TurboDesigner

The open-source turbomachinery designer

Axial Compressor

Axial Casing

Axial Rotor

About

TurboDesigner is a parametric turbomachinery design tool that takes high-level thermodynamic inputs (pressure ratio, mass flow rate, RPM, etc.) and produces:

1. Mean-line thermodynamic analysis — stage-by-stage temperature, pressure, and velocity calculations
2. Blade flow analysis — spanwise velocity distributions via free-vortex theory, metal angle computation with empirical deviation correlations
3. 3D CAD geometry — fully parametric blade, shaft, and casing models exported as STEP files

Currently focused on axial compressors, with plans to support axial turbines and turbopumps for liquid rocket engines.

Architecture

Module	Description
Turbomachinery	Top-level compressor model: overall pressure ratio, efficiency, stage count, inlet conditions
Stage	Single compressor stage: temperature rise, reaction, rotor + stator blade rows
FlowStation	Thermodynamic state at a station: total/static T & P, velocity triangles, Mach number, density
BladeRow	Blade row geometry: aspect ratio, solidity, metal angles, airfoil profiles at multiple span stations
Vortex	Spanwise velocity distribution (currently Free Vortex: $r \cdot c_\theta = \text{const}$)
MetalAngles	Blade metal angle data: incidence, deviation, camber, and stagger (computed by Johnsen-Bullock or equals-flow-angles methods)

CAD Modules

Module	Description
AxialCompressorCadModel	Full CAD assembly orchestrator: builds shaft + casing in parallel via multiprocessing
ShaftCadModel	Shaft/disk stage geometry: rotor disk, blade slots, stage-connect fastener holes
CasingCadModel	Outer casing stage geometry: casing shell, stator blade slots, clamp fastener holes
BladeCadModel	Single blade row: lofted 3D airfoil with optional fir-tree root attachment
BillOfMaterials	Part list generation: fasteners, blades, disks, casings with quantities per stage

Features

• Vortex methods: Free Vortex (constant work distribution)
• Airfoil types: Double Circular Arc
• Deviation models: Johnsen-Bullock empirical correlation, zero-deviation (metal = flow angles)
• CAD generation: Lofted 3D blades, shaft/disk, outer casing with clamps, fir-tree blade root attachments
• Parallel CAD builds: Multiprocessing with tessellation caching for fast iteration
• CLI: Full command-line interface for design management, analysis, and CAD export
• JSON analysis export: Auto-serialization with unit metadata annotations

Assumptions

• Ideal gas thermodynamic model
• Constant mean-line radius (set by hub-to-tip ratio)
• Blade calculations based on the mean radius station
• Free vortex spanwise distribution (more methods planned)
• Airfoil geometry limited to DCA and NACA 65 profiles

Installation

pip install turbodesigner

CAD Geometry Support

CAD commands (turbodesigner cad ...) require CadQuery, which depends on the OpenCASCADE kernel. If your system already has a compatible CadQuery installed, add it as an extra:

pip install "turbodesigner[cq]"

Otherwise, install CadQuery via conda first (recommended — handles the native OCC dependency):

# Install CadQuery (required for CAD geometry support)
conda install -c conda-forge -c cadquery cadquery=master

pip install turbodesigner

Development Setup

git clone --recurse-submodules https://github.com/OpenOrion/turbodesigner.git
cd turbodesigner
pip install -e ".[test,cq]"

Design Input

Designs are defined as JSON files with the following structure:

{
  "machine_type": "axial",
  "configuration": "compressor",
  "definition": {
    "gamma": 1.4,
    "axial_velocity": 136,
    "rpm": 10000,
    "gas_constant": 287,
    "mass_flow_rate": 4.37,
    "pressure_ratio": 3.0,
    "inlet_total_pressure": 101000,
    "inlet_total_temperature": 288,
    "isentropic_efficiency": 0.878,
    "num_stages": 5,
    "stage_temperature_rise": "equal",
    "stage_reaction": [0.5, 0.5, 0.5, 0.5, 0.5],
    "inlet_blockage": 0.0,
    "outlet_blockage": 0.0,
    "hub_to_tip_ratio": 0.5,
    "num_streams": 9,
    "aspect_ratio": {"rotor": 3.0, "stator": 3.25},
    "spacing_to_chord": {"rotor": 1.0, "stator": 1.0},
    "max_thickness_to_chord": {"rotor": 0.1, "stator": 0.1},
    "row_gap_to_chord": 0.25,
    "stage_gap_to_chord": 0.5
  }
}

Per-stage arrays are supported for non-uniform designs (e.g., higher reaction at inlet stages, variable aspect ratios).

CLI Usage

TurboDesigner includes a Click-based CLI for design management, analysis, and CAD generation:

# Design management
turbodesigner axial compressor design create <name> --from <json>
turbodesigner axial compressor design list
turbodesigner axial compressor design show <name>
turbodesigner axial compressor design export <name> <path>
turbodesigner axial compressor design schema          # Print the JSON schema
turbodesigner axial compressor design report           # Generate analysis report

# Analysis (requires an active design via `design use <name>`)
turbodesigner axial compressor analyze machine         # Overall machine parameters
turbodesigner axial compressor analyze stages          # Stage-by-stage summary
turbodesigner axial compressor analyze flow-stations   # All flow station properties
turbodesigner axial compressor analyze blade-rows      # Blade geometry per row

# CAD generation
turbodesigner axial compressor cad blade <N> <rotor|stator>  # Single blade row
turbodesigner axial compressor cad shaft               # Shaft/disk assembly
turbodesigner axial compressor cad casing              # Outer casing
turbodesigner axial compressor cad assembly            # Full compressor assembly
turbodesigner axial compressor cad annulus             # Flow annulus visualization

The --json flag goes on the root command for structured output:

turbodesigner --json axial compressor analyze machine

CAD commands accept --complex (high-fidelity geometry with fasteners) and --no-visualize (visualization is on by default).

Workspace state is persisted in a .turbodesigner/ directory (similar to .git).

Outputs

TurboDesigner generates the following artifacts in .turbodesigner/designs/<name>/output/:

Output	Description
shaft-stage-{N}.step	STEP file for each shaft/disk stage
casing-stage-{N}.step	STEP file for each casing stage
blade-{N}-rotor.step	Individual rotor blade STEP file
blade-{N}-stator.step	Individual stator blade STEP file
BOM.csv	Bill of materials (generated during cad assembly)
report.ipynb	Jupyter notebook with full design analysis
report.html	HTML export of the analysis report

BOM.csv

Generated during cad assembly. Columns: Part, Quantity, Category, Component. Includes all fasteners (heatsets, screws), blades, shaft disks, casing sections, and clamps with per-stage quantities.

Reports

Generated via turbodesigner axial compressor design report <name>. Produces a Jupyter notebook and HTML report containing:

• Machine overview (pressure ratio, efficiency, RPM)
• Stage-by-stage thermodynamic properties
• Flow station velocity triangles and Mach numbers
• Annulus visualization (hub/tip radii)
• Blade row geometry (scalars and per-stream distributions)

Python API

from turbodesigner.turbomachinery import Turbomachinery
from turbodesigner.cad.compressor import AxialCompressorCadModel
from pathlib import Path

# Load a design
machine = Turbomachinery.from_file("tests/designs/mark1.json")

# Access computed properties
print(f"Overall temperature rise: {machine.overall_temperature_rise:.1f} K")
print(f"Outlet pressure: {machine.outlet_flow_station.total_pressure:.0f} Pa")

# Inspect a stage
stage = machine.stages[0]
print(f"Stage 1 rotor inlet Mach: {stage.rotor.flow_station.mach_number}")

# Generate CAD (STEP export)
turbomachinery = machine.to_cad_export()
results = AxialCompressorCadModel.build_all(
    turbomachinery,
    output_dir=Path("/tmp/turbodesigner"),
    is_complex=True,
    visualize=True,
)
print("Shaft STEP files:", results["shaft"])
print("Casing STEP files:", results["casing"])

Running Tests

pip install -e ".[test,cq]"
python -m pytest tests/ -v

Help Wanted

Contributions are welcome in the following areas:

• Verifying thermodynamic calculations against published data
• CFD validation of generated geometries
• Additional vortex distributions (forced vortex, exponential)
• Axial turbine support

Join the Discord for collaboration