PSV Sizing For Two Phase Flow

PSV Sizing PRV set pressure Accumulation Pressure at PRV inlet Temperature at PRV inlet Liquid heat capacity Specific volume of two-phase system Specific volume of vapor Vapor mass fraction

Po T Cp Vo Vvo xo hvlo

latent heat of vaporization Ratio of specific heats of vapor vapor & liquid specific vol. difference

k Vvlo

Sp. Vol evaluated at 90% of Po Omega Parameter

V9 ω

Selected Value of Omega

ω ɳc

Crictical Pressure Ratio Downstream Back pressure Crictical Pressure

(two phase flow)

psig % psia R btu/lb.R ft3/lb ft /lb btu/lb

for D.2, D.4 for D.1, D.2 ft /lb 3

psia

Flow is ɳa

Mass Flux Mass Flow Rate Discharge Coefficient Back Presure Correction Factor Correction Factor For Rupture disk

G W Kd Kb Kc

0.3116

3

Pa Pc

back pressure ratio

60 10 80.7

0.3629 for D.3 #DIV/0! D.1 #DIV/0! D.2 1.482 D.3 #DIV/0! D.4 1.482 0.66 from graph D.1 29.7 53.262 Critical Flow 0.36803

lb/s.ft2 lb/hr

594.07 477430 0.85 1 from graph D.2 1

Calculated Area of the Orifice

A

in2

37.82

Selected Orifice Designation

0

in2

#N/A

INPUT OUTPUT

)

or D.2, D.4

or D.1, D.2 Boiling Range < 150 F Boiling Range < 150 F Boiling Range > 150 F For Nonflashing systems

om graph D.1

om graph D.2

Pc > Pa Pc < Pa

Critical Flow Sub-Critical Flow

API Orifice Designations D 0.11 E 0.196

0.11 0.196

F

0.307

0.307

G H

0.503 0.785

0.503 0.785

J K

1.287 1.838

1.287 1.838

L

2.853

2.853

M N P Q R T

3.6 4.34 6.38 11.05 16 26

3.6 4.34 6.38 11.05 16 26

D E F G H J K L M N P Q R T

PSV Sizing PRV set pressure Accumulation

(two phase flow)

psig %

260 10 300.7

Pressure at PRV inlet

Po

psia

Temperature at PRV inlet Saturation Pressure at To

To

R

519.67

Ps

Liquid heat capacity

Cp ρlo

psia btu/lb.R

107.6 0.6365

Liquid density at PRV inlet

lb/ft3

ρ9

lb/ft3

hvls

btu/lb

vapor & liquid specific vol. difference Omega Parameter

Vvls

ft3/lb

Selected Value of Omega Transition saturation pressure ratio

ωs ɳst

Saturation Pressure Ratio

ɳs

Critical Pressure Ratio Downstream Back pressure Crictical Pressure

ɳc

Density at 90% of Ps latent heat of vaporization at Ps

ωs

Pa Pc

152.3 0.9684 8.497 D.8 #DIV/0! D.9 8.5

0.358 psia

back pressure ratio

ɳa

Mass Flux

G

lb/s.ft2

Volumetric Flow Rate Discharge Coefficient Back Presure Correction Factor Correction Factor For Rupture disk

Q Kd Kb Kc

GPM

A F

in2

Selected Orifice Designation

for D.9

0.944 High Subcooling Region

Flow is

Calculated Area of the Orifice

31.92

from graph D.3 (used for L 24.7 0 used for Low Sub cooling Critical Flow 0.082

in

2

#DIV/0! D.10 for Low Subcooling R 7560.47 D.11 for High Subcooling 100 0.65 1 use graph D.4 1 0.21 0.307

INPUT OUTPUT

)

Boiling Range < 150 F Boiling Range >150 F

oling Region

om graph D.3 (used for Low Sub cooling Region)

sed for Low Sub cooling Region

.10 for Low Subcooling Region .11 for High Subcooling Region

se graph D.4

API Orifice Designations D

0.11

E F

0.196 0.307

0.11 0.196

G

0.503

0.307

H

0.785

0.503

J

1.287

0.785

K L M N

1.838 2.853 3.6 4.34

1.287 1.838 2.853 3.6

P Q

6.38 11.05

4.34 6.38

R

16

11.05

T

26

16 26

D E F G H J K L M N P Q R T

PSV Sizing PRV set pressure Accumulation

(two phase flow)

psig %

600 10 674.7

Pressure at PRV inlet

Po

psia

Temperature at PRV inlet

To

R

Vapor mass fraction at PRV inlet

xo

Specific volume of vapor Specific volume of two phase system Saturation Pressure at To Noncondensable gas partial pressure Liquid heat capacity Liquid density at PRV inlet Specific volume at 90% of Pvo

909.67 0.5596

Vvgo

ft3/lb

0.2462

Vo

ft3/lb

0.1549

Pvo

psia

Pgo

psia btu/lb.R

Cp ρlo

lb/ft3

v9

lb/ft3

Latent heat of vaporization at PRV inlet

hvlo

btu/lb

Vapor & liquid specific vol. difference Ratio of specific heats

Vvlo

ft3/lb

Inlet void fraction Omega Parameter

0.1737 for D.15

k αo

Nonflashing Critical Pressure Ratio

ω ɳgc

Flashing Critical Pressure Ratio

ɳvc

Critical Pressure Ratio Downstream Back pressure Crictical Pressure

ɳc Pa Pc

0.8894 If Conditions Satisfied #DIV/0! D.14 from graph D.1 from graph D.1 Not Required psia 0 Subcritical Flow

Flow is Back Pressure Ratio

ɳa

Non flashing partial pressure ratio

ɳg

Flashing partial pressure ratio

ɳv

0

#DIV/0! #DIV/0! Mass Flux

G

lb/s.ft2

#DIV/0! for Critical Flow

Non flashing Mas flux

Gg

lb/s.ft

2

#DIV/0!

Flashing Mass flux

Gv

lb/s.ft

2

Err:502

Mass Flux Mass Flow Rate Discharge Coefficient Back Presure Correction Factor Correction Factor For Rupture disk

G W Kd Kb Kc

lb/s.ft lb/hr

2

#DIV/0! for Subcritical Flow 0.85 1 use graph D.2 1

in2

#DIV/0! for Critical Flow

Calculated Area of the Orifice

in2

#DIV/0! for Subcritical Flow

Selected Orifice Designation

in

2

#DIV/0! for Critical Flow

in

2

Calculated Area of the Orifice

Selected Orifice Designation

A #DIV/0! #DIV/0!

for Subcritical Flow

INPUT OUTPUT

)

For systems that satisfy all the following conditions, use D.

itions Satisfied

If Conditions Not Satisfied 1.0923 D.15

om graph D.1

Not Required

om graph D.1

Not Required 0.62 from graph D.1 69.7 418.314 Critical Flow

iterate ɳg & ɳv to get same values in G31 & G32

or Critical Flow

0.103305

2665.816

or Subcritical Flow

se graph D.2

153830 0.85 1 use graph D.2 1

or Critical Flow

2.72

or Subcritical Flow

or Critical Flow

or Subcritical Flow

L

2.853

lowing conditions, use D.14 otherwise use D.15

API Orifice Designations D

0.11

E

0.196

0.11

F

0.307

0.196

G

0.503

0.307

H

0.785

0.503

J K

1.287 1.838

0.785 1.287

L

2.853

1.838

M

3.6

2.853

N

4.34

3.6

P Q

6.38 11.05

4.34 6.38

R T

16 26

11.05 16 26

D E F G H J K L M N P Q R T

D.1

D.2

D.3

D.4