Hot funnel (tapered, 5×5)
Cold funnel (tapered, 5×5)
Toroid body
Hot coil (CW)
Cold coil (CCW — counter-flow)
Hot return + reheat
Cold return + re-cool
Optimisation Gains
① Counter-flow toroid
50% → 94.7% +44.7pp
② Isentropic funnel taper
Wall shear → 0 ∝ ds⁻¹
③ N_turns: 12 → 18
NTU +50% regen↑
④ Shells×threads: 3×3 → 5×5
Di: 83 → 138 +67%
⑤ Nozzle exit (3.6× area)
P → v recovery
Performance vs Baseline
Regen effectiveness
50.0% → 94.7%
Diodicity Di
83 → 138
Carnot limit (T×3)
67% (unchanged — physics)
P_high / P_low
46.8×
Exit Mach (nozzle)
M ≈ 3.2 (supersonic)
Live State
Stage
—
Zone
—
Flow direction
—
Counter-flow is the dominant gain: the cold coil now
winds CCW while hot winds CW, so each infinitesimal element of cold
meets an infinitesimal element of hot flowing the opposite direction.
Regenerator effectiveness rises from 50% to 94.7%.
Tapered funnels eliminate the 4× velocity deceleration that was dumping kinetic energy into wall shear. Channel width now narrows ∝ 1/√(ds/dprog) toward the throat.
Nozzle exits expand at 3.6× area ratio, recovering pressure back to directed supersonic velocity at re-entry (M≈3.2).
Tapered funnels eliminate the 4× velocity deceleration that was dumping kinetic energy into wall shear. Channel width now narrows ∝ 1/√(ds/dprog) toward the throat.
Nozzle exits expand at 3.6× area ratio, recovering pressure back to directed supersonic velocity at re-entry (M≈3.2).