Turbo Physics Grade 12 Pdf -
Kael disassembled the twin volutes: the turbine housing (hot side) and compressor housing (cold side). Inside, he found two wheels connected by a common shaft. He knew the basics—exhaust gases spin the turbine, which spins the compressor, which shoves more air into the engine—but why did that make power?
He learned is the time to reach the boost threshold. It’s governed by the moment of inertia of the rotating assembly and the exhaust enthalpy flow . turbo physics grade 12 pdf
To reduce lag, Kael lightened the turbine wheel (lower I) and designed a smaller A/R (area/radius) turbine housing—which increased exhaust velocity but reduced top-end flow. At full throttle, boost climbed past 2.2 atm. The engine detonated. Dr. Vane pointed to a small actuator: the wastegate. It diverted exhaust around the turbine when boost exceeded a setpoint. Kael disassembled the twin volutes: the turbine housing
Density ratio vs. ambient: 1.89/1.18 = 1.60 → 60% more air. He learned is the time to reach the boost threshold
But his measured 135°C meant . The compressor efficiency (η_c) = (T₂_ideal – T₁)/(T₂_actual – T₁) = (78-25)/(135-25) = 53/110 ≈ 48%. The rest of the work became heat due to friction and turbulence. Chapter 4: The Density Battle Kael connected the compressor outlet to a small engine cylinder. More air pressure meant more oxygen molecules per volume—but the heat reduced density. Using the ideal gas law rearranged: ρ = P / (R_specific × T)
“More air means more fuel can be burned,” Kael said. “That’s the power gain.” But 135°C air caused engine knock. Dr. Vane handed him an intercooler—an air-to-air radiator. After the intercooler, temperature dropped to 45°C while pressure only dropped to 1.7 atm.