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Assignment -2
(To be done after studying the course material)
Course Code: MRW-002
Course Title: Heat Transfer
Assignment Code: MRW-002/TMA/2023
Maximum Marks: 100
Last Date of Submission: April 30, 2023
Note:
1. For any question worth 5 marks the word limit is 200 words, for a 10 mark question it is 350 words.
2. All questions are compulsory. All questions carry equal marks.
Q.1 Discuss in detail the aims of studying heat transfer and its various applications.
Q.2 a) What is convection heat transfer? Why is it considered to be a mode of heat transfer?
b) Give two examples each of natural and forced circulation 5
Q.3 A hot plate of area 0.5 m2 is maintained at a temperature of 600 C by a 100W electric heater when room temperature is 300 C. The appropriate convection coefficient is 2.15 (T)1/3 W/m2K. What fraction of the heat supplied is lost by natural convection? What happens to the rest of the heat supplied?
Q.4 The quantity of radiation received by earth from the sun is 1.4 kW/m2 (solar constant). Assuming that sun is an ideal radiator, calculate the surface temperature of the sun. The ratio of the radius of earth’s orbit to the radius of the sun is 216.
Q.5 a) What is Fourier’s law? What are its key features?
b) Calculate the net thermal resistance and the net heat transfer for a composite wall comprising of three walls of lengths L1, L2, L3 and thermal conductivities K1, K2, K3 respectively in series. Area of cross-section is the same for all three walls and is given as A.
Q.6 Derive the expression for critical radius of insulation for a cylinder and also discuss how thickness of insulation affects the heat transfer rate from a particular body.
Q.7 Derive the expression for the temperature reached by a solid at a given time ‘t’ in case of transient heat conduction.
Q.8 Explain with the help of a diagram the concept of hydrodynamic and thermal boundary layer for a laminar flow over a thin flat plate. Also define critical Reynolds number and the physical significance of Prandtl number?
Q.9 a) Explain the following terms: i) Radiosity ii) Emission iii) Spectral Intensity
b) What is a black body and what are its characteristics?
Q.10 State Kirchoff’s law and derive the expression for the law. Also explain what is a gray surface?
MRW2, MRW 2 ENGLISH MEDIUM
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