Experimental and CFD Study of an Exhaust Ejector With Round Entraining Diffuser

Abstract

This paper presents experimental and CFD data for the performance of a round straight air-air ejector with a 4-ring entraining diffuser. The effects of inlet swirl angle and flow temperature on the ejector pumping, back pressure, wall pressure distribution, and diffuser pressure recovery were studied. The ejector experiments were carried out on a hot flow wind tunnel that can provide primary flow rates up to 2.2 kg/s at ambient temperature and 1.8 kg/s at 500°C. Velocity, pressure and temperature measurements were taken in the annulus upstream of the primary nozzle, on the mixing tube and diffuser walls, and at the mixing tube and diffuser ring exits. A parallel computational study was conducted along with the experimental study. A commercial CFD solver, Fluent 6.216, was used for simulation. The Realizable k-ε turbulence model and non-equilibrium wall functions were implemented on the cases. The CFD inlet boundary conditions were chosen to replicate the experimental configuration.