2011 年 43 巻 2 号 p. 39-45
It is important to study a precise and practical way to predict temperature rise of oil hydraulic systems. It is interesting whether internal flow patterns have any effect on the temperature change in a cylinder. Nowadays, commercial CFD (Computational Fluid Dynamics) codes give accurate solutions of temperature as well as flow patterns. The authors have calculated the flow pattern in a cylinder using a reliable CFD code and have found that there is characteristic vortex flow with a strong three-dimensional effect on the flow pattern, and the internal flow patterns can be classified into two flow regions, a 3D vortex flow pattern and a 1D parallel flow pattern. So, it becomes possible to predict precisely and practically the temperature change in a cylinder by incorporating the difference of the internal flow patterns with a modeling method based on a lumped parameter system. A new method for prediction of temperature rise in a cylinder is proposed in this study.