Q.1
The maximum velocity of the turbulent regime is called the ___________ at which the fast fluidization regime occurs.
Questionheat-transfer-operations-questions-answers1.jpg
  • a) Terminal velocity
  • b) Transport velocity
  • c) Superficial velocity
  • d) Average velocity
Q.2
What happens at velocities above the transport velocity?
  • a) Particles coagulate
  • b) Particles are carried out of the system by the fluid
  • c) Particles break into smaller parts
  • d) Particles accumulate at the top
Q.3
Which one of the following working model is best suited for fluidized bed combustion boilers?
  • a) Bubbling fluidized beds
  • b) Laminar film fluidised bed
  • c) Pneumatic conveying regime
  • d) Moving bed (Dense flow)
Q.4
Parameters that describe the overall behaviour of the fluidized bed in the bubbling regime are:
  • a) (i) (ii)
  • b) (ii) (iii) (iv)
  • c) (i) (ii) (iii) (iv)
  • d) (i) (ii) (iii)
Q.5
Which one of the following method is the most reliable when it comes to determine fluidisation point?
  • a) Pressure Drop
  • b) Top surface particles starting random movement
  • c) Half of the particles getting free
  • d) All particles are free
Q.6
What is the correct expression for pressure drop in a fluidised bed at fluidisation?
  • a) ΔP=(1-∈)(ρP-ρg)gHB
  • b) ΔP=(∈)(ρP-ρg)gHB
  • c) ΔP=(1-∈)(ρP-ρg)gHC
  • d) ΔP=(1-∈)(ρP)gHB
Q.7
If the operation on a fluidised bed is a dense flowing fixed bed, then which one of the following method is used for pressure drop calculation?
  • a) Sieder Tate Equation
  • b) Ergun Equation
  • c) DeMentic Equation
  • d) Kozeny Carman Equation
Q.8
Which one of the heat transfer processes are not involved in a fluidised bed?
  • a) Gas-wall heat transfer
  • b) Heat transfer between different points in the bed
  • c) Heat transfer between the fluidized bed particles and the larger particles floating in the bed
  • d) Heat transfer to the submerged surfaces in contact with the bed
Q.9
On complete fluidisation, which one of the following is zero?
  • a) Gas-particle heat transfer
  • b) Heat transfer between different points in the bed
  • c) Heat transfer between the fluidized bed particles and the larger particles floating in the bed
  • d) Heat transfer to the submerged surfaces in contact with the bed
Q.10
If there arepellets of 3mm diameter, what is the heat transfer area?
  • a) 0.02m2
  • b) 0.05m2
  • c) 0.04m2
  • d) 0.03m2
Q.11
Active particles which are quite large sternly repel the emulsion phase and hence the mass transfer rate augments with the ________ of the inert bed material size and _________ with increase of its active particle’s diameter.
  • a) Increase, Decrease
  • b) Increase, Increase
  • c) Decrease, Increase
  • d) Decrease, Decrease
Q.12
Heat transfer between the active particle and the fluidized bed is controlled by three mechanisms given below, identify the wrong entry.
  • a) Radiation
  • b) Gas convection
  • c) Particle convection
  • d) Particle conduction
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