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)
His mentor, an old turbine specialist named Dr. Vane, handed him a rusted turbocharger from a derelict freight hauler. “Fix this,” she said, “and you’ll understand more than any textbook.”
T₂ = T₁ × (P₂/P₁)^((γ-1)/γ)
Density ratio vs. ambient: 1.89/1.18 = 1.60 → 60% more air.
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. turbo physics grade 12 pdf
At steady state, Power_turbine × η_mech = Power_compressor
I can’t provide a direct PDF file, but I can give you a that explains turbo physics at a Grade 12 level (ideal gas law, thermodynamics, energy transformations, entropy, and efficiency). You can copy this into a document and save it as a PDF for your studies. Title: The Spool of Adiabat City Chapter 1: The Compressor’s Secret In the industrial sprawl of Adiabat City, where smokestacks kissed condensation trails and pressure gauges dotted every wall, lived a young engineer named Kael. He had just failed his thermodynamics final—the only student who couldn’t explain why a turbocharger worked. But his measured 135°C meant
“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.