What is the degree of cooling caused by air flowing from smaller diameter into a large diameter? How much does air cool as it expands?

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If the air inlet was the biggest hole on the right and the outlets were the full smaller holes, would the air cool as it left each hole? Let's say that the surface area of the inlet equals the outlets.

Could these types of apparatus be linked in series to produce a staged cooling effect?

Does cooling only occur in change of pressure?

  • 1
    $\begingroup$ Will there be a big pressure change? $\endgroup$
    – Solar Mike
    Dec 12 '18 at 10:01
  • $\begingroup$ “Does cooling only occur in change of pressure”? If there’s no exchange of energy to the environment, yes. In your specific example? Maybe. Is the air above or below ambient temperature, for example? $\endgroup$ Dec 12 '18 at 13:06
  • $\begingroup$ I am theoretically trying to determine if air can be refrigerated significantly with simple geometric design as opposed to external energy intensive cooling $\endgroup$
    – Michael S.
    Dec 12 '18 at 16:49
  • $\begingroup$ Not that simple a design, but the formulas for cooling as a function of expansion are pretty well documented (i.e. Google them). Your design won't work (well, if at all) without a significant pressure head on the inlet pipe. Take a look at any air conditioner or refrigerator compressor. BTW, semi-antique Land Rovers had a double roof design specifically for Venturi cooling the interior as the truck travelled. $\endgroup$ Dec 12 '18 at 18:55
  • $\begingroup$ Also -- look up "Carnot Cycle" $\endgroup$ Dec 12 '18 at 18:56

The principal you are referring to is a fairly fundamental law. The Charles law. V/T = k. This assumes that there is no compression, and constant ambient temperature.

To answer your question without measurements is difficult, however it would appear from inspection that the unit surface area of the output is greater than the unit surface area of the input, so I would imagine temperature would drop proportionately.


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