Investigation Of Flow In A Variable Cross-section Isolator

Hypersonic technology and PSW were analyzed first; especially the shock train region that was the object of present study was expounded. By different cross-section varied rules, two kinds of rectangular-to-circular transition isolators, edge-varied and corner-varied, were selected. The characteristics of these variable cross-section isolators, such as shock train region, leading edge of shock train, length of shock train, mass weighted-average parameters at the exit, etc. were studied by numerically simulated CFD. The results indicated that, in contract to the conventional constant or nearly constant section area isolator, the performance of variable cross-section isolators is different. All the characteristics of different isolators are resulted by separation regions and the insight of flowfield are researched. Due to the analyze, the performance of edge-varied isolator is similar with the circular one, but the capability of supporting back-pressure, the internal drag and mass-weight average parameters are advanced; while the corner-varied duct is similar with the rectangular one, despite some characteristics are improved, the capability of supporting back-pressure is reduced. Based on an analysis of shock train, by resetting hydraulic diameter and exponent of Reθ, a modified correlation of formula that describes the shock train length in the edge-varied isolator was proposed. Finally, the combustion flowfield of ethylene fuel was studied numerically in a cylindrical combustor with edge-varied isolator. Due to the variable of cross-section in isolator, the lateral flow that is advantaged for the mixing of fuel and combustion efficiency appears.