In Tube Condensation:Changing the Pressure Drop into a Temperature Difference for a Wire-on-Tube Heat Exchanger  

作　　者：Louay Abd Al-Azez Mahdi Mohammed A.Fayad Miqdam T.Chaichan 

机构地区：[1]Energy and Renewable Energies Technology Center,University of Technology-Iraq,Baghdad,65035,Iraq

出　　处：《Fluid Dynamics & Materials Processing》2023年第9期2201-2214,共14页流体力学与材料加工（英文）

摘　　要：A theoretical study based on the Penalty factor(PF)method by Cavallini et al.is conducted to show that the pressure drop occurring in a wire-on-tube heat exchanger can be converted into a temperature difference for two types of refrigerants R-134a and R-600a typically used for charging refrigerators and freezers.The following conditions are considered:stratified or stratified-wavyflow condensation occurring inside the smooth tube of a wire-on-tube condenser with diameter 3.25,4.83,and 6.299 mm,condensation temperatures 35℃,45℃,and 54.4℃ and cover refrigerant massflow rate spanning the interval from 1 to 7 kg/hr.The results show that the PF variation is not linear with vapor quality and attains a maximum when the vapor quality is 0.2 and 0.18 for the R-134a and R-600a refrigerants,respectively.The PF increases with the refrigerant massflow rate if the inner diameter and saturation temperature constant,and it decreases on increasing the inner diameter to 6.299 mm for constant refrigerant massflow rate and saturation temperature.The PF for R-600a is higher than that for R-134a due to the lower saturation pressure in thefirst case.Furthermore,a stratifiedflow produces higher PF in comparison to the annularflow due to the effect of the surface tension.

关 键 词：CONDENSATION penalty factor pressure drop temperature difference TWO-PHASE wire condenser 

分 类 号：O35[理学—流体力学] TB3[理学—力学]