displacement volume of an internal combustion engine is 3 liters. The processes within each cylinder of the engine are modeled as an air-standard Diesel cycle with a cutoff ratio of 2.5. The state of the air at the beginning of compression is fixed by p1 = 95 kPa, T1 = 228 degree C, and V1 = 3.17 liters. Determine: a.) the net work per cycle, in kJ b.) the power developed by the engine, in kW c.)the thermal efficiency, if the cycle is executed 1000 times per min

a (a) Air in (b) (c) Diffuser Compressor Combustors 2 State State 1 80 State 2 3300 State 3 3200 State 4 400 State 5 80 wwww Pressure (kPa) 3 Turbine 4 Figure 1: Figure for Problem 2. In a modern jet engine, air passes through the following states from the inlet to the outlet, as shown in Figure 1: Product gases out 260 780 1500 900 640 K 5 > Nozzle justify them) to find the compressor specific work. Temperature (K) For this problem, you may neglect any heat transfer, as well as neglect kinetic energy except at the outlet (state 5). Use the tables for obtaining properties (do not assume constant specific heat). Assume air is an ideal gas with ideal gas constant of R = 0.287 kJ/kg-K. Use the appropriate conservation equations and make approximations (and In a similar manner, find the turbine specific work. And finally, using similar arguments, find the nozzle exit velocity.

Answer B) C) D)

1. Where necessary, assume air as an ideal gas and consider R = 287 J/(kg.K), Cp = 1005 J/(kg.K), v = 718 J/(kg K)- a) A nozzle is a device that is used to increase the velocity of a fluid by varying the cross-sectional area. At the last section of a jet engine (Fig Q1.a, section 5), air with a mass flow rate of 50 kg/s at a pressure of 500 kPa and a temperature of 600 K enters a nozzle with an inlet cross-sectional area of 5 m2 The exit area of the nozzle is 20% of its inlet area. The air leaves the nozzle at a velocity of 300 m/s. The nozzle is not well-insulated and during this process, 5 kl/kg heat is lost. 2 Compre 1 Conttnhanbe Figure Q1.a: Schematic of a Jet engine. (i) In analysing this nozzle using the 1st law of thermodynamics, the change in which type of energy is negligible? (ii) Determine the density and velocity of the air entering the nozzle. (ii) Calculate the density of the air as it leaves the nozzle. (iv) Determine the temperature of the air as it leaves the nozzle.…