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Projecte llegit

Títol: Study and Optimization of Semi-Trailer Truck Aerodynamics for Emissions Reduction

Estudiants que han llegit aquest projecte:

Director/a: ARIAS CALDERÓN, SANTIAGO

Departament: FIS

Títol: Study and Optimization of Semi-Trailer Truck Aerodynamics for Emissions Reduction

Data inici oferta: 06-03-2025     Data finalització oferta: 06-11-2025


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
Tipus: Individual
 
Lloc de realització: Fora UPC    
 
        Supervisor/a extern: Àlex de la Cruz Gargallo
        Institució/Empresa: IDIADA
        Titulació del Director/a: Master of Science in Engineering Design
 
Paraules clau:
Semi-trailer truck, Drag reduction, Emissions reduction, Computational Fluid Dynamics (CFD)
 
Descripció del contingut i pla d'activitats:
This project is carried out as a Bachelor's Final Project in Aerospace Systems Engineering at the School of Telecommunications and Aerospace Engineering of Castelldefels (EETAC), which is part of the Polytechnic University of Catalonia (UPC). In this study, the aerodynamics of cargo trailers are optimised to achieve a reduction in truck emissions. The design of aerodynamic appendages is detailed using CAD software, followed by analysis in a CFD tool. Due to the lack of resources that a student has, it is not possible to achieve a very precise simulation. That is caused by the limitation in terms of computation that a conventional computer has. The time of the numerical simulation increases significantly with the number of nodes that are needed to compute. Therefore, within this project an aproximation with low-cost resources will be performed. The CFD tool selected is ANSYS Fluent. The methodology to ensure a realistic simulation is also specified and compared with previous professional simulations in the industry. Finally, the reduction in aerodynamic drag is assessed. Using this data, the model is introduced into the European Union's VECTO tool to calculate emissions. This reduction is then analysed to determine whether it meets the requirements for EURO VI compliance. Therefore, some objectives and steps have to be followed to arrive at the final result: Identify the emission targets for the coming years. Study what the VECTO tool takes into account when calculating emissions (not in detail), focusing on the annex related to AirDrag. Analyse the current devices used to reduce aerodynamic drag in trailers. If possible, obtain CAD models of these devices. Additionally, obtain the generic CAD model used by the European Union, if available. Determine which CFD tool will be used in the project to begin learning and familiarisation. Two parallel tasks: Study how the chosen CFD tool works. Acquire the necessary knowledge to later test improvements or modifications made to the aerodynamic devices. Investigate how the existing aerodynamic devices could be improved. Analyse the aerodynamic behaviour of a trailer without any aerodynamic devices. Identify its shortcomings and potential for improvement. Implement the proposed improvements in CAD software. Use the newly designed CAD parts in the tool to assess whether they positively contribute to the trailer's performance. Design vortex generators in CAD software. Integrate this device into the trailer and evaluate its aerodynamic impact using the CFD tool. Justify, using VECTO, the extent to which emissions have been reduced (considering only the improved devices, as the new ones cannot be analysed).To sum up, the project will include the step by step process that is followed in order to understand, analyze, and upgrade the aerodynamic behavior of cargo trucks in a flow of air. At the same time, the CFD simulations will be endorsed by mesh specifications and with the comparison with a professional simulation done at IDIADA's installations. The results will be traduced into emissions in order to check if the modifications done help the different trailer manufacturers to meet with the emission levels stated in Euro VI.
 
Overview (resum en anglès):
Emissions are increasingly becoming one of the key parameters for automobile design and marketing. In the heavy-duty transport industry, the issue becomes complex as the behaviour of trucks on the road is affected by large and non-aerodynamic geometries. This project uses the CFD tool Ansys to simulate flow around semi-trailer trucks, with the objective of understanding the key aerodynamic aspects of the truck geometry and optimizing its drag performance.

The European Union (EU) provides the geometries that shall be simulated. The added geometries that are used in order to redirect the flow around the truck and improve the drag experienced by the semi-trailer are called aerodynamic appendixes. The appendixes tested during the work are the Tall Rear Flaps (TRF), implemented at the rear part of the trailer as deflectors, and the Long Side Covers (LSC), implemented at the lateral lower parts of the trailer and preventing the flow to enter the truck's bottom part.

This project proposed CFD method can be validated by the EU itself if it meets the requirements imposed for the simulation setup. Therefore, the simulations done during the project are evaluated with the objective of satisfying those EU guidelines. The evaluation starts with a 2D analysis that studies the dependence of the mesh, domain size, time step for transient simulations, and boundary conditions on the simulation results. Then, a 3D study is done in which all the valuable knowledge learned during the 2D study about the tool and the problem that is being simulated is put into practice.

During the 3D stage, the proposed aerodynamic appendixes are implemented and optimized so as to achieve the maximum possible drag reduction. After the optimization of the deflection angle of the TRF, a 0.52% of drag relative reduction is achieves in relation to the original proposed EU geometry. Combined with the LSC geometry, a total of more than a 9% of drag reduction was accomplished with respect to the trailer without appendixes.

In addition, tests are performed using a non-frequently used geometry concept called teardrop. Using this geometry, which gives the flow a more progressive surface to pass through, results are even slightly better than those proposed by the EU, without using any TRF and also achieving a drag reduction of more than 9%.

Finally, the data is entered into the EU tool called VECTO, which estimates that this aerodynamic reduction translates into a reduction of more than 3% in both fuel consumption and CO2 emissions. This result is scaled to a large fleet of trucks, resulting in a reduction of 20,000,000 kg of CO2 emitted into the atmosphere per year and contributing to the reduction of the carbon footprint of heavy transport. Moreover, the enterprises using those appendixes in the fleet would be saving 10.6 million euros, as the result of the 7.4 liters of fuel being saved annually.

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