What method can be used to correct blade fouling in axial compressors?

The correct answer identifies that all the listed methods can be employed to address blade fouling in axial compressors. Blade fouling occurs when foreign materials accumulate on the blades, impacting the compressor's efficiency and performance. Each of the methods mentioned has its unique benefits in mitigating this issue.

Adding crushed walnut shells while the compressor is running can help to physically clean the blades. The shells act as an abrasive medium that can dislodge fouling materials without causing damage to the blade surfaces. This method takes advantage of the fluid dynamics within the compressor to facilitate cleaning without the need for a shutdown.

Using special non-stick coatings on the blades can prevent material from adhering in the first place. These coatings create a surface that reduces the likelihood of fouling by minimizing the interaction between the blades and potential contaminants. This preventive measure is particularly useful in environments where fouling is known to be a frequent issue.

Increasing the RPM until the material loosens is another approach that can help shake off accumulations. By running the compressor at higher speeds, the increased aerodynamic forces may dislodge any fouling material stuck to the blades. This method must be used cautiously, as it can lead to other mechanical issues or excessive wear if not applied appropriately.

Together, these methods highlight a comprehensive