# src/cryo_tank/config.py
"""
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)
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)

# ---------- Tank limits ----------
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

# ---------- 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

# ---------- Heat transfer ----------
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)
RTOL = 1e-8
ATOL = 1e-10

# ---------- Output ----------
OUTPUT_DIR = "results/cryo_tank"

# ---------- Validation ----------
assert V_TOTAL > 0
assert H_TANK > 0
assert 0 < ULLAGE_FRACTION < 1
assert P_WORKING > 0
assert P_MAX > P_WORKING
assert T_INIT > 0
assert MDOT_IN_LN2 >= 0
assert MDOT_OUT_LN2 >= 0
assert T_IN_LN2 > 0
assert T_IN_HE > 0
assert H_CONV_SURFACE >= 0
assert T_ENV > 0
assert T_END > 0