Gas turbine designing is getting pushed to the extremes as the demand for power increases and more powerful turbojet engines get developed. The turbo-machines are ever-increasing in size as compared to those of the past. As the size and power of gas turbines increase, so do the chances and causes of turbine failure and blade degradation.
This post presents to you common gas turbine failures and blade degradation problems. It also highlights how turbine support borescope inspections can help in solving these problems.
Erosion damage occurs on your gas turbines when surface materials get removed by the action of fluids and solids that come into contact with such surfaces at high velocity. The high speed causes a material loss that is faster than expected. Also, unwanted solid particles caught up in the motion of your turbine blades cause deformation and cuts to the turbine’s blades and other components.
There are complex factors that determine the rate of erosion. These factors include particle angle, velocity, and particle materials. You can prevent corrosion by using durable coatings on the blades. Regular monitoring of turbine wear by the use of borescope inspection can also help you to respond in a quick way to any damages that may need proactive attention and repair.
Fatigue in turbine parts occurs when the turbine component materials weaken because of repeated cycling loads. The extent of fatigue has a direct correlation to material properties. You can determine the fatigue life of a turbine blade if you know the blade’s material and the kinds of stress acting on the blade.
The three classes of fatigue include as low cycle fatigue (LCF), high cycle fatigue (HCF), or fretting fatigue. LCF causes stress on bodies and compels them to undergo plastic deformation. The HCF results from stresses whose S-N curve is determinable.
Fret fatigue causes an increase in shear and tensile stresses, which can lead to cracks and fractures. To prevent damages from such strains, turbine parts showing any signs of damage should get replaced or repaired. You can also get a turbine support service provider to conduct regular boroscopic inspections to detect such fatigue problems.
Turbine blades experience high thermal stress because they get exposed to high-temperature gases from the turbine’s combustion chamber. First stage turbine parts get exposed to a high thermal load that leads to creep and thermal fatigue. The extreme heat can cause cracking on blade tips. Thermal stress problems can lead to reduced turbine efficiency and power loss.
Analyses on turbine blades show that chemicals such as chromium sulphide, oxides, and complex sulphides contribute to the reduction of the fatigue strength of your turbine’s blade. Blade failure often starts with erosion and continues due to corrosion resulting from high-temperature sulfidation. Unwanted particles that get into the turbine compartments also worsen the corrosion of the blades.
The combination of corrosion and high temperatures leads to hot corrosion. Hot corrosion is a corrosive process accelerated by the presence of salts resulting from the combustion process. The Sodium Chloride and Sodium Sulphate salts combine with debris to form molten deposits.
These deposits spoil the protective oxide layer and destroy the blades. Proper cleaning and lubrication of turbine parts can reduce corrosion damages. You’ll also need to get regular turbine support and borescope inspection services. The services will help you in detecting corrosion problems before they go too far.
As gas turbines strive to reach their optimal operation limits, failures often occur because of thermal stress, corrosion, fatigue, or erosion. As such, there is a need for you to get regular borescope inspection services from a turbine support service provider. These services can help you in detecting gas turbine failures and degradation problems before they can wear down your turbine components and cause further damage to your gas turbine.
Seek for borescope services and get a borescope inspection report to assess the performance and state of your land-based aero-derivative or heavy-frame engine gas turbines. Such turbine support will protect your turbine parts and prolong the life of your gas turbine and its components.