Q1.Consider steady laminar incompressible anti-symmetric fully developed viscous
flow through a straight circular pipe of constant cross-sectional area at a Reynolds
number of 5. The ratio of inertia force to viscous force on a fluid particle is
Answer : Option AExplaination / Solution: No Explaination.
Q2.A steel rod of length L and diameter D, fixed at both ends, is uniformly heated to a temperature rise of ΔT . The Young’s modulus is E and the co-efficient of linear expansion is α. The thermal stress in the rod is
Answer : Option CExplaination / Solution: No Explaination.
Q4.The inlet angle of runner blades of a Francis turbine is 90o. The blades are so
shaped that the tangential component of velocity at blade outlet is zero. The flow
velocity remains constant throughout the blade passage and is equal to half of the
blade velocity at runner inlet. The blade efficiency of the runner is
Answer : Option CExplaination / Solution: No Explaination.
Q5.The temperature distribution within the thermal boundary layer over a heated
isothermal flat plate is given by where
Tw and
T∞ are
the temperature of plate and free stream respectively, and
y is the normal
distance measured from the plate. The local Nusselt number based on the thermal
boundary layer thickness δt is given by
Answer : Option BExplaination / Solution: No Explaination.
Q6.In a counter flow heat exchanger, hot fluid enters at 60oC and cold fluid leaves
at 30oC. Mass flow rate of the fluid is 1 kg/s and that of the cold fluid is 2 kg/s.
Specific heat of the hot fluid is 10 kJ/kgK and that of the cold fluid is 5 kJ/kgK.
The Log Mean Temperature Difference (LMTD) for the heat exchanger in oC is
Answer : Option BExplaination / Solution: No Explaination.
Q7.The average heat transfer co-efficient on a thin hot vertical plate suspended in still
air can be determined from observations of the change in plate temperature with
time as it cools. Assume the plate temperature to be uniform at any instant of
time and radiation heat exchange with the surroundings negligible. The ambient
temperature is 25oC, the plat has a total surface area of 0.1m2 and a mass of
4 kg. The specific heat of the plate material is 2.5 kJ/kgK. The convective heat
transfer co-efficient in W/m2K, at the instant when the plate temperature is
225oC and the change in plate temperature with time dT/dt = -0.02 K/s, is
Answer : Option DExplaination / Solution: No Explaination.
Q8.The stroke and bore of a four stroke spark ignition engine are 250 mm and
200 mmrespectively. The clearance volume is 0.001 m3. If the specific heat ratio γ = 1.4, the air-standard cycle efficiency of the engine is
Answer : Option CExplaination / Solution: No Explaination.
Q9.A building has to be maintained at 21oC (dry bulb) and 14.5oC (wet bulb).
The dew point temperature under these conditions is 10.17oC. The outside
temperature is
-23oC (dry bulb) and the internal and external surface heat
transfer coefficients are 8 W/m2K and 23 W/m2K respectively. If the building
wall has a thermal conductivity of 1.2 W/m K, the minimum thickness (in m) of
the wall required to prevent condensation is
Answer : Option BExplaination / Solution: No Explaination.