7 Reasons why Simulation is useful

Computational fluid dynamics (CFD) is the discipline of science devoted to predicting fluid flow, heat transfer, mass transfer, chemical reactions, and related phenomena by solving the mathematical models that govern these processes using a numerical process. CFD is becoming an increasingly important design tool in engineering and also a substantial research tool in certain physical sciences. Due to the advances in numerical solution methods and computer technology, geometrically complex cases can be treated.

Glass Floating

Figure 1:

Glass temperature distribution including velocity vectors for the spout lip area within the glass floating process. In this area the glass flows from the spout lip onto the molten liquid tin.

By using these new techniques, designers can verify that their products will comply with customer’s specifications early in the design cycle. So, the product development process will be accelerated and the costs will be reduced by avoiding production trials. CFD can be used to compute material properties, heat transfer rates and chemical reactions during the process and for the final product. Those advantages are very important and have helped engineers to obtain insight in problems where analytical solutions are impossible and/or experimental measurements are too difficult or too expensive to obtain. For complex temperature problems (especially those involving thermal radiation) or simulation of systems with chemical reactions, very often CFD is really the only option because physical models are running usually at room temperature and for experiments in a productional environment the measurement of the temperature or species concentration is often very difficult and can contain very large inaccuracies. CFD models are run at the correct temperature always without parasitic drags, and take into account changes in density, viscosity, thermal conductivity, and the heat transfer coefficient.

7 reasons why simulation is useful:

1

Cost Reduction

The cost of simulations is usually much lower compared to the cost for experiments or production trials. The cost of simulations is relatively reasonable and is decreasing for years although computers become more powerful.
2

Development Time Reduction

The development time is much shorter compared to production trials or experiments.
3

Ideal Conditions

Specific effects or conditions can be computed in isolation or under ideal conditions. This is the basis for understanding the processes and a prerequisite for optimization and improvements.
4

Results at any Point and Time

The data in experiments can be measured only at a limited number of locations in the system. Compared to experiments, simulation result data is computed at any point and time. So, the level of detail is practically unlimited, and the more complex the situation the more advantage the simulation has.
5

Only CFD can look into

Compared to experiments sometimes only CFD simulation is able to look into the process and can make the flow pattern or the heat fluxes visible.
6

Fast Forecast and Prototyping

Prototypes can be analyzed and evaluated quickly, and the simulation is able to check what can happen, if for example a boundary condition is changed (how does the increase of the inlet mass flow rate influence the quality of the final product?).
7

Improves Knowledge

Simulation is able to contribute to a greater understanding of the problem. So, it will improve your knowledge, provide the basis to train the designer and engineers and helps to exchange the knowledge within the team. Furthermore, the documentation of the process and the documentation of the project progress is much better. Thereby the knowledge exchange in your company improves and on the long term, the quality and productivity will increase.

CFD modeling is almost always faster than physical modeling or performing production trials. In many cases, design results from a CFD model are available several weeks or months before similar results from experiment. And the more complicated or repetitive the model geometry is, the more advantage the CFD model has. Once a CFD model is built, it can be run simultaneously on separate computers. Thus, several designs can be evaluated at the same time, while only one real design exists for evaluation. CFD model studies are generally 30-70% less than a comparable experimental effort, especially if a CFD model is already existing. This is tied quite strongly to the product and the production process that influences the schedule. Also, many CFD tasks can be automated with the computer, including the design optimization process, whereas experiments or real design changes are mostly done manually.

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