZONTAL SMOOTH TUBE

WANG Zhence¹  DING Guoliang¹  HU Haitao¹  WANG Kaijian²

(1. Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240;
2. Fujitsu General Institute of Air-Conditioning Technology Limited, Kawasaki 213-8502, Japan )

Abstract: Evaporation heat transfer characteristics of R410A- oil mixture in 7 mm C-shape smooth tube are investigated and a new correlation for R410A-oil mixture in 7 mm C-shape smooth tube is developed. The experiment is carried out at evaporation temperature 5 ℃, and test quality ranges from 0.3 to 0.8, oil concentration ranges from 1% to 5%, mass flux range from 200 to 400 kg•m^–2•s^–1. Oil enhances the heat transfer, and the heat transfer coefficient becomes much larger with the increase of oil concentration, and the largest increase of heat transfer coefficient caused by oil is about 30.1% as compared to that of pure refrigerant. A new heat transfer correlation for R410A-oil mixture in 7 mm C-shape smooth tube is developed based on refrigerant-oil mixture properties. It can agree with more than 90% experimental data within the deviation of ±15% and the average deviation and maximum deviation are 5.1% and 21.9% respectively.

Key words: C-shape tube Oil Heat transfer Correlation R410A

CLC No: TK124

Received  20060821, received in revised form 20070129