Investigation of the Turbulence Modeling Effects on the CFD Predictions of Passenger Vehicle Underhood Airflow

Zhang, Chunhui; Uddin, Mesbah; Foster, Lee

doi:10.4271/2018-01-0476

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…11, ρc p U ∇ T 2 /2 represents the heat transport caused by the movement of air micro-clusters in the process of convective heat transfer, ∇ (λT ∇T ) represents the diffusion of entransy in the air, and −λ|∇T | 2 is the entransy dissipation. In the equilibrium equation of entransy, the change of entransy is equal to the sum of entransy flow and entransy dissipation (Zhao et al, 2019;Chen et al, 2019). From the expression of entransy dissipation in the core flow region of the passages in the compartment, it is found that in order to enhance convective heat transfer the entransy dissipation of air in the core flow region must be small.…”

Section: Tfhmentioning

confidence: 99%

“…The design of the cabin structure is not guided by the theoretical results of the multi-field coupling enhancement heat dissipation. Further, current research on improving engine compartment structures to enhance convective heat transfer mainly focuses on engine compartments for passenger cars (Zhang et al, 2018), buses (Shen et al, 2013) and heavy trucks (Yang et al, 2015;Vegendla et al, 2018;Pan et al, 2010) with traditional fuel, while the study of clean gas engine compartments with higher cabin temperatures is less involved. At the same time, although the technology on optimizing cooling systems is relatively mature, but most studies are based on the criterion of cooling airflow rates.…”

Section: Introductionmentioning

confidence: 99%

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Application of the multi-field coupling enhanced heat transfer principle to the engine compartment design of clean gas bus

2020

Mech. Sci.

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Abstract. Clean gas engines, such as liquefied petroleum gas (LPG) engines, have high thermal loads on parts under equivalent specific combustion. This study examines the multi-field coupling enhanced heat transfer principle and its applications to the engine compartment of a typical LPG city bus. The field synergy enhanced heat transfer principle (FSP) was applied in the radiator assembly area. The FSP model yielded an optimum velocity -temperature gradient matching field that would improve convective heat transfer in this area. To strengthen the convective heat transfer ability of the limited cooling air in the cabin, temperature field homogenization (TFH) in the core flow region of the engine block area was achieved. The TFH optimization model helped minimize the temperature gradient in the core flow region and maximize it at the heat transfer boundary, and the optimum vector field and flow path were obtained. More comprehensive changes to the structural design were made according to the multi-field coupling enhanced heat transfer principles. The simulation results showed that in the comprehensive structure, the heat transfer efficiency of the radiator increased by 14.66 %, the average temperature of the air passages in the engine block area decreased by 22.23 %, and the heat dissipation coefficient of the engine body and engine cover increased by 4.60 times and 3.49 times, respectively.

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Section: Tfhmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of the multi-field coupling enhanced heat transfer principle to the engine compartment design of clean gas bus

2020

Mech. Sci.

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“…Initial structural vulnerabilities identified through analysis are addressed through reinforcement strategies, such as adjusting weld sizes or adding bracing to enhance strength. Subsequent phases involve iterative analysis and design modifications until alignment with WSC specifications is achieved [11,12,13,14]. This research aspires to contribute to the ongoing evolution of solar-powered transportation systems, aligning with the objectives of the World Solar Challenge, and addressing contemporary challenges prevalent in the racing industry.…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of Solar Car Chassis for WSC 2023

Nakphan,

Khawlaor,

Chotikunnan

2023

ijmst

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The World Solar Challenger is a biennial global competition that plays a crucial role in testing and advancing the technological limits of solar-powered vehicles, particularly in the context of diverse travel conditions. The competition features three categories: Challenger Class, Cruiser Class, and Adventure Class. In 2023, Siam Technology University participated with the STC-4 model in the Cruiser Class. This research contributed to the vehicle's design, structural integrity, safety, and performance evaluation, essential for passing the scrutineering tests. Researchers were involved in shaping the vehicle's aerodynamics, analyzing structural aspects, and designing safety features compliant with World Solar Challenge 2023 requirements. The goal was to ensure the vehicle's safe participation and successful operation under varied conditions. The designed solar-powered vehicle, STC-4, aimed to address shortcomings from previous competitions. The structural framework, utilizing AISI 4130 steel, met safety standards, with a final weight of 258 kg. Structural testing ensured that the displacement did not exceed 25 mm. Finite Element Analysis confirmed the structural integrity, aligning with the team's objectives. In conclusion, this research significantly contributed to the design and safety aspects of solar-powered vehicles, as demonstrated by the successful participation of STC-4 in the World Solar Challenge 2023 Cruiser Class. The findings highlight advancements in structural design, safety measures, and performance capabilities, emphasizing the importance of continuous innovation in solar vehicle technology.

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“…As SAS approaches have shown suitable prediction accuracy at a much reduced computational cost, they remain a favored tool for the racing industry [1,[8][9][10]. It is therefore critically important that a suitable turbulence model is selected and that proper solver parameters are chosen [2,3,11].…”

Section: Introductionmentioning

confidence: 99%

On the Effectiveness of Scale-Averaged RANS and Scale-Resolved IDDES Turbulence Simulation Approaches in Predicting the Pressure Field over a NASCAR Racecar

Misar

Davis

Uddin

2023

Fluids

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Racecar aerodynamic development requires well-correlated simulation data for rapid and incremental development cycles. Computational Fluid Dynamics (CFD) simulations and wind tunnel testing are industry-wide tools to perform such development, and the best use of these tools can define a race team’s ability to compete. With CFD usage being limited by the sanctioning bodies, large-scale mesh and large-time-step CFD simulations based on Reynolds-Averaged Navier–Stokes (RANS) approaches are popular. In order to provide the necessary aerodynamic performance advantages sought by CFD development, increasing confidence in the validity of CFD simulations is required. A previous study on a Scale-Averaged Simulation (SAS) approach using RANS simulations of a Gen-6 NASCAR, validated against moving-ground, open-jet wind tunnel data at multiple configurations, produced a framework with good wind tunnel correlation (within 2%) in aerodynamic coefficients of lift and drag predictions, but significant error in front-to-rear downforce balance (negative lift) predictions. A subsequent author’s publication on a Scale-Resolved Simulation (SRS) approach using Improved Delayed Detached Eddy Simulation (IDDES) for the same geometry showed a good correlation in front-to-rear downforce balance, but lift and drag were overpredicted relative to wind tunnel data. The current study compares the surface pressure distribution collected from a full-scale wind tunnel test on a Gen-6 NASCAR to the SAS and SRS predictions (both utilizing SST k−ω turbulence models). CFD simulations were performed with a finite-volume commercial CFD code, Star-CCM+ by Siemens, utilizing a high-resolution CAD model of the same vehicle. A direct comparison of the surface pressure distributions from the wind tunnel and CFD data clearly showed regions of high and low correlations. The associated flow features were studied to further explore the strengths and areas of improvement needed in the CFD predictions. While RANS was seen to be more accurate in terms of lift and drag, it was a result of the cancellation of positive and negative errors. Whereas IDDES overpredicted lift and drag and requires an order of magnitude more computational resources, it was able to capture the trend of surface pressure seen in the wind tunnel measurements.

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Investigation of the Turbulence Modeling Effects on the CFD Predictions of Passenger Vehicle Underhood Airflow

Cited by 5 publications

References 24 publications

Application of the multi-field coupling enhanced heat transfer principle to the engine compartment design of clean gas bus

Application of the multi-field coupling enhanced heat transfer principle to the engine compartment design of clean gas bus

Design and Analysis of Solar Car Chassis for WSC 2023

On the Effectiveness of Scale-Averaged RANS and Scale-Resolved IDDES Turbulence Simulation Approaches in Predicting the Pressure Field over a NASCAR Racecar

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