Functions
	_lin (a, b)
	_synthetic ()
	test_ladder_elements_sum_to_end_to_end_and_head_is_a_gain ()
	test_ladder_reports_a_recorder_that_does_not_telescope ()
	test_ladder_without_network_is_unavailable_not_a_raise ()
	_he (p_psia, T_K)
	test_iec_capacity_by_hand_and_against_fluids (p2_psia, choked)
	test_iec_solenoid_drop_matches_the_audit_hand_check ()
	_reg_target (p_in, mdot)
	test_regulator_law_split_and_wide_open_by_hand ()
	test_solenoid_share_of_regulator_to_tank_by_hand ()
	_jt_by_integration (fluid, p1, T1, p2, steps=400)
	test_joule_thomson_sign_and_magnitude (fluid, sign)
	test_pressurant_budget_and_floor_by_hand ()
	_fake_prep (res)
	_fake_config ()
	test_saturation_margin_total_and_static_by_hand ()
	test_a_dead_leg_held_at_atmosphere_is_not_graded ()
	test_cavitation_number_by_hand_and_flip_risk ()
	test_injector_velocities_momentum_ratio_and_tilt_by_hand ()
	_fake_engine (p_O, p_F)
	_fed (p_out, K, side)
	_thrust_result (K_drift=0.0, accel=None)
	test_thrust_breakdown_by_closed_form ()
	test_thrust_breakdown_acceleration_head_when_flown ()
	test_ledger_rows_design_from_forward_delivered_from_the_burn ()
	test_ledger_with_the_erosion_replay_off_reads_the_twins_chamber ()
	_recorder_style (res)
	test_diagnostics_on_the_recorder_shape ()
	test_feed_diagnostics_on_the_le4_helium_burn (monkeypatch)

Variables
float	PSI = 6894.757293168361
int	N = 4
list	T = [-0.1, 0.0, 0.05, 0.10]
list	FIRING = [False, False, True, True]
dict	REG_PARAMS
float	ATM_PSIA = 101325.0 / PSI
float	PC0 = 400.0 * PSI
dict	C_FLOW = {"ox": 1.9 / math.sqrt(170.0 * PSI), "fuel": 1.25 / math.sqrt(160.0 * PSI)}
float	K_THRUST = 2300.0

Detailed Description

Feed diagnostics (engine/layerx/diag: ladder, regulator, solenoids, pressurant, saturation,
cavitation, injector, thrust shape, ledger) against hand calculations, CoolProp and ``fluids``.

Most tests run on a synthetic result with a contract-shaped ``network`` (DATA-CONTRACT 2), whose
numbers are chosen so each answer can be worked by hand in the test. One test burns the LE4 helium
drawing and is skipped unless ``LAYERX_GOLDEN=1`` and lib/feedtwin records the network.

Function Documentation

◆ _fake_config()

test_layerx_feeddiag._fake_config ( )

protected

Definition at line 418 of file test_layerx_feeddiag.py.

Referenced by test_cavitation_number_by_hand_and_flip_risk(), test_injector_velocities_momentum_ratio_and_tilt_by_hand(), test_ledger_rows_design_from_forward_delivered_from_the_burn(), and test_ledger_with_the_erosion_replay_off_reads_the_twins_chamber().

◆ _fake_engine()

test_layerx_feeddiag._fake_engine	(		p_O,
			p_F )

protected

mdot = c sqrt(p_line - Pc0), F = k (mdot_O + mdot_F): closed-form, so the feed solve has one.

Definition at line 573 of file test_layerx_feeddiag.py.

References max.

Referenced by _thrust_result().

◆ _fake_prep()

test_layerx_feeddiag._fake_prep ( res )

protected

What the diagnostics read off a prepared model: branch bores, node fluids, species.

Definition at line 402 of file test_layerx_feeddiag.py.

Referenced by test_a_dead_leg_held_at_atmosphere_is_not_graded(), test_cavitation_number_by_hand_and_flip_risk(), test_diagnostics_on_the_recorder_shape(), and test_saturation_margin_total_and_static_by_hand().

◆ _fed()

test_layerx_feeddiag._fed	(	p_out,
		K,
		side )

protected

Closed form of mdot = c sqrt(p_out - K mdot^2 - Pc0).

Definition at line 580 of file test_layerx_feeddiag.py.

Referenced by _thrust_result(), test_thrust_breakdown_acceleration_head_when_flown(), and test_thrust_breakdown_by_closed_form().

◆ _he()

test_layerx_feeddiag._he	(		p_psia,
			T_K )

protected

Definition at line 180 of file test_layerx_feeddiag.py.

Referenced by test_iec_capacity_by_hand_and_against_fluids(), test_iec_solenoid_drop_matches_the_audit_hand_check(), test_regulator_law_split_and_wide_open_by_hand(), and test_solenoid_share_of_regulator_to_tank_by_hand().

◆ _jt_by_integration()

test_layerx_feeddiag._jt_by_integration	(	fluid,
		p1,
		T1,
		p2,
		steps = 400 )

protected

dT along the isenthalp by integrating CoolProp's own Joule-Thomson coefficient (dT/dp)_h,
RK4 in pressure: a different path through the equation of state than the (p, h) flash.

Definition at line 303 of file test_layerx_feeddiag.py.

Referenced by test_joule_thomson_sign_and_magnitude().

◆ _lin()

test_layerx_feeddiag._lin	(		a,
			b )

protected

Definition at line 35 of file test_layerx_feeddiag.py.

Referenced by _synthetic().

◆ _recorder_style()

test_layerx_feeddiag._recorder_style ( res )

protected

lib/feedtwin's NetworkTrace puts ``<tank>.head`` (kind tank_head) on each path and calls a
drawn SOL main valve a solenoid. Reshape the synthetic stand the same way.

Definition at line 775 of file test_layerx_feeddiag.py.

Referenced by test_diagnostics_on_the_recorder_shape().

◆ _reg_target()

test_layerx_feeddiag._reg_target	(		p_in,
			mdot )

protected

Definition at line 247 of file test_layerx_feeddiag.py.

Referenced by test_regulator_law_split_and_wide_open_by_hand().

◆ _synthetic()

test_layerx_feeddiag._synthetic ( )

protected

Definition at line 39 of file test_layerx_feeddiag.py.

References _lin(), and max.

Referenced by test_a_dead_leg_held_at_atmosphere_is_not_graded(), test_cavitation_number_by_hand_and_flip_risk(), test_diagnostics_on_the_recorder_shape(), test_injector_velocities_momentum_ratio_and_tilt_by_hand(), test_ladder_elements_sum_to_end_to_end_and_head_is_a_gain(), test_ladder_reports_a_recorder_that_does_not_telescope(), test_ladder_without_network_is_unavailable_not_a_raise(), test_ledger_rows_design_from_forward_delivered_from_the_burn(), test_ledger_with_the_erosion_replay_off_reads_the_twins_chamber(), test_pressurant_budget_and_floor_by_hand(), test_regulator_law_split_and_wide_open_by_hand(), test_saturation_margin_total_and_static_by_hand(), and test_solenoid_share_of_regulator_to_tank_by_hand().

◆ _thrust_result()

test_layerx_feeddiag._thrust_result	(		K_drift = 0.0,
			accel = None )

protected

Definition at line 586 of file test_layerx_feeddiag.py.

References _fake_engine(), and _fed().

Referenced by test_thrust_breakdown_acceleration_head_when_flown(), and test_thrust_breakdown_by_closed_form().

◆ test_a_dead_leg_held_at_atmosphere_is_not_graded()

test_layerx_feeddiag.test_a_dead_leg_held_at_atmosphere_is_not_graded ( )

LE4 (3)'s capped LOX fill QD and its dump valve's outlet sit at 14.696 psia with no flow, LOX at
90.19 K on its own saturation line: -0.003 psi, amber on every LOX burn. A node no branch carries
flow through while firing is skipped and listed; the feed's own nodes are graded as before.

Definition at line 469 of file test_layerx_feeddiag.py.

References _fake_prep(), and _synthetic().

◆ test_cavitation_number_by_hand_and_flip_risk()

test_layerx_feeddiag.test_cavitation_number_by_hand_and_flip_risk ( )

Definition at line 494 of file test_layerx_feeddiag.py.

References _fake_config(), _fake_prep(), and _synthetic().

◆ test_diagnostics_on_the_recorder_shape()

test_layerx_feeddiag.test_diagnostics_on_the_recorder_shape ( )

Definition at line 795 of file test_layerx_feeddiag.py.

References _fake_prep(), _recorder_style(), and _synthetic().

◆ test_feed_diagnostics_on_the_le4_helium_burn()

test_layerx_feeddiag.test_feed_diagnostics_on_the_le4_helium_burn ( monkeypatch )

The baseline design on copv_study_he, pad, at AUDIT 9.6's 578 psia lockup and otherwise
default settings, with lib/feedtwin's network recorder on, against the hand checks of AUDIT
9.6-9.7 and the baseline (section 8).

Re-baselined 2026-10-07. The AUDIT's figures are the 2026-10-02 twin: adiabatic lines, the
578 psia lockup the default was then. Three things have moved them since, each deliberate:

* 2026-10-03 (night), line walls on (Layer X CHANGELOG): the press path's metal warms the gas
  the bottle's expansion cooled, so each ullage litre takes less helium. He used 0.0906 ->
  0.0818 kg; the bottle ends ~220 psi fuller, so the regulator's supply effect (17 psi/1000
  psi of inlet fall) is ~3.8 psi smaller and its outlet rise 47.1 -> 43.86 psi; the press flow
  at 0.5 s is 0.01105 kg/s of 304 K gas, not 0.01121 of 298 K, so the solenoid drops are
  1.704 / 1.393 psi (hand, Cv law at the twin's state: 1.7045 / 1.3935) and the regulator's
  peak use 14.3 %, not the AUDIT's 17.8 %.
* 2026-10-06, the ullage storage closure (a35563ce, ``Session._ullage_storage``): the
  momentum ratio's range 1.0283-1.0312 -> 1.0285-1.0315 (the press flow no longer held at the
  start-of-step tank pressure); with the closure stubbed out it returns, as does SV-LOX-PRESS's
  0.1 % (1.7060 -> 1.7045). The supply datum (35b98bf2) moves nothing here.
* 2026-10-07, the dome dial defaults to the drawn dome (b67edc93): 564.7 psia on this drawing.
  At that lockup every figure here moves (SV-LOX-PRESS 1.609 psi: 4.0 % less helium, 2.4 %
  thinner, dp ~ mdot^2/rho), and thrust never comes within 2 % of 7.2 kN. The lockup is stated
  below so the hand checks stay at the point they were made.

Definition at line 820 of file test_layerx_feeddiag.py.

References find(), max, and min.

◆ test_iec_capacity_by_hand_and_against_fluids()

test_layerx_feeddiag.test_iec_capacity_by_hand_and_against_fluids	(		p2_psia,
			choked )

Definition at line 191 of file test_layerx_feeddiag.py.

References _he(), and min.

◆ test_iec_solenoid_drop_matches_the_audit_hand_check()

test_layerx_feeddiag.test_iec_solenoid_drop_matches_the_audit_hand_check ( )

Definition at line 212 of file test_layerx_feeddiag.py.

References _he().

◆ test_injector_velocities_momentum_ratio_and_tilt_by_hand()

test_layerx_feeddiag.test_injector_velocities_momentum_ratio_and_tilt_by_hand ( )

Definition at line 533 of file test_layerx_feeddiag.py.

References _fake_config(), and _synthetic().

◆ test_joule_thomson_sign_and_magnitude()

test_layerx_feeddiag.test_joule_thomson_sign_and_magnitude	(		fluid,
			sign )

Definition at line 324 of file test_layerx_feeddiag.py.

References _jt_by_integration().

◆ test_ladder_elements_sum_to_end_to_end_and_head_is_a_gain()

test_layerx_feeddiag.test_ladder_elements_sum_to_end_to_end_and_head_is_a_gain ( )

Definition at line 125 of file test_layerx_feeddiag.py.

References _synthetic().

◆ test_ladder_reports_a_recorder_that_does_not_telescope()

test_layerx_feeddiag.test_ladder_reports_a_recorder_that_does_not_telescope ( )

Definition at line 157 of file test_layerx_feeddiag.py.

References _synthetic().

◆ test_ladder_without_network_is_unavailable_not_a_raise()

test_layerx_feeddiag.test_ladder_without_network_is_unavailable_not_a_raise ( )

Definition at line 168 of file test_layerx_feeddiag.py.

References _synthetic().

◆ test_ledger_rows_design_from_forward_delivered_from_the_burn()

test_layerx_feeddiag.test_ledger_rows_design_from_forward_delivered_from_the_burn ( )

Definition at line 678 of file test_layerx_feeddiag.py.

References _fake_config(), _synthetic(), and max.

◆ test_ledger_with_the_erosion_replay_off_reads_the_twins_chamber()

test_layerx_feeddiag.test_ledger_with_the_erosion_replay_off_reads_the_twins_chamber ( )

Nozzle erosion off (run 20261102-123645-807b98): no replay, no ``delivered``. The burn still
fired, on the twin's chamber; Pc, O/F, thrust, Isp and the flows read '—' in the Overview ledger.
They come from ``series.chamber`` and the sides' flows; what only the replay computes says why.

Definition at line 740 of file test_layerx_feeddiag.py.

References _fake_config(), and _synthetic().

◆ test_pressurant_budget_and_floor_by_hand()

test_layerx_feeddiag.test_pressurant_budget_and_floor_by_hand ( )

Definition at line 338 of file test_layerx_feeddiag.py.

References _synthetic().

◆ test_regulator_law_split_and_wide_open_by_hand()

test_layerx_feeddiag.test_regulator_law_split_and_wide_open_by_hand ( )

Definition at line 251 of file test_layerx_feeddiag.py.

References _he(), _reg_target(), and _synthetic().

◆ test_saturation_margin_total_and_static_by_hand()

test_layerx_feeddiag.test_saturation_margin_total_and_static_by_hand ( )

Definition at line 432 of file test_layerx_feeddiag.py.

References _fake_prep(), _synthetic(), and min.

◆ test_solenoid_share_of_regulator_to_tank_by_hand()

test_layerx_feeddiag.test_solenoid_share_of_regulator_to_tank_by_hand ( )

Definition at line 284 of file test_layerx_feeddiag.py.

References _he(), and _synthetic().

◆ test_thrust_breakdown_acceleration_head_when_flown()

test_layerx_feeddiag.test_thrust_breakdown_acceleration_head_when_flown ( )

Definition at line 652 of file test_layerx_feeddiag.py.

References _fed(), and _thrust_result().

◆ test_thrust_breakdown_by_closed_form()

test_layerx_feeddiag.test_thrust_breakdown_by_closed_form ( )

Definition at line 614 of file test_layerx_feeddiag.py.

References _fed(), _thrust_result(), and max.

Variable Documentation

◆ ATM_PSIA

float test_layerx_feeddiag.ATM_PSIA = 101325.0 / PSI

Definition at line 244 of file test_layerx_feeddiag.py.

◆ C_FLOW

dict test_layerx_feeddiag.C_FLOW = {"ox": 1.9 / math.sqrt(170.0 * PSI), "fuel": 1.25 / math.sqrt(160.0 * PSI)}

Definition at line 569 of file test_layerx_feeddiag.py.

◆ FIRING

list test_layerx_feeddiag.FIRING = [False, False, True, True]

Definition at line 32 of file test_layerx_feeddiag.py.

◆ K_THRUST

float test_layerx_feeddiag.K_THRUST = 2300.0

Definition at line 570 of file test_layerx_feeddiag.py.

◆ N

int test_layerx_feeddiag.N = 4

Definition at line 30 of file test_layerx_feeddiag.py.

◆ PC0

float test_layerx_feeddiag.PC0 = 400.0 * PSI

Definition at line 568 of file test_layerx_feeddiag.py.

◆ PSI

float test_layerx_feeddiag.PSI = 6894.757293168361

Definition at line 20 of file test_layerx_feeddiag.py.

◆ REG_PARAMS

dict test_layerx_feeddiag.REG_PARAMS

Initial value:

=  {
    "Cv": (0.8, "manufacturer: TB 1031"),
    "bore": (0.005842, "manufacturer: TB 1031"),
    "supply_coefficient": (0.017, "manufacturer: TB 1031"),
    "flow_droop": (8.3 * PSI, "measured"),
    "rated_flow": (0.09646, "measured"),
    "dome_bias": (50.0 * PSI, "manufacturer"),
    "dial": (528.25 * PSI, "Layer X dial"),
}

Definition at line 232 of file test_layerx_feeddiag.py.

◆ T

list test_layerx_feeddiag.T = [-0.1, 0.0, 0.05, 0.10]

Definition at line 31 of file test_layerx_feeddiag.py.

Functions

Variables

Detailed Description

Function Documentation

◆ _fake_config()

◆ _fake_engine()

◆ _fake_prep()

◆ _fed()

◆ _he()

◆ _jt_by_integration()

◆ _lin()

◆ _recorder_style()

◆ _reg_target()

◆ _synthetic()

◆ _thrust_result()

◆ test_a_dead_leg_held_at_atmosphere_is_not_graded()

◆ test_cavitation_number_by_hand_and_flip_risk()

◆ test_diagnostics_on_the_recorder_shape()

◆ test_feed_diagnostics_on_the_le4_helium_burn()

◆ test_iec_capacity_by_hand_and_against_fluids()

◆ test_iec_solenoid_drop_matches_the_audit_hand_check()

◆ test_injector_velocities_momentum_ratio_and_tilt_by_hand()

◆ test_joule_thomson_sign_and_magnitude()

◆ test_ladder_elements_sum_to_end_to_end_and_head_is_a_gain()

◆ test_ladder_reports_a_recorder_that_does_not_telescope()

◆ test_ladder_without_network_is_unavailable_not_a_raise()

◆ test_ledger_rows_design_from_forward_delivered_from_the_burn()

◆ test_ledger_with_the_erosion_replay_off_reads_the_twins_chamber()

◆ test_pressurant_budget_and_floor_by_hand()

◆ test_regulator_law_split_and_wide_open_by_hand()

◆ test_saturation_margin_total_and_static_by_hand()

◆ test_solenoid_share_of_regulator_to_tank_by_hand()

◆ test_thrust_breakdown_acceleration_head_when_flown()

◆ test_thrust_breakdown_by_closed_form()

Variable Documentation

◆ ATM_PSIA

◆ C_FLOW

◆ FIRING

◆ K_THRUST

◆ N

◆ PC0

◆ PSI

◆ REG_PARAMS

◆ T