For a turbofan engine write down the mathematical expressions for 1. The thrust force 2. The overall efficiency Prove that the maximum overall efficiency is given by (1+B)u fQR no,max= Question 4 Figure 2 illustrates a turbofan engine during testing in a test cell. It has the following characteristics: 1. B = 3, f = 2%, V = 3V 2. ma 200kg/s, thrust = 60kN. a) Calculate: m, m and my. b) Evaluate V, V if f is neglected. c) Calculate the propulsive efficiency. What are your comments? Figure 2 142