CFD tests of the exhaust system of a sports motorcycle

The content of this article describes the area of the operation of speedway racing motorcycles, it reflects the specific use, and thus, the special requirements placed on the internal combustion engines used there. Then, a research tool is presented in the form of Computational Fluid Dynamics methods. The article presents basic equations as a base for software, and emphasizes the essence and necessity of adequate selection of turbulence models. Presentation of the work tool is crowned with a brief description of the application in the form of Ansys numerical analysis software and a specific place and possibilities of its application. The practical part describes the work carried out during the tests of a GM 500 type combustion engine and attempts to compare two types of exhaust systems whose advantages and disadvantages in analytical calculations are difficult to determine, whereas CFD tests accurately represent pressure fields, velocities and the most important parameter in the form of resistance of the exhaust system. The article is crowned with the results of tests enabling determination and selection of the exhaust system with lower flow resistance and recommendations adjusting the exhaust system to a specific engine.