Page 129 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Fluid Flow 113

80 , ,
J IJ J J "
50 I/ [/ I II IJ I f
40 1, I, J , I, C7 7 , I/ I/ , I '
'
1, f
30 ' I I, IJ I 11 11 I
I/ I I/ II ' I II J I J
20 � ' ,
) , J ) I/ J I I II
ti: 1 S v � v v v 11
0 I ll ll � I/
0 10 1, LJ ' J ,
\\ - Ii ,, ,
I I ,,--1 --,, , I I I I
� '
i 8.0 :.J - - t-t- � L- ;.. '/- ;;."l- -:,r ._,.i l7 �.t'.J � �J -� 7
'J
�I
g 5.0 .::.1 - .... v I 17 I I
I
�
.,, � . / r J " , , J , , J -. , ' I,
': 4.0
--..
s 3.0 � J v J I I/ ,, I I 17 IJ
I � I/ I I II' I I I
'
e, 2.0 II' II ' J
0 ) II I I J J l
� i.s II' � v 'I'
w I I j I/ II I I J II I
� 1.? ' I / TEMP. •F CORRECTION
� 0.8 I , I I , I I I
w J IJ J 500 8.95:
"' 0.5 J I I J 550 5.77-
.....
3.72 -
600
0.4 J J I I/ I r , J J I I/ 650 2.40 �
I r J J J ,
0.3 I I r I II' I IJ I I , I I 700 1.55
750
1.00
I
J
0.2 v J I I r I/ � I/ I) 1, , I I/ I 11 I I ....
All sizes are schedule
J
J
40 except 1" & 1 'A" ....
.
which are schedule 80
2 3 8 10 20 30 50 80 100 200 300 500 800 1000 2000 5000 10,000
DOWTHERM VAPOR FLOW - LBS./HR. x 10 2
Figure 2-36. Pressure drop, Dowtherm "A"® vapor in steel pipe. By permission, Struthers Wells Corp., Bull. D-45.
(equation continuedfrom pag,: 110) For nozzles and orifices (vapors/gases):
k = ratio of specific heat of gas, at constant pressure to that at
constant volume, = cp/c, .. See Table 2-14
g = 32.2 ft/sec squared w, = 0.525Yd c' � (2-88)
'
2
' {V:-
p" = pressure, pounds per sq ft, abs (Psf abs) (note units)
p = the specific weight, lb/cu ft (see Appendix) at T and p"
For valves, fittings, and pipe (liquids):
This sonic velocity occurs in a pipe system in a restrict-
ed area (for example, valve, orifice, venturi) or at the out-
let end of pipe (open-ended), as long as the upstream . = 0 52- d2 /!lP (P1)
pressure is high enough. The physical properties in the '\ s . !J i I K (2-89)
above equations are at the point of maximum velocity.
For the discharge of compressible fluids from the end For nozzles and orifices (liquids):
ofa short piping length into a larger cross section, such as
a larger pipe, vessel, or atmosphere, the flow is considered
adiabatic. Corrections are applied to the Darcy equation w, = o.s2s d� c' � lip (p 1) (2-90)
to compensate for fluid property changes due lo the
expansion of the fluid, and these are known as Y net where V 1 = upstream specific volume of fluid, cu ft/lbs
expansion factors [3]. The corrected Darcy equation is: w, = rate of flow, lbs/sec
For valves, fittings, and pipe (vapors/gases): Af> = pressure drop across the system, psi (inlet-dis-
charge)
K = total resistance coefficient of pipe, valves, fittings,
w, = 0.525Ydf � P/(KYi), lbs/sec (2- 87) and entrance and exit losses in the line