SPACE SHUTTLE QMS HELIUM REGULATOR DESIGN 6 DEVELOPMENT FINAL REPORT

摘要

An integrated program of analysis, design, fabrication and design verification testing was conducted to determine the realistic technology level attainable for development of the helium pressurization regulator for the Space Shuttle OMS application. This program evaluated existing regulator concepts, identified their deficiencies, and generated new concepts which eliminated these deficiencies and added the features of long life and multimission use. The prototype regulator fabricated for this program was a single-stage design featuring the most reliable and lowest cost concept available.nA tradeoff study on regulator concepts indicated that a single-stage regulator with a lever arm between the valve and the actuator section would offer significant weight savings. Damping concepts, including pneumatic and mechanical, were evaluated by testing to deter¬mine the amount of damping required to restrict actuator travel to 0.002 inch during vibra-tion. The disadvantage of each device-size and friction, respectively, is not present in the hydraulic damper.nThe regulator was fabricated entirely of Inconel 718, except for the tungsten carbide seat/poppet and the Ni-span-c springs. Flanged joints for accessibility and an LVDT actuator position transducer were additional design features. Component design parameters such as spring rates, effective area, contamination cutting, and damping were determined by test prior to regulator final assembly. The unit was subjected to performance testing at flow rates from 44 to 340 scfm, temperatures from 310 to 610°R, and inlet pressures from 400 to 4000 psi, random vibration level3 to 26 grms, slam starts, leakage and 15,000 cycles during the design verification test program.nA test plan for propellant compatibility and extended life tests to be conducted by NASA-JSC is included. It is recommended that a flightweight level arm regulator with hydraulic damping be developed during the follow-on program.