Question

under what factor does the heat transfer coefficient is considered to be variable quantity??

Answer 1

heat transfer coefficient is considered to be a variable quantity under various factors

1. It varies when the geometry of the conduit is different so heat transfer coefficient will vary for different geometry.

2. it depends upon flow regime i.e laminar or turbulent flow regime. heat transfer coefficient will be different for laminar as well as for turbulent flow.

3. heat transfer coefficient is considered to be variable quantity when fluid-to-wall temperature ratio is different.

4. It varies when fluid's thermo-physical properties like heat capacity, density, viscosity, thermal conductivity etc are different.