Heat & Mass Transfer (HMT) SPPU Endsem Question Paper Jul 2022
All 8 questions from this SPPU endsem paper, as printed. Read them here or open the PDF.
- Subject code
- 302042
- Pattern
- 2019 pattern
- Exam
- Endsem
- Session
- Jul 2022
- Max. marks
- 70
- Time
- 2½ Hours
- Semester
- I
- Paper code
- [5870]-1021
Printed for: T.E. (Mechanical /Mechanical Sandwich )
Instructions to the candidates
- Solve Q1 or Q2, Q3 or Q4, Q5 or Q6, Q7 or Q8.
- Neat diagrams must be drawn wherever necessary.
- Figures to the right side indicate full marks.
- Use of Calculator is allowed.
- Assume Suitable data if necessary.
Questions
Q1
- a)[9]
A vertical plate is maintained at 40ºC in 20ºC still air. Determine the height at which the boundary layer will turn turbulent if turbulence sets in at A Gr. Pr = 10 9 . Repeat the problem for water flow at film temperature of 30ºC. Comment on the results of solution.
- b)[8]
Explain in brief (Any two) i) Local and average Heat Transfer coefficient ii) Hydrodynamic and Thermalboundary layer iii) Critical Heat Flux iv) Significance of any 2 non dimensionless numbers
OR- a)
Q2
- a)[8]
Explain the types of boiling and pool boiling phenomenon in detail with neat sketch of boiling curve.
- b)[9]
Air at atmospheric pressure and 40ºC flows with velocity of U = 5 m/sec over a 2 m long flat plate whose surface is kept at a uniform temperature of 120ºC. Determine the average heat transfer coefficient over 2 m length of plate. Also determine the rate of heat transfer between the plate and air per 1 m width of plate (Air at 1 atm. And 80ºC, v = 2.107 × 10 5 m 2 /sec, k = 0.03025 W/mk, Pr = 0.695).
- a)
Q3
- a)[8]
The energy received from the sun at the earth’s atmosphere has been measured as 1353 W/m 2 . The diameter of the earth = 1.29 × 10 7 m. Diameter of the sun = 1.39 × 10 9 m. Mean distance = 1.5×10 11 m. Estimate the emissive power of the sun and the surface temperature assuming it to be black. Assuming that the source of energy for the earth is from the sun and earth to be black, estimate the temperature of the earth. 2
- b)[10]
Explain in brief i) Kirchoffs Law ii) Stefan Boltzmans law iii) Wiens Displacement law iv) Shape Factor v) Electrical analogy for radiation
OR- a)
Q4
- a)[10]
Two large parallel plates with ε = 0.5 each are maintained at different temperatures and are exchanging heat only by radiation. Two equally large radiation shields with surface emissivity 0.05 are introduced in parallel to the plates; find the percentage reduction in net radiative heat transfer.
- b)[8]
Define shape factor algebra and explain any 4 salient features of shape factor.
- a)
Q5
- a)[8]
- b)[9]
The molecular weights of the two components A and B of a gas mixture are 24 and 28 respectively. The molecular weight of gas mixture is found to be 30. If the mass concentration of the mixture is 1.2 kgm 3 , determine the following i) Molar fractions ii) Mass fractions iii) Total pressure if temperature of mixture is 290K
Also asked:Nov 2023
ORQ6
- a)[8]
Explain in brief convective mass transfer and Explain the term conservation of species.
- b)[9]
Hydrogen gas is maintained at pressure of 2.4 bars and 1 bar on opposite sides of a plastic membrane 0.3 mm thick. The binary diffusion coefficient for hydrogen in the plastic is 8.6x 10-8 m 2 /s and solubility of hydrogen in the membrane is 0.00145 kg mole/m 3 -bar. (molecular weight of hydrogen - 2kg/kg mole) Calculate under uniform conditions of 24ºC, the following: i) Molar concentration of hydrogen at opposite face of membrane ii) Molar and mass diffusion of hydrogen through membrane 3
- a)
Q7
- a)[8]
- b)[10]
This part has equations that don’t show as text. Open the PDF to read it.
ORQ8
- a)[8]
- b)[10]
A counter flow double pipe heat exchanger uses superheated steam to heat water at the rate of 10500kg/h. The steam enters the heat exchanger at 180ºC and leaves at 130ºC. The inlet and exit temperatures of water are 30ºC and 80ºC, If the overall heat transfer coefficient from steam to water is 814 W/m 20 C. Calculate the heat transfer area. What would be the increase in area if the fluid passes are in parallel?
Also asked:May 2023