feat(cryo_tank): use ullage temperature state

src/cryo_tank/config.py

@@ -3,37 +3,38 @@
 Configuration for the cryogenic LN2 tank simulation.
 Pure data module -- no functions, no side effects.
 """
+
 import math
 
 # ---------- Tank geometry ----------
-V_TOTAL = 420.1e-3          # m^3  (420.1 L)
-H_TANK = 0.5                # m    (cylinder height)
+V_TOTAL = 420.1e-3  # m^3  (420.1 L)
+H_TANK = 0.5  # m    (cylinder height)
 A_CROSS = V_TOTAL / H_TANK  # m^2  (cross-section area)
 D_TANK = math.sqrt(4 * A_CROSS / math.pi)  # m (diameter)
-A_SIDE = math.pi * D_TANK * H_TANK         # m^2 (side wall)
-A_CAP = A_CROSS                             # m^2 (top or bottom cap)
-A_TOTAL = A_SIDE + 2 * A_CAP               # m^2 (total surface)
+A_SIDE = math.pi * D_TANK * H_TANK  # m^2 (side wall)
+A_CAP = A_CROSS  # m^2 (top or bottom cap)
+A_TOTAL = A_SIDE + 2 * A_CAP  # m^2 (total surface)
 
 # ---------- Tank limits ----------
-P_WORKING = 0.17e6          # Pa  (working pressure, absolute)
-P_MAX = 0.8e6               # Pa  (max bearing pressure)
+P_WORKING = 0.17e6  # Pa  (working pressure, absolute)
+P_MAX = 0.8e6  # Pa  (max bearing pressure)
 
 # ---------- Initial conditions ----------
-T_INIT = 78.0               # K
-ULLAGE_FRACTION = 0.30      # gas pocket = 30% of V_TOTAL
+T_INIT = 78.0  # K
+ULLAGE_FRACTION = 0.30  # gas pocket = 30% of V_TOTAL
 
 # ---------- Inlet / outlet ----------
-MDOT_IN_LN2 = 1.144         # kg/s
-T_IN_LN2 = 77.0             # K
-MDOT_OUT_LN2 = 1.1895       # kg/s
-T_IN_HE = 100.0             # K
+MDOT_IN_LN2 = 1.144  # kg/s
+T_IN_LN2 = 77.0  # K
+MDOT_OUT_LN2 = 1.1895  # kg/s
+T_IN_HE = 100.0  # K
 
 # ---------- Heat transfer ----------
-H_CONV_SURFACE = 50.0       # W/(m^2*K)  liquid-to-ullage surface convection
-T_ENV = 300.0                # K  ambient temperature
+H_CONV_SURFACE = 0.0  # W/(m^2*K)  liquid-to-ullage surface convection
+T_ENV = 300.0  # K  ambient temperature
 
 # ---------- Simulation control ----------
-T_END = 3600.0               # s  (1 hour)
+T_END = 3600.0  # s  (1 hour)
 RTOL = 1e-8
 ATOL = 1e-10