jH factor for heat transfer depends upon the ____________ number?
A. Biot
B. Nusselt
C. Reynolds
D. Prandtl
Month: March 2019
The actual temperature drop across the heating surface of an evaporator depends on the_______________?
The actual temperature drop across the heating surface of an evaporator depends on the_______________?
A. Liquid depth over the heating surface
B. Solution being evaporated
C. Pressure difference between the steam chest and the vapor space above the boiling liquid
D. All A., B. and C.
Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is_______________?
Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is_______________?
A. 0.2
B. 0.4
C. 0.6
D. 0.8
Indirect contact heat exchangers are preferred over direct contact heat exchangers, because_________________?
Indirect contact heat exchangers are preferred over direct contact heat exchangers, because_________________?
A. Heat transfer co-efficient are high
B. There is no risk of contamination
C. There is no mist formation
D. Cost of equipment is lower
Which of the following has the lowest overall heat transfer co-efficient ?
Which of the following has the lowest overall heat transfer co-efficient ?
A. Dowtherm
B. Molten sodium
C. Water
D. Air
Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator ?
Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator ?
A. Long vertical evaporator
B. Horizontal tube evaporator
C. Agitated film evaporator
D. Calandria vertical tube evaporator
The absorptivity of a grey body at a given temperature _____________ with increasing wavelength of radiation?
The absorptivity of a grey body at a given temperature _____________ with increasing wavelength of radiation?
A. Increases
B. Decreases
C. Remain constant
D. May increase or decrease; depends on the material
In case of heat transfer by conduction in a hollow cylinder, ______________ mean area is used to calculate the heat transfer rate?
In case of heat transfer by conduction in a hollow cylinder, ______________ mean area is used to calculate the heat transfer rate?
A. Geometric
B. Arithmetic
C. Logarithmic
D. Either A., B. or C.
The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are_______________?
The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are_______________?
A. Re.Gz
B. Nu, Pr
C. Nu, Pr, Re
D. Nu, Gz
One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to________________?
One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to________________?
A. Heat the water from 0°C to 100°C
B. Evaporate the water
C. To superheat the steam
D. Data insufficient, can’t be predicted