On-Demand Gas Generator with Real-Time, Open-Loop Control System for Gel Propulsion

The Army has a continuing need to improve the propulsion performance flexibility of missile systems for multi-mission tactical applications and bipropellant gel propulsion systems over the maximum flexibility. Bipropellant propulsion systems require pressurized tanks to expel fuel and oxidizer, thus the tank pressurization system must accommodate the flexibility required of the propulsion unit. Conventional approaches to on-demand tank pressurization have disadvantages: pressure measurement and feedback (transducer reliability) or a pressure regulator (heavy and bulky). A self-regulating bootstrap system would avoid the controllability issues without requiring an external source for gas generator pressurization, avoiding hazardous high pressure bottles or the need for external power. Stone Engineering Company proposes to investigate such a gas generator system in the context of a small (7-inch), volume limited missile application requiring a high degree of on-demand flexibility. The design approach will be based on differential area pistons, either in a two-stage design or a single stage with bellows. This first phase will consist of preliminary design, analysis, and simulation. The simulation will be the primary tool for determining the component sizes and control arrangement for stable operation. Selection among design alternatives will be based on packaging volume and producibility.