Compressor Washing in Aircrafts

Keeping a jet engine running as efficiently as possible is critical. An efficient engine is safer, works better, and uses less fuel to run. As such, operators are always looking for ways to maximize the efficiency of their jet engine. One such way is compressor cleaning.

Though they are not always visible, the air is filled with contaminants. This is especially true at ground level. Among the most common contaminants are fine dirt, oil vapors, soot, exhaust fumes, salt, and more, all of which can enter the engine compressor through the air supply. Furthermore, because the air in the jet engine compressor is under extreme temperatures and pressures, the build-up of contaminants on the compressor blades is accelerated.

In gas turbines such as those in jet engines, thermal efficiency is a key part of performance. Factors that affect thermal efficiency can include turbine inlet temperature, compressor inlet temperature, burner efficiency, compression ratio, and the efficiency of the compressor and turbine. Compressor washing is primarily used to deal with efficiency of the compressor and turbine. The build-up of contaminants interferes with airflow, eventually affecting the efficiency of the system as a whole. Another potential issue is that contaminants, especially salt, can corrode important components within the engine. This further disrupts aircraft, speeds up the degradation of parts, and ultimately results in engine failure.

So, what exactly is compressor washing? It’s exactly what it sounds like: washing of the engine compressor. It is done by using hot water or a mixture of water and specialized detergents to dissolve, dislodge, and remove contaminants. There are three steps to carrying out compressor washing:

1. Chemical wash: using special equipment, detergent is cast into the system as the compressor turns.
2. Water rinse: after the detergent has broken down the contaminants, water is used to flush the compressor with water and remove all residues including the cleaning fluids.
3. Engine run: once the cleaning is completed, the quickest and easiest way to dry the engine is to fire it up.

To ensure an effective clean, it’s important to use the right equipment. The wash system you use should be specifically designed for the job and have a track record of producing results. It is also important to use a detergent designed specifically for compressor cleaning. Finally, it is best to use demineralized water to clean and rinse the compressor. Using impure water can leave contaminants on the compressor - undoing the work of the cleaning.

Regular compressor washing will ensure that contaminants are not allowed to build up to such a level that they become a problem. The cleaner the compressor, the better it will run. Additionally, like with cleaning of any type, regular removal of contaminants will ensure they are easier to remove. How often you should conduct a cleaning should be detailed in the engine manual and will be based on cycles. That said, there are also different variables to consider, such as the kinds of trips the aircraft will be making. For example, if the aircraft is flying at lower altitudes where air is more polluted, more regular cleaning will be required.