many thanks. On Jul 17, 2014, at 1:13 PM, Wayne Thayer wrote: > I believe UCSB is working on microfluidic heat pipes and has had some > success. But from university to practicality is a long journey! CIC > cores > will be with us for many years. > > Are you trying to just spread, or do you have somewhere for this > heat to go? > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Yuan-chia Joyce > Koo > Sent: Thursday, July 17, 2014 11:25 AM > To: [log in to unmask] > Subject: Re: [TN] LIst of thermal conduction effective design > > thanks bob and wayne. I am more intend to looking for next gen > tech, such > as phase transition material build in core of the PWB. with high > density > and super hot chip down to the road with compound semi, something > need to be > addressed on the thermal side. Yes, I am fully aware of the FEM > power, > however, the limitation still in the thermal conduction - BN and > diamond > coating are still pricy and not compatible to many of the HDI cct. > Just try > to see if there is any new trick out there. Thanks again. > Best regards, > joyce > On Jul 17, 2014, at 9:40 AM, Bob Landman wrote: > >> Hi Joyce, >> >> Well, even PC's these days esp. with very powerful processors) use >> heat pipes. Of course they also use huge fans. (warning! Pun >> ahead!!) >> >> What's really cool about heat pipes is they spread the heat and >> conduct it to the exterior of the enclosure where there can be a >> radiator. My Apple MacBook Air gets so hot I can't rest it on my >> lap! >> The aluminum case spreads the heat. There is a tiny fan inside but >> the fan's vents are under the laptop so if you do place it on your >> lap, or when it bed reading, on a pillow, the vents are blocked. >> Haven't had it crash on me "yet". Why they didn't put the vents on >> the sides? Esthetics, I'll bet, knowing Steve Jobs. >> >> E,g, http://www.thermacore.com/industries/communications.aspx >> http://www.aavid.com/product-group/microprocessors/notebook >> >> They offer design assistance. >> >> Bob >> >> >> -----Original Message----- >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer >> Sent: Thursday, July 17, 2014 9:20 AM >> To: [log in to unmask] >> Subject: Re: [TN] LIst of thermal conduction effective design >> >> Hi Joyce- >> >> Basically, you have to model the bejeesus out of the arrangement. >> Nowadays that modeling is CFD (Computational Fluid Dynamics). Big >> finite element model. And you really need a physical model in >> addition >> to make sure all of the fudge factors are properly calculated. Then, >> after you begin production, you will find your customer changed >> something in the environment which rendered most of the modeling >> moot! >> Getting good representations for actual airflow in the application >> can >> be difficult to do also. >> >> If you are longer on time and short on money, a bunch of physical >> models can also get you there, but if you are going to be playing >> with >> the number of copper planes in the pcb that can get expensive too. >> Used to be that someone, like a university, would run a bunch of >> those >> kinds of modeling tests and publish results so you could interpolate >> for your problem, but not any more: the math models have taken over. >> >> Wayne >> >> -----Original Message----- >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Yuan-chia Joyce >> Koo >> Sent: Thursday, July 17, 2014 6:34 AM >> To: [log in to unmask] >> Subject: [TN] LIst of thermal conduction effective design >> >> Gurus, >> The most challenge in my short career of 24 years is application of >> thermal >> components: the requirements just go up non stop. How do you handle >> the thermal load in terms of static, dynamic or transient thermal >> load on high density PWB/PWA, besides known build in heat sink. I am >> seeking for the low provide conduction type, with limited or no >> convection cooling. Many thanks. >> (IBM's metal backing PWB is nice, but for multi-layer, >8 is a bit >> difficult. Besides, double side or high density might have some >> limitation - any new development in the field? ) Thanks in advance. >> (net a bit quiet, I guess many on summer vacation mode with BBQ ;-). >> joyce >> >> >> _____________________________________________________________________ >> _ >> This email has been scanned by the Symantec Email Security.cloud >> service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> _____________________________________________________________________ >> _ >> >> >> >> _____________________________________________________________________ >> _ >> This email has been scanned by the Symantec Email Security.cloud >> service. >> For more information please contact helpdesk at x2960 or >> [log in to unmask] >> _____________________________________________________________________ >> _ > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud > service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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