Name of the College : Sphoorthy Engineering College
University : JNTUH
Department : CHEMICAL ENGINEERING
Subject Name : HEAT TRANSFER
Degree : B.Tech
Year/Sem : III/I
Website : sphoorthyengg.com
Document Type : Model Question Paper
Download Model/Sample Question Paper : https://www.pdfquestion.in/uploads/sphoorthyengg.com/4735-RR310803%20-%20HEAT%20TRANSFER.pdf
Heat Transfer Question Paper :
B. Tech III Year I Semester Examinations, December – 2011
(CHEMICAL ENGINEERING)
Time: 3 hours
Related : Sphoorthy Engineering College RR311001 Linear & Digital IC Applications B.Tech Question Paper : www.pdfquestion.in/4732.html
Max. Marks: 80
Answer any five questions :
All questions carry equal marks :
1. Derive the general heat conduction equation in Cartesian system and hence deduce the expression for temperature distribution through a plane wall. [16]
2. Steam at 3000C flows in a stainless steel pipe of thermal conductivity 30 W/mK whose inner and outer diameters are 5 cm and 5.5 cm respectively. The pipe is covered with 5 cm thick glass wool of thermal conductivity 0.038W/mK.
Heat is lost to the surroundings at 200C by convection and radiation with a combined heat transfer coefficient of 15W/m2K. Taking the inside heat transfer coefficient as 80W/m2K, calculate the heat lost per metre length of the pipe. [16]
3.a) Distinguish between steady state conduction and unsteady state conduction.
b) A 3cm diameter aluminium sphere of thermal conductivity 204 W/mK, density 2700 kg/m3, specific heat 0.896 KJ/kgK is initially at 1750C.
It is suddenly immersed in a well-stirred fluid at 250C. The temperature of the sphere is lowered to 1000C in 42 sec. Calculate the heat transfer coefficient. [16]
4.a) What is entrance length and how do you find it for laminar and turbulent flow conditions through a tube.
b) Liquid mercury flows through a long tube of 2.5 cm inner diameter with a velocity of 1 m/sec. Calculate the heat transfer coefficient for the constant wall temperature boundary condition. Assume the following properties for mercury.
Density = 12,870 Kg/m3, Viscosity = 0.000863 N-s/m2
Specific heat = 0.134 KJ/KgK, Thermal conductivity = 14W/mK. [8+8]
5.a) What is the difference between heat transfer for liquid metal flow and ordinary fluids?
b) Air at 1atm and 270C flows across a cylinder of 2.5cm diameter with a velocity of 30m/sec. The cylinder surface is maintained at 1200C.
Calculate the mean heat transfer coefficient and heat transfer rate per metre length of the cylinder. If the air pressure is 2 atm, what is the heat transfer? [8+8]
6.a) Define Rayleigh number and explain its significance in natural convection.
b) A vertical plate of 0.3m height and 0.1m width maintained at a uniform temperature of 800C is exposed to ambient air at 250C. Calculate the heat lost from the plate. [8+8]
7.a) Compare horizontal and vertical condensation.
b) Describe horizontal tube evaporator with a neat sketch. [8+8]
8.a) Explain how good emitters can be treated as good absorbers.
b) A black solid cylinder of emissivity 0.95 and at 1000C is kept concentrically in a large cylinder maintained at 300C, having emissivity 0.2. Calculate the radiation heat exchange between two surfaces per m2 area. [8+8]
RR Code No: RR310803 SET-2
1.a) Distinguish between steady state conduction and unsteady state conduction.
b) A 3cm diameter aluminium sphere of thermal conductivity 204 W/mK, density 2700 kg/m3, specific heat 0.896 KJ/kgK is initially at 1750C. It is suddenly immersed in a well-stirred fluid at 250C. The temperature of the sphere is lowered to 1000C in 42 sec. Calculate the heat transfer coefficient. [16]
2.a) What is entrance length and how do you find it for laminar and turbulent flow conditions through a tube.
b) Liquid mercury flows through a long tube of 2.5 cm inner diameter with a velocity of 1 m/sec. Calculate the heat transfer coefficient for the constant wall temperature boundary condition. Assume the following properties for mercury.
Density = 12,870 Kg/m3, Viscosity = 0.000863 N-s/m2
Specific heat = 0.134 KJ/KgK, Thermal conductivity = 14W/mK. [8+8]
3.a) What is the difference between heat transfer for liquid metal flow and ordinary fluids?
b) Air at 1atm and 270C flows across a cylinder of 2.5cm diameter with a velocity of 30m/sec. The cylinder surface is maintained at 1200C.
Calculate the mean heat transfer coefficient and heat transfer rate per metre length of the cylinder. If the air pressure is 2 atm, what is the heat transfer? [8+8]
4.a) Define Rayleigh number and explain its significance in natural convection.
b) A vertical plate of 0.3m height and 0.1m width maintained at a uniform temperature of 800C is exposed to ambient air at 250C. Calculate the heat lost from the plate. [8+8]
5.a) Compare horizontal and vertical condensation.
b) Describe horizontal tube evaporator with a neat sketch. [8+8]
6.a) Explain how good emitters can be treated as good absorbers.
b) A black solid cylinder of emissivity 0.95 and at 1000C is kept concentrically in a large cylinder maintained at 300C, having emissivity 0.2. Calculate the radiation heat exchange between two surfaces per m2 area. [8+8]
7. Derive the general heat conduction equation in Cartesian system and hence deduce the expression for temperature distribution through a plane wall. [16]
8. Steam at 3000C flows in a stainless steel pipe of thermal conductivity 30 W/mK whose inner and outer diameters are 5 cm and 5.5 cm respectively. The pipe is covered with 5 cm thick glass wool of thermal conductivity 0.038W/mK.
Heat is lost to the surroundings at 200C by convection and radiation with a combined heat transfer coefficient of 15W/m2K. Taking the inside heat transfer coefficient as 80W/m2K, calculate the heat lost per metre length of the pipe. [16]