DR. BABASAHEB AMBEDKAR TECHNOLOGICAL UNIVERSITY, LONERE
Mid Semester Examination – Sept./Oct. 2019
Course: TY Mech- I and II
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Subject: Heat Transfer
Max Marks: 20
Date:- 23/09/19
Sem: Vth
Subject Code: BTMEC501
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Duration:- 1 Hr.
Instructions to the Students:
- Draw figures wherever possible.
- Assume suitable data if required.
Q.E Answer the following questions
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- State different modes of heat transfer.
- Write equation of 'Newton's law of heating/cooling'.
- Write an application of ‘Extended Surfaces or Fins'.
- Write equation/formula of Reynolds Number and Prandtl Number.
- Define 'Critical Radius of Insulation'
- State any two factors which affects thermal conductivity of material
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Q.2 Solve Any Two of the following.
- Write short note on ‘Hydrodynamic Boundary Layer'.
- A hollow cylinder of 50mm inner dia and 80mm outer diameter is 5m long. The thermal conductivity of cylinder material is 110 W/m-°C. If the inner and outer surfaces of cylinder are at 210°C and 30°C, determine the rate of heat loss from the cylinder.
- A wall of furnace is made up of inside layer of silica brick 120 mm thick covered with a layer of magnesite brick 240 mm thick. The temperatures at the inside surface of silica brick wall and outside surface of magnesite brick wall are 730°C and 105°C resp. The contact thermal resistance between two wall at the interface is 0.0035 °C/W per unit area. If thermal conductivities of Silica and magnesite brick are 1.7 W/m-°C and 5.8 W/m-°C, calculate a) The rate of heat loss per unit wall area. b) Temperature drop at interface.
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Q.3 Solve Any One of the following.
- (A) Derive generalized three dimensional conduction equation in Cartesian co-ordinates and reduce it to various forms.
- (B) Twelve thin brass fins ( K= 65 W/m-°C) of 0.8 mm thick are placed axially on a 5 cm dia cylinder which stands vertically and is surrounded by air at 40°C. The fins extend 3.5 cm from the cylinder surface. What is the rate of heat transfer to air per meter length of cylinder when its surface is at 150°C? Take h = 20 W/m² C.
*** End ***
| Level | Marks | |
|---|---|---|
| TY-mech | ||
| L-1 | 6 | |
| L-1 | ||
| L-2 | ||
| L-1 | ||
| L-1 | ||
| L-2 | ||
| 3X2 | ||
| L-2 | ||
| L-3 | ||
| L-3 | ||
| L-3 | ||
| L-3 | 8 |
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This download link is referred from the post: DBATU B-Tech Last 10 Years 2010-2020 Previous Question Papers || Dr. Babasaheb Ambedkar Technological University
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