Thermal Convection

Convection heat transfer occurs between a surface and a moving fluid (liquid or gas) when they are at different temperatures. The figure below introduces convection heat transfer, and the local heat flux is expressed as

Convection-1

Both convection heat transfer coefficient and local heat flux changes over the surface because flow conditions vary from point to point, The total heat transfer rate may be obtained as :

Convection-2

 

 

where

Convection-3

Factors affecting the thermal convection coefficient include:
Flow conditions, flow rate and direction, etc.
Types of fluids and the properties
Solid surface shape and surface state
The following table shows typical convection coefficient range for reference :

Convection-4

Fluids Convection coefficient (w∕m² ∙K)
Air / Natural convection
5~25
Air / Forced convection
20~120
Water / Natural convection
100~1200
Water / Forced convection
300~10,000
Water / Phase change
3,000~20,000

 

Comments are closed.

  • ABOUT US

    Founded in August 2010,Cooling House is an established Asia-based design house for innovative thermal solutions and is headquartered in Taipei. Cooling House holds patents for several cooling technologies and product concepts.



    Read more.....

  • Newsletter Subscription

  • HQ Address

    Cooling House Co., Ltd.
    2F No.10, Wugong 5th Road, Wugu District, New Taipei City 24890, Taiwan (R.O.C.)

    冠昊有限公司
    24890 新北市五股區五工五路10號2樓

    Tel: +886 (0)2 2298 3872
    Fax: +886 (0)2 2298 3872

    General enquiries:
    Tel: +886 (0)2 2298 3872
    E-mail: sw@coolinghouse.com
  • Office Directions

Copyright © 2014 - 2019 Cooling House All rights reserved.