Diffusers
are based on the Venturi effect. This
effect states that if you restrict fluid flow pressure will drop, and as a
result the velocity of that fluid will increase. Think of when you go to a fast
food place and you order a soda that comes with a Styrofoam cup, After you
drink it use the straw poke a hole in the bottom . When you blow into the straw
and seal it with your face the fluid flow will increase in the straw , and the
pressure will increase inside the cup. A blown Diffuser is a system used in F1,
and other automotive vehicles that does the exact opposite. You have low pressure high velocity air flowing
through a constricted area, Then that restricted area is given an expansion
chamber in which the air is able to expand making the pressure increase, while
the velocity decreases. The reason this happens is because the space needed to
fill by the fluid (in this case air) is bigger. In a Formula 1 this principle
is evident as the air travels at a very high speed with very low pressure
underneath the car,
because the car is moving at a very high speed. Behind the car you have a
chamber where the air comes in and decreases in speed as it increases in
pressure. This means that the greater the size of the chamber. the greater the
difference in the pressure between the air flowing under the car and the one in
the chamber. The important thing to remember here is that the greater the
pressure difference the greater the vacuum created under the car pulling it
closer to the ground. Combine this with the orchestrated air flowing through
the top of the car with help from the front wing, pushing down on the car, and
you have a much greater down force. One thing that is very important to note is that the height of the
chamber on the back of the car is regulated in formula 1 limiting the size of
the chamber. This obviously makes the sport more competitive, and most of all
it improves the drivers' safety as it controls the speed in which they go into
corners. Diffusers also have dividers which force the air to flow out the
exhaust in a linear fashion. What this dividers do is vital as they avoid
turbulent air, therefore preventing you from losing the benefits you were gaining
in the first place.
