Isentropic Expansion of Dry Saturated Vapor—Application to the Design of Safety Valves

Abstract

Accepted standards relative to the design of safety valves are based on calculations of the maximum (flow rate) during isentropic expansion through a converging nozzle. The theoretical value is then corrected with an empirical coefficient K d for a better approach of reality. In this paper, after reviewing the calculation which is the basis for the various existing standards, we indicate the limits of their applications and present a more rigorous method in the case of saturated vapors as well as the first results of systematic computer calculations.