At 1.8 atm and 135°C (408 K): ρ = (1.8 × 101325 Pa) / (287 J/kg·K × 408 K) ρ ≈ 182385 / 117096 ≈ 1.56 kg/m³
“Cooling after compression is like cheating physics,” Kael grinned. “You increase density without losing the work already put in.” The turbo didn’t work instantly. At low RPM, exhaust flow was weak. Kael plotted mass flow rate vs. pressure ratio on a compressor map. The surge line showed where airflow reversed—flutter. The choke line where flow stalled.
Without turbo, ambient air density was 1.18 kg/m³. Density ratio = 1.56/1.18 = 1.32 → 32% more air molecules.
At steady state, Power_turbine × η_mech = Power_compressor 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 .
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.” Kael plotted mass flow rate vs
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)
Power_compressor = ṁ_air × cp_air × (T_out – T_in) / η_mech
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. The choke line where flow stalled
Kael calculated: Using (η_t = (T₁ - T₂_actual)/(T₁ - T₂_ideal)), he found that 68% of the exhaust’s enthalpy (h = u + Pv) converted into shaft work. The rest became entropy—random molecular motion—which heated the turbine housing.
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.
“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.
Density ratio vs. ambient: 1.89/1.18 = 1.60 → 60% more air.