@PhdThesis{duepublico_mods_00046600,
  author = 	{Hu, Bo},
  title = 	{Numerical and experimental investigation on the flow in rotor-stator cavities},
  year = 	{2018},
  month = 	{Jul},
  day = 	{20},
  abstract = 	{The leakage flow (centripetal or centrifugal through-flow) can be found in the side cavities between the rotor and the stationary wall in nearly all kinds of radial pumps and turbines. The cavity flow has a strong impact on the disk friction loss, leakage loss, which in this way influence the efficiency of radial pumps and turbines. Many more effects are related to the side cavity flow, such as the resulting axial force on the impeller and rotordynamic. To better understand the effects the flow in rotor-stator cavities is investigated by means of analytical, numerical and experimental approaches in this thesis.
In chapter 1 and chapter 2, the research status and the progress for the core swirl ratio, the axial thrust coefficient and the moment coefficient are introduced.
In chapter 3, the design of the test rig is described. The uncertainties of the experimental parameters are estimated. The experimental results from the test rig are also compared with those from literature to show that the results from the test rig are reliable.
In chapter 4, the numerical simulation set-up is illustrated. To minimize the error, the selection of a turbulence model and the generation of the mesh are accomplished. The simulation results are in good agreement with those from the literature, indicating that the numerical simulation set-up is reasonable.
In chapter 5, the experimental results are presented for the core swirl ratio, the axial thrust coefficient and the moment coefficient. The former correlations for the core swirl ratio are modified based on the pressure measurements of the author and are extended by introducing the impact of surface roughness. The values of core swirl ratio deduced from the pressure measurements are in good agreement with the simulation results. Correlations for the axial thrust coefficient are determined which cover the impact of global Reynolds number, axial gap width, through-flow coefficient, surface roughness for both centripetal and centrifugal through-flow. The experimental results for the moment coefficient are also compared with those from the correlations in the literature according to the flow regimes, where a large gap occurs. The gap is explained by the difference of surface roughness. The former correlations therefore are modified by introducing the surface roughness based on the torque measurements with rough disks. Some experimental results are also provided to understand how the pre-swirl impacts the above mentioned parameters.
In chapter 6, two examples are presented on the applications of the results in this thesis. The first example is to accomplish the geometry optimization of the rear chamber of a submersible multi-stage slurry pump based on the flow pattern. The service life of the pump is dramatically improved by around 30{\%}. The second example is to predict the axial thrust for a deep-well pump. The axial thrust from the correlation is also in good agreement with the experimental results. The applications indicate that the results in this thesis should be reasonable.
All the results will provide a database for the calculation of the axial thrust and the frictional loss in order to better design radial pumps and turbines.},
  url = 	{https://duepublico2.uni-due.de/receive/duepublico_mods_00046600},
  file = 	{:https://duepublico2.uni-due.de/servlets/MCRFileNodeServlet/duepublico_derivate_00045845/Diss_Hu.pdf:PDF},
  language = 	{en}
}