How do we determine the convection coefficient for extended surfaces or fins?

  • Thread starter no183
  • Start date
  • Tags
    Convection
In summary, the convection coefficient, h, is a measure of a fluid's ability to transfer heat through convection and is calculated using the heat transfer equation. It is affected by the properties of the fluid and surface, as well as flow conditions. Convection coefficient differs from thermal conductivity in that it takes into account fluid movement. To improve or increase convection coefficient, one can increase fluid velocity and surface area, reduce boundary layer thickness, and use materials with higher thermal conductivity and smoother surfaces.
  • #1
no183
16
0
For extended surface or fin, how do we find the convection coefficient ? Explain some general idea? thanks
 
Physics news on Phys.org
  • #2
There are many possibilities. First, determine if the flow on the fin is natural or forced convection. In other words, is it just sitting there or is there a fan or pump blowing fluid on it.

For example, suppose it is a rectangular horizontal fin exposed to natural outside air. You could than apply natural circulation correlations for flat horizontal flat plates.
 

1. What is the definition of convection coefficient, h?

The convection coefficient, h, is a measure of the ability of a fluid to transfer heat through convection. It represents the rate of heat transfer per unit area per unit temperature difference between the fluid and the surface it is in contact with.

2. How is convection coefficient, h, calculated?

Convection coefficient, h, is calculated using the heat transfer equation: Q = hA∆T, where Q is the heat transfer rate, A is the surface area, and ∆T is the temperature difference between the fluid and the surface.

3. What are the factors that affect convection coefficient, h?

The factors that affect convection coefficient, h, include the properties of the fluid (such as density, viscosity, and specific heat), the properties of the surface (such as roughness and shape), and the flow conditions (such as velocity and turbulence).

4. How does convection coefficient, h, differ from thermal conductivity?

Convection coefficient, h, and thermal conductivity are both measures of the ability of a material to transfer heat. However, convection coefficient takes into account the movement of a fluid, while thermal conductivity only considers the material itself. Convection is typically a more effective heat transfer mechanism due to the movement of the fluid.

5. How can convection coefficient, h, be improved or increased?

Convection coefficient, h, can be improved by increasing the velocity of the fluid, increasing the surface area of contact, and reducing the thickness of the boundary layer between the fluid and the surface. Using materials with higher thermal conductivity and smoother surfaces can also improve convection coefficient.

Similar threads

  • Mechanical Engineering
Replies
34
Views
4K
  • General Engineering
Replies
19
Views
4K
  • Materials and Chemical Engineering
Replies
3
Views
1K
  • Differential Equations
Replies
3
Views
1K
  • Mechanical Engineering
Replies
5
Views
1K
Replies
6
Views
506
Replies
9
Views
642
  • High Energy, Nuclear, Particle Physics
Replies
21
Views
1K
  • Classical Physics
Replies
7
Views
4K
  • Classical Physics
Replies
8
Views
2K
Back
Top