Pro/Forums - View Single Post - thermal radiation and thermal conductivity

KnightElite · 04-20-2003, 02:42 AM

Alright, I'm now breaking out the heat transfer notes from last semester

.

Yeah, with a passive heatsink you have what is called free convection. Forced Convection, with a fan, can be up to 100 times more efficient than free convection. From my textbook:

Code:

Type of Convection                          Convection Coefficient (W/(m^2 * ºC))
--------------------------------            -------------------------------------
Free Convection: Atmospheric air            5-25
Free Convection: Water                      400-1000
Forced Convection: Air                      15-500
Forced Convection: Water                    1000-15000
Forced Convection: Engine Oil               1000-2000

Those represent some typical values.

As for radiation, you are correct. I was misguided, because the table lists aluminium foil

. Black paint has the best emissivity, followed by red brick and asbestos.

04-20-2003, 02:42 AM	#11
KnightElite Cooling Savant Join Date: Sep 2002 Location: Saskatoon, Saskatchewan Posts: 294	Alright, I'm now breaking out the heat transfer notes from last semester . Yeah, with a passive heatsink you have what is called free convection. Forced Convection, with a fan, can be up to 100 times more efficient than free convection. From my textbook: Code: Type of Convection Convection Coefficient (W/(m^2 * ºC)) -------------------------------- ------------------------------------- Free Convection: Atmospheric air 5-25 Free Convection: Water 400-1000 Forced Convection: Air 15-500 Forced Convection: Water 1000-15000 Forced Convection: Engine Oil 1000-2000 Those represent some typical values. As for radiation, you are correct. I was misguided, because the table lists aluminium foil . Black paint has the best emissivity, followed by red brick and asbestos. __________________ Can anyone else here say that they have a watercooled monster that's 45" tall?