Gas turbine blade geometry variation due to fouling

Abstract

Solid particles ingestion is a severe problem for gas turbines. In the aero-propulsion field the main problems related to this phenomenon occur on the hot sections of the machinery. Impinging particles can stick or Erode the blade material. The deposition on the turbine blades is the main issue among the two and the clogging of cooling holes can even speed up this process rising the blade surface temperature. An higher temperature affects negatively the deposition problems, increasing particle stickiness. In this paper an innovative approach to account for fouling and erosion effects on turbine vanes is presented. An energetic model to predict the sticking probability is used (EBFOG, from Energy Based FOulinG) and the erosion is evaluated through the model proposed by Tabakoff. Geometry variation of blades subject to fouling are investigated by means of a moving mesh technique which accounts for the boundary displacement of the blade surface.