scholarly journals CFD Simulation of Defogging Effectivity in Automotive Headlamp

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2609
Author(s):  
Michal Guzej ◽  
Martin Zachar
Keyword(s):  
Traffic Safety ◽  
3D Model ◽  
Cfd Simulation ◽  
Dew Point ◽  
Dynamics Simulation ◽  
Ambient Conditions ◽  
Computational Fluid Dynamics Simulation ◽  
The Past ◽  
Direct Exposure ◽  
Technical Solutions

In the past decade, the condensation of internal air humidity in automotive headlamps has become more prevalent than ever due to the increased usage of a new light source—LEDs. LEDs emit far less heat than previously-used halogen lamps, which makes them far more susceptible to fogging. This fogging occurs when the internal parts of the headlamp fall to a temperature below the dew point. The front glass is most vulnerable to condensation due to its direct exposure to ambient conditions. Headlamp fogging leads to a decrease in performance and the possibility of malfunctions, which has an impact not only on the functional aspect of the product’s use but also on traffic safety. There are currently several technical solutions available which can determine the effectivity of ventilation systems applied for headlamp defogging. Another approach to this problem may be to use a numerical simulation. This paper proposes a CFD (computational fluid dynamics) simulation with a slightly simplified 3D model of an actual headlamp, which allows simulation of all the phenomena closely connected with fluid flow and phase change. The results were validated by real experiments on a special fogging–defogging test rig. This paper compares three different simulations and their compliance with real experiments.

Experimental and simulation study of thermal accumulation in an enclosed vehicle

2019 ◽  
Vol 233 (14) ◽  
pp. 3621-3629
Author(s):  
Sing Ngie David Chua ◽  
Boon Kean Chan ◽  
Soh Fong Lim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
Heat Accumulation ◽  
Ansys Fluent ◽  
Direct Exposure ◽  
Car Park

Thermal accumulation in a car cabin under direct exposure to sunlight can be extremely critical due to the risk of heatstroke especially to children who are left unattended in the car. There are very limited studies in the literature to understand the thermal behaviour of a car that is parked in an open car park space and the findings are mostly inconsistent among researchers. In this paper, the studies of thermal accumulation in an enclosed vehicle by experimental and computational fluid dynamics simulation approaches were carried out. An effective and economical method to reduce the heat accumulation was proposed. Different test conditions such as fully enclosed, fully enclosed with sunshade on front windshield and different combinations of window gap sizes were experimented and presented. Eight points of measurement were recorded at different locations in the car cabin and the results were used as the boundary conditions for the three-dimensional computational fluid dynamics simulation. The computational fluid dynamics software used was ANSYS FLUENT 16.0. The results showed that the application of sunshade helped to reduce thermal accumulation at car cabin by 11.5%. The optimum combination of windows gap size was found to be with 4-cm gap on all four windows which contributed to a 21.1% reduction in car cabin temperature. The results obtained from the simulations were comparable and in agreement with the experimental tests.

CFD Simulation of Human Coughs and Sneezes: A Study in Droplet Dispersion, Heat, and Mass Transfer

2010 ◽  
Author(s):  
Amir A. Aliabadi ◽  
Steven N. Rogak ◽  
Sheldon I. Green ◽  
Karen H. Bartlett
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Cfd Simulation ◽  
Near Field ◽  
Dynamics Simulation ◽  
Evaporation Process ◽  
Buoyancy Effect ◽  
Computational Fluid Dynamics Simulation ◽  
Droplet Dispersion ◽  
Ambient Relative Humidity

A Computational Fluid Dynamics simulation of near-field cough and sneeze droplet dispersion and heat and mass transfer is developed. In this study various sources of variability in cough and sneeze processes are considered. These are variations in injection volume (0.5l, 2.5l, and 5.0l) and ambient relative humidity (20%, 40% and 60%). There are a total of 9 simulations for coughs and sneezes in a quiescent background. A large ensemble (5000) of droplets are tracked with diameters in the range 1–500micron. Evaporation and dispersion are predicted as a function of droplet size. Generally, fine droplets evaporate faster than large droplets. Higher relative humidities slow the evaporation process. Larger droplets have greater axial penetration. They also exhibit greater vertical drop due to the effect of gravity. Sideway penetration is increased by higher injection volumes. The buoyancy effect due to thermal energy of the injection is very weak, at least for the 10-second computation duration.

Stability of the Interface Between Two Immiscible Liquids in a Model Eye Subject to Saccadic Motion

2021 ◽  
Author(s):  
Ru Wang ◽  
Jheng-han Tsai ◽  
Martin Snead ◽  
Philip Alexander ◽  
D. Ian Wilson
Keyword(s):  
Weber Number ◽  
3D Model ◽  
Silicone Oil ◽  
Dynamics Simulation ◽  
Saccade Amplitude ◽  
Computational Fluid Dynamics Simulation ◽  
Immiscible Liquids ◽  
Bulk Fluid ◽  
The Stability ◽  
Particle Imaging

Abstract The interface between silicone oil and saline layers in a 3D model of the eye chamber was studied under different eye-like saccadic motions in order to determine the stability of the interface and propensity for emulsification in the bulk. The effect of level of fill; saccade amplitude, angular velocity, latency time; and orientation were investigated experimentally in spherical flasks with internal diameters 10, 28 and 40 mm, as well as a 28 mm diameter flask with an indent replicating the lens or the presence of a buckle. The deformation of the interface was quantified in terms of the change in its length in 2-D images. The deformation increased with Weber number, We, and was roughly proportional to We for We > 1. The presence of the lens gave rise to higher deformation near this feature. In both cases emulsification was not observed in either bulk fluid. The velocity profile in the spherical configuration was mapped using particle imaging velocimetry and is compared with an analytical solution and a short computational fluid dynamics simulation study. These confirm that the saccadic motion induces flow near the wall in the saline layer and significantly further into the chamber in the silicone oil. Surfactants soluble in the aqueous and oil phases reduced the interfacial tension, increasing deformation but did not lead to emulsification in the bulk.

scholarly journals High-speed prediction of computational fluid dynamics simulation in crystal growth

CrystEngComm ◽  
2018 ◽  
Vol 20 (41) ◽  
pp. 6546-6550 ◽  
Author(s):  
Yosuke Tsunooka ◽  
Nobuhiko Kokubo ◽  
Goki Hatasa ◽  
Shunta Harada ◽  
Miho Tagawa ◽  
...  
Keyword(s):  
Machine Learning ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Cfd Simulation ◽  
Large Diameter ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
High Quality ◽  
Speed Prediction

The combination of the CFD simulation and machine learning thus makes it possible to determine optimized parameters for high-quality and large-diameter crystals.

scholarly journals CFD Simulation Analysis on Make-up Air Supply by Distance from Cookstove for Cooking-Generated Particle

2020 ◽  
Vol 17 (21) ◽  
pp. 7799
Author(s):  
Hyungkeun Kim ◽  
Kyungmo Kang ◽  
Taeyeon Kim
Keyword(s):  
Fluid Dynamics ◽  
Cfd Simulation ◽  
Simulation Analysis ◽  
Dynamics Simulation ◽  
Living Room ◽  
Computational Fluid Dynamics Simulation ◽  
Apartment House ◽  
Indoor Airflow ◽  
Contaminant Source ◽  
Air Supply

Indoor cooking is the main cause of particulate matter (PM) within residential houses along with smoking. Even with the range hood turned on, cooking-generated PM can spread quickly into the living room due to the heat generated by the cookstove. In order to improve the PM spread prevention performance of the range hood, a supply of make-up air is needed. Generally, make-up air is supplied through a linear diffuser between the kitchen and living room. In such cases, it is necessary to determine the appropriate location of the supply diffuser. This study evaluates the spread of PM according to different locations of the supply diffuser, which feeds in make-up air. For this purpose, indoor airflow and PM spread were analyzed through CFD (Computational Fluid Dynamics) simulation analysis. By changing the location of the supply diffuser from the contaminant source, PM concentration was analyzed in the kitchen and living room of an apartment house in Korea. Based on the results, the optimal installation location was determined. In this study, 1.5 m from the source was the most effective location of make-up air supply to prevent the spread of cooking-generated particles.

Computational Fluid Dynamics Simulation of Steel Bars Cooling by Free Convection and Thermal Radiation

2015 ◽  
Vol 798 ◽  
pp. 170-174
Author(s):  
Paulo Henrique Terenzi Seixas ◽  
Paul Campos Santana Silva ◽  
Rudolf Huebner
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Thermal Radiation ◽  
Cfd Simulation ◽  
Dynamics Simulation ◽  
Cfd Model ◽  
Computational Fluid Dynamics Simulation ◽  
Slow Cooling ◽  
Steel Bars ◽  
Computational Fluid Dynamics Cfd

In this article, the pilling process of hot steel bars is analyzed. During the loading three bars are placed over a wood surface, after those other three are placed over the previous for two times with 5 minutes intervals between them.They are all subject to a slow cooling by thermal radiation and free convection.A Computational Fluid Dynamics (CFD) model to predict the temperature profile of them is developed. Comparison between the CFD simulation results and experimental data yielded an average difference in the bars temperature between -0.3oC and 3.5oC.

Sign in / Sign up

Export Citation Format

Share Document