ORIGINAL: iron eagel
"... Then the heated air needs to be accelerated to the free air stream with as little turbulance as possible."
If I may ask what do you think is the best way to do this?
I subscribe to the 1:1.4 ratio of intake to exhaust. But lately I am thinking that how and where the exit air is blended with the airflow around the plane is just as important.
Do I need the lower air stream to stay attached to the rear of the fuselage? I want to accelerate the heated air, by using the step concept used in float design. By that I mean about venting your hot high temp/pressure air into a high pressure area by creating a relative low pressure zone in a high pressure area, do you think there is any merit to this approach?
Since pressure cowls work on the theory that you give the cooling air no place to go on entry other than into the cooling fins or against whatever it is you want to cool, and then to give it as unrestricted exit path as possible, and then to help coax it out with negative pressure at the exit opening, I certainly would have to guess how you'd do otherwise to "accelerate" it..... if you plan to accelerate you'd have to have something doing the accelerating. Locate the exhaust opening in an area of lower pressure and nature does the work for you and provides "acceleration". More than that?????
But lately I am thinking that how and where the exit air is blended with the airflow around the plane is just as important.
That's actually already a part of the pressure cowl theory. Place the exhaust opening where it'll naturally experience negative pressure. Or create the area. As the flaps that originally completely surrounded the Corsair's cowling and opened when needed were.. Or the flap on the back of the P51's radiator bulge. The bulge created an area of negative pressure so the flap didn't need to be very far open until the cooling requirements were heavy, then the flap opened and created even more negative pressure.
But you're right to look at where the hot air comes out for help.