This study is the first to map the flow regimes, which identify the form and structure of liquid and vapor, of R-134a in small-channel cross-flow condensers. The condenser tested here is used in automotive applications and uses smaller internal volumes than conventional heat exchangers to perform the same task.

The flow regimes are documented for the pipes, headers, and small-channel condenser tubes. Consistent with the Damianides flow map, intermittent flow is the predominate flow regime in the small channels. The flow transitioned from a dispersed liquid to a bubble flow regime through the inlet header. The flow regime in the outlet header was always a dispersed gravity-driven liquid in the core with a thin liquid annulus on the wall.

Units: Dual