Investigation of Wall Heat Transfer Models applied to HPDI Engines

Topic: Thesis Seminar - Amartya Prusty
Time: Sep 22, 2025 01:00 PM Stockholm

MSc thesis seminar by Amartya Prusty. The work has been carried out at Volvo Cars.
Title : Investigation of Wall Heat Transfer Models applied to HPDI Engines

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Abstract:
Impinging jets are widely employed in engineering applications due to their high heat transfer capability, with particular relevance to internal combustion engines. However, accurate prediction of near-wall transport remains a challenge, as it strongly depends on turbulence modeling and wall heat transfer formulations. In this work, computational fluid dynamics simulations of impinging jet configurations were performed and systematically compared against experimental data and previous studies to assess the performance of different turbulence models and wall treatments. The study focused on the RNG k–ε model, as it is the primary choice for industrial combustion simulations and therefore serves as the benchmark for evaluation. In the canonical cold case, this model accurately captured mean velocity distributions, but underpredicted heat transfer at the stagnation point and overpredicted wall shear stress. Furthermore, none of the models reproduced the secondary Nusselt peak characteristic of H/D = 2. In the hot case, the RNG k–ε model consistently underpredicted heat transfer, with slope deviations traced to limitations in turbulence transport representation rather than insufficient wall-parallel velocities. An angled jet configuration further highlighted the role of turbulence redistribution in shaping heat flux trends. For the engine case, the Nusselt number distribution resembled that of canonical impinging jets, but was highly transient due to pulsed injection and strongly influenced by flame front propagation.