Turbulence Model Comparative Study for Complex Phenomena in Supersonic Steam Ejectors with Double Choking Mode

Abstract

Scholars usually ignore the non-equilibrium condensing effects in turbulence-model comparative studies on supersonic steam ejectors. In this study, a non-equilibrium condensation model considering real physical properties was coupled respectively with seven turbulence models. They are the k-ε Standard, k-ε RNG, k-ε Realizable, k-ω Standard, k-ω SST, Transition SST, and Linear Reynolds Stress Model. Simulation results were compared with the experiment results globally and locally. The complex flow phenomena in the steam ejector captured by different models, including shock waves, choking, non-equilibrium condensation, boundary layer separation, and vortices were discussed. The reasons for the differences in simulation results were explained and compared. The relationship between ejector performance and local flow phenomena was illustrated. The novelty lies in the conclusions that consider the non-equilibrium condensing effects. Results show that the number and type of shock waves predicted by different turbulence models are different. Non-equilibrium condensation and boundary layer separation regions obtained by various turbulence models are different. Comparing the ejector performance and the complex flow phenomena with the experimental results, the k-ω SST model is proposed to simulate supersonic steam ejectors.

Numerical Analysis of Steam Ejector Performance with Non-Equilibrium Condensation for Refrigeration Applications

“…where B and C are both functions of temperature, representing the second virial coefficient and the third virial coefficient, respectively; R is the specific gas constant for gaseous mixture of air and vapor [60].…”

Study on the sensitivity of steam ejector simulation to wall treatment methods

“…When Yiqiao Li [10] et al studied the double-resistance characteristics of the non-equilibrium condensing three-dimensional steam ejector, the finite volume method was used to solve the threedimensional steady-state N-S equation, and the convection term and diffusion term were used to use the second-order inverse style discretization, and the density solver was chosen to implicitly couple. The SST model is selected, and the results show that the SST model can better predict the blockage of the steam ejector in the diffusion section.…”