Convergent/divergent nozzle

Most racing engines that are naturally aspirated use some method of locating there air intake in such a fashion as to take advantge of the higher pressure available while the vehicle is in motion. (unless rules restricted not to do so). Take a look under the hood of a Nextel cup car or the hood scoop of a NHRA pro stock and you'll get the idea.-------Phil

Ok... I understand the principle behind ram air. Not what i'm going for. If the air entering the nozzle is subsonic, then passes through the nozzle and becomes supersonic... could you feed this supersonic air into the motor... Like i said, a type of natural forced induction...

No, a supersonic choke will form and your mass flow rate will remain constant (and low)

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

A convergent/divergent nozzle is capable of producing supersonic flow, but that is not what you want in an air intake. You want maiximum pressure. Energy is required for compression and energy in lost in any nozzle.

But you could use a convergent/divergent nozzle in the exhaust tip and point it at your competitor's car so that his engine sucks in your exhaust. Pole position!