Browse Topic: Computational fluid dynamics (CFD)

Items (981)

3D-CFD Simulations of H2 ICEs: A Preliminary Evaluation of a Laminar Flame Speed Correction for Thermo-Diffusive Instability

2024-32-007404/18/2025

In recent years, climate change and geopolitical instability have intensified the focus on sustainable power generation. This shift seeks alternatives that balance environmental impact, cost-effectiveness, and practicality. Specifically, in transportation and power generation, electric motors face challenges against internal combustion engines due to the high cost and mass of batteries required for energy storage. This makes electric solutions less favorable for these sectors. Conversely, internal combustion engines, when properly fueled, offer cost-effectiveness and a quasi-environmentally-neutral option. To address these challenges, researchers have explored e-fuels derived from renewable sources as a carbon-neutral supply for internal combustion engines. Among these, hydrogen is particularly promising. In hydrogen-powered internal combustion engines, 3D-CFD (Computational Fluid Dynamics) in-cylinder models are crucial. Once validated, these models can speed up the design process. A

Sfriso, Stefano, Berni, Fabio, Breda, Sebastiano, Fontanesi, Stefano, Cordisco, Ilario, Leite, Caio Ramalho, Brequigny, Pierre, Foucher, Fabrice

Representative Point of Measurement of Engine ECU and Effect of Vortices and Ambient Wall on Forced Air-Cooling

2024-32-003604/18/2025

The Electric Control Unit (ECU) is a crucial computing unit responsible for engine regulating various functions. However, non-airflow thermal design due to the complexity of engine bay turbulent flow simulation is limiting ECU’s potential with the increasing demand of computation power consumption, thermal design faced additional challenges. Moreover, the lack of standardized ECU design guidelines forced substantial investments in customized thermal solutions for different engine bay packaging. Through this research, the method of finding representative points of ambient temperature efficiently and reliably is investigated, so that thermal design can be achieved by estimating flow properties during the ECU design stage efficiently. This research involves studying the effects of airflow on ECU cooling using experimental and numerical analysis in Computational Fluid Dynamics (CFD). Alongside the representative points of ambient temperature uncovered from the numerical result

Zhong, Jiajun, Inaba, Kazuaki, Yamaguchi, Ryota, Yasui, Ryuta, Umeno, Masafumi

DoE-Based Numerical Optimization of Intake and Exhaust Port Geometry of a Small Opposed-Piston 2-Stroke (OP2S) Hydrogen Engine

2024-32-005404/18/2025

The future potential of an opposed-piston two-stroke (OP2S) engine has attracted the attention of researchers worldwide as it offers a high thermal efficiency and power-to-weight ratio with a simple engine configuration. This engine can be used with low-carbon fuels and hydrogen to reduce greenhouse gas emissions. However, the two-stroke operation has always been limited by its low scavenging efficiency and short-circuit of fresh charge. The current work is focused on optimizing scavenging efficiency and short-circuit in a small 200 cc single-cylinder OP2S SI engine using 3-D computational fluid dynamic (CFD) simulations. The effect of four parameters, namely, area of intake ports, area of exhaust ports, and angular orientations of intake ports (swirl and tilt) on scavenging efficiency and short-circuit, has been assessed and optimized. A Latin-hypercube based Design of Experiments (DoE) methodology is used to sample the design space spanning over a range of four parameters. A response

Singh, Saurabh, Boggavarapu, Prasad, Himabindu, M., Ravikrishna, R.V.

Machine-Learning-Accelerated Simulations for the Design of Airbag Constrained by Obstacles at Rest

2023-22-0001

03/04/2024

Abstract Predicting airbag deployment geometries is an important task for airbag and vehicle designers to meet safety standards based on biomechanical injury risk functions. This prediction is also an extraordinarily complex problem given the number of disciplines and their interactions. State-of-the-art airbag deployment geometry simulations (including time history) entail large, computationally expensive numerical methods such as finite element analysis (FEA) and computational fluid dynamics (CFD), among others. This complexity results in exceptionally large simulation times, making thorough exploration of the design space prohibitive. This paper proposes new parametric simulation models which drastically accelerate airbag deployment geometry predictions while maintaining the accuracy of the airbag deployment geometry at reasonable levels; these models, called herein machine learning (ML)-accelerated models, blend physical system modes with data-driven techniques to accomplish fast

Valenzuela del Rio, Jose E., Lancashire, Richard, Chatrath, Karan, Ritmeijer, Peter, Arvanitis, Elena, Mirabella, Lucia

Machine-Learning-Accelerated Simulations for the Design of Airbag Constrained by Obstacles at Rest

2023-22-0001-TEST-REC03/04/2024

Valenzuela del Rio, Jose E., Lancashire, Richard, Chatrath, Karan, Ritmeijer, Peter, Arvanitis, Elena, Mirabella, Lucia

Study of Critical Vias Design Parameters for Power Electronics Thermal Management

2024-26-031701/16/2024

With the advent of wide band gap semiconductor devices like SiC based MOSFETs/Diodes, there is a growing demand for utilizing electrical power instead of the conventional fuel-based power generation in both automotive and aerospace industry. In automotive/aerospace industry the focus on electrification has resulted in a need for sub-systems like inverters, power distribution units, motor controllers, DC-DC converters that actively utilize SiC based power electronics devices. To address the growing power density requirements for electronics in next generation product families, more efficient & reliable thermal management solution plays a critical role. The effective thermal management of the power electronics is also critical aspect to ensure overall system reliability. The conventional thermal management system (TMS) optimization targets heat sink/ cold plate design parameters like fin spacing, thickness, height etc. or sizing of the required cooling pump/fan. This paper focuses on

Bhardwaj, Divyanshu, Patil, Sachin, Datta, Sauradeep, Pawar, Sunny, Dougherty, Derek

3-D Multiphase Flow Simulation of Coolant Filling and Deaeration Processes in an Engine Coolant System

2024-26-031001/16/2024

The thermal performance of an engine coolant system is efficient when the engine head temperature is maintained within its optimum working range. For this, it is desired that air should not be entrapped in the coolant system which can lead to localized hot spots at critical locations. However, it is difficult to eliminate the trapped air pockets completely. So, the target is to minimize the entrapped air as much as possible during the coolant filling and deaeration processes, especially in major components such as the radiator, engine head, pump, etc. The filling processes and duration are typically optimized in an engine test stand along with design changes for augmenting the coolant filling efficiency. However, it is expensive and time-consuming to identify air-entrapped locations in tests, decide on the filling strategy and make the design changes in the piping accordingly. In the current effort, a simulation-based testing method for coolant filling and deaeration processes is

Khandagale, Vitthal, Pasunurthi, Shyam Sundar, Maiti, Dipak, Bollu, Theja, Saha, Rohit

Lubrication Effectiveness Determination for Wet-Sump Transmissions using Multiphase Computational Fluid Dynamics Modeling

2024-26-029801/16/2024

Wet-sump transmissions are widely used in heavy duty and medium duty vehicles. As these transmissions do not have a dedicated forced lubrication system, it is important that the gear train, shafts, and enclosure are designed appropriately so that enough oil splashes to critical locations to ensure sufficient lubrication. The lubrication effectiveness of such transmissions can be studied through detailed tests or numerical simulations. Often, the vehicle, and therefore the transmission, encounters some severe operating conditions, such as climbing on an incline, driving downhill, etc. Studying these conditions through tests is an expensive process and this imposes the need for an analysis first approach. In this paper, 3D multiphase Volume of Fluid (VOF) method is used to examine two such extreme cases: an 8-degree tilted installation of transmission in a vehicle, and an inclined condition of transmission during 10-degree uphill climb. By studying the oil volume fraction on gears and

r, Shamini, Sachdeva, Aniket, Handa, Joji, Sena, Carlos, Marson, Luigi

Qualitative and Quantitative Correlation Study for Exterior Aerodynamics for Automotive Vehicle

2024-26-026201/16/2024

The main objective of the external aerodynamic performance assessment of automotive vehicles is to reduce the aerodynamic drag, which improves overall energy consumption of the vehicle. Almost 40% of the energy is required to overcome the drag force offered by the air on the automotive vehicle. With the increase in high performance computing power (HPC) and its affordability, computational fluid dynamics (CFD) has become a popular and more effective tool for aerodynamic design and analysis in the automobile industry. In the real-world scenario, automotive vehicle is subjected to varying wind and operating conditions which affect its aerodynamic characteristics, and therefore it is difficult to reproduce such physical phenomenon in a conventional wind tunnel. Hence, the entire aerodynamic assessment was done in S2A wind tunnel which is equipped with advanced aerodynamic assessment techniques like wheel rotations, boundary layer suction, moving ground etc. The current work mainly focuses

Biswas, Kundan, Tare, Kedar, Chalipat, Sujit

Design Implementation through Computational fluid dynamics (CFD) analysis to reduce Fuel filling time in NGVs

2024-26-030901/16/2024

In the past few decades CNG (Compressed Natural Gas) fuel growing as an alternate fuel due to its more economically as compared to Gasoline & Diesel fuels by vehicle running cost in both passenger as well as commercial vehicles, additionally it is more environment friendly & safer fuel with respect to gasoline & diesel. At standard temperature & pressure fuel density of Natural Gas (0.7-0.9 kg/m3) is lower than Gasoline (715-780 kg/m3), Diesel (849~959 kg/m3), therefore CNG fuel require higher storage space as compared to Gasoline & Diesel & also it stores at very high pressure (200-250 bar) to further increase the fuel density 180 kg/m³ (at 200 bar) and for 215 kg/m³ (at 250 bar) in CNG cylinders so that max fuel contains in the cylinders and increase the vehicle running capacity per fuel filling & reduces its fuel filling frequency at filling stations. Therefore to gain max vehicle running mileage in a single fuel filling, NGVs (Natural Gas powered vehicles) require more numbers CNG

Singh, Gaurav Kumar, Kumar, Satish, Patil, Praveen, Sharma, Mukesh

Thermal Management of An Automotive Headlamp

2024-26-028601/16/2024

These days, the use of virtual simulations through Computation Fluid Dynamics (CFD) methodology is increasing exponentially during the development phase of an automotive headlamp. Thereupon, the automotive industries are becoming competent enough to build an ingenious and creative design with optimal performance within the coherent time. Considerable amount of heat is generated inside the headlamp when it is switched on for a longer time. Hence it becomes vital to reduce the risks if any during the development phase by providing an adequate thermal management strategy within the headlamp. The present study conducted an experimental analysis on an automotive headlamp to determine its thermal characteristics and behavior. Numerical analysis was also performed to determine the airflow and temperature distributions within a headlamp. This study also focuses on finding the main hotspot regions over the headlamp through virtual simulations. The methodology shows a consensus with the

Kolhe, Shailesh Madhukar

A Machine Learning Approach for Hydrogen Internal Combustion (H2ICE) Mixture Preparation

2024-26-025401/16/2024

The present work discusses the potential benefits of using computational fluid dynamics (CFD) simulation and artificial intelligence (AI) in the design and optimization of hydrogen internal combustion engines (H2ICEs). A Machine Learning (ML) model is developed and applied to the CFD simulation data to identify optimal injection system parameters on the Sandia H2ICE Engine to improve the mixing. This approach can aid in developing predictive ML models to guide the design of future H2ICEs. For the current engine configuration, it is observed that hydrogen (H2) gas injection contributes mixing of H2 with air. If the injector parameters are optimized, mixture preparation is better and eventually combustion. A base CFD model is validated from the Sandia H2ICE engine data against Particle Image Velocimetry (PIV) data for velocity and Planar Laser Induced Fluorescence (PLIF) data for H2 mass fraction. Design of Experiments (DoE) was derived for the injection system parameters to train the ML

Jose, Alen, Probst, Daniel, Biware, Mukul

A Mid-Infrared Laser Absorption Sensor for Gas Temperature and Carbon Monoxide Mole Fraction Measurements at 15 kHz in Engine-Out Gasoline Vehicle Exhaust

03-17-01-000201/16/2024

Quantifying exhaust gas composition and temperature in vehicles with internal combustion engines (ICEs) is crucial to understanding and reducing emissions during transient engine operation. This is particularly important before the catalytic converter system lights off (i.e., during cold start). Most commercially available gas analyzers and temperature sensors are far too slow to measure these quantities on the timescale of individual cylinder-firing events, thus faster sensors are needed. A two-color mid-infrared (MIR) laser absorption spectroscopy (LAS) sensor for gas temperature and carbon monoxide (CO) mole fraction was developed and applied to address this technology gap. Two quantum cascade lasers (QCLs) were fiber coupled into one single-mode fiber to facilitate optical access in the test vehicle exhaust. The QCLs were time-multiplexed in order to scan across two CO absorption transitions near 2013 and 2060 cm–1 at 15 kHz. This enabled in situ measurements of temperature and CO

Airlines Electronic Engineering Committee

Experimental and Numerical Investigation of Combustion and Noise, Vibrations, and Harshness Emissions in a Drone Jet Engine Fueled with Synthetic Paraffinic Kerosene

01-17-01-0006

08/14/2023

Emissions and effects of climate change have prompted study into fuels that reduce global dependence on traditional fuels. This study seeks to investigate engine performance, thermochemical properties, emissions, and perform NVH analysis of Jet-A and S8 using a single-stage turbojet engine at three engine speeds. Experimental Jet-A results were used to validate a CFX simulation of the engine. Engine performance was quantified using thermocouples, pressure sensors, tachometers, flow meters, and load cells fitted to the engine. Emissions results were collected using an MKS Multigas Emissions Analyzer that examined CO, CO₂, H₂O, NOx, and THC. NVH analysis was conducted using a multifield, free-field microphone, and triaxial accelerometer. This study found that Jet-A operates at higher temperatures and pressures than S8, and S8 requires higher fuel flow rates than Jet-A, leading to poorer efficiency and thrust. S8 produced stronger vibrations over 5 kHz compared to Jet-A. S8 showed a

Soloiu, Valentin, Mcafee, John, Ilie, Marcel, Rowell, Aidan, Willis, James, Dillon, Nicholas

HVAC Noise

2025-01-005705/05/2023

Within automobiles, the HVAC is a critical system to regulate the occupants’ thermal comfort. However, at its high operating speeds, it can contribute significantly to the overall sound levels perceived by the cabin occupants, impacting their experience. This is especially true in the case of electric vehicles due to their overall quieter operation. This work has the intention to validate HVAC noise predictions using computational fluid dynamics (CFD) simulations. In addition, CFD simulations provide detailed flow field insights which are essential to identify and rank the main noise sources, and it ultimately allows a better understanding of the physical mechanisms of noise generation on similar systems. These insights are very difficult, if not impossible, to obtain with physical testing and are key to designing a quiet and efficient HVAC system. Sound levels were measured experimentally at eight different locations inside of a Class-8 Nikola TRE hydrogen fuel cell electric semi

Ihi, Rafael, Fougere, Nicolas, Passador, Stephen, Woo, Sangbeom, Kim, James, Desouky, Mohamed

Underbody contribution simulation for vehicle wind-noise.

2025-01-002605/05/2023

Wind noise is one of the largest sources to the interior noise of modern electric and hybrid vehicles. This noise is encountered when driving on roads and freeways from medium speed and generate considerable fatigue for passengers on long journeys. Aero-acoustic noise is the result of turbulent and acoustic pressure fluctuations created within the flow. They are transmitted to the passenger compartment via the vibro-acoustic excitation of vehicle surfaces and underbody cavities. Generally, this is the dominant flow-induced source at low frequencies. The transmission mechanism through the vehicle floor and underbody is a complex phenomenon as the paths to the cavity can be both airborne and structure-borne. This study is focused on the floor contribution to wind noise of different type of vehicles (SUV and Sport car), whose underbody structure are largely different. Aero-Vibro-acoustic simulations are performed to clarify the transmission mechanism of the underbody wind noise and

Mordillat, Philippe, Zerrad, Mehdi, Errico, Fabrizio

A computational process to predict and mitigate liftgate gap noise

2025-01-002805/05/2023

Noise comfort significantly influences vehicle purchasing decisions. With wind noise being a primary contributor to the overall cabin experience vehicle manufacturers must focus on optimizing the exterior shape of their models to minimize wind noise while balancing fuel efficiency and aesthetic appeal. High-speed airflow over gaps in the vehicle’s exterior can generate considerable noise, which often enters the cabin through seals. A good sealing strategy could be very helpful to address these gap noise issues. However, doing this with traditional experimental processes can be challenging, since early stage prototypes may lack detailed gap information. Modifying the seal design after the tooling stage to address these noise issues can be costly for manufacturers, as suppliers often incur expenses related to tool modifications and redesigns. Overdesigning by incorporating multiple layers of seals for all the gaps can inflate part and manufacturing costs, ultimately impacting profit

Moron, Philippe, Jantzen, Andreas, Kim, Minsuk, Senthooran, Sivapalan

Saw-Tooth Ramps for the Suppression of Flow-Acoustic Coupling in a High-Frequency Silencer for Turbocharger Compressors

2025-01-002305/05/2023

The ported shroud casing treatment for turbocharger compressors is desirable for mitigating broadband/whoosh noise and enhancing boost pressures at low to mid flow rates. Yet, it is accompanied by elevated narrowband noise at the blade-pass frequency (BPF). Compressor BPF noise occurs at high frequencies where wave propagation is often multi-dimensional, rendering traditional planar wave silencers invalid. An earlier work introduced a novel reflective high-frequency silencer (baseline) targeting BPF noise in the 8-12 kHz range using an “acoustic straightener” that promoted planar wave propagation along arrays of quarter-wave resonators (QWRs). The design, however, faced challenges with high-amplitude tonal noise generation at specific flow conditions due to flow-acoustic coupling at the opening of the QWRs, thereby compromising the noise attenuation. The current study explores two QWR interface geometries that weaken the coupling, including linear and saw-tooth ramps on the upstream

Sriganesh, Pranav, Selamet, Ahmet

Sonic Boom Velocity and Altitude Sensitivity Analysis of a Hypersonic Aircraft Concept

2025-01-003505/05/2023

During the last decades there has been a renewed interest in the development of a new generation of supersonic aircraft for civil purposes. However, the noise generated by supersonic aircraft during supersonic flight, commonly referred to as "sonic boom", is still creates annoyance to community on the ground that prohibits supersonic overland flight. To prepare for the advent of a new generation of supersonic aircraft and to define new regulations for them, an increasing number of sonic boom studies is being published. This paper presents numerical simulations of the sonic boom of a hypersonic (Mach 5) aircraft concept. The study describes a sensitivity analysis of the two parameters velocity and altitude. The extensive simulations characterize the sonic boom carpet of the aircraft for different speeds between Mach 1.2 and Mach 5.0, and for two altitudes of 11.3 km and 28.0 km above sea level. The simulation approach is divided into two main regions. This approach is well understood

Graziani, Samuele, Jäschke, Jacob Jens, Viola, Nicole, Gollnick, Volker

Sonic Boom propagation using high and low-fidelity methods

2025-01-003405/05/2023

A bottle neck to the introduction of civil supersonic aircraft is represented by the noise produced by shock waves during the cruise flight, the so-called "sonic boom". Authorities prohibit supersonic flight over land due to the exceeding noise levels produced by sonic boom. This work deals with a comprehensive methodology for assessing the aircraft sonic-boom signature at ground level starting from an accurate estimation of the near-field pressure signature caused by shock-wave pressure. High fidelity computational fluid dynamics (CFD) is typically used to calculate near-field sonic booms, whereas proper models are used for propagating at long distances, since CFD becomes computationally demanding as propagation distances exceed 10 km. The present study focuses on assessing a low-fidelity technique (e.g. Whitam's equation) against the direct application of a high-fidelity CFD method for sonic boom propagation at a medium distance. The former propagates the pressure signature through

Glorioso, Antimo, Fasulo, Giovanni, Petrosino, Francesco, Barbarino, Mattia

Aerodynamics of Landing Maneuvering of an Unmanned Aerial Vehicle in Close Proximity to a Ground Vehicle

2023-01-0118

04/11/2023

Autonomous takeoff and landing maneuvers of an unmanned aerial vehicle (UAV) from/on a moving ground vehicle (GV) have been an area of active research for the past several years. For military missions requiring repeated flight operations of the UAV, precise landing ability is important for autonomous docking into a recharging station, since such stations are often mounted on a ground vehicle. The development of precise and efficient control algorithms for this autonomous maneuvering has two key challenges; one is related to flight aerodynamics and the other is related to a precise detection of the landing zone. The aerodynamic challenges include understanding the complex interaction of the flows over the UAV and GV, potential ground effects at the proximity of the landing surface, and the impact of the variations in the surrounding wind flow and ambient conditions. While a large body of work in this area can be found on the control aspect of the UAV landing and takeoff maneuvers

Uddin, Mesbah, Nichols, Spencer, Hahn, Cortney, Misar, Adit, Desai, Shishir, Tison, Nathan, Korivi, Vamshi

A Methodology to Design the Flow Field of PEM Fuel Cells

2023-01-0495

04/11/2023

Proton Exchange Fuel Cells (PEMFCs) are considered one of the most prominent technologies to decarbonize the transportation sector, with emphasis on long-haul/long-range trucks, off-highway, maritime and railway. The flow field of reactants is dictated by the layout of machined channels in the bipolar plates, and several established designs (e.g., parallel channels, single/multi-pass serpentine) coexist both in research and industry. In this context, the flow behavior at cathode embodies multiple complexities, namely an accurate control of the inlet/outlet humidity for optimal membrane hydration, pressure losses, water removal at high current density, and the limitation of laminar regime. However, a robust methodology is missing to compare and quantify such aspects among the candidate designs, resulting in a variety of configurations in use with no justification of the specific choice. This contrasts with the large operational differences, especially regarding the pressure loss

Corda, Giuseppe, Cucurachi, Antonio, Diana, Martino, Fontanesi, Stefano, D'Adamo, Alessandro

Aerodynamic Investigation by Computational Fluid Dynamics to Exterior Design Modifications in a Simplified Bus Model

2023-01-5003

01/04/2023

Abstract Exterior design modifications have crucial importance on vehicle aerodynamics. Therefore, it makes one of the key parameters to achieve to reduce the fuel consumption in diesel-, CNG-, and hybrid-powered engines and increase the range of electric vehicles (EVs). The slightest change in the vehicle exterior design can directly affect the vehicle aerodynamics. Thus, four different parameters (front windshield angle, front diffuser angle, rear diffuser angle, and fillet [bending] on the rear and front top) are reviewed on a conceptual 12 m long bus which is to be designed at Anadolu Isuzu. Computational fluid dynamics (CFD) simulations become a source for comparative evaluations in these studies. Simulations are carried out for all different models with a realizable k-epsilon turbulence model and enhanced wall treatment wall function. In conclusion, a positive aerodynamic effect is observed with parameters that are the windshield, front diffuser angle, and fillet on the rear and

Özcan, Onur, Yıldız, Alp Eren