Créé le : 27/09/2010 - Mis à jour le : 15/11/2012
The first stage blade assemblies in a steam turbine are very heavily loaded by instationnary forces, essentially due to control by partial steam injection, which is used in order to adapt the turbine to the power demand. The resulting thermal gradients also contribute to the high loads sustained by these blades. These instationnary loads are difficult, if not impossible to obtain by direct measurement. A steam turbine first stage model allows us to simulate operation in partial or total injection mode. The turbine operates in water. Its internal flow is of free surface type. A wheel blade equipped with capacitive gauges allows us to measure the instantaneous water heights on the blade assembly and it is, therefore, possible to deduce instationnary pressure values on the blade. This paper presents the experimental results pertaining to four guide vane assembly/wheel geometries.