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>
72 lines
2.8 KiB
Markdown
72 lines
2.8 KiB
Markdown
# Modelica Fixed/Free — sources consulted (Entropyk alignment)
|
||
|
||
## Official MSL (fetched)
|
||
|
||
1. **Package** `Modelica.Fluid.Sources`
|
||
https://doc.modelica.org/om/Modelica.Fluid.Sources.html
|
||
|
||
2. **`MassFlowSource_T`** — prescribed **mass flow + temperature** (not pressure)
|
||
https://doc.modelica.org/om/Modelica.Fluid.Sources.MassFlowSource_T.html
|
||
|
||
Quote from OpenModelica HTML (fetched 2026-07-17):
|
||
|
||
> Models an ideal flow source, with prescribed values of flow rate, temperature…
|
||
> - Prescribed mass flow rate.
|
||
> - Prescribed temperature.
|
||
|
||
No “prescribed pressure” in the component description.
|
||
|
||
3. **`Boundary_pT`** — prescribed **pressure + temperature** (not ṁ)
|
||
https://doc.modelica.org/om/Modelica.Fluid.Sources.Boundary_pT.html
|
||
|
||
Quote (fetched 2026-07-17):
|
||
|
||
> - Prescribed boundary pressure.
|
||
> - Prescribed boundary temperature.
|
||
|
||
4. **Context7** `/modelica/modelicastandardlibrary` — `SimplePipeline` example:
|
||
|
||
`Boundary_pT` → `StaticPipe` (wall friction / ΔP) → `Boundary_pT`
|
||
|
||
Double Fixed P is legal **only** with hydraulic resistance between the ends.
|
||
An isobaric secondary path must **not** Fixed-P both ends.
|
||
|
||
## Community
|
||
|
||
Rene Just Nielsen — legal pipe-end combinations:
|
||
https://stackoverflow.com/questions/79349553/how-pressure-and-flow-ports-are-different-in-modelica
|
||
|
||
| Inlet | Outlet | OK? |
|
||
|-------|--------|-----|
|
||
| Boundary_pT | Boundary_pT | Yes → ṁ from ΔP |
|
||
| Boundary_pT | MassFlowSource_T | Yes |
|
||
| MassFlowSource_T | Boundary_pT | Yes |
|
||
| MassFlowSource_T | MassFlowSource_T | **No** |
|
||
|
||
Quote: *“There is no boundary component specifying both mass flow rate and pressure.”*
|
||
|
||
## Entropyk mapping
|
||
|
||
| Mode | Source | Sink | HX secondary |
|
||
|------|--------|------|--------------|
|
||
| MassFlowSource_T (default) | Fixed T, Fixed ṁ, **Free P** | Fixed P (anchor), Free T_out | `P_out−P_in+ΔP_sec(ṁ)=0` |
|
||
| Boundary_pT + friction | Fixed P, Fixed T, Free ṁ | Fixed P | Needs frictional ΔP (pipe / HX) |
|
||
| T_out rating | Free ṁ, Free P | Fixed P + Fixed T_out | Same secondary momentum |
|
||
|
||
Secondary water ΔP (quadratic, Modelica `dp_nominal` style):
|
||
`secondary_rated_pressure_drop_pa` + `secondary_rated_m_flow_kg_s`
|
||
— **not** refrigerant `dp_model=msh` (tube two-phase only).
|
||
|
||
### Why HX secondary isobaric P was missing (bug)
|
||
|
||
Entropyk stores **two edges** on a water loop (`source→HX`, `HX→sink`), each with its own `P`.
|
||
Without `P_out − P_in = 0` on the HX, Free P on the source left `P_in` unconstrained → DoF under by 1 per loop.
|
||
|
||
Modelica closes that via the connection/pipe graph; Entropyk now closes it on Condenser / Evaporator / FloodedEvaporator secondary residuals.
|
||
|
||
Implementation:
|
||
|
||
- UI: `apps/web/src/lib/boundaryFix.ts`
|
||
- Components: `condenser.rs`, `evaporator.rs`, `flooded_evaporator.rs` (`n_secondary` + residuals)
|
||
- Ledger: `apps/web/src/lib/dofLedger.ts`
|