| Ejectors are widely used in exhaust systems of modern helicopters and ships as a passive cooling device, and are often installed in a space with limited clearance on one side or all around the device. In other words, ejectors are confined by other adjacent systems or walls.; Effects of wall/s and confinement on the performance and behavior of air-air ejectors have been addressed in this work. An experimental and computational study has been carried out. Experiments have been performed in a cold-air wind-tunnel present at the Gas Turbine Laboratory of Department of Mechanical and Materials Engineering of Queen's University, capable of blowing air at the rate of 2 kg/s (Mach No ≈ 0.4). Varied inlet conditions included two different conditions of swirl viz. zero and twenty degrees. Computational study was conducted to predict the flow pattern using a commercial 3D Navier Stokes CFD solver, using k - epsilon turbulence model.; The results show that the effects of confinement on ejector-pumping ratio, secondary air entrainment, and local flow distortion are significant. An increase in the degree of confinement (increase in number of walls or distance of walls from the system) decreases secondary air entrainment, and hence the performance of ejectors. |
