b) (i) With the aid of a clear sketch explain how a centrifugal compressor produces a pressure rise. (ii) Starting with the Euler turbomachinery equation, w = Cw2U - CwU (usual notation applies) derive an expression for the ideal work for a centrifugal compressor with impeller tip speed Utip. (iii) A centrifugal compressor has a 20 cm diameter impeller and rotates at 25000 revolutions per minute. Air mass flow rate into the impeller is 0.9 kgs at stagnation temperature 288 K. What are the ideal power requirement and pressure ratio that could be achieved? [15] For this question you should use 71.4, Cp 1.004 kJ kg-K-. =