A method and system augments shaft output of gas turbine engines that can be used in multiple modes of operation. The system comprises a washing unit capable of injecting atomized water into the gas turbine engine, thereby obtaining a release of fouling material from the at least one compressor blade; and at least one water injection unit capable of injecting atomized water into the air stream of the gas turbine engine's inlet duct or at the gas turbine, under the control of a computational fluid dynamic model, in order to increase a mass flow of said air flow, wherein the power output from said gas turbine engine can be augmented.