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Innovative spherical turbulator configurations for enhanced solar air heater performance: A numerical and analytical study

Author

Listed:
  • Bisht, Vijay Singh
  • Singh, Desh Bandhu
  • Kumar, Pushpendra
  • Jain, Supriya
  • Bhandari, Prabhakar
  • Mumtaz, Mohd Aamir
  • Rahman, Mohammod Hafizur

Abstract

This study presents a detailed numerical and analytical assessment of solar air heaters (SAHs) enhanced with spherical turbulent promoters arranged in five distinct geometrical configurations—V-shaped, inclined, arc-shaped, W-shaped, and multi-V. The numerical simulations were performed in ANSYS FLUENT using the RNG k–ε turbulence model, while the analytical evaluation was conducted in MATLAB. The design parameter, relative roughness pitch (P/D), was varied between 3 and 9, and the Reynolds number (Re) ranged from 3500 to 23,500. Results reveal that the V-shaped configuration consistently outperforms other designs, achieving the highest thermohydraulic performance parameter (THPP) of 2.005 at P/D = 3, whereas the inclined arrangement shows the lowest performance. The arc-shaped configuration records the highest Nusselt number (Nu = 178) at Re = 23,500, but with the greatest frictional losses. Post-processing analysis of velocity vectors, streamlines, absorber plate temperature profiles, and turbulence kinetic energy contours indicates that the V-shaped arrangement generates symmetrical flow disturbances, promoting periodic breakdown of the laminar sublayer and enhancing convective heat transfer. The velocity, turbulence kinetic energy, and local wall heat transfer coefficient contours indicate that the turbulence generated by different sphere arrangements effectively disrupts the boundary layer, resulting in a significant improvement in the SAH's heat transfer performance. Analytical results further confirm that the V-shaped configuration attains the highest effective efficiency (ηeff = 76.02 %) and exergetic efficiency (ηex = 2.5 %), while inclined and W-shaped arrangements exhibit greater irreversibility as reflected in their Bejan numbers. Empirical correlations for the Nusselt number and friction factor were developed for all configurations, enabling predictive performance modeling. Comparative benchmarking against previously published designs demonstrates that the V-shaped spherical turbulator delivers the most favorable trade-off between heat transfer enhancement and pressure drop. These findings establish the V-shaped configuration as the optimal choice for improving the thermohydraulic efficiency of SAHs, offering significant potential for energy-efficient solar thermal applications.

Suggested Citation

  • Bisht, Vijay Singh & Singh, Desh Bandhu & Kumar, Pushpendra & Jain, Supriya & Bhandari, Prabhakar & Mumtaz, Mohd Aamir & Rahman, Mohammod Hafizur, 2026. "Innovative spherical turbulator configurations for enhanced solar air heater performance: A numerical and analytical study," Energy, Elsevier, vol. 342(C).
    • Handle: RePEc:eee:energy:v:342:y:2026:i:c:s0360544225052430
    DOI: 10.1016/j.energy.2025.139601
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    References listed on IDEAS

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