An inward radial flow turbine is to develop 400 hp when supplied with air at 800C and 3 bar (abs), the exhaust total pressure being 1.07 bar. The total head isentropic efficiency is 80% and the speed 25000 rpm. The vanes reduc the nominal flow area by 10% and are radial at inlet but twisted at exhaust to give zero swirl. Determine the rotor diameter and the nozzle angle if the vane width is 12.7 mm, clearly indicating the assumptions made. For the gas assume, Cp= 1.13 kJ/kgC and sp. Heat ratio = 1.33.