FROST CHARACTERISTICS AND HEAT AND MASS TRANSFER OF FIN-TUBE MODEL UNDER HEAT PUMP CONDITION

摘要

The present study investigated frost characteristics and heat and mass transfer coefficient of fin-tube model under heat pump condition. The test condition was air temperature from 0.5 to 7°C, absolute humidity from 3.17 to 4.01 g/kgDA, air velocity from 0.5 to 2.5 m/s, coolant temperature from -15 to -5°C and fin pitch from 1.3 to 2 mm. The effect of the distance from the leading edge on the frost thickness was larger than the effect of distance of tube. The frost surface temperature at the leading edge was higher than that at the trailing edge, because the frost blocks heat transfer between fin surface and air due to its thermal resistance. Correlation equations for the average frost thickness, frost surface temperature, heat transfer coefficients, and mass transfer coefficients were proposed. The proposed correlation equation for the average frost thickness agreed with the measured data within the maximum deviation of 20% when the average frost thickness was over 0.2 mm. The proposed correlation equation for the average frost surface temperature agreed with the measured data within the maximum deviation of 15%. The proposed correlation equation for the heat and mass transfer coefficients agreed with the measured data within the maximum deviation of 13 and 8%, respectively.