Thermal diffusivity is given by__________________?
A. k/ρCp
B. ρCp/k
C. μCp/a
D. μ/hCp
Chemical Heat Transfer
In a forward feed multiple effect, the pressure build up will be____________________?
In a forward feed multiple effect, the pressure build up will be____________________?
A. Least at the inlet of the first effect
B. Least at the outlet of the last effect
C. Highest at the inlet of the last effect
D. Highest at the outlet of the last effect
Which of the following has the minimum absorptivity ?
Which of the following has the minimum absorptivity ?
A. Aluminium foil
B. Coal dust
C. Refractory bricks
D. Iron plates
Convective heat transfer, in which heat is transferred by movement of warmed matter is described by___________________?
Convective heat transfer, in which heat is transferred by movement of warmed matter is described by___________________?
A. Fourier’s law
B. Newton’s law of cooling
C. Fick’s law
D. None of these
If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is________________?
If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is________________?
A. Always less than h1
B. Always between h1 and h2
C. Always higher than h2
D. Dependent on metal resistance
In an extended surface heat exchanger, fluid having lower co-efficient________________?
In an extended surface heat exchanger, fluid having lower co-efficient________________?
A. Flows through the tube
B. Flows outside the tubes
C. Can flow either inside or outside the tubes
D. Should not be used as it gives very high pressure drop
The critical radius ‘r’ of insulation on a pipe is given by____________________?
The critical radius ‘r’ of insulation on a pipe is given by____________________?
A. r = 2k/h
B. r = k/h
C. r = k/2h
D. r = h/k
In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of___________________?
In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of___________________?
A. Concentrations
B. Chemical potentials
C. Activity co-efficients
D. Mass transfer co-efficients
A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________________?
A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________________?
A. Greater than that for un-insulated steam pipe
B. Less than that of the un-insulated steam pipe
C. Equal to that of the un-insulated steam pipe
D. Less than the steam pipe with 5 cms insulation
Sensible heat of hot industrial flue gases cannot be recovered by a/an________________?
Sensible heat of hot industrial flue gases cannot be recovered by a/an________________?
A. Economiser
B. Regenerator
C. Ceramic recuperator
D. None of these