Q.1
Which of the following is having the lowest value of overall heat transfer coefficient?
  • a) Feed water heaters
  • b) Air condensers
  • c) Air to low viscosity liquids
  • d) Steam condensers
Q.2
A cross-flow type air heater has an area ofcmThe overall heat transfer coefficient isW/m2 K and the heat capacity of both hot and cold streams isW/m K. The value of NTU is
  • a) 0.2
  • b) 6
  • c) 1000
  • d) 5
Q.3
An oil cooler in a high-performance engine has an outside surface area 0.m2 and a surface temperature ofdegree Celsius. At any intermediate time air moves over the surface of the cooler at a temperature ofdegree Celsius and gives rise to a surface coefficient equal to 45.4 W/ m 2 K. Find out the heat transfer rate?
  • a) 564.98 W
  • b) 324.67 W
  • c) 190.68 W
  • d) 768.43 W
Q.4
Which of the following statement is incorrect according to heat transfer?
  • a) Heat flow doesn’t depend on temperature
  • b) A material medium is not necessary for heat transmission
  • c) The process of heat transfer is an irreversible process
  • d) For heat exchange, a temperature gradient must exist
Q.5
Consider a convective heat flow to water atdegree Celsius from a cylindrical nuclear reactor fuel rod ofmm diameter. The rate of heat generatioN isW/m3 and convective heat transfer coefficient is I kW/m2 K. The outer surface temperature of the fuel element would be
  • a) 400 degree Celsius
  • b) 625 degree Celsius
  • c) 700 degree Celsius
  • d) 550 degree Celsius
Q.6
For a cylindrical rod with uniformly distributed heat sources, the thermal gradient at half the radius location will be
  • a) One half
  • b) One fourth
  • c) Four times
  • d) Twice
Q.7
Water (specific heat = 4 k J/kg K) enters a cross flow exchanger (both fluids unmixed) atdegree Celsius and flows at the rate of 7.5 kg/s. It cools air (C P = 1 k J/kg K) flowing at the rate ofkg/s from an inlet temperature ofdegree Celsius. For an overall heat transfer coefficient ofk J/m2 hr degree and the surface area ismdetermine the NTU
  • a) 1.2
  • b) 8.2
  • c) 6.2
  • d) 5.2
Q.8
A heat exchanger to preheat oil for a furnace was designed without considering the possibility of scale formation, and the overall heat transfer coefficient based on the fuel oil side wask J/m2 hr degree. What would be the corrected coefficient of heat transfer if a fouling factor of 0.m2 hr degree/k J for the fuel oil is taken into account?
  • a) 1222.78 k J/m2 hr degree
  • b) 1555.78 k J/m2 hr degree
  • c) 1777.78 k J/m2 hr degree
  • d) 1233.78 k J/m2 hr degree
Q.9
Which of the following is the value of fouling factor for engine exhaust?
  • a) 0.001 m2 K/W
  • b) 0.002 m2 K/W
  • c) 0.003 m2 K/W
  • d) 0.004 m2 K/W
Q.10
The value of fouling factor for industrial liquids is ______
  • a) 0.0002 m2 K/W
  • b) 0.0001 m2 K/W
  • c) 0.0003 m2 K/W
  • d) 0.0004 m2 K/W
Q.11
Which of the following is the value of overall heat transfer coefficient for steam condensers?
  • a) 2000-9500 W/m2 K
  • b) 1500-5000 W/m2 K
  • c) 200-9000 W/m2 K
  • d) 3000-5500 W/m2 K
Q.12
The value of overall heat transfer coefficient for air to low viscosity liquid _______
  • a) As high as 700 W/m2 K
  • b) As high as 900 W/m2 K
  • c) As high as 600 W/m2 K
  • d) As high as 800 W/m2 K
Q.13
Mark the system where heat transfer is given by forced convection
  • a) Heat flow from hot pavement to the surrounding atmosphere
  • b) Heat exchange on the outside of cold and warm pipes
  • c) Chilling effect of cold wind on a warm body
  • d) Fluid passing through the tubes of a condenser and other heat exchange equipment
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