CFD simulation and analysis of a gas to water two-phase closed thermosyphon-based heat exchanger

Wickless heat pipes are devices with high reliability and heat transfer potential per unit area. Owed to that fact, their application range has been widened in the past 20 years. In the process industry, they are usually coupled to waste heat recovery devices, namely heat exchangers. Heat-pipe-based heat exchangers offer many advantages when compared to conventional waste heat recovery systems, such as increased reliability and reduced cost of production. The design of such devices, however, is not a straightforward process due to the complex modes of heat transfer mechanisms involved. In this paper, the characterisation of a cross-flow heat pipe based heat exchanger is made via the use of ANSYS Fluent, a CFD solver. A design tool with the purpose of predicting the performance of the test unit is also developed and validated through comparison between the CFD model and previous experimental results.