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
Support mcqgeeks.com by disabling your adblocker.
Please disable the adBlock and continue. Thank you.