Delta T across a flat ceramic plate

[TeejT]

I need a ceramic plate to insulate between a hot mounting surface and a piece of equipment mounted to the other side of the plate - so the plate will have a hot and cold side. I know the temperature of the hot mounting surface and the ambient temperature, but don't know heat load in Watts or anything like that (also have no way of measuring it). I also know the length, width, height, thickness, and thermal conductivity (in Btu/hr x in/sq. ft) of the ceramic plate. How would I go about determining the temperature of the cold side of the ceramic plate in this scenario?
Thanks in advance!

 

[Cockroach]

Conduction of heat between the source and the plate itself with convection losses to the surrounding air given the thermodynamic properties.

Regards,
Cockroach

 

[zekeman]

You get the film coefficient between the cold side and ambient ( as a first estimate I use 100 BTU/hr-ft^2/degF and then calculate the resistance thru the ceramic plate,l/K.

The overall temperature drop is Th-T0, where TH = hot end and T0= ambient temperature
Temperature drop across the ceramic plate is
L/K/(L/K+1/h)*(Th-T0)
Therefore, temperature at cold side is
Th-L/K/(L/K+1/h)*(Th-T0)

 

[TeejT]

zekeman,

So you're saying that h (heat transfer coefficient) = 100 BTU/hr-ft^2/degF, correct?

Why assume 100 BTU/hr-ft^2/degF, and how can I have any idea whether this is a roughly correct assumption? In particular we're talking about a hot well head here - and I have no idea whether this value is realistic or not...

 

[zekeman]

Well, I used a first cut natural convection coefficient.
If if you need more accuracy you will have to go to the Heat Transfer books and get convection correlations between Nusselt, Reynolds and Prandtl numbers, and possibly radiation
Or better still, post the entire problem including ambient temperatures and hot plate temperature.

 

[desertfox]

http://www.roymech.co.uk/Related/Thermos/Thermos_HeatTransfer.html#Convection.

The link above might help with values of heat coefficients etc