Page 230 - 48Fundamentals of Compressible Fluid Mechanics

192 CHAPTER 11. EVACUATING AND FILLING A SEMI RIGID CHAMBERS

direct integration of equation (11.40) results in

(11.34)

> E
It has to be realized that this is “reversed” function i.e. >* is a function of P

and can be reversed for case. But for the chocked case it appears as
>
>*
E
(11.35)

The function is drawn as shown here in figure 11.6. The figure 11.6 shows
>

E
>*

1.0
>
P(t) V(t) = P (t)
0.8
V(t) = P (0)
0.6

0.4

0.2

0
0 0.2 0.4 0.6 0.8 1.0

t ¯
Fig. 11.5: The reduce time as a function of the modified reduced pressure

that when the modified reduced pressure equal to one the reduced time is zero.
The reduced time increases with decrease of the pressure in the tank.
At certain point the flow becomes chockless flow (unless the back pressure
The big struggle look for sug- is complete vacuum). The transition point is denoted here as $ . Thus, equation
gestion for better notation.