Description: Physical Sciences Inc. proposes to develop a unique venturi for future monopropellant feed systems that uses a passively controlled throat area to adjust propellant flow rate. The adaptive venturi eliminates water hammer in monopropellant thruster manifolds by rapidly adjusting flow area to prevent pressure surges. These benefits are achieved with a one-to-one replacement of existing cavitating venturis without added weight, volume, or power requirements. Furthermore, the total lifetime impulse of the propulsion system will increase due to increased flow area during nominal flow conditions. In Phase I, we will optimize the venturi design and measure key performance metrics in full-scale flow tests. The Phase I will conclude with a miniaturized adaptive venturi design accompanied by performance analysis results. In Phase II, a set of geometric models will be created to meet the range of flow conditions required for attitude and reaction control thrusters, as well as divert/insert thrusters up to 100 lbf. Upon successful technology development under the SBIR program, protoflight components and venturis for ground testing will be developed in technology transition programs.

Benefits: Successful demonstration of the adaptive venturi will have applications in any cost and weight saving efforts ranging from expendable and reusable launch vehicles to small spacecraft. Extending the lifetime and total impulse of DACS and RCS is a critical technology requirement for lengthening the duration of spacecraft missions. The adaptive venturi will provide for an advanced blowdown propellant feed system with lower pressure drop and increased useable lifetime, providing for longer missions that require orbit raising or station keeping.

The adaptive venturi can simplify propellant loading and priming operations for liquid propulsion systems in Air Force satellites and missile defense systems employed by the MDA, Army, and Navy. In addition to DoD monopropellant propulsion applications, the adaptive venturi will provide a simple solution for all high-pressure plumbing systems subject to rapid pressurization and water hammer. The adaptive venturi provides a compact in-line solution superior to valves and pipe extensions.