What is heat transfer coefficient

[Su Solberg]

What is "heat transfer coefficient"

What is heat transfer coefficient?

and where can i find a table listing it?

 

[TVP45]

Hello,

I'm making a guess, so please take that into account. If you explain your situation a bit more, that might help sort out exactly what you need, but here's an attempt.

Typically, physicists treat elementary heat transfer as three separate modes: conduction, convection, and radiation. In that case, I'd guess your question refers to thermal conductivity, and tables of thermal conductivity are found in most physics textbooks or any of the standard reference handbooks. For many materials you can also go to
www.matweb.com
and find more values than you probably ever wanted.

But, in engineering, the modes of heat transfer are sometimes lumped together in various ways in order to give a quick computational answer that is perhaps 85% correct. Often that coefficient will be called something like overall heat transfer coefficient. Those values can be found in standard engineering handbooks or perhaps at this site
http://www.engineersedge.com/heat_transfer/overall_heat_transfer_co.htm

Please come back with details if this doesn't answer your question.

 

[gmax137]

the heat transfer coefficient describes the rate heat leaves a surface, as a function of the temperature difference between the surface and the ambient. Calculating the value of the coefficient for a given situation is actually pretty difficult, and normal engineering methods use empirical relationships (stated in terms of non-dimensional parameters such as Reynolds, Nusselt & Prandtl numbers). Sometimes (if highly accurate values are required) testing must be done on the actual situation to determine the value. Look in any introductory text on heat transfer (for engineers). Or Google "dittus-boelter" for a starting point.

 

[Naty1]

Wikipedia has a short table of thermal conductivities: http://en.wikipedia.org/wiki/Thermal_conductivity#List_of_thermal_conductivity_values


And Wikipedia has some brief explanations:

http://en.wikipedia.org/wiki/Heat_transfer_coefficient

Also, it turns out that many electrical conductors, say metals, are also efficient conductors of heat...hence heat sinks in electronics are typically metals...

I checked and Wikipedia notes:

Thermal and electrical conductivity often go together (for instance, most metals are both electrical and thermal conductors). However, some materials are practical electrical conductors without being a good thermal conductor.

at http://en.wikipedia.org/wiki/Electrical_conductor

What's a brief explanation, or source, of what makes a good heat conductor??

I found:

Thermal conductivity depends on many properties of a material, notably its structure and temperature. For instance, pure crystalline substances exhibit very different thermal conductivities along different crystal axes, due to differences in phonon coupling along a given crystal axis.

at http://en.wikipedia.org/wiki/Thermal_conductivity Can this affect how ice forms and melts?