Technology Transfer Opportunity: Supersonic Spike Diffuser (ssc-tops-10)

Description: Standard cylindrical and second-throat diffusers allow supersonic gas flows to expand within their walls and pull a vacuum on any upstream void. However, the high-Mach-number shock reflections that occur in the center of the plume create substantial losses and result in an inefficient pumping process. Centerbody diffuser designs provide an improvement by reducing the maximum Mach number of the core flow, but also increase the number of oblique shocks in the system by introducing multiple turns into the system. A new type of spike diffuser recently developed by NASA Stennis Space Center is able to provide approximately double the pumping performance of second-throat diffusers via Pareto-efficient reduction of both core Mach number and flow deflection. This enables substantially lower vacuum pressures to be achieved for a given feed pressure/mass flow via the use of higher-expansion-ratio driving nozzles. Spike diffusers are also spatially compact, requiring only ~25% of the length of second-throat designs.