Compact Axial Hydraulic Turbine — Integrated Turbomachinery Design

Hydraulic sizing · CAD & structural verification · CFD · electromechanical conversion · additive-manufacturing prototyping · industrialisation

This repository documents the end-to-end engineering design of a compact axial (Kaplan-type) hydraulic turbine, carried out as a multidisciplinary study (Bureau d'Etudes) at Arts et Metiers ParisTech (ENSAM). The project follows a single design thread from first principles to an industrial deployment scenario:

1. Hydraulic preliminary sizing in MATLAB, using similarity parameters and a digitised Cordier diagram.
2. Blade-row and CAD modelling in CATIA V5, with a preliminary finite-element check of the blade root.
3. CFD analysis in STAR-CCM+ (moving-reference-frame, steady segregated flow) to extract power, efficiency, and cavitation-risk trends.
4. Electromechanical conversion: a surface-mounted permanent-magnet synchronous generator pre-sized analytically and cross-checked with FEMM/OctaveFEMM, driving a PWM voltage-source converter modelled in SIMBA.
5. Additive-manufacturing prototyping (FFF, PLA) and wind-tunnel testing as a reduced-scale aerodynamic analogue of the hydraulic runner.
6. Industrialisation study: production planning, make-or-buy, location strategy, and a discounted business case for a 167-unit modular fleet.

The full write-up is included in docs/Compact_Axial_Hydraulic_Turbine_Report.pdf.

This was a team project (group GIE2-ED2, Semester 7): Dev Kumar, Thien Ho, Seyf Daab, Wilhem Abboura, supervised by Christophe Sarraf, Florent Ravelet, Pascal Caestecker, and Jean-Frederic Charpentier. This repository packages the MATLAB, FEMM, and SIMBA source files together with the consolidated report for portfolio purposes; the FEMM base template (electromagnetic/femm) was originally provided by J.-F. Charpentier and parameterised here for the project's operating point.

flowchart LR
    A[Cordier diagram\nsimilarity sizing] --> B[Velocity triangles\n+ blade mean line]
    B --> C[Modified NACA\nthickness law]
    C --> D[CATIA V5\nsurface + solid CAD]
    D --> E[Blade root FEA\nscreening]
    D --> F[STAR-CCM+ CFD\nmoving reference frame]
    F --> G[PMSM generator\nsizing + FEMM check]
    G --> H[PWM converter\n+ d-q current control\n SIMBA]
    D --> I[FFF prototype\n+ wind-tunnel test]
    F --> J[Industrialisation\n+ business case]

The runner is sized from the engineering specific speed and the Cordier diagram:

Nsq = N * sqrt(qv) / H^0.75          (specific speed)
Omega = pi * Nsq / (30 * g^0.75)     (dimensionless specific angular velocity)

with the design point N = 1500 rpm, N_sq = 200, H = 3.8 m, q_v = 0.132 m³/s, giving an outer radius R_e = 0.103 m and a hub radius R_i = 0.039 m (hub-to-tip ratio 0.38).

Local velocity triangles then follow from the Euler turbine equation:

U(r)      = omega * r
Cu2_th(r) = -g*H / U(r)
beta_1(r) = atan( U(r) / Ca )
beta_2(r) = atan( (U(r) - Cu2(r)) / Ca )

The generator's average electromagnetic torque follows from the fundamental air-gap flux density and the linear current loading:

<Cem> = sqrt(2) * B1 * A * V * cos(Psi)          (V = bore volume, A = linear current loading)

which is maximised for Ψ = 0 (current aligned with the EMF). The associated PWM converter is analysed for carrier-frequency sensitivity and closed-loop d-q current control.

.
├── docs/
│   └── Compact_Axial_Hydraulic_Turbine_Report.pdf   # full write-up
├── matlab/
│   ├── hydraulic_sizing/     # Cordier sizing, velocity triangles, blade geometry, CATIA export
│   └── data_reduction/       # test-bench characteristic curves, affinity-law scaling
├── electromagnetic/
│   └── femm/                 # OctaveFEMM parametric PMSM field/flux/inductance script
├── simulink_simba/           # PWM converter + d-q current-control model (SIMBA)
├── cad/                      # STEP fluid-domain geometry used for the CFD study
├── data/                     # test-bench characteristic-curve dataset (multi-speed)
└── assets/                   # figures used in this README

Final blade-row geometry exported from the hydraulic sizing script	Blade-root equivalent-stress distribution (finite-element screening)
FFF-printed PLA runner prototype	Prototype installed in the recirculating wind-tunnel test section

matlab/hydraulic_sizing/main_turbine_sizing.m      % full sizing pipeline + CATIA point-cloud export
matlab/hydraulic_sizing/fit_naca_thickness.m       % modified NACA thickness-law identification (requires an XFoil point-save file)
matlab/hydraulic_sizing/cordier_digitisation.m     % Cordier-diagram specific-radius lookup
matlab/data_reduction/characteristic_curve_reduction.m   % reduces data/RIM_test_bench_data.xlsx into head/efficiency curves and BEPs
matlab/data_reduction/affinity_law_scaling.m       % turbine affinity-law speed scaling example

The FEMM script (electromagnetic/femm/pmsm_femm_field_analysis.m) requires a local FEMM installation and the OctaveFEMM/MATLAB toolbox. Set the FEMM_MFILES environment variable to FEMM's mfiles directory before running; the script no longer assumes a machine-specific Windows path or modifies MATLAB's global path.

The SIMBA model (simulink_simba/pwm_converter_speed_control.jsimba) can be opened directly in SIMBA.

This project is released under the MIT License.

Dev Kumar · dev-kumar.com · contact@dev-kumar.com