Question 18Gas Turbine - 1st Asst/Chief

The correct answer is D) Blade rub. Blade rub is the primary cause of compressor rotor blade tip curl. When the compressor blades come into contact with the casing or surrounding components, it can lead to excessive friction and wear, causing the blade tips to curl or deform. This blade-to-case rub is a common issue in compressor systems and is typically caused by factors such as thermal expansion, rotor imbalance, or mechanical wear. The other options are not the primary causes of blade tip curl. Misalignment (A) can contribute to blade rub, but it is not the direct cause. Object damage (B) and vane rub (C) may also occur in compressor systems, but they are not the primary reasons for the specific issue of blade tip curl.