Design of the LOX and GOX Systems for the Stennis Space Center High Heat Flux Facility

Abstract

The High Heat Flux Facility (HHFF) was designed to test the high temperature performance of materials for the National Aerospace Plane (NASP) by directing the exhaust of several gas generators at actively cooled panels of the test materials. To accomplish this, a supply of high pressure gaseous oxygen (GOX) is required to feed the gas generators. In addition, a low pressure liquid oxygen (LOX) loading, storage, and supply system is required. The low pressure LOX system was designed for a maximum operating pressure of 722 KPa (90 psig) for the loading area and 1 135 KPa (150 psig) for the storage portion. A pump increases the operating pressure of the LOX from approximately 1 135 KPa (150 psig) to a maximum of 31.13 MPa (4 500 psig). An ambient air vaporizer converts the high pressure LOX to GOX. The high pressure GOX system was also designed for a maximum operating pressure of 31.13 MPa (4 500 psig). This paper discusses the approach used for designing and constructing the LOX and GOX systems for the HHFF. Stennis Space Center and NASA requirements for the use of materials in oxygen systems are discussed. Particular emphasis is placed on the materials of construction and the selection of materials for the high pressure GOX components, piping, and other hardware. Several examples of actual components modified for use in oxygen are illustrated and the rationale used for selecting piece part materials for these components are provided. The system design philosophy is discussed and several general oxygen system design principles are mentioned. Specific portions of the design intended to reduce the likelihood of ignition are also addressed. Drawings of the systems and components are included to provide more specific information that could be used as a model for the design of similar systems.