Design of a multipart wicket gate for Wuskwatim Generating Station : final design report

Abstract

The purpose of this report is to present a solution to Manitoba Hydro’s request for a multipart wicket gate that can be installed and removed from Wuskwatim Generating Station without requiring major disassembly of the generating equipment. The team has designed a multipart wicket gate that addresses the requirements of the project. This report includes a discussion of the design, a method of installation and removal, drawings of the designed wicket gate assembly and a finite element analysis. The current wicket gate is one solid part, and significant disassembly of generating equipment must occur before the gate can be removed and refurbished. Disassembly of the generating station takes several months and results in substantial costs to Manitoba Hydro due to loss of revenue. Therefore, Manitoba Hydro has requested a multipart wicket gate be designed in order to greatly reduce generator downtime. The final design is made up of three major components: the top stem section, the gate body, and the bottom stem section. These three sections can be bolted together inside the scroll case, which eliminates the need for removal of any generating equipment. The top and bottom stem sections mate with the gate body in such a way that the torque required to rotate the gate can be transmitted to the body through the mating surfaces as well as the bolts. Due to the large stress concentrations present in the corners of the stem-to-gate mating surfaces, it is recommended that large fillets be present at those corners and that a high strength material be used for the top stem section. Preliminary finite element analysis showed maximum Von Mises stresses below the allowable stress for some, but not all of the loading conditions. In addition to performing the finite element analysis, the team was asked to produce a detailed installation procedure for the multipart wicket gate. The team recommends that a detailed review of the installation procedure, as well as further finite element analysis, be performed before manufacture and implementation of the multipart gate.