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.
For air, γ = 1.4, so (0.4/1.4) = 0.286.
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) turbo physics grade 12 pdf
Without turbo, ambient air density was 1.18 kg/m³. Density ratio = 1.56/1.18 = 1.32 → 32% more air molecules.
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. To reduce lag, Kael lightened the turbine wheel
That diagram became the cover of a new PDF guide: Turbo Physics for Grade 12 . If you want, I can convert this story into a clean, printable PDF layout with diagrams (described in text) and a formula summary page. Just let me know, and I’ll generate the PDF-ready content.
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.” For air, γ = 1
Power_compressor = ṁ_air × cp_air × (T_out – T_in) / η_mech
He applied the (from the First Law of Thermodynamics, ΔU = Q – W, with Q=0 for rapid compression):
New density at 1.7 atm, 45°C (318 K): ρ = (1.7×101325)/(287×318) ≈ 172252/91266 ≈ 1.89 kg/m³