enginehistory.org

[szielinski]

Thought I'd just separate this idea out from Kim & Jukka's thread-weaving.
This is a scrape from my (as yet unposted) ultimate PD engine idea.

"Operating temperature is reached swiftly as no cooling occurs until sufficient heat convents through the internal wicks. Once operating temperature is reached, the phase of the cooling liquid changes from liquid (next to the cylinder) and travels through internal screens and orifices where it changes to gas. Once evaporated, the gas condenses on internal fins and travels back to the cylinder wall. This system has no moving parts and can dissipate large amounts of heat if sufficient cooling air is provided. Transcalent cooling systems are also lightweight as the internal cavity is mostly empty space."

Currently this technology is used when space is at a premium. ie in high-wattage thyristors in the power industry. As an example, the book I have at home shows a thyrisor <2" diameter, <4" long that can dissipate 500 Watts (with 300cfm airflow - sorry dunno air temperature). These dimensions include the cooling fins.

The point is, semiconductors are MOST intolerant of excess temperature, and if such devices are used where reliability is a concern, then we have an idea worth pursuing, especially considering the TBO.

Plusses:- No moving parts, high heat dissipation, low/no maintenance, looks trick.
Minusses:- External fins and fans, head and barrel may need separate systems.

I will try and post some more info on this method soon.

[gryan]

I tried posting a reply to you previously but something went wrong.

Die casters use the method described to control the internal temperatures of their high and low pressure dies. The approach gives close and accurate control of temperature. It can be made spot or area specific and is known to be capable of dealing with high rates of heat transfer.

This is a clever idea. Wish I'd thought of it.