Initial Design of an Optical-Access Piston Expansion Chamber for Wet-Expansion
Two-phase expansion processes are seen in various applications and in many cases they allow increasing the overall efficiency of the system. One application is found in LNG liquefaction plants where Joule Thompson valves are replaced with two-phase expanders to increase the overall process efficiency. Among various other examples, also low-temperature thermodynamic power cycles, like the organic Rankine cycle (ORC), benefit from two-phase expansion. However the key challenge is the availability
... is the availability of two-phase expanders. An extensive overview on the knowledge gaps on two-phase expansion is presented in this work. In general, experimental results are scarce and there is no model that can fully predict the expansion process. This is mainly due to the knowledge gap on the fundamental aspects of two-phase expansion and the non-equilibrium effects. Studies based on in-situ flow measurements are solely available for static and circulatory flashing. They however provide a sound basis for a mechanistic process description. Therefore, the concept of a new unique variable volume piston expansion chamber test-rig is described. Preliminary design simulations are performed to evaluate and size the test-rig. The minimum response time of the solenoid valves is flagged as a crucial constraint when sizing the system.