What is the difference between the natural and forced convection?
The key difference between natural and forced convection is that in natural convection, the motion of the fluid is influenced by natural means whereas, in forced convection, the motion of fluids is influenced by external means.
What are the two differences between free and forced convection?
Free convection: If the motion of the fluid is only due to its density difference because of temperature variation, then it is free convection. Forced convection: In this mode of heat transfer some external source like blower is used to cause the motion of the air.
Is wind natural or forced convection?
The convection caused by winds is natural convection for the earth, but it is forced convection for bodies subjected to the winds since for the body it makes no difference whether the air motion is caused by a fan or by the winds.
What is temperature in forced convection flow?
The difference in temperature between the tube wall and the water is small, typically less than 10 K in the convection section.
Which NO is used in forced convection?
The parameter of importance in forced convection is the Péclet number, which is the ratio of advection (movement by currents) and diffusion (movement from high to low concentrations) of heat.
Which number has a significant role in forced convection?
Which dimensionless number has a significant role in forced convection? Explanation: It is indicative of the relative importance of inertial and viscous effects in a fluid motion. Reynolds number is important in forced convection.
What is the analogous in forced convection?
10.1. In forced convection, the Nusselt number depends on the rate of heat transfer through a boundary layer from a surface hotter or cooler than the air passing over it, a process analogous to the transfer of momentum by skin friction.
What is the significance of Grashof number?
The significance of the Grashof number is that it represents the ratio between the buoyancy force due to spatial variation in fluid density (caused by temperature differences) to the restraining force due to the viscosisty of the fluid.