Numerical modeling of inlet ports testing of two-strokes engines

Аuthors

Grishin Y. A.^1*, Bakulin V. N.^2**, Zenkin V. A.^1*

1. Bauman Moscow State Technical University, MSTU, 5, bldg. 1, 2-nd Baumanskaya str., Moscow, 105005, Russia
2. Institute of Applied Mechanics of Russian Academy of Science, IAM RAS, 32a, Leninskii av., Moscow, В-334, GSP-1, 119991, Russia

*e-mail: grishin@power.bmstu.ru
**e-mail: vbak@yandex.ru

Abstract

Two-stroke piston engine is the most economical for usage in structure of power plant of pilotless vehicle of different purpose. For the vehicles of light class two-stroke engines with simplified system of interchange of gases through intake and exhaust ports are used. Gas-dynamic characteristics of intake (scavenging) ports are the main parameters for calculating and experimental optimization of working process of the engine and, as a consequence for definition and getting the power and other required measures of the engine.
Under gas-dynamic characteristics, at the first place are understood the dependence of discharge coefficient and spatial field of velocity of incoming air charge into cylinder from opening stroke, inclinations of walls and structural implementation of intake part of the port.
In the present work the numerical investigations of the above mentioned characteristics were made with the help of created in MSTU by Bauman software complex of calculating gas-dynamics NFS based on the new implicit version of the method of large particles, providing second degree of accuracy by time and space.
At that the representation of inclined secants inside orthogonal regular calculating grid is being used. Version provides higher accuracy and reduces the time of calculation by major increasing the grid number of Courant. Also different physical models of gases are implemented, including polytropic and isothermal. Application of different models of viscosity is provided. As the result of calculations, the necessary dependences for discharge coefficient were received, which matches well with given experiments. The influence of degree of port opening and configuration of intake receiver and performance of intake part of the intake port to discharge coefficient examined. Fields of velocity, defining the peculiarities of entering of charge into cylinder of the engine at scavenging- through the ports are received and analysed. Results of work will be used at calculating-experimental investigations and finishing the engines.

Keywords:

two-stroke engine, inlet ports, discharge coefficient, modified method of large particles, numerical investigation

References

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