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Champion Plan || Convection (App update required to attempt this test)

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Question 1

Air at 20 °C flows past a 250 mm long plates at a velocity of 45 m/s. If the surface of the plate is maintained at 300 °C. Take properties of air as: k = 0.03638 W/m-K, Pr = 0.682. The heat transferred from the entire plate length to air assuming unit width of the plate will be ____ W.

Question 2

In an experiment, the local heat transfer over a flat plate were correlated in the form of local Nussel number as expressed by the following correlation.
Description: Description: E:\Gate\SSC JE Mechanical Part 1\Made Easy Questions\08_Heat-Transfer_BLok_files\image076.png
The ratio of the average convection heat transfer coefficient (Description: Description: E:\Gate\SSC JE Mechanical Part 1\Made Easy Questions\08_Heat-Transfer_BLok_files\image077.png) over the entire plate length to the local convection heat transfer convection heat transfer coefficient (hx) at x=L is ____________.

Question 3

Calculate the percentage of power lost by free convection from 50W incandescent bulb at 120°C to ambient air at 30°C. Assume the bulb as sphere of 50mm diameter. The correlation is given by: Nu= 0.6(.The thermo physical properties at 75°C are as follows: k=2.964× W/m°C, 𝝼=20.02×/sec, Pr=0.67

Question 4

Heat is lost from a 150 mm diameter pipe vertically placed in ambient at 30 °C. The height of the cylinder is 200 mm and thermal conductivity of air is 0.04W/mK. If the Nusselt number is 30, then the heat transfer coefficient will be

Question 5

A flat plate(3x4)m2 is immersed in a liquid having constant temperature of 27 and the plate temperature is 127 if the heat transferred from the plate to the liquid at the rate of 500kW. Assume that heat transfer is at steady state. Find the heat transfer coefficient(in W/m2k ) of the liquid side ______.

Question 6

The side surface of car is given as flat plate of 3m length. It receives solar heat at the rate of 500 W/m2 while car is in speed of 50 km/hr. Assume inside surface as an insulated one. Calculate nusselt number.
Given properties are ν = 1.6 x 10-5 m2/sec , Pr = 0.5
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