Validation of the CFD Tools against In-House Experiments for Predicting Condensing Steam Flows in Nozzles

Sima Shabani, Mirosław Majkut, Sławomir Dykas, Krystian Smołka (), Esmail Lakzian and Guojie Zhang
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Sima Shabani: Department of Power Engineering and Turbomachinery, Silesian University of Technology, 44-100 Gliwice, Poland
Mirosław Majkut: Department of Power Engineering and Turbomachinery, Silesian University of Technology, 44-100 Gliwice, Poland
Sławomir Dykas: Department of Power Engineering and Turbomachinery, Silesian University of Technology, 44-100 Gliwice, Poland
Krystian Smołka: Department of Power Engineering and Turbomachinery, Silesian University of Technology, 44-100 Gliwice, Poland
Esmail Lakzian: Center of Computational Energy, Department of Mechanical Engineering, Hakim Sabzevari University, Sabzevar 9617976487, Iran
Guojie Zhang: School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou 450001, China

Energies, 2023, vol. 16, issue 12, 1-20

Abstract: The issues addressed in this work concern the condensing steam flows as a flow of a two-phase medium, i.e., consisting of a gaseous phase and a dispersed phase in the form of liquid droplets. The two-phase character and the necessity to treat steam as a real gas make the numerical modeling of the flow in the last steam turbine channels very difficult. There are many approaches known to solve this problem numerically, mainly based on the RANS method with the Eulerian approach. In this paper, the two Eulerian approaches were compared. In in-house CFD code, the flow governing equations were defined for a gas–liquid mixture, whereas in ANSYS CFX code, individual equations were defined for the gas and liquid phase (except momentum equations). In both codes, it was assumed that there was no velocity slip between phases. The main aim of this study was to show how the different numerical schemes and different governing equations can affect the modeling of wet steam flows and how difficult and sensitive this type of computation is. The numerical results of condensing steam flows were compared against in-house experimental data for nozzles determined at the Department of Power Engineering and Turbomachinery of the Silesian University of Technology. The presented experimental data can be used as a benchmark test for researchers to model wet steam flows. The geometries of two half nozzles and an International Wet Steam Experimental Project (IWSEP) nozzle were used for the comparisons. The static pressure measurements on the walls of the nozzles, the Schlieren technique, and the droplet size measurement were used to qualitatively identify the location of the condensation onset and its intensity. The CFD results obtained by means of both codes showed their good capabilities in terms of proper prediction of the condensation process; however, there were some visible differences in both codes in the flow field parameters. In ANSYS CFX, the condensation wave location in the half nozzles occurred much earlier compared to the experiments. However, the in-house code showed good agreement with the experiments in this region. In addition, the results of the in-house code for the mean droplet diameter in the IWSEP nozzle were closer to the experimental data.

Keywords: condensing steam flows; steam turbine; nozzles; wet steam flows (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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