An Investigation into Air Ejector with Pulsating Primary Flow

Authors: Václav Dvořák, Petra Dančová

Abstract:

The article deals with pneumatic and hot wire anemometry measurement on subsonic axi-symmetric air ejector. Performances of the ejector with and without pulsations of primary flow are compared, measuring of characteristic pressures and mass flow rates are performed and ejector efficiency is evaluated. The pulsations of primary flow are produced by a synthetic jet generator, which is placed in the supply line of the primary flow just in front of the primary nozzle. The aim of the pulsation is to intensify the mixing process. In the article we present: Pressure measuring of pulsation on the mixing chamber wall, behind the mixing chamber and behind the diffuser measured by fast pressure transducers and results of hot wire anemometry measurement. It was found out that using of primary flow pulsations yields higher back pressure behind the ejector and higher efficiency. The processes in this ejector and influences of primary flow pulsations on the mixing processes are described.

Keywords: Air ejector, pulsation flow

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1334562

References:

[1] A. S. Ginevsky, Y. V. Vlasov, R. K. Karavosov, "Acoustic Control of Turbulent Jets", Springer-Verlag Berlin Heidelberg 2004, Germany.
[2] P. Havelka, V. Linek, J. Sinkule, J. Zahradnik, M. Fialova, "Effect of the ejector configuration on the gas suction rate and gas hold-up in ejector loop reactors", Chemical Engineering Science, Vol. 52, No. 11, 1997, pp. 1701 - 1713.
[3] I. A. Waitz, Y. J. Qiu, T. A. Manning, A. K. S. Fung, J. K. Elliot, J. M. Kerwin, J. K. Krasnodebski, M. N. O'Sullivan, D. E. Tew, E. M. Greitzer, F. E. Marble, C. S. Tan and T. G. Tillman II, "Enhanced Mixing with Flowwise Vorticity", Proy. Aerospace Sci., Vol. 33, 1997, pp. 323-351.
[4] V. Dvoř├ík, "Study of optimization of lobed nozzle for mixing", Colloquium Fluid Dynamics, Institute of Thermomechanics AC CR, Prague, Czech Republic, 2007, pp 17-18.
[5] Y. J. Chang, Y. M. Chen, "Enhancement of a steam-jet refrigerator using a novel application of the petal nozzle", Experimental Thermal and Fluid Science 22, 2000, pp. 203-211.
[6] R. A. Tyler, R. G. Williamson, "Confined mixing of coaxial flows", Aeronautical report LR-602, NRC no. 18831, Division of Mechanical Engineering, Ottawa, Canada 1980.
[7] V. Dvoř├ík, "Shape Optimization and Computational Analysis of Axisymmetric Ejector", 8th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, July 2-5, 2007 - Ecole Centrale de Lyon, France, 2007, pp 273-278.
[8] V. Dvoř├ík, P. Dan─ìov├í, "Experimental Investigation into Flow in an Ejector with Perpendicular Synthetic Jet", In: Experimental Fluid Mechanics 2009, Liberec 25. - 27. November 2009. pp 44 - 51.
[9] Z. Trávníček, T. Vít, "Hybrid synthetic jet intended for enhanced jet impingement heat/mass transfer", In.: Proc. 13th International Heat Transfer Conference IHTC-13, Sydney, NSW Australia 2006.