Study of Boiling and Condensation Heat Transfer Coefficients of Refrigerant Mixtures in Horizontal Tube

Name: อุเทน กันทา

Name: Uthern Kuntha

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: Boiling

; Condensation

Abstract: Boiling and coi~deilsatioil heat transfer coefficients and pressure drops of R-12 arid its alternatives which are R-134a and R22/R152a/R124 (33%/15%/52%) flowing inside horizoiltal tube have been carried out with the conditions similar to those in domestic refrigerators. The range of mass flow rates examined is between 0.0025 and 0.0125 kl;/s. The data has been taken at three different evaporator temperatures (5, 10 and 15 ?C) and two different condenser temperatures (30 and 40 ?C). The boiling heat transfer coefficients of the refrigerants in the grooved tubes are higher than those in the smooth tubes. In the smooth tube, R-12 shows the highest boiling heat transfer coefficient, following by R-134a and MP-52, respectively. In the grooved tube, R- 134a shows the l~ighest boiling heat transfer coefficient, following by R-12 and MP- 52, respectively. At the condenser, condei~sation heat transfer coefficieilt has been investigated in a smooth tube. R-134a shows the highest, following by MP-52 and R- 12, respectively. The heat transfer correlations have also been developed. In case of the pressure drop in the evaporator, the two-phase friction multiplier $G* increases with Martinelli parameter and there is no effect of the tube roughness and the types of the refrigerants. Boiling and condensation heat transfer coefficients and pressure drops of R-22 and its alternatives which are R32/R125a/R134 (23%/25%/52%) and R321R125a (50%/50%) flowing inside horizontal tube have been carried out with the conditions similar to the previous case. The boiling heat transfer coefficients of the refrigerants in the grooved tubes are higher than those in the smooth tubes and R-22 shows the best perforinailce of both tubes. At the smooth tube condenser, condensation heat transfer coefficient of R-22 is the highest, following by SUVA-9100 and SUVA- 9000, respectively. The heat transfer correlations have also been developed. In case of the pressure drop in the evaporator, the two-phase friction multiplier $G2 increases with Martinelli parameter and there is no effect of the tube roughness and the types of the refrigerants.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร (Bangkok)

Email: info.lib@mail.kmutt.ac.th

Name: Prof.Dr. Tanongkiat Kiatsiriroat

Role: Supervisor

Created: 2544

Issued: 2006-12-26

Modified: 2006-12-26

ISBN: 9746281887

CallNumber: JGSEE3

eng

DegreeName: Master of Engineering

Level: Master's Degree

Descipline: Mechanical Engineering

Grantor: King Mongkut's University of Technology Thonburi

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