Unit 2 Flashcards
Heat transfer by convection occurs due to:
Bulk movement of fluid
What is a key factor in convection heat transfer
Surface roughness
Mechanism involved in convection based heta transfer
Molecular vibration
Convection is most effective in which phase of matter
Liquids and gases
Newton’s law of cooling states that the rate of heat loss of a body is
Proportional to temp difference
Newton’s law of cooling equation
Q = hA (Ts - Tx)
Which dimensionless number is used to characterize natural convection
Greshof number
In newton’s law of cooling, h represents
Convective heat transfer coefficient
In natural convection, fluid motion occurs due to
Density difference caused by temperature variation
In forced convection, heat transfer us enhanced by
Wind, fans or pumps
Which one has a high heat transfer coefficient
Natural convection
Forced convection
Radiation
Freezing
Forced convection
Nusselt number represents the ratio if
Convective to conductive heat transfer
Grashof number is used in
Natural convection
The Reynolds number determines
The type of fluid flow (laminar or turbulent)
The prandtl number is defined as
Ratio of momentum diffusivity to thermal diffusivity
The prandtl number is defined as
Ratio of momentum diffusivity to thermal diffusivity
Main purpose of heat exchanger is to
Transfer Heat between two fluids
In heat exchanger, a large surface area leads to
Higher heat transfer rate
