Wanna to share some findings today...some notes from Dr. Shankar Subramanian, University of Clarkson.
Heat Transfer to or from a Fluid Flowing Through a Tube
A common situation encountered by the chemical engineer is heat transfer to fluid flowing through a tube. This can occur in heat exchangers, boilers, condensers, evaporators, and a host of other process equipment. Therefore, it is useful to know how to estimate heat transfer coefficients in this situation.
We can classify the flow of a fluid in a straight circular tube into either laminar or turbulent flow. It is assumed from hereon that we assume fully developed incompressible, Newtonian, steady flow conditions. Fully developed flow implies that the tube is long compared with the entrance length in which the velocity distribution at the inlet adjusts itself to the geometry and no longer changes with distance along the tube.
R. Shankar Subramanian, University of Clarkson
External flows occur when the fluid is confined in such a large channel or container such that it can be considered practically unbounded in extent when considering heat transfer to a stationary solid surface. The ideal starting point for this is flow over a flat plate that is long and wide. We know that in this situation, for flow at large values of a suitably defined Reynolds number, a boundary layer forms on the surface in which the velocity varies from zero (no slip) at the solid surface to the value in the free stream. Outside the boundary layer, viscous forces are entirely negligible, and potential flow can be assumed to prevail. Potential flow means flow in which the vorticity is zero and viscous forces are neglected.
R. Shankar Subramanian, University of Clarkson
R. Shankar Subramanian, University of Clarkson
No comments:
Post a Comment