Back to the original question: what component suppliers provide Delphi-type resistor models for their component packages? The answer is, in my experience, not very many. It is a chicken/egg problem. It takes a relatively large effort to derive the multi-resistor models. At this time, nobody uses...
Now I'm getting curious why you say it is the formula for a horizontal plane. Hydraulic diameter is for a duct. It is a construct for creating fudge factors so that pressure drop and convection coefficient correlations for circular pipes can be applied to ducts of other cross sections, like...
Can't let that go! I have the 1989 reprint of "Thermal Computations for Electronic Equipment" by Ellison. Page 56 has the definition of hydraulic diameter:
D = 4 Ac/Pw where Ac is the cross-section area and Pw is the wetted perimeter.
Obviously I can't check every instance in the book, but I...
I have the same 1991 edition of Steinberg's book "Cooling Techniques for Electronic Equipment."
In the index it lists three places where hydraulic diameter is mentioned. In all three places it is correctly printed:
Dh = 4x area/perimeter (page 170)
for a rectangular duct Dh = 2ad/(a+d)
Can...
Your idea is feasible. Small thermoelectric refrigerators are commercially available from several sources. They are commonly used to keep food and drink cold in the car, powered by the DC power from the car electrical system. Check amazon. They won't be the exact shape you want, but they will...
In general, the two temperatures do sum.
But there are two reasons why they actually will not.
Two heat transfer mechanisms determine the temperature rise above ambient of a heated object: natural convection and radiation.
Natural convection flow is driven by the temperature difference...
The instructors for the course you linked to are quite good and are fluent in English. I suggest you contact them by email and ask if they intend to offer their course in the US or on-line at some point. They frequently visit the US to attend conferences and may be interested in offering their...
Phase change material is not primarily a replacement for roof insulation. The purpose is to reduce cooling energy costs for a building. It does this by evening out the daily temperature swing between day and night. For example, if the days are hot and the nights are cool, the PCM is exposed to...
This constant heat flux does not seem to give a realistic result at the leading edge because it is based on unrealistic assumptions:
1. the heat flux is absolutely uniform (how do you get that in real life, especially at the edges?"
2. the flat plate has no heat conduction within itself...
Are you looking for servers that can operate at -40C, or for an enclosure that will protect the electronics from an outdoor environment that is -40C? There are several companies that develop and manufacture outdoor cabinets for electronics, such as telephone switch equipment. One that I am...
It can be done. My father started his PhD in 1961 and finished in 1969. He also got married and had six kids. On Sundays he would take the kids to the park. My most common memory is him sitting under a tree asleep with a fat textbook open on his chest. If you do it, don't get married and don't...
Convergence with natural convection is a common issue, because the driving force for flow is so weak. I would check things first:
1. Make sure gravity is turned on. By default many tools leave this option turned off. Check the Help for how to specify the value and direction of gravity. Without...
Here is how I try to diagnose these kinds of problems.
You drilled a hole in a piece of copper and inserted a thermocouple, then filled the gap around it with thermal adhesive. You suspect that there is an air bubble or some kind of gap between the thermocouple and the copper because the...
You are right to be worried if the air flow through the system does not balance out. The mass flow in and out should be the same. Of course there will always be some small discrepancies in a numerical solution, but it has to balance out better than your example. The first things I would check...
