APPLICATIONS

AUTOMOTIVE | ELECTRONICS | FANS AND PUMPS

AUTOMOTIVE

SIDE VIEW MIRROR

A side view mirror is a critical component in the automotive aerodynamics. The surface pressure distribution is calculated by SC/Tetra to predict the noise by wind shear, the vibration by the pressure disturbance and its influence to the angular movement of the mirror. While conventional structured mesh requires cautious meshing for such delicate aerodynamic problems, the unstructured mesh generator of SC/Tetra enables highly accurate predictions by just specifying mesh-element density. The simulation of the flow inside a mirror can also be done simultaneously by inserting an extra mesh in the internal structure, taking full advantage of the low memory consumption.

AIR CONDITION VENTILATION DUCT

An air conditioner ventilation duct is a very complex channel that passes through the frame structure of a car to distribute compressed air to the cabin. The design goal is to reduce the power requirement of the compressor by minimizing the drag in a channel while maintaining the total flow rate and the distribution rate to each outlet. In a designing process, many trials-and-errors are necessary to shape a duct under several restrictions, such as instrument arrangements and the shape of an interior roof. CFD is an indispensable tool for this type of applications. Just by preparing for multiple CAD data, SC/Tetra runs analysis semi-automatically towards the completion. In the present case, an undesired breakup was found on the model when the CAD data were converted to the STL format. Of course the analysis cannot be carried out with this hole on the model. With just one mouse click, however, the STL correction scheme in SC/Tetra fills up the deteriorated polygons and leads you back to the job. Many Japanese automakers and their subsidiaries have installed SC/Tetra for the analysis of ventilation ducts, utilizing its speediness.

ENGINE MANIFOLD

There are two types of manifold connected to an engine: intake manifold to take air into cylinders; exhaust manifold to discharge the exhaust gas. In a designing process of exhaust manifold, in which high temperature gas blows down, the heatproof characteristic of the material is an important factor. This particular example posts that the heat transfer coefficients between the pipe and exhaust rise up sharply in the rendezvous area of branches. It is also clear that the reason mainly comes from the higher velocity of the exhaust at that point. If we take a conventional approach using structured mesh, it would be many hours of work to set up hexahedral elements that correctly represents the topology of a manifold, and it may take days to conduct a whole analysis. SC/Tetra is of great help because this analysis is finished within a day. Furthermore, the heat transfer coefficients obtained in this calculation can be used for the input of a thermo-structural analysis. It can be easily done to map the analyzed data of solids onto an FEM mesh for a structural analysis, which enables us to accurately estimate the influences of fluid motions to structures. You can collaborate with other CAE software for the analysis of an intake manifold as well; for example, provided 1-D data of engine performance simulations from another application can be utilized in SC/Tetra for the inlet boundary to conduct a pressure wave propagation analysis.

HEAT EXCHANGER

CFD is utilized frequently for the analysis of heat exchangers with a liquid coolant. The design process can be effectively improved by using SC/Tetra. In this example, the coolant behavior in the heat exchanger was analyzed to optimize the configurations of the duct and the chamber (both spaces at the end of cooling fins) to equally distribute the fluid to each fin with the number and shape of fins pre-determined. The results were visualized for the pressure distribution in the capillaries of fins and the velocity field in the chamber which connects the duct and the fins. As a case study, only the chamber configurations can be modified and re-connected to the already meshed fin section, using the completely discontinuous mesh interface function.

AIR INDUCTION PORT

CFD has many applications in the combustion analysis of an engine cylinder. However, it is not always very practical for its complexity; for example, the simulations of chemical reactions and piston-valve motions require the vast amount of settings and computational hours to capture the transient change. SC/Tetra does not offer such options, by now, but it does work very effectively for steady state analyses. In the experiments of an air intake port, flow and swirl rates are measured while valve lift is usually fixed. These measurements will be repeated again and again to optimize the shape of intake port at the design stage. However, by using SC/Tetra, these required data can be obtained more quickly and precisely. Many automakers have been replacing this experimental work by CFD analyses to promote the efficiency at the design process.

REAR WING

Here is a rear wing analysis of a Formula-Three racing car using SC/Tetra. The drag and down forces acting on the wing were estimated for various angles of attack. Our analysis has reproduced the tendency that the rear wing down force goes up as the angle of attack increases. Furthermore, it is confirmed in the simulation that air density, or ambient temperature, affects this down force, as is proven in the race scene.