Question 138Gas Turbine - Assistant Engineer

The correct answer is B) To minimize vibration while the engine is passing through critical speed ranges. Explanation: Large axial compressors in turbine engines can experience vibration issues as the engine's rotational speed passes through certain critical speed ranges. To mitigate this, the first few stages of the compressor use loose-fitting blades. This allows the blades to move slightly and dampen the vibrations, preventing damage to the compressor and other engine components. The loose tolerances on these initial blades help the engine safely traverse the critical speed ranges during startup and operation. The other answer choices are incorrect because they do not accurately describe the primary reason for using loose-fitting blades in the initial compressor stages.