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Heat-transfer Questions Set 6:

Quiz Mode

What is the emissivity of a black body?

100

infinite

Solution:

What is the dimension of velocity?

L T

L T^-2

L T^1

L T^-1

Solution:

The ratio of surface convection resistance to the internal conduction resistance is known as the?

Biot number

Prandtl number

Reynolds number

Stanton number

Solution:

All the factors relating to the geometry of the sections are grouped together into a single constant called the shape factor.

True

False

None of the above

Solution:

To find the Nusselt number, if given the convective heat transfer and diameter, which additional parameter is required?

Thermal conductivity

Density

Volume

Kinematic viscosity

Solution:

Which of the following methods is useful for increasing the heat transfer rate?

Increasing temperature difference

Increasing surface area

Increasing convective heat transfer

Increasing material density

Solution:

If we have the density of the material and the specific heat capacity of the material, which additional parameter is required to calculate the thermal diffusivity?

Prandtl number

Thermal conductivity

Reynolds number

Convective heat transfer

Solution:

The temperature distribution in the case of a fin insulated at the tip is given by:

t - t0/t0 - ta = cosh m (3 - x)/cosh ml

t - t0/t0 - ta = cosh m (2 - x)/sinh ml

t - t0/t0 - ta = cosh m (l - x)/cosh ml

t - t0/t0 - ta = cos m (l - x)/sin ml

Solution:

The primary purpose of fins on heat transfer surfaces is to:

decrease the pressure drop of the fluid

increase the turbulence in flow for enhancing heat transfer rate

increase the temperature gradient to enhance heat transfer

increase the surface area to promote the rate of heat transfer

Solution:

Which of the following statements is true about regeneration-type heat exchangers?

Heat transfer takes place by direct mixing of hot and cold fluids

Heat transfer takes place by generation of heat again and again

None of the above

Heat transfer takes place between fluids not being directly in contact

Heat-transfer Questions Set 6:

What is the emissivity of a black body?

Solution:

What is the dimension of velocity?

Solution:

The ratio of surface convection resistance to the internal conduction resistance is known as the?

Solution:

All the factors relating to the geometry of the sections are grouped together into a single constant called the shape factor.

Solution:

To find the Nusselt number, if given the convective heat transfer and diameter, which additional parameter is required?

Solution:

Which of the following methods is useful for increasing the heat transfer rate?

Solution:

If we have the density of the material and the specific heat capacity of the material, which additional parameter is required to calculate the thermal diffusivity?

Solution:

The temperature distribution in the case of a fin insulated at the tip is given by:

Solution:

The primary purpose of fins on heat transfer surfaces is to:

Solution:

Which of the following statements is true about regeneration-type heat exchangers?

Solution:

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