expansion ratio The ratio between the area of the combustion chamber exit and the area of the nozzle exit. A large expansion ratio improves the performance of an engine in a vacuum since the exhaust is expanded further, thus converting potential energy into kinetic energy. However, at sea level a high expansion ratio can result in flow separation, which can drastically reduce or eliminate the net thrust of the engine. Related category ROCKETRY TERMINOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |