CH128 SQ M2

Which property of a material determines its ability to conduct heat?

Thermal Conductivity

which dimensionless number characterizes the ratio of conductive to convective heat transfer resistances?

Biot number

This dimensionless number is useful in calculations involving free convection where buoyancy forces dominantly drive fluid motion

Ra

which parameter primarily influences the Prandtl number?

the ratio of momentum diffusivity to thermal diffusivity

Which dimensionless number characterizes the ratio of convective to conductive heat transfer driving force?

Nusselt number

The prandtl number of liquids is a strong function of:

temperature

Which of the following is a correct collection of units for thermal conductivity

W/(m*K)

The wall of a brick oven has a thickness of W and thermal conductivity of k. The inside temperature is T1 and the outside temperature is T2 (T1>T2). Which of the following changes will double the rate of heat transfer, assuming all other variables are held constant?

W/2

In steady-state heat conduction, how does the temperature distribution behave?

Remains constant over time

Which of the following best describes the Prandtl number?

ratio of the momentum diffusivity to the thermal diffusivity

What is the fundamental law governing heat conduction?

Fourier’s law

Which type of heat conduction occurs within a homogeneous solid without any bulk fluid motion?

Pure conduction

How does an increase in fluid velocity affect convective heat transfer?

it increases the heat transfer coefficient

Which mode of heat transfer involves the movement of fluid to transport thermal energy?

convection

What is the primary difference between forced and natural convection?

Forced convection requires an external driving force, such as a fan or pump

Which process is an example of convection-dominated heat transfer?

cooling of a hut cup of coffee in air

How does increasing the thickness of a material affect its thermal resistance to conduction?

increases thermal resistance

Which condition enhances heat transfer in turbulent convection compared to laminar convection?

increased mixing of fluid layers

Which type of convection occurs due to density differences within a fluid?

Natural convection

Fourier's First Law applies to the heat transferred by:

conduction