SEMI-SPIRAL CASING AND RUNNER NAVIER-STOKES SIMULATION FOR A REFURBISHMENT PROJECT

摘要

The refurbishment of the KEMBS hydropowerplant unit 1 is planned in the years to come, due to mechanical wear and tear. To perform the renovation of this Kaplan machine in good conditions and if possible with an increased flowrate, EDF has engaged a program of studies. Among them a numerical study of the flow in the whole existing turbine was led by two divisions of EDF : the high pressure part (semi-spiral casing, stay vanes) and the guide vane and runner at one operating point were studied by CNEH, while the runner (with guide vanes) and the draft tube were studied by the Research and Development Division (DER). This paper presents the first numerical study.The first calculations were performed for the semi-spiral casing for 5 operating conditions. The numerical computation was made using an industrial Navier-Stokes code, CFX-Tascflow. The inlet velocity profiles were deduced from experimental flow measurements at the inlet of the casing performed by the technical division EDF/DTG. The results and notably the losses obtained by the numerical flow analysis were compared to those obtained through the experiments. The correlation is satisfactory for all operating conditions. An estimation of the casing behaviour for other operating conditions resulting from an increased flow rate was also made. A numerical analysis was also carried out for the guide vanes and the runner under two operating conditions. This paper shows the interest of numerical methods for EDF in such a project.