A Reduced Ejector Equation,
AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH
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In this presentation, I would like to show the features of a Reduced Ejector Equation. If one applies the three pertinent conservation laws to the mixing section of an ejector arrangement, one arrives, after some algebraic manipulation, at a relation which, for a given mixing section layout, contains the inlet conditions on one side and exit conditions on the other side. Since the treatment accounts for wall pressure forces, mixing is not restricted to constant area or constant pressure. The separation of the variables, in respect to inlet and exit conditions, leads to a reduced ejector equation, which is plotted for two different mixing section layouts. The magnitude E on the ordinate stands for an expression containing all the inlet conditions as given by mass flow ratio, inlet area ratio, inlet Mach numbers, and thermodynamic properties of primary and secondary operating medium. The abscissa gives the mixing section exit Mach number. This plot shows that for small E values there is no supersonic solution. Only if E is sufficiently large, a supersonic solution is possible.