|
Methodology for Designing Gas Generator
Systems for the Instantaneous Principal Investigators Inclusion Dates: 03/01/99 - Current Background - The major goal of this program is to develop at SwRI the technology to design inflation systems. Special emphasis will be placed on application to the SwRI-developed instantaneous personal protection system (IPPS), but the technology will be applicable to inflation systems in general. Approach - Development of the design methodologies will require engineering models to describe bag inflation and the solid-propellant gas-generating processes. The approach calls for the use of available analytical and numerical models, similitude analysis, and carefully designed experiments to generate an easy-to-use engineering model. Independent models will first be developed for bag inflation and gas generation. The models will then be merged to describe the complete system. The team’s intent is to develop either a personal computer-based or a nondimensional graphical model that captures the essential physics of the gas-generation and inflation processes without the mathematical complexities. Graphical similitude models are typically developed from extensive experimental data. In this program, much of the data will be generated through the application of analytical and numerical models that have been validated by experiment. Finally, all the analytical, numerical, and experimental results will be statistically analyzed to develop a similitude model. Accomplishments - Models have been developed to describe propellant combustion, venting from the combustion chamber, venting from a high-pressure reservoir of compressed gas, and erection of the IPPS system. The models have been combined to provide a numerical simulation of the process from propellant initiation through erection of the IPPS system. Preliminary calculations have indicated the high gas temperature may create problems in a system driven totally by burning propellant. Simulations to date have been with gun propellants for which data already exist. Gun propellants have high burning rates that are probably too high for the IPPS system. Characterizations are being sought for a variety of different propellants with a wide range of pressure-dependent burning rates to determine which propellants can best meet IPPS system requirements. Materials Research and
Structural Mechanics Program |
