Turbo Physics Grade | 12 Pdf
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 .
He applied the (from the First Law of Thermodynamics, ΔU = Q – W, with Q=0 for rapid compression): turbo physics grade 12 pdf
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 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 pressure meant more oxygen molecules per
Using angular dynamics: τ = I × α, where τ = torque from turbine, I = rotational inertia, α = angular acceleration.
New density at 1.7 atm, 45°C (318 K): ρ = (1.7×101325)/(287×318) ≈ 172252/91266 ≈ 1.89 kg/m³
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.
