Accumulation of gas in a vessel at constant temperature

Following the dimensional analysis of Appendix 2, Section A2.2, the mass flow, IV1, may be written generally as 

ATn is the number of velocity heads characterizing the frictional drop over the upstream pipe (dimensionless) by equation (6.61), Kt is related to the upstream conductance, Cti (m ), by Kn = 2Af/Ci  

Specific realizations of the compressible flow function, ffloK, are given in Chapters 6 and 10. 

The vessel pressure constitutes the upstream pressure for the discharge flow, and so IV2 will have the form  

The mass of gas in the vessel will obey the same differential equation as derived in the previous section, namely 

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