Pressure Relief Valve for Cryogenic Gases with Modulating Pressure Control

This proposal is aimed at the development of a gas pressure relief valve with modulating pressure control that provides for low- or no-impact during venting of low temperature cryogens in the range of pressures from 20 to 44 MPa. The development will concentrate on designs which provide inherent valve stability during opening and closing with modulated pressure control characteristics. Unique features will be incorporated into the design to provide modulation and stability, including disk and seat shapes with staged (distributed) energy dissipation, variable tortuosity, and directionally biased damping. Quasi-steady disk fluid forces will be evaluated by the use of computational fluid dynamics as input to a disk dynamic analysis program. The successful completion of this project will not only fulfill NASA's objectives, but will also provide significant commercial benefits in the nuclear power and petrochemical industries in which relief valve problems have been an ongoing source of high maintenance costs and low reliability.