Turbulence Model Comparison and Optimal Geometry Identification in Trapped Vortex Combustors: A RANS-based Study

Strategic Insights -

Researchers at the Department of Mechanical Engineering have conducted a detailed numerical investigation of the flow dynamics and turbulence characteristics in a Trapped Vortex Combustor (TVC). The study aimed to evaluate the predictive accuracy of three turbulence models - Reynolds Stress Model (RSM), Realizable k-epsilon, and SST-k omega - in capturing pressure drop, recirculation behavior, and flow structure across various Reynolds numbers and cavity geometries. The results revealed that the RSM model offered the highest accuracy, with a maximum deviation of 12.1%, compared to 23.9% and 26.7% for SST-k omega and Realizable k-epsilon, respectively. The analysis also showed that increasing the Reynolds number by 300% intensified turbulence levels ten-fold and strengthened recirculation zones three-fold, without altering the overall vortex structure.

Key Takeaways:

  • The study utilized three turbulence models - Reynolds Stress Model (RSM), Realizable k-epsilon, and SST-k omega - to evaluate their predictive accuracy in capturing pressure drop, recirculation behavior, and flow structure in a Trapped Vortex Combustor (TVC).
  • The results showed that the RSM model offered the highest accuracy, with a maximum deviation of 12.1%, compared to 23.9% and 26.7% for SST-k omega and Realizable k-epsilon, respectively.
  • The analysis revealed that increasing the Reynolds number by 300% intensified turbulence levels ten-fold and strengthened recirculation zones three-fold, without altering the overall vortex structure.
  • An optimal cavity aspect ratio (H/Df approximate to 0.6) was identified, producing two dominant vortices and minimizing pressure loss.
  • The study highlighted the importance of turbulence model selection and cavity design in enhancing combustor performance and offered guidance for the preliminary design of efficient, low-pressure-loss propulsion systems.
  • The research concluded that the RSM model is the most suitable choice for predicting flow dynamics and turbulence characteristics in a TVC, especially at high Reynolds numbers.

Statistics:

  • Maximum deviation of 12.1% for the RSM model compared to 23.9% and 26.7% for SST-k omega and Realizable k-epsilon, respectively.
  • Intensification of turbulence levels ten-fold and strengthening of recirculation zones three-fold when Reynolds number is increased by 300%.
  • Optimal cavity aspect ratio (H/Df approximate to 0.6) identified for producing two dominant vortices and minimizing pressure loss.
  • 30000 cells used in ANSYS Fluent as the optimal grid size for balancing accuracy and computational cost.

Sources:

  • Turbulence Model Comparison and Optimal Geometry Identification In Trapped Vortex Combustors: a Rans-based Study. International Journal of Modern Physics C, 2025.
  • World Scientific Publ Co Pte Ltd, 5 Toh Tuck Link, Singapore 596224, Singapore.
  • Department of Mechanical Engineering, Dr Dy Patil Inst Technol, Dept. of Mechanical Engineering, Pune 411018, Maharashtra, India.
  • Authors: Anant Sidhappa Kurhade, Gulab Dattrao Siraskar, Shital Yashwant Waware, Govindarajan Murali, M. Arul Prakash, N. Bharathiraja, and Dipa Dattatray Dharmadhikari.
  • Keywords: Maharashtra, India, Asia, Physics, Department of Mechanical Engineering.