New Method for Turbine Blade Internal Cleaning

Abstract

A program was undertaken to develop an improved internal cleaning procedure for high pressure turbine blades. HP turbine blades, such as JT8D and JT9D 1st stage blades, experience a build up of Si-Ca rich dirt/debris during engine service that inhibits the flow of cooling air creating localized “hot spots”. These “hot spots” lead to accelerated internal corrosion that may cause through-wall material failure. Autoclave processes, utilizing heated, pressurized caustic, are ineffective at removing large amounts of internal debris. A new process, called the TURBO-CLEAN℠ process (patent pending), effectively removes large deposits of internal debris in as few as 2 hours. This process involves pumping heated caustic at pressures approaching 400psi through the internal cavities of turbine blades. The increased caustic flow from this process, compared to autoclave processes, improves cleaning effectiveness. This new process does not harm the parent material or damage protective aluminide coatings. The development of this process has led to reduced repair costs for JT8D 1st blades by improving part yield during repair.