engine.pipeline.feed_loss Namespace Reference

Functions
float	colebrook_darcy (float Re, float eD)
float	darcy_friction_factor (float Re, float eD)
float	fittings_K (FeedSystemConfig config)
float	delta_p_feed (float mdot, float rho, FeedSystemConfig config, float P_tank, Optional[float] mu=None)

Variables
	_fluids_friction_factor = None
	_log = logging.getLogger(__name__)
bool	_warned_no_mu = False
float	LAMINAR_TRANSITION_PIPE = 2040.0

Detailed Description

Generalized feed system pressure loss model with K_eff(P)

For twin balanced parallel runs each with nominal diameter ``d_line``, set YAML
``A_hydraulic = 2 × π (d_line/2)²`` with ``d_inlet`` omitted (the schema derives the equal-area
bore) so bulk velocity halves vs a single tube at fixed ṁ.

See constants: ``FEED_LINE_DUAL_3_8_EQUIVALENT_D_INLET_M`` and
``FEED_LINE_DUAL_3_8_EQUIVALENT_A_HYDRAULIC_M2`` for two 3/8″ lines.

Function Documentation

colebrook_darcy()

float engine.pipeline.feed_loss.colebrook_darcy	(	float	Re,
		float	eD )

Darcy f from Colebrook-White, 1/sqrt(f) = -2 log10(eD/3.7 + 2.51/(Re sqrt(f))).

Solved to machine precision by fixed-point iteration on x = 1/sqrt(f) from the Haaland
(1983) explicit start. This is the fallback for when ``fluids`` is not importable; the
tests hold it to fluids.friction.Colebrook. Laminar (Re < 2040) returns 64/Re, as
fluids.friction.friction_factor does.

Definition at line 31 of file feed_loss.py.

Referenced by darcy_friction_factor().

darcy_friction_factor()

float engine.pipeline.feed_loss.darcy_friction_factor	(	float	Re,
		float	eD )

Darcy friction factor: fluids.friction.friction_factor (Clamond's exact Colebrook
solution) when fluids is installed, colebrook_darcy() otherwise.

Definition at line 54 of file feed_loss.py.

References _fluids_friction_factor, and colebrook_darcy().

Referenced by delta_p_feed().

delta_p_feed()

float engine.pipeline.feed_loss.delta_p_feed	(	float	mdot,
		float	rho,
		FeedSystemConfig	config,
		float	P_tank,
		Optional[float]	mu = None )

Calculate feed system pressure loss using generalized K_eff(P) model.

Δp_feed = K_eff(P) × (ρ/2) × (ṁ/(ρ×A_hyd))²  +  K_exit × (ρ/2) × (ṁ/(ρ×A_exit))²

where K_eff(P) = K_base + ΣK_fittings + K1 × φ(P), K_base = K0, or (roughness_m set and mu
given) K_entrance + f L/d_inlet with Darcy f from Colebrook-White at Re = ρ v d_inlet/μ;
and the second term is the exit bore's velocity head
dumped into the manifold (Borda-Carnot; K_exit = 1 for a plenum). P_tank minus this is the
still-manifold pressure that drives the orifices.

Parameters:
-----------
mdot : float
    Mass flow rate [kg/s]
rho : float
    Fluid density [kg/m³]
config : FeedSystemConfig
    Feed system configuration
P_tank : float
    Tank pressure [Pa] (used for pressure-dependent K_eff)
mu : float, optional
    Liquid dynamic viscosity [Pa s]. Needed only by the friction path (``roughness_m``
    set): K0 is replaced by K_entrance + f L/d_inlet with Colebrook f at
    Re = rho v d_inlet / mu. Without mu that path cannot run and the K0 path is used
    (logged once).

Fittings (``config.fittings``) add to K_eff on either path.

Returns:
--------
delta_p : float
    Pressure loss [Pa]

Definition at line 76 of file feed_loss.py.

References darcy_friction_factor(), fittings_K(), and max.

fittings_K()

float engine.pipeline.feed_loss.fittings_K

(

FeedSystemConfig

config

)

Sum of the itemised fitting K's (line velocity heads); 0.0 when none are declared.

engine/accel/params.py folds this into K0 for the kernel, so the order of summation here
is the order there.

Definition at line 64 of file feed_loss.py.

Referenced by delta_p_feed().

Variable Documentation

_fluids_friction_factor

engine.pipeline.feed_loss._fluids_friction_factor = None

protected

Definition at line 21 of file feed_loss.py.

Referenced by darcy_friction_factor().

_log

engine.pipeline.feed_loss._log = logging.getLogger(__name__)

protected

Definition at line 23 of file feed_loss.py.

_warned_no_mu

bool engine.pipeline.feed_loss._warned_no_mu = False

protected

Definition at line 24 of file feed_loss.py.

LAMINAR_TRANSITION_PIPE

float engine.pipeline.feed_loss.LAMINAR_TRANSITION_PIPE = 2040.0

Definition at line 28 of file feed_loss.py.