Advanced Heat Transfer – II Question Paper 2014 for M.Tech 2nd Semester in Mechanical Engineering or Heat Power Engineering is given below. In this subject you will get questions from the Heat Transfer Text Book By Mahesh Rathod. Here is a BPUT M.Tech Previous year questions is given for practice. The questions will come from Convective Heat Transfer and Mass Transfer Chapters.
Advanced Heat Transfer – II Question Paper 2014
M.TECH HTPC202 / TFPC202
2nd Semester Regular/Back Examination
ADVANCED HEAT TRANSFER – II (CONVECTIVE HEAT & MASS TRANSFER)
BRANCH(S): MECHANICAL ENGINEERING (HEAT POWER ENGINEERING)
Time. 3 Hours, Max Marks: 70
Answer Question No.1 which is compulsory and any five from the rest.
(steam tables are allowed in the examination hall)
Q1 Answer the following questions:
a). Show the laminar and turbulent boundary flow regimes over a flat plate.
b) What do you mean by thermal boundary layer? How is this different from hydrodynamic boundary layer?
c) What Eckert number.
d) What is laminar sub layer?
e) Show the momentum and thermal boundary layers for natural convection on a vertical plate.
f) What is the importance of critical heat flux?
g) What do you mean by homogeneous equilibrium model?
h) What are the effects of relative humidity in mass transfer case?
i) Write Fick’s law of diffusion.
j) Write down the Dittus-Boelter equation and mention its terms.
Q2 a) Derive the energy equation in the thermal boundary layer in laminar flow over a flat plate.
b) Air at 20°C and 1 atm flows over a flat plate at 50 m/s. the plate is 100 cm long and is maintained at 60°C. The width of the plate is 2m. Calculate the total heat transfer from the plate.
Q3 a) Derive the expression for Nusselt number for constant wall heat flux case considering laminar flow in tube.
b) Water at 25°C enters a pipe with constant wall heat flux of 1 kW/m2. The flow is hydro dynamically and thermally fully developed. The mass flow rate of water is 0 01 kg/s and the pipe radius is 1cm. Calculate. a) Reynolds number b) the heat transfer coefficient and c) the difference between the local wall temperature and the local mean (bulk)temperature.
Q4. a) With sketch explain regimes of boiling.
b) Derive an expression to obtain the pressure drop in two phase flow
Q5. Design a counter flow, concentric tube heat exchanger to use water for cooling hot engine oil from an industrial power station. The mass flow rate of the oil is given as 0.2 kg/s, and its inlet temperature is 90°C. water is available at 20°C but its temperature rise is restricted to 12.5°C because of environmental concerns. The outer tube diameter must be less than 5 cm, and the inner tube diameter must be greater than 5 cm due to constrains arising from space and piping considerations The engine oil must be cooled to a temperature below 50°C. Obtain an acceptable design if the length of the heat exchanger must not exceed 200 m. Cp (in J/kgK), μ (in kg/sm) , and k (W/mK) for oil and water are 2100,0.03,0.15 and 4179, 8.55×10^-4, 0.613 respectively. Assume the thickness of the inner tube (made of brass) to be small.
Q6. a) Write down the governing equations of natural convection heat transfer.
b) A 0.5 m high flat plate of glass at 93C is removed from an annealing furnace and hung vertically in the air at 28 C,1 atm. Calculate the initial rate of heat transfer to the air. The plate is 1 m wide.
Q7 a) Write down governing equations of forced convection with mass transfer over a flat plate laminar boundary layer
b) Explain Evaporative cooling with neat sketch
Q8. Write short notes (any two)
a) Flow boiling
b) NTU method
c) Fi!mwise condensation