Numerical model for the prediction of the induced flow in pulse jet ejector with experimental verification

Unsteady pulsed ejector is based on energy transfer mode that depends on wave action and pressure exchange that become reversible under ideal conditions and therefore, offer higher efficiency and compact design. The lack of fundamental understanding and insufficient analytical tools for design and development presumably appears to have caused of little research work in the area. A numerical model of the pulse ejector is developed to simulate the non-linear wave motion resulting from a pulse generator in both the primary and associated augmenter tubes. The one-dimensional non-steady conservation equations are solved for variable area geometry with the influence of wall friction, heat transfer and capable to resolve wave formation with flow discontinuities. The developed model is set up with sufficient generality to include all significant processes, which occur in the pulsed ejector. Adequate boundary conditions for the two flow fields and interactions are supplied. An experimental set up is constructed to provide results for comparison with the numerical predictions for steady cyclic operation of the ejector. Excellent agreement is demonstrated between experimental and theoretical results in the pulse frequency range of 50 - 220 Hz and primary stagnation pressures up to 4 bar, based on pressure traces and ratio of secondary to primary mass flow rates. The correlation indicates that the wave events in the ejector are understood in very good detail.