🔍 Key Concepts

• Axial thrust in multistage turbines and what causes it • Purpose of a dummy (balance) piston and cylinder in steam or gas turbines • Difference between thrust control, rotor balance, and measurement functions in turbine design

💭 Think About

• Ask yourself: In a multistage reaction turbine, what direction does the main unbalanced force act on the rotor, and what component is normally used to oppose that force? • Which choice describes a continuous mechanical function built into the turbine’s pressure system, rather than a one-time test or measurement device? • Does a dummy piston operate by changing pressure distribution, by adding weights, or by providing a gauge/indicator?

✅ Before You Answer

• Verify which option is directly related to controlling axial forces on the rotor rather than measuring or observing them. • Check whether dynamic balance is normally done by special pistons, or by adding/removing material/weights from the rotor. • Confirm that a dummy piston works with pressure differences across its faces inside a cylinder, and consider what kind of force that produces.