A simplified sizing and mass model for axial flow turbines
A mass model has been developed and used to study axial flow turbines for space power systems. Hydrogen, helium-xenon, hydrogen-water-vapor, air, and potassium vapor working fluids have been investigated to date. The impact of construction material, inlet temperature, rotational speed, pressure ratio, and power level on turbine mass and volume has been analyzed. The turbine model is described, and results of parametric studies showing general design trends characteristic of any axial flow machine are reported. Axial flow turbine designs using helium-xenon mixtures and potassium vapor working fluids which are used in Brayton and Rankine space power systems, respectively, are compared. >
Abstract We compute tr(−1) F for N = 1 supersymmetric Yang-Mills in ten dimensions, and for the dimensionally reduced theory N = 4 extended supersymmetric Yang-Mills in four dimensions. Supersymmetry is unbroken. We discuss the meaning of the θ angle in these theories.