Flow boiling of R134a in an open-cell metal foam mini-channel evaporator

Open-cell metal foam mini-channel evaporator (OMFME) is proposed to enhance heat transfer in electronics cooling. In present study, flow boiling in an OMFME is investigated using R134a. The OMFME has nine channels, which are 507 μm in width and 1097 μm in depth. Comparing with a mini-channel evaporator (ME) with the same footprint area, the heat transfer coefficient (HTC) is enhanced up to 1.5 times and the dry out is delayed. Flow patterns are presented and compared with an existed flow patterns map. HTCs generally increases with the quality, the heat flux and it is slightly influenced by the mass flow rate. Nucleate boiling and evaporation in the porous fins are the two heat transfer mechanisms in different quality range. A correlation is presented to calculate frictional pressure drop.