🔍 Key Concepts

• Impulse vs. reaction turbines – where the pressure drop occurs in each type • How energy exits the turbine in reaction designs compared to impulse designs • Different types of turbine losses: throttling, windage, tip leakage, and leaving

💭 Think About

• In a reaction turbine, does all of the fluid’s kinetic energy get used before it leaves the runner, or does some remain at outlet? What kind of loss would that create? • Which of these losses could logically occur in BOTH impulse and reaction turbines, and which would be unique to a design where pressure drop happens partly in the runner? • Think about the flow leaving the blades of a reaction turbine: if its direction or speed is not perfectly matched to ideal conditions, what kind of energy loss does that represent?

✅ Before You Answer

• Make sure you understand how pressure and velocity change across the nozzles and runner in impulse vs. reaction turbines • Identify which losses are due to mechanical effects (like friction or air resistance) and which are due to fluid still having usable energy at discharge • Check turbine diagrams in your notes that show velocity triangles at outlet and see which named loss fits the situation where discharge velocity is not fully recovered