# Description of Bleed Schematic

The bleed models simulate a bleed boundary without the need to grid
and simulate the bleed plenum on the other side. In the main passage,
the properties at the edge of the local boundary layer are given by
the Mach number (*M*_{δ}),
total pressure (*p*_{tδ}), and
total temperature (*T*_{tδ}).
The surface through which the bleed passes has
a total surface area of *A*_{region} and
porosity (*φ*).
The actual area of the bleed holes is denoted as *A*_{bleed}
and the mass flow rate though the holes is denoted by
*m*_{bleed} or
*m*_{holes} .

The bleed plenum total pressure and total temperature are
denoted as
*p*_{t plenum} and
*T*_{t plenum}.
Since the plenum is at a near-stagnation condition, with
a Mach number (*M*) approximately zero, the plenum static
pressure (*p*_{plenum}) is nearly the same as the
plenum total pressure.
The plenum chamber has an exit passage of area *A*_{exit}
and discharge coefficient *C*_{D}. The mass flow
through the exit is *m*_{exit} and the static pressure
at the end of the passage is *p*_{exit}.

During steady operation, the bleed mass flow rate (*m*_{bleed})
must be the same as
the mass flow rate through the bleed holes (*m*_{holes}) and also
the mass flow rate through the plenum exit (*m*_{exit}).

Last updated 31 Oct 2011