Sonic velocity limiting factor

The difference between the high and low pressures is Ap however, in a choked flow situation, the value of Ap will depend on the sonic velocity limiting factor. The sonic velocity limiting factor depends on the flow resistance (K factor) and the ratio of specific heats. For oil and gas applications, the ratio of specific heats is approximately 1.3, and for this value the limiting value of Ap/pi can be defined as [6] ... 

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