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A mathematical model of the adjustable ejector was established and the flow of the adjustable ejector was simulated by FLUENT on different spindle positions. The experimental results indicate that the axial pressure of an adjustable ejector increases linearly in the constant area mixing section, sharply in the beginning of diffuser section and then slowly in the other sections of diffuser. The velocity of flow in the mixing section differs significantly at the axis and boundary. The movement of spindle into the nozzle makes the position of shock wave upstream and motive flow rate decreases. [ABSTRACT FROM AUTHOR]

The objective of the present study is to analyse the transient flow through the vacuum ejector system with the help of a computational fluid dynamics method. An attempt is made to investigate the interesting and conflicting phenomenon of the continuous entrainment into the primary stream with limited mass supply from the secondary chamber. The results obtained show that the one and only condition in which a continuous mass entrainment can be possible in such types of ejectors is the generation of a recirculation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium of pressure at the onset of the recirculation zone. A steady flow assumption in such ejector systems is valid only after the dynamic equilibrium state. [ABSTRACT FROM AUTHOR]

Coanda effect is the phenomena in which a jet flow attaches itself to a nearby surface and remains attached even when the surface curves away from the initial jet direction. In free surroundings, a jet of fluid entrains and mixes with its surroundings as it flows away from a nozzle. When a surface is brought close to the jet, this restricts the entrainment in that region. As flow accelerates to try balance the momentum transfer, a pressure difference across the jet results and the jet is deflected closer to the surface - eventually attaching to it. [ABSTRACT FROM AUTHOR]

The present study deals with the visualization of the air flow inside a supersonic ejector. Our attention is more precisely focused on the choked flow phenomenon which occurs along the mixing chamber of the secondary nozzle and which can be visualized by CFD. laser tomography visualizations are used to validate the CFD model. The evolution of flow configuration in the ejector with the primary stagnation pressure is examined both in the case of zero secondary flow and in the case of free entrainment of induced air. [ABSTRACT FROM AUTHOR]

Assesses the legitimacy of using methods based on use of nomograms that correlate the ejection factor with the degree of expansion of the ejecting gas and degree of compression of the ejected gas for systems with thermophysical properties different from the vapor-air mixtures for which it is recommended. Simulation of the compression in the converging and diverging diffuser sections by two successive compressors.