🔍 Key Concepts

• Turbine reaction blading and why these blades are more flexible than impulse blades • How designers mechanically secure and stiffen groups of blades to change their natural frequency • What parts like dummy pistons, casing seals, diaphragms, and binding wire actually do in a turbine

💭 Think About

• Which of the listed items directly touches or connects to the moving blades themselves, rather than the stationary casing parts? • Which item is commonly used to tie together or support the tips or mid‑sections of blades to reduce vibration and change their natural frequency? • For each wrong choice, ask: is this mainly for sealing/pressure balance, or does it actually restrain blade motion?

✅ Before You Answer

• Identify which components are stationary casing/sealing parts versus which are attached to or wrapped around the rotating blades • Recall that reducing vibration usually involves changing stiffness or natural frequency of the blades, not just improving steam sealing • Eliminate any choice whose primary purpose is pressure balance or sealing, rather than direct blade vibration control