Effect of metal foam arrangement on R۱۳۴a flow boiling heat transfer in horizontal filled tubes: An experimental study

Metal foams have been introduced as promising materials for heat transfer enhancement and heat exchangers size reduction. The present study aims to investigate the boiling heat transfer coefficient of R۱۳۴a refrigerant in different ۱۰ and ۲۰ PPI copper foams implemented inside tubes with an internal diameter of ۸ mm. The effects of various parameters such as mass velocity, mean vapor quality, and different arrangements of metal foam inserts on flow boiling heat transfer coefficient are considered. Experiments were conducted at three mass velocities of ۹۰, ۱۱۰, and ۱۳۰ kg/m۲s, mean vapor qualities range from ۰.۱۵ to ۰.۸۵ at constant heat flux of ۵.۰۲ kW/m۲. Results show that metal foams significantly influenced the heat transfer. The heat transfer coefficient of the tube filled with ۲۰ PPI metal foam is at most approximately ۲.۹ times of the plain tube. The enhancement ratio for the tube filled with mixed arrangement of ۲۰/۱۰ PPI copper foam is calculated to be in the range of ۲.۲–۲.۵۵.

Keywords:

Metal foam , R۱۳۴a , Heat transfer , Boiling , Enhancement , Experimental