Piotr Czyżewski
Turbomachinery Engineer — Compressor · Propulsion Engineering
Warsaw, Poland
Turbomachinery Engineer specializing in axial compressor aerodynamics. Primary expertise is multi-stage HPC design and off-design performance prediction using steady and unsteady CFD. Has led compressor map generation campaigns for both production engines and new development programs, and has experience integrating CFD predictions with system-level cycle models.
Expertise
- axial compressor aerodynamic design
- compressor map generation
- surge margin assessment
- VIGV schedule optimization
- rotor-stator interaction CFD
Technologies
Work History
2025-02
Rotor-stator interaction unsteady CFD for stage 3 of the HPC using ANSYS CFX time-marching with blade count scaling. Quantified blade passing frequency forcing on rotor 3 for HCF risk assessment.
Challenge: Blade count ratio of stage 3 rotor to stator (23:27) does not allow integer scaling without significant distortion. Used Fourier transformation phase-lagged boundary conditions — required careful validation against full-annulus reference solution.
Learned: Phase-lagged boundary conditions for rotor-stator interaction require validation against a full-annulus reference, especially for high count-ratio stages. The approximation error can be 10-15% of the unsteady pressure amplitude — non-negligible for HCF.
2024-05
Variable Inlet Guide Vane (VIGV) schedule optimization to maximize surge margin at part-speed while minimizing efficiency penalty at top-of-climb. Ran 48 CFD cases with varying VIGV angles at 3 speed lines.
Challenge: VIGV angle changes the inlet flow angle to stage 1 rotor, which shifts the stall point non-linearly. The optimal VIGV schedule at each speed line is non-obvious and cannot be estimated from 1D velocity triangles alone — requires full 3D CFD.
Learned: VIGV schedule optimization needs 3D CFD because the benefit is driven by 3D corner flow behavior, not just mean-line velocity triangles. Investing in the full CFD campaign paid off with 4% additional surge margin vs. the 1D estimate.
2023-10
Tip clearance sensitivity study for stage 4 and 5 rotor rows — quantified efficiency and pressure ratio change per 0.1 mm tip gap increment. Provided clearance budget recommendations for mechanical design team.
Challenge: Meshing sensitivity at small tip clearances was a major issue — ANSYS TurboGrid required manual intervention for clearances below 0.3 mm to avoid degenerate cells. Developed a parameterized mesh script that automatically adjusts tip block distribution based on clearance value.
Learned: Tip clearance meshes are highly sensitive to block topology. Automating the mesh parametrization up front saves significant time when running clearance sweeps — do not try to manually re-mesh for each clearance value.
2023-04
Compressor performance map generation for a 7-stage HPC using ANSYS CFX steady-state mixing-plane simulations. Covered the full operating range from choke to near-stall at 4 corrected speed lines.
Challenge: Near-stall operating points regularly diverged due to the formation of corner separations in the rear stages. Used a continuation method — start from a converged mid-speed solution and march toward stall in small steps — reducing divergence rate from 60% to 8% of near-stall points.
Learned: Compressor map generation near stall requires a robust continuation strategy. Direct initialization at stall conditions from free-stream is almost always divergent. Small parametric steps from a converged interior point is the reliable approach.