STUDY OF THE CONFIGURATION AND PERFORMANCE OF AIR-AIR EJECTORS BASED ON CFD SIMULATION | ||
| ERJ. Engineering Research Journal | ||
| Article 3, Volume 38, Issue 1, January 2015, Pages 15-30 PDF (2.14 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/erjm.2015.66771 | ||
| Authors | ||
| A.M El-Zahaby1; Mofreh H Hamed2, 3; Z.M Omara4; A.M Eldesoukey5 | ||
| 1Mechanical Power Engineering Department, Faculty of Engineering,Tanta University, Tanta, Egypt. | ||
| 24Mechanical Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh, Egypt | ||
| 3Dean of Higher Engineering Institute, Kafrelsheikh, Egypt | ||
| 44Mechanical Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh, Egypt. | ||
| 5Mechanical Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh, Egypt | ||
| Abstract | ||
| This paper describes a numerical study of gas-gas ejector (jet pump) performance. The developed model used to study performance determination for different operating conditions and geometrical configurations of ejector. The performance of ejector obtained based on a simulation procedure of linearized and axisymmetric subsonic and supersonic flow using Fluent Package. The CFD model used to evaluate the performance of three different ejector geometries that tested under different working conditions. A conventional finite-volume scheme utilized to solve two-dimensional transport equations with the standard k-ω SST turbulence model. The model is solved in three regions namely, the primary flow nozzle, the secondary flow channel, and the region of interaction between the supersonic nozzle jet and the secondary flow. The effect of the mixing part and tail section (pipe or diffuser) geometries on the ejector performance studied. In addition, the effects of gas motive pressure on the static pressure distributions are also studied. The computational results are validated using published experimental data, where acceptable agreements exist. The numerical results indicate that the ejector geometry has a pronounced effect on the flow parameters (i.e., pressure and gas velocity) and the ejector performance. In addition, predicted numerical results indicate that when the motive-stream velocity exceeds the speed of sound, shock waves are unavoidable inside ejectors and that shock wave pattern in mixing part has a dominant effect on ejector performance. In addition, the results indicate that the shock location inside the nozzle and the separation point are affected by the motive pressure. The results show also that configuration with convergent-divergent mixing section is much better for mixing process than the other tested configurations. | ||
| Keywords | ||
| ejector; shock wave; two-phase flow; supersonic flow; turbulent flow; CFD | ||
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