🔍 Key Concepts

• Axial flow compressor blade tip clearances in gas turbines • Methods used to allow safe rubbing between blade tips and casing • Difference between precise machining vs. sacrificial/abradable materials

💭 Think About

• Which method allows the clearance to "self-adjust" during operation without causing serious damage if the blades touch the casing? • Which choice sounds like it relies too much on perfect manufacturing versus accommodating thermal growth and deflection in service? • Think about which materials you would want at the blade tip and on the casing if rubbing is expected to occur.

✅ Before You Answer

• Identify which options mention coatings rather than just tight machining • Decide which option uses materials that are intended to wear or abrade safely instead of causing major damage • Ask whether the rotor mounting should be rigid and precise or deliberately loose in a high-speed compressor