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BARC 2019: Heat Transfer Nuclear Quiz-1
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Question 1
A 0.8 mm diameter nickel- alumel thermocoupl is used to measure the temperature difference of a fluid. The sensitivity of the thermocouple (in s) is
Given data:
Convective heat transfer coefficient = 500 W/mK
Specific heat of fluid = 350 J/kgK
Density of thermocouple material = 9500 Kg/m3
Given data:
Convective heat transfer coefficient = 500 W/mK
Specific heat of fluid = 350 J/kgK
Density of thermocouple material = 9500 Kg/m3
Question 2
A solid sphere (
= 0.8) of radius, r1 = 15 cm maintained at 700 K and is placed concentrically inside a hollow sphere (
= 0.6) of radius r2 = 25 cm maintained at 500 K as shown in figure.
The net radiative heat transfer from surface 1 to 2 is (Stefan- Boltzmann constant = 5.67×10-8 W/m2K4)
= 0.8) of radius, r1 = 15 cm maintained at 700 K and is placed concentrically inside a hollow sphere ( = 0.6) of radius r2 = 25 cm maintained at 500 K as shown in figure. The net radiative heat transfer from surface 1 to 2 is (Stefan- Boltzmann constant = 5.67×10-8 W/m2K4)
Question 3
Two large parallel plates having temperatures T1 = 1500K and T2 = 500K are kept in such a way that radiation leaving from each surface is completely reached the 2nd surface. Emissivity values for plates are 0.5 and 0.25 respectively. Then heat transfer between the plates __________ (in kW/m2).
Question 4
Match the following list1 and list2
List - I
A) Prandtl No.
B) Nusselt No.
C) Stanton No.
D) Schmidt No.
E) Reynolds No.
List - II
1) 
2) 
3) 
4) 
5) 
Question 5
A device is designed to cool 0.14 kg/s of hot liquid of specific heat 3 KJ/kg K at 100
using a parallel flow arrangement. The cooling water of specific heat 4.18 kJ/kg K is available for cooling purpose at the rate of 0.54 kg/s at a temperature of 10
. The effectiveness of heat exchanger is (take overall heat transfer coefficient is 1360 W/m2K and the surface area of the heat exchanger is 0.35 m2)
using a parallel flow arrangement. The cooling water of specific heat 4.18 kJ/kg K is available for cooling purpose at the rate of 0.54 kg/s at a temperature of 10. The effectiveness of heat exchanger is (take overall heat transfer coefficient is 1360 W/m2K and the surface area of the heat exchanger is 0.35 m2) Question 6
A cubical body, which is closely approximates a blackbody, is having dimension 20 cm and it is suspended in the air at 750 K. The spectral blackbody emissive power (in KW/m2-μm) at a wavelength of 4 micrometre is
Question 7
Air flows at a heated plate at a velocity of 30m/s. The local skin friction coefficient of plate is 0.002. Estimate the local heat transfer coefficient at that point. The properties of air are as follows: ρ = 0.89kg/m3, μ= 2.478×10-5kg/m-s, Cp= 1.001kJ/kgK, k= 0.05W/mK. Use St× 
= 
.
= . Question 8
In a counter flow heat exchanger having an area of 50m2 and heat capacity of hot and cold fluid is 3.050kW/K. If the overall heat transfer coefficient is 250W/
K, then find the effectiveness of heat exchanger if heat exchanger area is
K, then find the effectiveness of heat exchanger if heat exchanger area isQuestion 9
Steam enters counter flow heat exchanger at 180 °C and leaves at 310 °C, while hot gases enters at 600 °C and leaves at 350 °C, the mass flow rate of steam and gas is 13.33kg/sec and gas is 23.33kg/sec. If the tubes are 35mm diameter and 4m long, find the number of tubes required for effective heat transfer. Neglect the resistance offered by metallic tubes.
(Take: Cps=2.71kJ/kgK, Cpg=1 kJ/kgK, hs= 600W/
K, hg= 150W/
K)
(Take: Cps=2.71kJ/kgK, Cpg=1 kJ/kgK, hs= 600W/
K, hg= 150W/K) Question 10
A thin flat plate 2m * 2m is hanging freely in air. The temperature of the surroundings is 10 °C solar radiation is falling on one side of the plate at the rate of 1000 W/m2. What should be the convection heat transfer coefficient in W/m2 °C, if the temperature of the plate is to remain constant at 30 °C?
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