StmEng_VPS
- Last UpdatedSep 17, 2025
- 1 minute read
- PI System
- PI Server 2023
- PI Server
Calculates the vapor specific volume as a function of pressure and entropy—all variables expressed in English units. Use for both superheated or wet steam.
Format
StmEng_VPS(P, S)
Arguments
-
P
Pressure of the steam in psia. The valid range is 0.08865 to 14503.77 psia.
-
S
Specific entropy of the steam in BTU/lbm/R. The valid range is -3.691353466E-05 to 1.67208 BTU/lbm/R.
Returns
Computed vapor specific volume in ft3/lbm or Error digital state.
Sample Values
|
Pressure |
Entropy |
Volume |
State |
|
300. |
1.7964 |
2.8581 |
Superheated |
|
800. |
1.6807 |
1.047 |
Superheated |
|
1400. |
1.6096 |
0.5814 |
Superheated |
|
5000. |
1.4001 |
0.1312 |
Superheated |
|
300. |
1.4183 |
1.3902 |
90 % vapor |
Note: The computed result may differ slightly from that computed using the saturated liquid volume, saturated vapor volume and vapor fraction. The difference increases with the moisture content of the steam.