Accession Number : ADP007951

Title :   Design Considerations of a High Expansion Ratio Hydrogen Turbine,

Corporate Author : ROLLS-ROYCE LTD BRISTOL (UNITED KINGDOM)

Personal Author(s) : Holmes, A. T. ; Varvill, R.

Report Date : DEC 1990

Pagination or Media Count : 30

Abstract : The high specific heat of hydrogen compared with air leads to turbine stages which have low pressure ratios for comparable levels of specific work. In high speed propulsion systems designed for reusable space launch vehicles, the choice of scantlings is influenced by the need to minimise weight consistent with the achievement of the required efficiency. The effect of unit increase of mass in a component is, typically, to increase the take-off weight by approximately five units, and efficiencies significantly lower than those of normal aero-gas turbine practice are adopted. A multi-stage turbine design with overall pressure ratio of 7.6 and overall loading AH/ U2 = 31.4 is described in the paper. A parametric study covering a range of mean diameters and number of stages was performed, in which the aim was to establish the trends of efficiency against weight. The final design has ten stages with a common hub diameter.

Descriptors :   *GAS TURBINES, *HYDROGEN, AIR, COVERINGS, DIAMETERS, EFFICIENCY, HEAT, HUBS, LAUNCH VEHICLES, LOW PRESSURE, MASS, MEAN, NUMBERS, PAPER, PRESSURE, PROPULSION SYSTEMS, RATIOS, SELECTION, SPECIFIC HEAT, TURBINES, VEHICLES, VELOCITY, WEIGHT, WORK.

Subject Categories : Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE