PipelineStudio (LPS / TGNET & TLNET)

ModelScript provides first-class, polyglot support for Emerson / Energy Solutions PipelineStudio, including its dual simulation kernels:

• TGNET (Transient Gas Network): Compressible gas hydraulics, real-gas equations of state (AGA-8 Detailed Characterization & Peng-Robinson), line pack dynamics, compressor stations, gas heating value tracking, and hydrogen blending.
• TLNET (Transient Liquid Network): Incompressible/liquid hydraulics, multi-product batch tracking (gasoline/diesel/jet fuel interfaces), transmix dispersion, pump stations, drag-reducing agents (DRA), and water hammer / acoustic surge analysis.

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Supported File Formats

Format	Extension	Description
PipelineStudio Project	.lps, .xml	Complete graphical network model defining nodes, pipes, compressor stations, pump stations, regulators, and study scenarios.
TGNET Gas Study	.tgx, .psg	Dedicated compressible gas transmission network studies with gas composition and line pack profiles.
TLNET Liquid Study	.tlx, .psl	Dedicated liquid transmission network studies with batch injection schedules and fluid property libraries.
Legacy Keyword Decks	.tgn, .tln	Standard industrial keyword decks specifying network geometry, equipment ratings, and boundary conditions.

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3-Tier Execution Architecture

ModelScript implements a 3-tier operational execution framework for pipeline networks:

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1. Tier 1: In-WASM DAE Solvers

• Zero Intermediate Allocations: Lowers directly into ModelScript's DAEBuilder linear memory arena.
• High-Accuracy Thermodynamics:
  • AGA-8 (ISO 20765-1): High-precision calculation of compressibility factor $Z(P,T,\mathbf{y})$, molar density, speed of sound, and Joule-Thomson cooling.
  • Hydrogen Blending: Native support for $H_2$ blending in natural gas from 0% to 100%, capturing density drop, speed of sound increases, and compressor power shifts.
  • Peng-Robinson Cubic EOS: General flash calculation for heavy hydrocarbons and dense-phase supercritical $C{O}_2$ pipeline transport.
• Transient Compressible Gas Dynamics:
  • Solves 1D staggered-grid continuity and momentum equations:$$\frac{\partial P}{\partial t}=-\frac{a^2}{A}\frac{\partial w}{\partial x}$$$$\frac{\partial w}{\partial t}=-A\frac{\partial P}{\partial x}-\frac{fw|w|}{2\rho DA}-\rho gA\sin \theta$$
  • Simulates dynamic line packing, demand drafting, and decompression acoustic waves.
• Water Hammer & Surge Analysis:
  • Solves Joukowsky acoustic wave propagation ($\mathrm{\Delta }P=\rho a\mathrm{\Delta }v$) during rapid emergency shutdown (ESD) valve closures and pump trips.
  • Monitors transient pressure spikes against ASME B31.4 limits ($P\le 1.1\times \text{MAOP}$) and screens for liquid column separation / cavitation.
• Multi-Product Liquid Batch Tracking:
  • Tracks discrete fuel slugs (Diesel, Regular Gasoline, Jet-A) along transmission pipelines.
  • Austin-Palfrey interface mixing length and transmix volume calculation at delivery manifold cut-points.

2. Tier 2: Gas-Power Sector Coupling & Co-Simulation

Enables cross-vector energy system co-simulation via FMI 2.0/3.0 and SSP:

• Coupled with @modelscript/psse: Simulates how rapid ramp-up of gas-fired combined-cycle power plants (CCGTs) draws on pipeline line pack, ensuring minimum delivery pressures are sustained during electric grid peaks.
• Coupled with @modelscript/pscad: Evaluates fast sub-second electrical generator trips and their acoustic pressure waves on pipeline fuel supply manifolds.
• Power-to-Gas: Simulates green hydrogen injection from wind/solar electrolyzers into regional gas grids.

3. Tier 3: Industrial Engine Orchestration

Automates invocation of local Emerson PipelineStudio CLI engines (tgnet.exe / tlnet.exe), dynamically ingesting results into ModelScript for unified verification.

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Pre-Flight Pipeline Diagnostic Linter

12 rules6 error6 warning Run with msx lint

Code	Rule	Severity	Message
M8001	maop-exceeded	error	Pipe '<pipeName>' operating pressure (<value> bar) exceeds Maximum Allowable Operating Pressure (<value> bar).
M8002	compressor-surge-hazard	error	Compressor '<compName>' operating flow (<value> m\xB3/h) is below the aerodynamic surge limit (<value> m\xB3/h).
M8003	compressor-stonewall-limit	warning	Compressor '<compName>' throughput (<value> m\xB3/h) approaches sonic choke/stonewall limit (<value> m\xB3/h).
M8004	unconnected-pipeline-node	error	Node '<nodeName>' is isolated and has no connecting pipes or equipment links.
M8005	delivery-pressure-deficit	error	Delivery node '<nodeName>' is hydraulically unreachable from any supply or storage cavern.
M8006	erosional-velocity-hazard	warning	Gas velocity in pipe '<pipeName>' (<value> m/s) exceeds API RP 14E erosional limit (<value> m/s).
M8007	liquid-column-separation	error	Transient pressure in pipe '<pipeName>' (<value> bar) drops below liquid vapor pressure (<value> bar), risking cavitation.
M8008	hydrogen-embrittlement-risk	warning	Hydrogen blend fraction in pipe '<pipeName>' (<value>%) exceeds 10% on steel without fracture toughness certification.
M8009	batch-transmix-excess	warning	Batch transmix interface on pipe '<pipeName>' exceeds allowable contamination threshold: <detail>.
M8010	joule-thomson-freezing	warning	Joule-Thomson throttling across regulator '<regName>' reduces outlet temperature to <value>\xB0C, risking ice/hydrate blockage.
M8011	pump-npsh-deficit	error	Pump '<pumpName>' net positive suction head available (<value> m) is below required NPSHr (<value> m).
M8012	line-pack-depletion-risk	warning	Network total line pack is depleting rapidly: <detail>.

Generated from languages/lps/src/errors.ts. All languages →

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Programmatic Usage

import {
  parseLps,
  lintLpsModel,
  SteadyNetworkSolver,
  LinePackEngine,
  GasEulerDaeSolver,
  lpsToSysml2,
  PipelineVerifier,
} from "@modelscript/lps";

// 1. Ingest PipelineStudio XML or ASCII keyword deck
const model = parseLps(sourceText);

// 2. Run Pre-Flight Diagnostic Linter
const diagnostics = lintLpsModel(model);

// 3. Solve Steady-State Network Hydraulics
const steady = SteadyNetworkSolver.solve(model);

// 4. Evaluate Line Pack Storage & Deliverability Reserves
const linePack = LinePackEngine.analyze(model, steady);
console.log(`Total Line Pack: ${(linePack.totalLinePackSm3 / 1e6).toFixed(2)} MMSm3`);
console.log(`Energy Stored: ${linePack.totalEnergyStoredGWh.toFixed(1)} GWh`);

// 5. Verify Formal Safety & MAOP Compliance
const report = PipelineVerifier.verifySteady(model, steady);
console.log("Verification passed:", report.passed);

// 6. Simulate 1D Transient Dynamics
const trajectory = GasEulerDaeSolver.simulate(model, {
  durationSeconds: 7200,
  timeStep: 10,
});

// 7. Generate Formal SysML v2 Architecture
const sysmlCode = lpsToSysml2(model);

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Advanced Machinery, Thermodynamics & Physical Models

1. Multi-Wheel Compressor Maps & Anti-Surge Control

ModelScript supports non-dimensional head-flow parameterization ($\mathrm{\Psi }$ vs $\mathrm{\Phi }$) for multi-stage centrifugal compressors:

• Affinity Scaling: Speed governor modulates $\omega \in [{\omega }_{min},{\omega }_{max}]$ to maintain target discharge pressure setpoints.
• Surge Line & Anti-Surge Recycle Valve: Parabolic surge locus detection with automatic recycle valve modulation maintaining a minimum $10\mathrm{\%}$ safety buffer.
• Stonewall (Choke): Detects maximum volumetric throughput beyond which sonic shock waves restrict further flow.

2. Centrifugal Pump Station Curves & NPSH Verification

Centrifugal pipeline booster pumps are modeled via cubic polynomial head $H(Q)$ and hydraulic efficiency $\eta (Q)$ curves with variable frequency drive (VFD) affinity scaling:

$$H(Q,\alpha )={\alpha }^2{H}_{\text{rated}}(Q/\alpha ),\alpha =\omega /{\omega }_{\text{rated}}$$

• Computes Net Positive Suction Head Available ($NPSHA$) against liquid vapor pressure.
• Triggers diagnostic M8011 if $NPSHA<NPSHR(Q)$, preventing catastrophic impeller cavitation.

3. GERG-2008 Helmholtz Free-Energy EOS (ISO 20765-2)

Implements the multi-fluid Helmholtz free-energy formulation $\alpha (\delta ,\tau )={\alpha }^0(\delta ,\tau )+{\alpha }^r(\delta ,\tau )$ for 21 natural gas components:

• Covers gas, liquid, supercritical dense phase, LNG cryogenic, and hydrogen blending regimes.
• Computes speed of sound $w$, isobaric heat capacity $C_p$, isochoric heat capacity $C_v$, and Joule-Thomson coefficient ${\mu }_{JT}$.

4. Slack Line Open-Channel Gravity Flow in Steep Pipelines

For pipelines traversing mountain passes with steep downward slopes, liquid column separation occurs when pressure drops to liquid vapor pressure ($P\le P_{\text{sat}}$):

• Transitions from pressurized pipe flow to open-channel gravity flow governed by the Manning-Gauckler-Strickler equation ($Q=\frac{1}{n}A{R}_h^{2/3}{S}^{1/2}$).
• Tracks dynamic void fraction ${\alpha }_{\text{void}}(x,t)=1-A_{\text{flow}}/A_{\text{pipe}}$ and calculates slack collapse re-pressurization surge spikes upon valley impact.

5. 1D Radial Cylindrical Soil Thermal Conduction Mesh

Discretizes the ground surrounding buried transmission pipelines into a 10-layer concentric radial cylindrical finite-difference mesh:

• Solves ${\rho }_{\text{soil}}{c}_{\text{soil}}\frac{\partial T}{\partial t}=\frac{1}{r}\frac{\partial }{\partial r}(k_{\text{soil}}r\frac{\partial T}{\partial r})$.
• Captures ground thermal inertia, depth-dependent seasonal phase lag, and pipeline cooldown following emergency station shutdowns.

6. Station Supervisory Multi-Variable PID Overrides

SCADA compressor and pump station automation with min/max auctioneering selector gates:

• Arbitrates between discharge pressure control, low-suction override, driver shaft power limits, and flow dispatch.
• Integrates velocity PID controllers with anti-windup tracking, synchronizing inactive integrator loops to prevent reset overshoot during control transfer.

7. Hot-Start State Checkpointing (.sav / .rst)

Zero-copy state snapshot serialization with SHA-256 integrity verification:

• Saves all nodal pressures, pipe mass flows, fluid temperatures, soil thermal layers, and controller integrator states.
• Enables instantaneous resumption of multi-day transient simulations and what-if contingency branching.

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Command-Line Interface (msx lps)

# Pre-flight safety linting
msx lps lint network.lps

# Steady-state hydraulics with slack line & soil thermal analysis
msx lps solve network.lps --slack --soil --eos=GERG2008

# Line pack inventory & deliverability buffer
msx lps linepack network.lps

# Transient simulation with hot-start checkpointing
msx lps simulate network.lps --duration=7200 --step=10 --save-checkpoint=state.sav

# Resume simulation from intermediate snapshot
msx lps simulate network.lps --duration=3600 --restart=state.sav

# Export formal SysML v2 architectural model
msx lps sysml network.lps -o network.sysml