Semi-analytical model for the prediction of the Wilson point for homogeneously condensing steam flows

Journal article (2018)

Authors

L. Azzini Flight Performance and Propulsion - Aerospace Engineering
M. Pini Flight Performance and Propulsion - Aerospace Engineering
Piero Colonna Flight Performance and Propulsion - Aerospace Engineering
Research Group
Flight Performance and Propulsion (Aerospace Engineering) (TU Delft)
Copyright: © 2018 L. Azzini, M. Pini, Piero Colonna
DOI: https://doi.org/10.1016/j.ijheatfluidflow.2018.01.004
Wilson point Non-equilibrium condensation Supersonic nozzles Steam expansion
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Published Date

2018

Language

English

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Faculty

Aerospace Engineering

Department

Flow Physics and Technology

Research Group

Flight Performance and Propulsion

Abstract

An investigation on non-equilibrium condensing steam flow is conducted to attain a semi-analytical model for the prediction of the Wilson point up to the critical point. The database for the analysis includes experimental observations in various nozzles and conditions (ranging from 20 to 150 bar) taken from the literature as well as additional data at lower and higher reduced pressures, generated by means of a calibrated quasi-1D model based on the method of moments.

The simplified model is based on a reformulation of the Wilson point in terms of activation time, defined as the temporal interval between the instant at which the flow is at saturation conditions and the inception stable of condensation. This allows to incorporate the dependency of the Wilson point on the cooling rate and dew-point temperature, which are found the key parameters affecting the delay of condensation.

The accuracy of the approach is proved by predicting the degree of subcooling on four different test cases, with deviations against experiments in the range of 1−10%. As demonstrated, the same approach can be exploited to design nozzles free of condensation.