System and method for treating an installed and assembled gas turbine engine

A method for treating at least one component of an installed and assembled gas turbine engine, the gas turbine engine comprising a core gas turbine engine, the core gas turbine engine having an absence of powered rotation during the treating, the method comprising:

• operably coupling a delivery assembly to an annular inlet of the core gas turbine engine, the delivery assembly being coupled to a control unit and a storage vessel containing a treating fluid;
• atomizing a portion of the treating fluid with the delivery assembly to develop a treating mist, the treating mist comprising a plurality of atomized droplets;
• suspending the atomized droplets of the treating mist within an airflow within at least one flow path of the core gas turbine engine, wherein the treating mist occupies a cross-sectional area of the at least one flow path to establish a simultaneous cross-sectional contact therein, wherein at least a portion of the atomized droplets remain suspended within the at least one flow path from the annular inlet to an axial position downstream of a high-pressure compressor of the core gas turbine engine;
• and
• impacting or precipitating a portion of the treating mist onto the at least one component so as to wet at least 80% of an exposed, inlet-facing surface of the at least one component.