Engineering method for calculating initial condensation parameters in high-speed water vapor streams

An approximate method for calculating the gas and thermodynamic parameters of homogeneously condensing highspeed steam streams is described, including calculation of steam turbines and other power equipment flow sections. The exact calculation of spontaneous condensation, based on the general theory of multiphase flows and the kinetic theory of nucleation in a vapor, takes into account the kinetics of the process, and requires the use of modern, rather complex computer programs. The developed approximate method that takes into account all the fundamental physical features of the real flow makes it possible to determine the flow parameters quite simply, using the results of systematic accurate calculations. In accordance with the actual flow, the current is divided into three regions: total supercooling, condensation front, thermodynamic equilibrium. Calculations in the supercooling region and thermodynamic equilibrium are performed for an isentropically expanding ideal gas with different adiabatic values for each of the values. The end of the supercooling region is determined by the threshold supercooling value, and the beginning of the thermodynamic equilibrium region is determined by the extension of the front itself. The gradient of the channel area expansion and the pressure on the saturation line under isentropic expansion of the flow are chosen as the criteria determining these parameters. The location and extension of the condensation front are determined from generalized diagrams constructed from the results of systematic calculations performed by the «Wet Steam» program complex. The change in the parameters in the condensation front itself is determined from the known gas-dynamic relations for the heat nozzle. A comparison of the exact and approximate calculation with experiment is given, showing the satisfactory accuracy of the method.

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