Two-phase expansion occurs in various applications and often allows for an increase of the total system efficiency. One application is found in the cryogenic industry, where the Joule Thompson valves can be substituted with two-phase expanders resulting in better efficiencies and more liquid at the storage pressure. Another example are thermodynamic cycles such as the trilateral flash cycle or the Organic rankine flash cycle which both perform better than the classic Organic rankine cycle. The main challenge with the implementation of these more efficient cycles is the construction of efficient two-phase expanders, for which the technology is not yet available. A first step is to analyze the process experimentally for which a new setup has been designed and constructed.
The goal is to measure and predict the evaporation rate within a reciprocating expander. For this an experimental setup is build and the process has been modeled with the homogeneous relaxation model. This is a rather straightforward method to describe the evaporation rate of a metastable mixture. This model requires parameters to be fitted to experimental data and the results have to be experimentally validated. Secondly, the impact of the findings can be linked to complete TLC and ORC cycles.