Investigation of CFD models for ammonia ejector design.

In this work the flow structures inside a transonic- single phase ammonia ejector is investigated using CFD. The efficiency of ammonia (R717) vapor compression cycles can be improved by including an ejector component in the system. A good understanding of the flow phenomena inside the ejector is required for proper design of these components. In the present work a 2D axisymmetric CFD model using ANSYS Fluent software is used to investigate the flow characteristics of the ejector. The model uses a steady-state coupled pressure-based solver together with the k-omega SST turbulence model. A mesh refinement study has been done to investigate grid independency. Results indicate that the model can predict the correct trends of ejector operation, however, fails to accurately reproduce the experimental results. The results suggest that a more advanced multiphase models may be required to accurately model super-sonic ammonia ejectors.