Approximate similarity principle for a full-scale STOVL ejector

Full-scale ejector experiments are expensive and difficult to implement at engine exhaust temperatures. For this reason the utility of using similarity principles, in particular the Munk and Prim principle for isentropic flow, was explored. Static performance test data for a full-scale thrust augmenting ejector were analyzed for primary flow temperatures up to 1560 R. At different primary temperatures, exit pressure contours were compared for similarity. A nondimensional flow parameter is then used to eliminate primary nozzle temperature dependence and verify similarity between the hot and cold flow experiments. Under the assumption that an appropriate similarity principle can be established, properly chosen performance parameters were found to be similar for both hot flow and cold flow model tests. (Author)