Mechanical Engineering Written Exam Questions (Part-1)

 Mechanical Engineering Written Exam Questions (Part-1)

➤ Show that, specific speed of pump is a dimensionless number.

➤ Draw P-V & T-S diagram of Otto & Diesel cycle and write down the corresponding process name.

➤ Find the absolute pressure in Pa of 100 mm mercury vacuum pressure.

            

            We Know that,
                        Absolute Pressure = atmospheric pressure – vacuum pressure
                                                      = 760 – 100 = 660 mm of mercury
            We also know,
                                        P = hρg
                                           = 0.660 x 13600 x 9.81
                                           = 88054.56 Pa

            Where,
                    P = Absolute pressure, Pa
                    h = Manometer height, m
                    ρ = Density of mercury = 13600 Kg/m³
                    g = 9.81 m/sec²

➤ Draw block diagram & T-S diagram for gas-steam combine cycle power plant. (For more details, click here)

➤ A 4 cylinder petrol engine has developed MEP=650 KPa, its engine diameter is 80 mm, stroke length is 100 mm, speed 3000 rpm. Find engine power in KW?

➤ For counter flow heat exchanger T_h1=160^oC, T_h2=125^oC, T_c1=20^oC, T_c2=80^oC, Draw temperature distribution curve. Also find arithmetic mean temperature difference & logarithmic mean temperature difference.

➤ A wire has got diameter of 20 mm, if heat transfer co-efficient is 20 W/m².K and thermal conductivity is 0.5 W/m.k. Then find the distance at which maximum heat dissipation will occur.

➤ A 1.5m x 1.5m x 2m tank is kept at 11 m above from the ground. If a pump installed on ground having efficiency of 60% can fill the tank in 30 minutes, then find the required pump power.

➤ Engine power developed 40 KW, solid shafts rpm 200, if the shaft diameter 40 mm then, find maximum torsional stress developer in the shaft.

➤ Find the deflection of a solid circular steel bar having load 500 Kg, length 2.5 meter, diameter 60 mm & E=200 GPa.

➤ A 60 mm metal ball at 220^oC is being cooled by air jet of 20^oC, heat transfer co-efficient 200 W/m.k & 100 W/m².K, if the specific heat of the metal ball 400 J/Kg.K, density 9000 Kg/m³, Find the temperature of the ball after 90 sec.

➤ An aeroplane makes a complete half circle of 50 meters radius, towards left, when flying at 200 Km/hr. the rotary engine and the propeller of the plane has a mass of 400 Kg and a radius of gyration of 0.3 meter. The engine rotates at 2400 rpm clockwise when viewed from the rear. Find the gyroscopic couple on the aircraft.

➤ In a vapor compression refrigeration cycle inlet condenser enthalpy is 283 KJ/Kg, exit condenser enthalpy is 116 KJ/Kg, and exit evaporator enthalpy is 232 KJ/Kg, Find COP.