DryGasDownChoke.xlsThis spreadsheet calculates downstream pressure at choke for dry gases.

Input Data:

Upstream pressure: 600 psiaChoke size: 32 1/64 inchFlowline ID: 2 inGas production rate: 2500 Mscf/dGas specific gravity: 0.75 1 for airGas specific heat ratio (k): 1.3Upstream temperature: 110 FChoke discharge coefficient: 0.99

Calculated Values:

Choke area: 0.19625Critical pressure ratio: 0.5457Maximum downstream pressure for minimum sonic flow: 327.44 psiaFlow rate at the minimum sonic flow condition: 3306.84 Mscf/dFlow regime (1=sonic flow; -1=subsonic flow): -1

The maximum possible down stream pressure in sonic flow: 327.44 psiaDown stream pressure given by subsonic flow equation: 508.15 psiaEstimated down stream pressure: 508.15 psia

in2

Instructions:Step 1: Update parameter values in blue;Step 2: Run Macro Solution;Step 3: View results.

Residual error of objective function:2.9841398827557E-05

q=879CApup√( kγ gT up )(

2k+1 )

k+1k−1

Q sc=1 ,248CApup√ k(k−1)γ g Tup [( pdnpup )

2k−( pdnpup )

k+1k ]

( poutletpup )c=( 2k+1 )

kk−1