Boiling Heat Transfer and Pressure Drop of R410A Inside Horizontal Circular Tube Inserting a Twisted-Tape

UZUHASHI Hideo, TSUNODA Hiroyuki, KAWAI Toshiyuki, TORIKAI Eiko, ICHIMIYA Koichi

doi:10.11322/tjsrae.21-22

Bibliographic Information

Other Title

ねじりテープ挿入水平円管内におけるR410A の沸騰熱伝達と圧力損失

Abstract

<p> This paper aims to investigate the effect of a twisted-tape insert on heat transfer enhancement in the evaporator of air conditioner. A mixed refrigerant R410A was used in this experiment. Two types of evaporation tubes with different inner diameters, 17.05 mm and 7.93 mm, were prepared at the test section. Experiments were conducted over a wide range of mass velocities from 77 to 613 kg/m²s. In addition, several types of twisted tapes with different twist pitches were made for each tube. The pressure drop and heat transfer coefficient of the test section were measured by changing the refrigerant quality for the smooth tube and the tape-inserted tube. Furthermore, the refrigerant flow patterns were visualized upstream and downstream of the test section. It was found that the increase in pressure drop due to the twisted-tape insert was more pronounced when the flow pattern was a stratified-wavy. While the heat transfer coefficient of the tape-inserted tube was almost the same as that of the smooth tube when the flow pattern was annular, the increase in the heat transfer coefficient due to the tape insertion was clearly observed as the pattern shifted to a mist flow.</p>

Journal

Transactions of the Japan Society of Refrigerating and Air Conditioning Engineers

Transactions of the Japan Society of Refrigerating and Air Conditioning Engineers 38 (4), 287-, 2021-12-31

Japan Society of Refrigerating and Air Conditioning Engineers

Keywords

Details 詳細情報について

CRID: 1390576118538952448

DOI: 10.11322/tjsrae.21-22

ISSN: 2185789X; 13444905

Text Lang: ja

Data Source

JaLC

Abstract License Flag: Disallowed

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