| Title |
Flow Condensation Heat Transfer Coefficients of R22, R410A and Propane in Aluminum Multi-Channel Tube |
| Keywords |
Flow condensation ; 흐름 응축 ; Multi-channel flat tube ; 다채널 평판관 ; R22 ; 냉매 22 ; R410A ; 냉매 410A ; Propane ; 프로판 |
| Abstract |
Flow condensation heat transfer coefficients(HTCs) of R22, R410, Propane (R290) were measured inside a horizontal 9 hole aluminum multi-channel flat tube. The main test section in the refrigerant loop was made of a 0.53m long multi-channel flat tube of hydraulic diameter of 1.4mm. Refrigerant was cooled by passing cold water through an annulus surrounding the test section. Data were obtained in qualities of 0.1～0.9 at mass flux of 200～400kg/m2s and heat flux of 7.3～7.7kW/m2 at the saturation temperature of 40℃. All popular heat transfer correlations in single-phase subcooled liquid flow and flow condensation originally developed for large single tubes predicted the present data of the multi channel flat tube within 25% deviation when effective heat transfer area was used in determining experimental data. This suggests that there is little change in flow characteristics and patterns when the tube diameter is reduced down to 1.4mm diameter range. Hence, a modified correlation based on the present data was proposed which could be applied to small diameter tubes with effective heat transfer area. The correlation showed a mean deviation of less than 20% for all data. |