TY - GEN
T1 - Heat transfer and pressure drop model of in-tube condensation in a vapor-compression system
AU - Xiao, Jiange
AU - Hrnjak, Pega
N1 - Funding Information:
The authors thankfully acknowledge the support provided by the Air Conditioning and Refrigeration Center at the University of Illinois at Urbana-Champaign, and technical support from Creative Thermal Solutions, Inc. (CTS).
Publisher Copyright:
© 2019 International Institute of Refrigeration. All rights reserved.
PY - 2019
Y1 - 2019
N2 - A typical “3-zone” models assume uniform temperature in the cross section of the tube during condensation. The first droplet occurs when the bulk quality is 1. However, as soon as wall temperature drops to the saturation, condensation begins regardless of what the bulk temperature is. The new heat transfer and pressure drop models use “5-zone” approach, seeking to capture the two-phase mechanisms in the condensing superheated (CSH) and condensing subcooled (CSC) regions. Heat transfer coefficient and pressure drop measured in 4 and 6 mm tubes are used to validate the new approach in the range: mass flux from 50 to 400 kg m-2 s-1; heat flux 5 to 15 kW m-2; condensing temperatures 30 and 50oC. The refrigerants explored are R744, R32, R410A, R134a, and R1233zd(E). The new models are more physical and better fit the experimental data than the conventional models, especially in the CSH region. This is because the latent heat and vapor-liquid interaction are present even though the bulk temperature indicates otherwise.
AB - A typical “3-zone” models assume uniform temperature in the cross section of the tube during condensation. The first droplet occurs when the bulk quality is 1. However, as soon as wall temperature drops to the saturation, condensation begins regardless of what the bulk temperature is. The new heat transfer and pressure drop models use “5-zone” approach, seeking to capture the two-phase mechanisms in the condensing superheated (CSH) and condensing subcooled (CSC) regions. Heat transfer coefficient and pressure drop measured in 4 and 6 mm tubes are used to validate the new approach in the range: mass flux from 50 to 400 kg m-2 s-1; heat flux 5 to 15 kW m-2; condensing temperatures 30 and 50oC. The refrigerants explored are R744, R32, R410A, R134a, and R1233zd(E). The new models are more physical and better fit the experimental data than the conventional models, especially in the CSH region. This is because the latent heat and vapor-liquid interaction are present even though the bulk temperature indicates otherwise.
KW - Condensing superheated region
KW - Heat transfer
KW - Non-equilibrium
KW - Pressure drop
KW - Vapor-compression system
UR - http://www.scopus.com/inward/record.url?scp=85082669814&partnerID=8YFLogxK
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U2 - 10.18462/iir.icr.2019.0812
DO - 10.18462/iir.icr.2019.0812
M3 - Conference contribution
AN - SCOPUS:85082669814
T3 - Refrigeration Science and Technology
SP - 1150
EP - 1158
BT - ICR 2019 - 25th IIR International Congress of Refrigeration
A2 - Minea, Vasile
PB - International Institute of Refrigeration
T2 - 25th IIR International Congress of Refrigeration, ICR 2019
Y2 - 24 August 2019 through 30 August 2019
ER -