Thermal Equilibrium & Heat Transfer in Porous Media Contd. — Lesson 3

This lesson covers the concept of heat transfer during fluid flow through porous media. It explains the progression of the heat transfer front along with the flow front and the assumption of thermal equilibrium. The lesson also introduces the mean field model based on the volume averaging approach, which is a non-equilibrium model. It discusses the temperature profile within capillaries and solid phases and the concept of homogenization treatment. The lesson further explains the equations for fluid and solid phases, thermal conductivity, and the concept of thermal resistors. It also discusses the concept of Nusselt number and its correlation with Reynolds number and Darcy number in the context of porous media. The lesson concludes with a comparison of temperature evaluated along the centerline in the z direction for thermal equilibrium and non-equilibrium models.

Video Highlights

00:48 - Explanation of thermal equilibrium and volume averaging
03:56 - Understanding of thermal conductivity and its directions
07:42 - Explanation of heat transfer coefficient and Nusselt number
24:59 - Comparison of temperature evaluated along centerline in z direction for thermal equilibrium and non-equilibrium models

Key Takeaways

- Heat transfer during fluid flow through porous media involves the progression of the heat transfer front along with the flow front.
- The mean field model based on the volume averaging approach is a non-equilibrium model that considers two different temperature fields for liquid and solid.
- Thermal conductivity in porous media can be understood in terms of three directions: x, y, and z.
- The Nusselt number, a dimensionless number, is used to understand heat transfer in a fluid in the context of fluid flow in a macro scale pipe.
- The Nusselt number for porous media is modified due to the increased surface area when a porous medium is introduced in a forced convection channel.