Behaviour and modelling of non-spherical particles in compressible flows

• Applicant: Professor Dr. Berend van Wachem
• Subject Area: Fluid Mechanics ; Mechanical Process Engineering
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 447633787

• Final Report Year: 2025

Final Report Abstract

In this project we investigated the behavior of non-spherical particles in compressible flows, addressing a gap in particle-laden flow modeling. While previous studies focused on spherical particles in incompressible flows, this work explored the forces and torques on non-spherical particles in transonic and supersonic regimes, crucial for technologies such as cold spraying and transdermal drug injection. Particle-resolved direct numerical simulations (PR-DNS) were performed using body-fitted hexahedral meshes. Three particle shapes (a prolate spheroid, an oblate spheroid, and a rod-like particle) were analyzed across Mach numbers (0.3 to 2.0), angles of attack (0◦ to 90◦ ), and Reynolds numbers (100 to 300). Results show that particle shape significantly affects aerodynamic forces and flow behavior. Oblate spheroids exhibit the largest bow shocks, unstable wakes, and the highest drag, lift, and torque coefficients. As the Mach number increases, the drag coefficient increases sharply in the transonic regime before decreasing in the supersonic regime. Validated correlations for the aerodynamic forces and torque coefficients achieve median errors of 1–2%, enabling accurate point-particle simulations. The methodological advancements, including PR-DNS with body-fitted meshes and accurate aerodynamic correlations, represent a significant step forward in multiphase flow modeling. While this study focused on three specific particle shapes, the correlations and techniques can be extended to other shapes through interpolation or empirical approaches. This work provides a foundation for more accurate and more efficient designs in engineering applications involving non-spherical particles in compressible flows, opening pathways for advancements in fields such as cold spraying, drug delivery, and other particle-laden flow systems.

Publications

• A Unified Algorithm for Interfacial Flows with Incompressible and Compressible Fluids. Forum for Interdisciplinary Mathematics, 179-208. Springer Nature Singapore.
  Denner, Fabian & van, Wachem Berend
  
• A hybrid immersed boundary method for dense particle-laden flows. Computers & Fluids, 259, 105892.
  Chéron, Victor; Evrard, Fabien & van, Wachem Berend
  
• Data for the paper: Drag, lift and torque correlations for axisymmetric non-spherical particles in locally non-uniform flows
  V. Chéron, F. Evrard & B. van Wachem
  
• Data for the paper: Correlations for aerodynamic force coefficients of non-spherical particles in compressible flows
  C. Gorges, F. Denner, V. Chéron & B. van Wachem
  
• Data for the paper: Drag, lift, and torque correlations for axi-symmetric rod-like non-spherical particles in linear wall-bounded shear flow
  V. Chéron & B. van Wachem
  
• Drag, lift and torque correlations for axi-symmetric rod-like non-spherical particles in locally linear shear flows. International Journal of Multiphase Flow, 171, 104692.
  Chéron, Victor; Evrard, Fabien & van, Wachem Berend
  
• Drag, lift, and torque correlations for axi-symmetric rod-like non-spherical particles in linear wall-bounded shear flow. International Journal of Multiphase Flow, 179, 104906.
  Chéron, Victor & Wachem, Berend van
  
• Correlations for aerodynamic force coefficients of non-spherical particles in compressible flows, accepted for presentation at: 12th International Conference on Multiphase Flow, ICMF 2025, Toulouse, May 12 - 16 (2025)
  F. Denner, V. Chéron, A. Chopra, C. Gorges & B. van Wachem
  
• Correlations for aerodynamic force coefficients of non-spherical particles in compressible flows. International Journal of Multiphase Flow, 184, 105111.
  Gorges, Christian; Chéron, Victor; Chopra, Anjali; Denner, Fabian & van, Wachem Berend