Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 16, 2023 - March 17, 2023
The aim of this study is to investigate the effects of twisted tape insert on the refrigerant horizontal evaporator tube on pressure drop increase and heat transfer enhancement. R410A was used as the refrigerant. Experiments were conducted under seven different tape insert conditions: five types of twisted tape with different pitches, flat tape without tape twist and smooth tube. Pressure drop in the test section and heat transfer coefficient were measured by varying the refrigerant quality under mass velocity conditions of 360-630 kg/m2s. Insert of twisted tapes resulted in an increase of the pressure drop in all conditions, but the increase ratio from the smooth tube decreased as the twist pitch ratio H/d increased. On the other hand, the effect of tape insert on heat transfer enhancement was more pronounced in a dryout region where the refrigerant quality was above 0.85, and the increase ratio of the heat transfer coefficient compared to the smooth tube increased up to about 1.7 at a high mass velocity over 500 kg/m2s.
