QUESTIONS CARRY TWO MARKS EACH
An open cycle constant pressure gas turbine uses a fuel of calorific value 40,000 kJ/kg, with air fuel ratio of 80: 1 and develops a net output of 80 kJ/kg of air. The thermal efficiency of the cycle will be ________
-
Solution
QUESTIONS CARRY TWO MARKS EACH
A composite wall of a furnace has two layers of equal thickness having thermal conductivities in the ratio of 3: 2. The ratio of temperature drop across the two layer will be :
-
Solution
QUESTIONS CARRY TWO MARKS EACH
An oil of kinematic viscosity 0.5 stoke is flowing through a pipe of 5 cm diameter. The velocity at which the flow through pipe becomes critical will be ________
-
Solution
QUESTIONS CARRY TWO MARKS EACH
Air at 20°C blows over a hot plate of 50 ×60 cm made of carbon steel maintained at 220°C. The convective heat transfer coefficient is 25 w/m2-k. The heat loss from the plate will be ________
-
Solution
General heat loss equation is
Q= U× A× ΔT
where,Q = heat loss
A= area of plate
ΔT= Temperature difference
U= Heat transfer coefficient
Given :A= (50 × 60) = 3000 cm2
= 0.3 m2
ΔT= (220 – 20) = 200° C
U= 25 w/m2K
Q = 25 × 0.3 ×200 = 1500 w
QUESTIONS CARRY TWO MARKS EACH
0.70 kg/s of air enters with a specific enthalpy of 290 kJ and leaves it with 450 kJ of specific enthalpy. Velocities at inlet and exit are 6m/s and 2 m/s respectively.Assuming adiabatic process, the power input to the compressor is ________
-
Solution
QUESTIONS CARRY TWO MARKS EACH
A bar produces a lateral strain of magnitude – 60×10–5 m/m, when subjected to tensile stress of magnitude 300MPa along the axial direction. If the Poisson’s ratio is 0.3,then elastic Modulus of the material will be ×105.
-
Solution
Using the following relation,
QUESTIONS CARRY TWO MARKS EACH
A steel shaft is designed on the basis of maximum shear stress theory. The principal stresses induced at its critical section are 70MPa and – 70 MP a respectively. If yield stress for the shaft material in 390 MPa, the factor of safety of the design is ________
-
Solution
QUESTIONS CARRY TWO MARKS EACH
A pelton wheel with single jet rotates at 600 rpm. The velocity of jet from the nozzle is 100 m/s. If the ratio of the Vane velocity of jet velocity is 0.44. Then the diameter of pelton wheel is ________
-
Solution
QUESTIONS CARRY TWO MARKS EACH
A gear having 100 teeth is fixed and another gear having 25 teeth revolves around it, centre lines of both the gears being jointed by an arm. The number of revolutions made by the gear of 25 teeth for one revolution of arm will be________
-
Solution
QUESTIONS CARRY TWO MARKS EACH
A hollow shaft of outer diameter 40 mm and inner diameter 20 mm is to be replaced by a solid shaft to transmit the same torque at the same maximum stress. The diameter of solid shaft should be ________
-
Solution