Heat transfer with phase change in plate-fin heat exchangers
Abstract
A theoretical and experimental study was conducted for convective evaporation and condensation in plate-fin compact heat exchangers. The overall performance of a brazed-aluminum heat exchanger in the evaporation mode with ammonia and in the condensation mode with both ammonia and refrigerant R-22 as working fluids. The heat exchanger has straight perforated fins on the working-fluid side and extruded rectangular channels on the single-phase (water) side. The two-phase flow in narrow channels of the heat exchanger is modeled using a triangular relationship between pressure gradient, liquid film flow rate, and film thickness. The overall performance of the heat exchanger is calculated by employing local heat-transfer analysis and integrating mass- and heat-balance equations along the heat-exchanger length. Theoretical predictions are found to agree favorably with experimental results for a prototypical heat exchanger unit.
- Publication:
-
National Heat Transfer Conference
- Pub Date:
- August 1984
- Bibcode:
- 1984nht..confR....P
- Keywords:
-
- Heat Exchangers;
- Heat Transfer;
- Aluminum;
- Ammonia;
- Evaporation;
- Fins;
- Phase Change Materials;
- Plates (Structural Members);
- Predictions;
- Refrigerants;
- Two Phase Flow;
- Fluid Mechanics and Heat Transfer