Fluid Flow mode results for the F2 example simulation
- Last UpdatedOct 04, 2024
- 3 minute read
The following table shows the Relief Valve back pressures for the Global Cooling Water Failure case (GLOB 1).
|
Name |
Size |
Type |
Area |
Capacity |
Set Pressure |
Inlet Pressure |
Back Pressure |
Back Pressure Fraction |
Required Flow |
|---|---|---|---|---|---|---|---|---|---|
|
in2 |
fraction |
psi |
psia |
psia |
% |
lb/h |
|||
|
RV59 |
N |
Balanced |
4.340 |
0.914 |
175 |
207.196 |
16.754 |
1.2 |
82,500 |
|
RV102 |
L |
Conventional |
2.852 |
0.583 |
130 |
157.696 |
15.546 |
0.7 |
26,700 |
|
RV49 |
K |
Balanced |
1.837 |
0.034 |
435 |
493.196 |
15.988 |
0.3 |
1,283 |
|
RV11 |
RR |
Conventional |
52.000 |
0.918 |
75 |
97.196 |
16.958 |
3.0 |
410,000 |
|
RV14 |
R |
Pilot |
15.999 |
0.682 |
150 |
179.696 |
16.456 |
1.2 |
250,000 |
|
RV44 |
K |
Pilot |
1.837 |
0.859 |
110 |
135.696 |
15.730 |
0.9 |
17,000 |
|
RV39 |
M |
Conventional |
3.601 |
0.512 |
655 |
735.196 |
16.852 |
0.3 |
124,000 |
|
RV32 |
K |
Conventional |
1.837 |
0.823 |
100 |
124.696 |
26.173 |
12.7 |
7,000 |
Relief valve RV32 has a high back pressure and a high inlet pipe pressure drop. Check the inlet pipe and tail pipe for this relief valve for proper sizing to obey the 3% rule and 10% superimposed back pressure rule, respectively.
The following table shows the original sizing based on the initial sizes provided in Process mode and also the recommended sizing for the inlet and tail pipes for RV32, respectively, at rated flow.
|
Name |
Diameter |
Length |
DP Percent of RV Set Pressure |
Outlet Mach |
RV32 Back Pressure |
RV32 Back Pressure Fraction |
Required Flow |
Rated Flow |
|
|---|---|---|---|---|---|---|---|---|---|
|
NPS |
ft |
% |
psia |
% |
lb/h |
lb/h |
|||
|
Original |
PI32 (inlet) |
2 in |
20 |
15.4 |
7,000 |
15,224 |
|||
|
PT32 (tail) |
4 in |
25 |
13.0 |
0.378 |
26.173 |
12.7 |
7,000 |
15,224 |
|
|
Recommended |
PI32 (inlet) |
3 in |
20 |
2.0 |
7,000 |
15,224 |
|||
|
PT32 (tail) |
6 in |
25 |
1.1 |
0.167 |
24.229 |
9.5 |
7,000 |
15,224 |
We can take the same approach to analyze results during the Global Power Failure case (GLOB 2), as shown in the following table. Since none of the relief valves show a high back pressure fraction, we can conclude that we have adequately sized all the inlet pipes and tail pipes at the relief valves.
|
Name |
Size |
Type |
Area |
Capacity |
Set Pressure |
Back Pressure |
Back Pressure Fraction |
Required Flow |
|---|---|---|---|---|---|---|---|---|
|
in2 |
fraction |
psi |
psia |
% |
lb/h |
|||
|
RV43 |
K |
Balanced |
1.837 |
0.819 |
100 |
15.617 |
0.92 |
15,000 |
|
RV67 |
Q |
Conventional |
11.050 |
0.599 |
145 |
16.266 |
1.08 |
73,389 |
|
RV49 |
K |
Balanced |
1.837 |
0.036 |
435 |
16.326 |
0.37 |
1,328 |
|
RV60 |
Q |
Balanced |
11.050 |
0.970 |
150 |
17.341 |
1.76 |
175,000 |
|
RV88 |
M |
Balanced |
3.601 |
0.376 |
170 |
17.121 |
1.43 |
25,000 |
|
RV86 |
L |
Balanced |
2.852 |
0.579 |
305 |
17.620 |
0.96 |
39,700 |
|
RV89 |
J |
Conventional |
1.287 |
0.095 |
725 |
17.106 |
0.33 |
16,500 |
|
RV108 |
N |
Balanced |
4.340 |
0.112 |
240 |
16.781 |
0.87 |
10,000 |
|
RV17 |
TT |
Conventional |
52.000 |
0.488 |
125 |
24.502 |
7.84 |
390,312 |
|
RV11 |
TT |
Conventional |
52.000 |
0.898 |
50 |
16.658 |
3.92 |
285,000 |
The following table summarizes the inlet pipes and tail pipes for the relief valves shown in the preceding table.
|
Name |
Type |
Length |
Diameter |
Pressure Drop |
Inlet Pipe: DP Percent of RV Set Pressure |
Tail Pipe: RV Back Pressure Fraction |
Outlet Mach |
Required Flow |
Rated Flow |
|---|---|---|---|---|---|---|---|---|---|
|
ft |
NPS |
psi |
% |
% |
lb/h |
lb/h |
|||
|
PI43 |
Inlet |
24 |
3in |
2.293 |
0.023 |
15,000 |
18,304 |
||
|
PT41 |
Tail |
4 |
6in |
0.104 |
0.92 |
0.316 |
15,000 |
18,304 |
|
|
PI45 |
Inlet |
5 |
6in |
0.726 |
0.005 |
73,389 |
122,522 |
||
|
PT67 |
Tail |
5 |
16in |
0.088 |
1.08 |
0.420 |
73,389 |
122,522 |
|
|
PI50 |
Inlet |
1 |
3in |
0.456 |
0.001 |
1,328 |
37,309 |
||
|
PT49 |
Tail |
75 |
18in |
0.160 |
0.37 |
0.165 |
1,328 |
37,309 |
|
|
PI62 |
Inlet |
20 |
6in |
2.816 |
0.019 |
175,000 |
180,473 |
||
|
PT61 |
Tail |
60 |
16in |
1.127 |
1.76 |
0.441 |
175,000 |
180,473 |
|
|
PI87 |
Inlet |
4 |
3in |
2.353 |
0.014 |
25,000 |
66,450 |
||
|
PT87 |
Tail |
25 |
10in |
0.479 |
1.43 |
0.354 |
25,000 |
66,450 |
|
|
PI88 |
Inlet |
20 |
4in |
3.122 |
0.010 |
39,700 |
68,543 |
||
|
PT86 |
Tail |
75 |
12in |
0.994 |
0.96 |
0.330 |
39,700 |
68,543 |
|
|
PI90 |
Inlet |
26 |
3in |
7.036 |
0.010 |
16,500 |
173,101 |
||
|
PT89 |
Tail |
20 |
10in |
1.639 |
0.33 |
0.655 |
16,500 |
173,101 |
|
|
PI108 |
Inlet |
20 |
4in |
5.617 |
0.023 |
10,000 |
89,192 |
||
|
PT108 |
Tail |
75 |
12in |
1.676 |
0.87 |
0.439 |
10,000 |
89,192 |
|
|
PI17 |
Inlet |
3 |
8in |
1.832 |
0.015 |
390,312 |
799,263 |
||
|
PT16 |
Tail |
6 |
20in |
0.712 |
7.84 |
0.762 |
390,312 |
799,263 |
|
|
PI11 |
Inlet |
20 |
24in |
0.027 |
0.001 |
285,000 |
317,468 |
||
|
PT10 |
Tail |
75 |
24in |
0.500 |
3.92 |
0.345 |
285,000 |
317,468 |