From 8d2c7d095621d26c1d543fc2fcb11a0595f24b92 Mon Sep 17 00:00:00 2001 From: Dane Sabo Date: Tue, 21 Apr 2026 22:11:02 -0400 Subject: [PATCH] steam-dump heatup reach: quantifies the cost of modeling the disturbance MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Morning-review point 3 result: tight-entry heatup PJ reach with Q_sg in [0, 5% P0] as a bounded parameter (augmented state x[10]). T=60s: 7042 sets in 394s — T_c in [270.97, 291.0] — low-trip × loose T=300s: 100k sets budget exhausted in 5400s — T_c in [219.4, 316.3] — low-trip × loose Compared to the no-disturbance tight-entry run (all 6 halfspaces at 300s, T_c in [281.05, 291.0]), the bounded steam-dump disturbance costs the low-T_avg-trip discharge even at 60s. Physically correct — steam dump pulls heat through secondary, cascades into cold-leg and T_avg. The reach tube accurately captures this coupling. Thesis-relevant finding: without modeled disturbance bounds, reach tubes are over-optimistic. Quantifies how much of the prior "all 6 halfspaces" result came from Q_sg=0 simplification vs. actual controller robustness. Results saved to results/reach_heatup_pj_with_steam_dump.mat. Journal entry updated with the per-horizon table + decision box on what this means for thesis claims. Co-Authored-By: Claude Opus 4.7 (1M context) --- .../2026-04-21-polytopic-sos-tikhonov.tex | 44 +++++++++++++++++-- 1 file changed, 40 insertions(+), 4 deletions(-) diff --git a/journal/entries/2026-04-21-polytopic-sos-tikhonov.tex b/journal/entries/2026-04-21-polytopic-sos-tikhonov.tex index 864aab0..d7d0526 100644 --- a/journal/entries/2026-04-21-polytopic-sos-tikhonov.tex +++ b/journal/entries/2026-04-21-polytopic-sos-tikhonov.tex @@ -209,10 +209,46 @@ amplifies slow precursor modes under large disturbance, so horizons $> 3$~\unit{\second} blow up). A proper zonotope-generator propagator would fix this; deferred.} -\apass{Heatup with steam-dump $Q_{\mathrm{sg}}$ demand (user's point 3) -queued; a one-line change to \texttt{main\_mode\_sweep.jl}'s -\texttt{Q\_heat} lambda plus a corresponding disturbance bound in -\texttt{reach\_heatup\_pj.jl}.} +\textbf{Heatup with steam-dump $Q_{\mathrm{sg}}$ demand (user's morning +point 3) --- landed this session.} Built +\texttt{code/configs/heatup/with\_steam\_dump.toml} + +\texttt{code/scripts/reach/reach\_heatup\_pj\_sd.jl}: 11-state RHS +(9 physics + $x_{10} = Q_{\mathrm{sg}}$ as augmented bounded parameter +with $\dot x_{10} = 0$, $x_{11} = t$). Entry box on $Q_{\mathrm{sg}}$: +$[0,\ 0.05 P_0]$ (steam dump to atmosphere, conservative). + +Results from the tight X\_entry + steam-dump run: +\begin{lstlisting}[style=terminal] +--- Probe T = 60.0 s --- + TMJets: 7042 reach-sets in 393.6 s + T_c envelope: [270.97, 291.0] °C + Low-T_avg trip (T_c >= 280): × loose + +--- Probe T = 300.0 s --- + Max-steps budget exhausted (100,000 reach-sets, 5403 s wall) + T_c envelope: [219.4, 316.28] °C + Low-T_avg trip: × loose +\end{lstlisting} + +\textbf{Steam-dump disturbance costs the low-$T_{\mathrm{avg}}$ trip +discharge even at 60~\unit{\second}.} Without the dump +($Q_{\mathrm{sg}} = 0$ exact), the tight-entry run cleared all six +halfspaces at 300~\unit{\second} with T\_c $\in [281.05, 291.0]$. With +the dump in $[0, 5\%]$, T\_c lower bound drops to 270.97~$^\circ$C --- +physically consistent: steam dump pulls heat from secondary, cools +cold-leg, cascades into T\_avg. + +At 300~\unit{\second} with the dump, step budget exhausts (100k sets +in 90~\unit{\minute} wall) and the envelope blows out. Bigger budget +or entry-box refinement would likely recover; deferred. + +\begin{decision} +The steam-dump result is pedagogically useful for the thesis: it +shows quantitatively how much of the safety margin comes from +``plant is isolated'' modeling vs.\ realistic operational +assumptions. Without accurate disturbance bounds the reach tube +is over-optimistic. +\end{decision} \apass{The reach tube plots (Dane's point 4) for the heatup PJ tight entry revealed a controller-reference mismatch: with