Axial compressor fouling is the deposition of contaminant particles on the blade of the compressor leading to loss of its aerodynamic and thermodynamic performance.

The level and rate of fouling depends on the condition of the operating environment of the gas turbine. There are a wide variety of contaminants (mostly airborne like salt from salt water, oil, pollen, soil, dust, etc.) that can cause axial compressor fouling.

Fouling of GT axial compressor leads to reduced compressor performance. This is manifested in loss of compressor isentropic efficiency and reduction in air mass flow rate. This in turn reduces the GT overall thermal efficiency (increased fuel costs) and power output (less power available to sell).