🔍 Key Concepts

• Positive vs non-positive displacement blowers (how they move air) • Relationship between rotor design and air flow shown in the illustration • How blower speed (tied to engine speed) affects the amount of air moved per revolution

💭 Think About

• Look closely at the blower rotors in the illustration: do they trap fixed pockets of air and physically carry them along, or do they accelerate air like a turbine or centrifugal compressor? • If each revolution of the blower traps and moves nearly the same volume of air, what does that tell you about how air flow changes when the engine (and blower) speed doubles? • For the type of blower you identify, is the air flow mainly determined by geometry and rpm, or by pressure/velocity effects as in a turbocharger?

✅ Before You Answer

• Identify from the drawing whether the blower is positive displacement (moves discrete air pockets) or non‑positive displacement (relies on velocity/pressure change). • Decide whether the volume per revolution is essentially fixed by the rotor shape, or varies significantly with conditions. • Match your conclusions to the answer choice that combines the correct blower type with the correct relationship between displacement and engine speed.