Worksheets02 Transport Phenomena part 2
Total questions: 15
Worksheet time: 8mins
What is the formula for total flux?
Total flux = Characteristic velocity x Characteristic length
Total flux = Diffusivity x Gradient of quantity volume
Total flux = Mass flow rate + Mole flow rate
Total flux = Molecular flux + Convective flux
What does the Peclet number (Pe) indicate?
The mass of a substance
The velocity of a fluid
The total energy in a system
The ratio of convective to diffusive transport
What is the formula for convective flux?
Convective flux = Characteristic velocity x (quantity/volume)
Convective flux = Diffusivity x (gradient of quantity/volume)
Convective flux = Characteristic velocity x (gradient of quantity/volume)
Convective flux = Diffusivity x (quantity/volume)
When is total flux equal to convective flux?
When Pe ≈ 1
When Pe = 0
When Pe << 1
When Pe >> 1
What happens when Pe << 1?
Total flux equals molecular flux
Total flux equals convective flux
Total flux is undefined
Total flux is zero
What is the role of thermal diffusivity in energy transport?
It measures how quickly energy spreads through a material
It determines the total energy in a system
It measures the velocity of a fluid
It calculates the mass flow rate
What is the formula for the rate of energy entering a system if Pe<<1?
Ė = Density x Velocity
Ė = Mass flow rate x Energy content
Ė = Thermal diffusivity x Gradient of energy / Volume
Ė = Energy / Volume
What does the term 'convective energy flux' refer to?
The energy carried by the bulk movement of a fluid
The energy lost through radiation
The energy stored in a system
The energy transferred by conduction
What is the relationship between mass flow rate and mole flow rate?
Mass flow rate = Concentration x Flow Area
Mass flow rate = Energy flow rate / Flow Area
Mass flow rate = Mole flow rate x Volume
Mass flow rate = Density x Velocity x Flow Area
What is the effect of Pe ≈ 1 on total flux?
Total flux is influenced equally by both molecular and convective flux
Total flux is only convective
Total flux is negligible
Total flux is only molecular
What is the significance of a high Peclet number (Pe >> 1)?
Dominance of diffusive transport over convective transport
Dominance of convective transport over diffusive transport
Equal contribution from both convective and diffusive transport
No significant transport occurs
How does the characteristic velocity affect convective flux?
Higher characteristic velocity increases convective flux
Lower characteristic velocity increases convective flux
Characteristic velocity has no effect on convective flux
Convective flux is independent of velocity
What is the significance of a low Peclet number (Pe << 1) in heat transfer?
Dominance of molecular diffusion over convection
Dominance of convection over molecular diffusion
Equal contribution from both molecular and convective processes
No significant heat transfer occurs
What is the significance of a Peclet number close to zero (Pe ≈ 0) in mass transfer operations?
Dominance of diffusive transport over convective transport
Dominance of convective transport over diffusive transport
Equal contribution from both transport mechanisms
No mass transfer occurs
How does the density of a fluid affect its mass flow rate?
Higher density increases mass flow rate
Lower density increases mass flow rate
Density has no effect on mass flow rate
Mass flow rate is independent of density
