A simple air turbine can be used to produce emergency power on an aircraft. In its simplest form (see figure), it can consist of a diffuser (inlet) that uses area change to slow the oncoming air, and a turbine that extracts power from the air by expanding it back to the local ambient pressure, pa. Consider an air-turbine that operates at steady-state with T, an airflow of 0.5 kg/s, and is attached to an aircraft flying at 900 km/hr at an altitude where the ambient pressure is 1.1 psia and the ambient temperature is 250 K. Also, for the purposes of this problem, you must assume the molecular weight of air Is 29.

a) Assuming air is a calorically perfect gas with a specific heat ratio of 1.4 determine a value for cp for air (in units of kJ/kgK). b) What is the maximum amount of power that can be produced by this ram turbine? c) How much power could be produced if the device produced entropy at the rate of 38 J/Ks?

T Pa u Diffuser Turbine