Submission
Comparative study of R744 ejector CFD models
DOI: 10.18462/iir.compr.2021.0380
Session: Technologies with CO2, ammonia and hydrocarbons
Accept state: Submission accepted
Authors
| Name | Organization | |
|---|---|---|
| Knut Emil Ringstad | NTNU | |
| Armin Hafner | NTNU |
Abstract
This work presents a comparison of different numerical Computational Fluid Dynamics (CFD) models for two-phase R744 ejectors. Natural refrigeration systems using CO2 are greatly enhanced by two-phase ejectors for work recovery. To develop improved two-phase ejectors, accurate and efficient numerical models has been a focus point of research. However, the complex flow physics of two-phase ejectors are not well understood. Current state-of-the-art models are still not able to accurately predict ejector performance for general operating conditions. In this work, the homogeneous equilibrium model and the UDRGM mixture model are compared for their accuracy and convergence properties. The results are compared to previous numerical and experimental work. The results are in agreement with previous literature, namely that the HEM accuracy is acceptable only for super critical motive conditions. The UDRGM mixture model, however had very poor convergence properties, and would not yield a converged solution within reasonable time. The results are discussed and the models are compared.
Keywords
Two-Phase Ejectors, CO2, CFD, Numerical Simulation