1Hydrology and Materials Laboratory, Sidi Bel Abbès University, Algeria.
2Faculty of Engineering Sciences, Sidi Bel Abbès University, BP 89, 22000, Algeria.
In order to increase the turbine gas efficiency and its power, the clearances between rotaring blades and the interior casing should be as small as possible. To obtain that, one sprays a sacrificial material on the casing by the thermal blowtorch flame-powder process and one obtains a coating layer. During the blades rotation, they scrape the (Al2O3.4SiO2.H2O-Na-Ca-Mg)-AlCrNi coating and tear off a fine layer in small remains. It creates itself a functional gap between the blades and the casing seal. The combustion gases do not escape through the clearance, and contribute consequently in the power production. The aim of this work is to investigate the behaviour of a particular sacrificial material, the Bentonite-metallic phase and its effect on the turbine blades wear during inter-reaction between them under experimental conditions of operating rotor blades. For this purpose, we use a Sulzer Metco abradability test. To determine this problem, we carried out several tests by changing 4 functional parameters. They are the incursion speed within the seal coating, the linear blades speed, the blades depth incursion inside the casing seal and the operating temperature. The obtained results are shown in form of graphs and maps, and the comments explain when there is the blades wear or material transfer, and the different effects observed on the coating surface.
Blades wear, material transfer, casing seal, wear map, sacrificial material
