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The impact of fuel droplets on heated surfaces is of great importance in internal combustion engines. In engine computational fluid dynamics (CFD) simulations, the drop-wall interaction is usually considered by using models derived from experimental data and correlations rather than direct simulations. This paper presented a numerical method based on smoothed particle hydrodynamics (SPH), which can directly simulate the impact process of fuel droplets impinging on solid surfaces. The SPH method is a Lagrangian meshfree particle method. It discretizes fluid into a number of SPH particles and governing equations of fluid into a set of particle equations. By solving the particle equations, the movement of particles can be obtained, which represents the fluid flows. The SPH method is able to simulate the large deformation and breakup of liquid drops without using additional interface tracking techniques.

Spray impingement is an important phenomenon that introduces turbulence into the spray that promotes fuel vaporization, air entrainment and flame propagation. However, liquid impingement on the surface leads to wall-wetting and film deposition. The film region is a fuel-rich zone and it has potentials to produce higher emission. Film deposition in a non-reacting spray was studied previously but not in a reacting spray. In the current study, the film deposition of a reacting diesel spray was studied through computational fluid dynamic (CFD) simulations under a variety of ambient temperatures, gas compositions and impinging distances. Characteristics of film mass, distribution of thickness, soot formation and temperature distributions were investigated. Simulation results showed that under the same impinging distance, higher ambient temperature reduced film mass but showed the same liquid film pattern.

High-speed spray-to-spray liquid impingement could be an effective phenomenon for the spray propagation and droplet vaporization. To achieve higher vaporization efficiency, impingement from two-hole nozzles is analyzed in this paper. This paper focuses on investigating vaporization mechanism as a function of the impingement location and the collision breakup process provided by two-hole impinging jet nozzles. CFD (Computational Fluid Dynamics) is adopted to do simulation. Lagrangian model is used to predict jet-to-jet impingement and droplet breakup conditions while KH-RT breakup and O'Rourke collision models are implemented for the simulation. The paper includes three parts: First, a single spray injected into an initially quiescent constant volume chamber using the Lagrangian approach is simulated to identify the breakup region, which will be considered as a reference to study two-hole impinging jet nozzles. Lagrangian simulation results would be validated via experimental results.

The future of the Hybrid Electric Vehicle (HEV) is very promising for the automotive industry. In order to take a full advantage of this concept, a better thermal performance of the electric motor is required. In this study, Computational Fluid Dynamics (CFD) model was first verified through several prototypes testing and then is going to be used to execute a series of design of experiment via simulation. Based on the thermal studies in this paper, the integrated coolant jacket design has a better performance than that of separated one. The thermal performance of the stator with the 3M coating is better than the one with paper liner. In addition, using 3M coating reduces the packaging size of the stator.

Three pickup truck variants of the Generic Truck Utility (GTU) are evaluated and compared using wind tunnel test data and computational fluid dynamics (CFD) simulations. The configurations analyzed are the short cab/long box, medium cab/medium box, and long cab/short box geometries, which all share a common vehicle length and wheelbase. Both cab and box length are known to influence the total bluff body drag through the interaction of the cab wake in the pickup box with the total vehicle wake, and the GTU provides an excellent test box to investigate the details of these interactions. Experimental testing was conducted at the WindShear wind tunnel on a full-scale GTU model, while transient CFD simulations were carried out with IconCFD®, an open-source based solver. Experimental and CFD results are used to describe the general flow field around the vehicle, and a comparison is made with the wind tunnel integral force data as well as centerline pressure tap data.

A new CFD simulation model and methodology for oil jet piston cooling has been developed using the modern level set approach. In contrast to the widely used volume of fluid (VOF) method, the level set approach explicitly tracks the interface surface between oil and air, using an additional field equation. The method has been extensively tested on two- and three-dimensional examples using results from literature for comparison. Furthermore, several applications of oil jet piston cooling on Ford engines have been investigated and demonstrated. For example, three-dimensional simulations of piston cooling nozzle jets on a diesel engine have been calculated and compared to test-rig measurements. Laminar jets, as well as jets with droplets and fully atomized jets, have been simulated using realistic material properties, surface tension, and gravity.

The conventional ported shroud recirculation casing treatment elevates narrowband noise at blade pass frequency. A new ported shroud recirculating casing treatment was implemented in Ford’s 3.5L turbo gas engine as Noise Vibration and Harshness (NVH) counter measure to reduce whoosh (broadband flow noise) noise without elevating narrowband noise at blade pass frequency. The new ported shroud design incorporates holes between the main and secondary recirculating passage and a slight cross-sectional area reduction just upstream of the impeller. These design features reduce whoosh noise without elevating the first order and the sixth order tonal noise at blade pass frequency. The new ported shroud design decreases narrowband tonal noise sound pressure level by 3-6 dB in the low to mid flow region compared to the baseline design. Computational Fluid Dynamics (CFD) tools were used to develop this casing treatment design.

Automotive exhaust noise is one of the major sources of noise pollution and it is controlled by passive control system (mufflers) and active control system (loudspeakers and active control algorithm). Mufflers are heavy, bulky and large in size while loudspeakers have a working temperature limitation. Carbon nanotube (CNT) speakers generate sound due to the thermoacoustic effect. CNT speakers are also lightweight, flexible, have acoustic and light transparency as well as high operating temperature. These properties make them ideal to overcome the limitations of the current exhaust noise control systems. An enclosed, coaxial CNT speaker is designed for exhaust noise cancellation application. The development of a 3D multi-physics (coupling of electrical, thermal and acoustical domains) model, for the coaxial speaker is discussed in this paper. The model is used to simulate the sound pressure level, input power versus ambient temperature and efficiency.

Variable Displacement Oil Pump (VDOP) is becoming the design of choice for engine friction reduction and fuel economy improvement. Unfortunately, this pump creates excessive pressure ripples, at the outlet port during oil pump shaft rotation, causing oscillating forces within the lubrication system and leading to the generation of objectionable tonal noises and vibrations. In order to minimize the level of noise, different vanes spacing and porting geometries are used. Moreover, an oil pressure relief groove can be added, at the onset of the high pressure port, to achieve this goal. This paper presents an optimization method to identify the best geometry of the oil pressure relief groove. This method integrates adaptive meshing, 3D CFD simulation, Matlab routine and Genetic Algorithm based optimization. The genetic algorithm is used to create the required design space in order to perform a multi-objective optimization using a large number of parameterized groove geometries.

Since the introduction of the DrivAer in 2012 this model has become the standard generic aerodynamic benchmark and aerodynamic research model used by automotive OEMs, software vendors and researchers. In 2017, the relevance of the DrivAer has been furthered by the inclusion of a simplified engine bay. Whilst the DrivAer has become the popular standard, the availability of detailed wind tunnel test data, a key enabler for more sophisticated aerodynamic benchmarking and research, remains limited. This paper presents a comprehensive set of wind tunnel test data of the notchback version of the Ford Open Cooling DrivAer, including aerodynamic force measurements, detailed surface pressure measurements and flow field measurements at 3 cross-sections in the vicinity of the model. In addition, the paper will discuss the sensitivity of the experimental data to wind tunnel repeatability and facility-to-facility variations.

In the present work, a practical semi-detailed soot model has been integrated with a recently developed turbulent premixed combustion model and an improved TRF (toluene reference fuel) chemical kinetic mechanism. The practical semi-detailed soot model includes a reduced PAH (polycyclic aromatic hydrocarbon) sub-mechanism, soot particle inception (or nucleation) through pyrene (A4), C2H2-assisted and PAH-assisted surface growth, soot coagulation, and soot oxidation by both O2 and OH. In the TRF mechanism recently improved by the author, eight dominant reactions for high-temperature operating conditions (T > 750 K) were identified and corrected. The turbulent premixed combustion model recently developed by the author includes a mechanism-dynamic-selection sub-model and a dynamic turbulent diffusivity sub-model in which Schmidt number is constructed as a function of local turbulence/thermodynamics conditions.

The 2nd Automotive CFD Prediction workshop (AutoCFD2) was organized to improve the state-of-the-art in automotive aerodynamic prediction. It is the mission of the workshop organizing committee to drive the development and validation of enhanced CFD methods by establishing publicly available standard test cases for which high quality on- and off-body wind tunnel test data is available. This paper reports on the AutoCFD2 workshop for the Ford DrivAer test case. Since its introduction, the DrivAer quickly became the quasi-standard for CFD method development and correlation. The Ford DrivAer has been chosen due to the proven, high-quality experimental data available, which includes integral aerodynamic forces, 209 surface pressures, 11 velocity profiles and 4 flow field planes. For the workshop, the notchback version of the DrivAer in a closed cooling, static floor test condition has been selected.

Computational Fluid Dynamic (CFD) analysis was performed using FLUENT to analyze the fluid thermal performance of a Battery cell container for the Ford Fusion Hybrid Electric Vehicle. The objective of the design was to maintain the cells in their desired operating temperature range with a near uniform temperature among the battery cells in the container, while minimizing energy losses associated with the pressure drop. Groupings of multiple such containers were assembled for bench test confirmation. Excellent agreement was obtained for air side pressure drop between the CFD and hardware physical properties. Multiple design iterations were made to improve the baseline design. Ultimately, the thermal gradient within the physical property was reduced to 1.8°C with a minimal increase in system pressure drop.

Thermal modeling of liquid-cooled vehicle traction battery assemblies using Computational Fluid Dynamics (CFD) usually involves large models to accurately resolve small cooling channel details, and intensive computation to simulate drive-cycle transient solutions. This paper proposes a segregated method to divide the system into three parts: the cells, the cold plate and the interface between them. Each of the three parts can be separated and thermally characterized and then combined to predict the overall system thermal behavior for both steady-state and transient operating conditions. The method largely simplifies battery thermal analysis to overcome the limitations of using large 3D CFD models especially for pack level dynamic drive cycle simulations.

When manufacturing the stators in EV motors, stator wires are first coated with a layer of resin to provide primary insulation. After winding, impregnating varnish fills all voids within the windings and between the windings and lamination. In addition to electrically insulating the copper wires, another function of the varnish fill is to mechanically secure the copper wires from movement. The process is not complicated in terms of physics. In essence, the mechanics of the varnish flow is the balance of inertia force, viscous force, gravity and surface tension. However, understanding the fluid dynamics of the varnish flow is critical to predicting the quality of the varnish fill, which has a tremendous impact on motor performance. With the advancement of computational fluid dynamics (CFD), the industry can benefit greatly if the varnish trickling process can be tuned, without physical tryouts, to achieve optimal fill.

This paper documents the processes and methods used by the Ford GT team to meet aerodynamic targets. Methods included Computational Fluid Dynamics (CFD) analysis, wind tunnel experiments (both full-size and scale model), and on-road experiments and measurements. The goal of the team was to enhance both the high-speed stability and track performance of the GT. As a result of the development process, significant front and rear downforce was achieved while meeting the overall drag target.

Metal cutting/machining is a widely used manufacturing process for producing high-precision parts at a low cost and with high throughput. In the automotive industry, engine components such as cylinder heads or engine blocks are all manufactured using such processes. Despite its cost benefits, manufacturers often face the problem of machining chips and cutting oil residue remaining on the finished surface or falling into the internal cavities after machining operations, and these wastes can be very difficult to clean. While part cleaning/washing equipment suppliers often claim that their washers have superior performance, determining the washing efficiency is challenging without means to visualize the water flow. In this paper, a virtual engineering methodology using particle-based CFD is developed to address the issue of metal chip cleanliness resulting from engine component machining operations. This methodology comprises two simulation methods.

The performance of autonomous vehicle (AV) sensors, such as lidars or cameras, is often hindered during rain. Rain droplets on the AV sensors can cause beam attenuation and backscattering, which in turn causes inaccurate sensor readings and misjudgment by AV algorithms. Most AV systems are equipped with cleaning systems to remove contaminants, such as rain, from AV sensors. One such mechanism is to blow high-speed air over the AV sensors. However, the cleaning air can be hindered by incoming headwind, especially at higher vehicle speeds. An innovative idea proposed here is to use a visor to improve the cleaning performance of AV cleaning systems at higher vehicle speeds. The effectiveness of a baseline visor design was studied using computational fluid dynamics (CFD) air flow analysis and Lagrangian rain droplet tracking. The baseline visor improved the AV sensor cleaning performance in two ways. First, the visor protects the cleaning air flow from being disturbed by headwind.

Quarter-wave resonators are commonly used as acoustic silencers in automotive air induction systems. Similar closed side branches can also be formed in the idle air bypass, exhaust gas recirculation, and positive crankcase ventilation systems of engines. The presence of a mean flow across these side branches can lead to an interaction between the mean flow and the acoustic resonances of the side branch. At discrete flow conditions, this coupling between the flow and acoustic fields may produce high amplitude acoustic pressure pulsations. For the quarter-wave resonator, this interaction can turn the silencer into a noise generator, while for systems where a valve is located at the closed end of the side branch the large pressure pulsations can cause the valve to fail. This phenomenon is not limited to automotive applications, and also occurs in natural gas pipelines, aircraft, and numerous other internal and external flows.

This paper presents a mechanical energy control volume analysis for incompressible flow around road vehicles using results from Detached Eddy Simulation Computational Fluid Dynamics calculations. The control volume approach equates the rate of work done by surface forces of the vehicle to (i) the rate of work and kinetic energy flux at the control volume boundaries (particularly in the vehicle wake) and (ii) the rate of energy loss in the domain. At the downstream control volume boundary, the wake terms can be divided into lift-induced and profile drag terms. The rate of energy loss in the domain can be used as a volumetric analog for drag (drag counts/m3, when normalized). This allows for a quantitative break down of the contributions of different flow features/regions to the overall drag force.