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1.15.0
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STAR
Cal STAR — firmware, DAQ server, and engine design
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Variables | |
| PSI = get_unit("psi").factor | |
| float | R_UNIVERSAL = 8.31446261815324 |
Tank geometry, ullage collapse, and constant-pressure expulsion. The headline check is :func:`test_expulsion_matches_closed_form`: for an ideal gas with no interfacial loss, holding a tank at constant pressure while liquid leaves needs exactly ``m = p dV / (R T_in)``, *independent of the ullage's starting temperature*. That independence is a strong test -- it fails loudly if the expansion-work term is missing or mis-signed, which is the single easiest thing to get wrong in a tank model.
| CylindricalTank test_tank.geometry | ( | ) |
6 in. tank, 600 mm barrel, 2:1 ellipsoidal heads. The team's shape.
Definition at line 43 of file test_tank.py.
| Fluid test_tank.gn2 | ( | ) |
Definition at line 54 of file test_tank.py.
| Fluid test_tank.lox | ( | ) |
Definition at line 49 of file test_tank.py.
| None test_tank.test_a_step_carries_what_it_does_not_integrate | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
A field added to the state later rides through a step untouched. Built field by field, the step returned a plain :class:`TankState` and reset anything it did not list -- how ``vapour_mass`` was once zeroed every step (docs/PHYSICS-BENCHMARK.md 4.3). A subclass stands in for that field.
Definition at line 417 of file test_tank.py.
| None test_tank.test_collapse_costs_pressurant_not_pressure | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
The point of the whole collapse model. With the regulator holding tank pressure, interfacial heat loss does not show up in the pressure trace at all -- both runs hold 500 psi exactly. It shows up as extra pressurant, which drains the COPV faster, which lowers regulator inlet, which moves the outlet through the supply coefficient.
Definition at line 304 of file test_tank.py.
| None test_tank.test_collapse_flux_decays_with_contact_time | ( | Fluid | lox | ) |
Why repressurising right before ignition helps: it resets the clock.
Definition at line 179 of file test_tank.py.
| None test_tank.test_conduction_rate_integrates_to_the_closed_form | ( | Fluid | lox | ) |
The instantaneous flux must integrate to 2 A dT sqrt(k rho c t / pi).
Definition at line 146 of file test_tank.py.
| None test_tank.test_cross_section_is_the_derivative_of_volume | ( | CylindricalTank | geometry | ) |
dV/dh must equal the horizontal area, or collapse gets the wrong area.
Definition at line 105 of file test_tank.py.
| None test_tank.test_cylinder_volume_matches_closed_form | ( | CylindricalTank | geometry | ) |
Definition at line 61 of file test_tank.py.
| None test_tank.test_enhancement_increases_demand_monotonically | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
Definition at line 339 of file test_tank.py.
| None test_tank.test_expulsion_deviation_is_the_compressibility | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
The ~0.5% gap from ideal is Z, not numerical slop.
Definition at line 280 of file test_tank.py.
| None test_tank.test_expulsion_matches_closed_form | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry, | ||
| float | ullage_temperature ) |
Constant-pressure expulsion needs ``m = p dV / (R T_in)``. From the energy balance with ``p`` held: ``(cv/R) p Vdot = mdot cp T_in - p Vdot`` reduces to ``mdot = p Vdot / (R T_in)``, which does **not** contain the ullage's own temperature. Getting the same answer from a 150 K ullage and a 400 K one is the real content of this test; a missing or mis-signed expansion-work term breaks that independence immediately.
Definition at line 247 of file test_tank.py.
| None test_tank.test_flat_heads_give_a_cylinder | ( | ) |
Definition at line 83 of file test_tank.py.
| None test_tank.test_geometry_registry | ( | ) |
Definition at line 133 of file test_tank.py.
| None test_tank.test_helium_needs_less_mass_than_nitrogen | ( | Fluid | lox, |
| CylindricalTank | geometry ) |
Sanity on the pressurant choice: helium's R is 7x nitrogen's.
Definition at line 359 of file test_tank.py.
| None test_tank.test_hemispherical_heads_give_a_sphere | ( | ) |
Zero barrel with two hemispherical heads is a sphere, exactly.
Definition at line 67 of file test_tank.py.
| None test_tank.test_initial_state_round_trips_pressure | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
Definition at line 201 of file test_tank.py.
| None test_tank.test_interface_shrinks_in_the_head | ( | CylindricalTank | geometry | ) |
A nearly-empty tank has far less interface than a half-full one.
Definition at line 114 of file test_tank.py.
| None test_tank.test_level_inverts_volume | ( | CylindricalTank | geometry | ) |
Definition at line 99 of file test_tank.py.
| None test_tank.test_liquid_in_the_ullage_refuses | ( | CylindricalTank | geometry | ) |
A pressurant that condenses at tank conditions is not an ullage gas.
Definition at line 378 of file test_tank.py.
| None test_tank.test_no_collapse_is_a_named_model | ( | ) |
Definition at line 188 of file test_tank.py.
| None test_tank.test_outlet_pressure_includes_the_liquid_column | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
Definition at line 230 of file test_tank.py.
| None test_tank.test_overfull_tank_refuses | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
Definition at line 217 of file test_tank.py.
| None test_tank.test_penetration_depth_is_millimetres_over_a_burn | ( | Fluid | lox | ) |
The physical claim behind using a transient model at all.
Definition at line 166 of file test_tank.py.
| None test_tank.test_repressurisation_resets_the_interface_clock | ( | Fluid | lox, |
| Fluid | gn2, | ||
| CylindricalTank | geometry ) |
Definition at line 390 of file test_tank.py.
| None test_tank.test_tabulated_geometry_rejects_a_shrinking_tank | ( | ) |
Definition at line 128 of file test_tank.py.
| None test_tank.test_tabulated_geometry_round_trips | ( | ) |
Definition at line 119 of file test_tank.py.
| None test_tank.test_volume_endpoints_are_exact | ( | CylindricalTank | geometry | ) |
Definition at line 92 of file test_tank.py.
| test_tank.PSI = get_unit("psi").factor |
Definition at line 38 of file test_tank.py.
| float test_tank.R_UNIVERSAL = 8.31446261815324 |
Definition at line 39 of file test_tank.py.
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