Flow condensation heat transfer of R۱۳۴a inside the tubes filled with hydrophilic metal foam: An experimental approach

In this study, the effect of metal foam surface wettability on flow condensation heat transfer inside tubes is investigated. R۱۳۴a is used as working fluid. The diameter and the length of the tube are ۸mm and ۴۰cm, respectively. Metal foams are ۲۰PPI, and the vapor mass flow rate ranges from ۷۵ to ۱۲۵kg/m۲s. The impact of vapor quality, mass flow rate and metal foam surface wettability on flow condensation heat transfer are analyzed. Results show that in high vapor quality, more than ۰.۵, the heat transfer coefficient in the hydrophilic metal foam filled tube is increased by ۲-۲۲% compared with that for the uncoated one. In contrast, for low vapor quality, heat transfer coefficient is decreased by ۱-۱۳%. As well, flow condensation heat transfer is improved when mass flux and vapor quality are increased in both hydrophilic and uncoated metal foam filled tubes.

Keywords:

metal foam , surface wettability , heat transfer coefficient , condensation , experimental.