Questions Archive - Page 5 of 38

Mech_59
Heat is being transferred connotatively from a cylindrical nuclear reactor fuel rod of 50 mm diamater to water at 75°C, under steady state condition, the rate of heat generation within the fuel element is 10^6 W/m³ and the convective heat transfer coefficient is 1 kW/m²K.
- fluids
- heat and mass transfer
on 14th August 2023 in Mechanical engineering.
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Mech_59
An electrical transmission line made of a 25mm annealed copper wire carries 200 A and has a resistance of 0.4 x 10^-4 Ω/cm length. Determine the heat tansfer coeffficient between the wire surface and the ambient air and the maximum temperature in the wire.
- fluids
- heat and mass transfer
on 14th August 2023 in Mechanical engineering.
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Mech_59
A plane wall 10 cm thick generates heat at the rate of 4×10^4 W/m³ when an electric current is passed through it. Determine: (a) the surface temperaure (b) the maximum temperatrure in the wall.
- fluids
- heat and mass transfer
on 14th August 2023 in Mechanical engineering.
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Mech_59
The variation of temperature in a plane wall is determined to be T(x) = 65x + 25 where x is in m and T is in °C. What is the thickness of the wall for a 13 °C temp drop?
- fluids
- heat and mass transfer
on 14th August 2023 in Mechanical engineering.
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Mech_59
A 30 mm OD pipe is to be insulated with asbestos having a thermal conductivity of 0.1 W/mK. The convective heat transfer coefficient is 5W/m²K. What is the critical radius of insulation for this pipe?
- fluids
- heat and mass transfer
on 14th August 2023 in Mechanical engineering.
- 2K
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Mech_59
What is the ratio of heat flows from two walls of same area and thickness ratio 1:2 and thermal conductivity ratio 3:1 for the same temperature diiference on the two sides?
- fluids
- heat and mass transfer
on 7th August 2023 in Mechanical engineering.
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Mech_59
The temperature at the inner and outer surfaces of a 15 cm thick plane wall are measred to be 40°C and 28°C, respectively. What is the expression for steady, one-dimensional variation of temperature in the wall ?
- fluids
- heat and mass transfer
on 7th August 2023 in Mechanical engineering.
- 1K
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Mech_59
A composite wall having three layers of thickness 0.3m, 0.2 m and 0.1 m and with thermal conductivities 0.6, 0.4, 0.1 W/(m-K), respectively, is having surface area 1 m2.
- fluids
- heat and mass transfer
on 7th August 2023 in Mechanical engineering.
- 1K
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Mech_59
The variation of temperature in a plane wall is determined to be T(x) = 110 – 48x where x is in m and T is in °C. If the thickness of the wall is 0.75 m, what the temperature difference between the inner and outer surface of the wall?
- fluids
- heat and mass transfer
on 2nd August 2023 in Mechanical engineering.
- 1K
- 1
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Mech_59
A hollow sphere is made up of two materials, first with k = 70 W/m K having an I.D. of 10 cm and O.D. of 30 cm and the second with k = 15 W/m K forms the outer layer with O.D. of 40 cm. The inside and outside temperature are 300°C and 30°C, respectively.
- fluids
- heat and mass transfer
on 2nd August 2023 in Mechanical engineering.
- 1K
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- 0