sepehr
3358b74342
Ship the Next.js cycle editor with CAD chrome, technical HX symbols, Fixed/Free boundary guidance, and secondary water/air pressure drop support in the solver stack. Co-authored-by: Cursor <cursoragent@cursor.com>
3.7 KiB
BphxEvaporator / BphxCondenser (Brazed Plate HX)
Config types: "BphxEvaporator", "BphxCondenser"
Source: crates/components/src/heat_exchanger/bphx_evaporator.rs, bphx_condenser.rs, shared geometry/correlation helpers
EN
Purpose & model
Brazed-plate HX with geometry + two-phase correlation → h → UA estimate, then runtime solve on an inner ε-NTU residual model.
Correlations (selectable)
Default Longo 2004. Also Shah 1979, Shah 2021.
Full registry (also Kandlikar, Gungor–Winterton, Gnielinski, Dittus–Boelter, Ko 2021, Friedel ΔP): see correlations-and-maps.md.
Equivalent Reynolds construction (schematic):
Re_l = G · d_h / μ_l
Re_eq = Re_l · (1 − x + x · √(ρ_l / ρ_v))
Longo-style Nu (illustrative forms used in the implementation path):
Evaporation: Nu ~ f(Re_eq, Pr_l) (e.g. 0.05 · Re_eq^0.8 · Pr_l^0.33)
Condensation: Nu ~ f(Re_eq, Pr_l, ρ*) (e.g. 1.875 · Re_eq^0.35 · Pr_l^0.33 · …)
h = Nu · k_l / d_h
UA_est = h · A · z_ua
Pressure drop (schematic):
ΔP = z_dp · 2 · f · L · G² / (ρ · d_h)
Important: the Newton system residuals for the component are the inner ε-NTU residual set (n_equations of the inner model, typically 2 for the base HX path). The correlation updates UA (when update_ua_from_htc / geometry path is engaged); it is not a full multi-zone moving-boundary residual stack.
Modes / targets
| Type | Mode | Notes |
|---|---|---|
BphxEvaporator |
DX only | Outlet is superheated vapor. target_superheat_k (default 5 K) is diagnostic/target storage — not a flooded shell model. For flooded shell-and-tube use FloodedEvaporator. |
BphxCondenser |
Subcooling target | target_subcooling_k (default 3 K) |
Ports
4-port Modelica-style naming in the system graph when wired:
| Port | Role |
|---|---|
inlet / outlet |
Refrigerant |
secondary_inlet / secondary_outlet |
Secondary fluid |
Geometry fields: plate length/width, thickness, chevron, channel spacing, optional dh_m / area_m2 overrides.
Calibration
| Key | Meaning | Default |
|---|---|---|
z_ua / Z_UA |
UA scale | 1.0 |
z_dp / Z_dpc |
ΔP scale | 1.0 |
ua explicit |
sets z_ua = ua / UA_nom |
– |
Legacy f_ua / f_dp accepted in JSON.
JSON parameters (main)
| Key | Meaning | Default |
|---|---|---|
n_plates |
plate count | 20 |
plate_length_m / plate_width_m |
geometry | – |
chevron_angle_deg |
chevron | 60 |
correlation |
Longo2004 / Shah1979 / Shah2021 | Longo2004 |
target_superheat_k |
DX target (evap) | 5 K |
target_subcooling_k |
SC target (cond) | 3 K |
refrigerant / secondary_fluid |
fluids | – |
z_ua, z_dp |
calib | 1.0 |
DoF / system usage
Prefer live secondary wiring for closed loops. Pair z_ua free + measured SST/SDT for inverse calibration (same Fixed/Free discipline as other HX).
FR
But & modèle
Échangeurs à plaques brasées : géométrie + corrélation biphasique (Longo 2004 / Shah) → coefficient h → UA, puis solveur sur modèle ε-NTU interne.
Formes types :
Re_eq = Re_l · (1 − x + x · √(ρ_l/ρ_v))
Nu = f(Re_eq, Pr, …) # Longo / Shah selon `correlation`
h = Nu · k / d_h
UA = h · A · z_ua
Le Newton ne résout pas la corrélation plaque par plaque : il résout le HX ε-NTU ; la corrélation calibre/estime UA.
Modes
- BphxEvaporator : DX uniquement (pas un flooded shell).
- BphxCondenser : cible de sous-refroidissement.
Calibration
z_ua = 1, z_dp = 1 par défaut. Alias BOLT Z_UA, Z_dpc.
Ports / JSON
Voir tableaux EN.