counter flow, and cross flow is the kind of heat transfer that is a fan.
counter flow, and cross flow is the kind of heat transfer that is a fan.
what kind of heat transfer is a fan?
counter flow, and cross flow
the most convenient way for characterizing the single-phase heat transfer is based on an empirical approach, where the temperature difference between the wall and bulk flow can be obtained from the heat transfer coefficient. the heat transfer coefficient depends on several factors: mode of heat transfer (e.g., internal or external flow), type of fluid, geometry of the system, flow regime (e.g., laminar or turbulent flow), boundary condition, etc.









































examples of heat transfer correlations are dittus-boelter correlation (turbulent forced convection), churchill & chu (natural convection).









































section::::multi-phase heat transfer.
thermal hydraulics
the thermal conductivity of the tube material usually depends on temperature; the mean thermal conductivity is often used.









































section::::combining convective heat transfer coefficients.









































for two or more heat transfer processes acting in parallel, convective heat transfer coefficients simply add:









































for two or more heat transfer processes connected in series, convective heat transfer coefficients add inversely:









































for example, consider a pipe with a fluid flowing inside. the approximate rate of heat transfer between the bulk of the fluid inside the pipe and the pipe external surface is:









































where









































section::::overall heat transfer coefficient.
heat transfer coefficient