A comparison of homogeneous equilibrium and relaxation model for CO2 expansion inside the two-phase ejector

7th European Thermal-Sciences Conference

Palacz, M.^1 ; Haida, M.^1 ; Smolka, J.^1 ; Nowak, A.J.^1 ; Hafner, A.^2

Institute of Thermal Technology, Silesian University of Technology, Konarskiego 22, Gliwice

44-100, Poland^1

Department of Energy and Process Engineering, NTNU, Kolbjorn Hejes vei 1d, Trondheim

7465, Norway^2

关键词: Computational process;    Computational tools;    Fully automated;    Homogeneous equilibrium models;    Operating condition;    Operating regimes;    Relaxation models;    Two-phase ejector;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/745/3/032158/pdf
DOI  :  10.1088/1742-6596/745/3/032158

来源: IOP

【 摘 要 】

In this study, the comparison of the accuracy of the homogeneous equilibrium model (HEM) and homogeneous relaxation model (HRM) is presented. Both models were applied to simulate the CO2expansion inside the two-phase ejectors. Moreover, the mentioned models were implemented in the robust and efficient computational tool ejectorPL. That tool guarantees the fully automated computational process and the repeatable computations for the various ejector shapes and operating conditions. The simulated motive nozzle mass flow rates were compared to the experimentally measured mass flow rates. That comparison was made for both, HEM and HRM. The results showed the unsatisfying fidelity of the HEM for the operating regimes far from the carbon dioxide critical point. On the other hand, the HRM accuracy for such conditions was slightly higher. The approach presented in this paper, showed the limitation of applicability of both two-phase models for the expansion phenomena inside the ejectors.