Time Left - 30:00 mins

GATE 2019: Heat Transfer Super Quiz-1

Attempt now to get your rank among 857 students!

Question 1

Temperature distribution in a slab is given as

Thermal diffusivity of the material is give as . Calculate the rate of change of temperature of the slab at x=1 m in ℃/hr.

Question 2

Two rectangular blocks, having identical dimensions, can be arranged either in configuration I or in configuration II as shown in figure. One of the blocks has thermal conductivity k and the other 2k. The temperature difference between the ends along the x-axis is the same in both the configurations. It takes 9s to transport a certain amount of heat from the hot end to the cold end in the configuration I. The time to transport the same amount of heat in the configuration II is

Question 3

A hollow sphere is made up of two materials, first with k=70 W/m-K is having internal diameter of 10 cm and outer diameter of 30 cm and second with k=15 W/m-K forms the outer layer with outer diameter of 40 cm. The inside and outside temperature are 300⁰C and 30⁰C. The rate of heat flow through the sphere assuming perfect contact between two materials is __________kW.

Question 4

The inlet temperature of a counter flow heat exchanger for hot and cold fluid is 170

and 30

. The ratio of capacity rate for hot and cold fluid is 1. Find the LMTD (degree celcius) of the heat exchanger. Take effectiveness ε=0.7

Question 5

Two infinitely long rods of same diameter, one made of brass (k= 109W/m ºC) and other made of copper (k= 400W/m ºC) have one of their ends inserted in a heated furnace. Both the rods are exposed to same environment. At a distance of 150mm from the furnace end, the temperature of the brass rod is 170 ºC. At what distance(mm) from the furnace end the same temperature will reach in copper rod.

Question 6

A counter flow double pipe heat exchanger using superheated steam is used to heat water at the rate of 10500 kg/h. The steam enters the heat exchanger at 180 °C and leaves at 130 °C. The inlet and exit temperatures of water are 30 °C and 80 °C respectively. If overall heat transfer coefficient from steam to water is 814 W/m2 °C. The heat transfer area is

Question 7

A square plate of 1000 Watt electric heater 15 cm × 15 cm is inserted between two slabs. Slab A is 2 cm thick (k = 50 W/m-K) and slab B is 1 cm thick (k = 0.2 W/m-K). The outside heat transfer coefficients on side A and side B are 200 W/m²-K and 50 W/m²-K respectively. The temperature of surrounding air is 30 °C. The maximum temperature in the system is ___________ °C.

Question 8

In a parallel flow shell and tube heat exchanger having air and hot flue gases as cold and hot fluids. The inlet and exit temperature of cold fluid is 50 °C and 110 °C, while for hot fluid the inlet and exit temperature being 400 °C and 220 °C respectively. The heat transferred per hour is 155850kJ, overall heat transfer coefficient is 68W/

K. If the outside diameter of tube is 70mm, find the length of the tube required for necessary heat transfer to occur.

Question 9

The diagram shows a conical section fabricated from pyroceram (k = 3.46 W/m-K). It is of circular cross-section with the diameter where . The small end is at and the large end at The end temperature are and , while the lateral surface is well insulated. The heat rate through the cone is

Question 10

A long laddle is used to fry potatoes in hot oil kept at a temperature of 200℃ as shown in the figure. The section of the handle of the ladle is 6mm×18mm. The surroundings are at 27℃. The conductivity of the material is 195W/m℃. If the temperature at a distance of 350mm from the oil should not reach 45℃, determine the convective heat transfer coefficient.

Question 11

Water at a rate of 2.08 kg/s enters a parallel flow heat exchanger at 15°C to cool 2.22 kg/s of air at 100°C . The overall heat transfer coefficient is 140 W/m²K , and the exchanger area is 20m². Find the exit temperature of the air in ‘K’.

Question 12

Heat flows through a composite slab as shown below, The depth of the slab is 10 cm. The k values are in W/m-K. The heat flow rate through the composite wall in W is
$Description: Description: E:\Gate\SSC JE Mechanical Part 1\Made Easy Questions\08_Heat-Transfer_BLok_files\image060.png$

857 attempts
4 upvotes
11 comments

Tags :

ESE & GATE ME General

Jan 28ESE & GATE ME