Numerical Simulated Calculation And Analysis Of Flow Field On The Novel Two-stroke Micro Free-Piston Swing Engine

The task stated in this thesis is a part of the inner Mongolia-funded project for natural science, which is the investigation about designing theory and device for the high energy density Micro Free Piston Swing Engine (MFPSE). It is mainly to make CFD (Computational fluid dynamics) analysis for the MFPSE with FLUENT. There are two parts about this analysis: one is for pre-compress progress, the other is for sweep and exhaust gas progress.The MFPSE's Capability mostly lies on that whether the sweep gas progress is perfect. Furthermore, the core of the sweep gas progress is gas flow, on the other hand, MFPSE requires fresh charge flow from the sweep vent must impulse the exhaust gas to flow out the combustion chamber as much as possible. By way of model the sweep progress more efficiency, pre-compress and exhaust progress also be analysis in this thesis.The MFPSE's center swing swaying during the work progress persistently. At the same time, the calculate areas (include pre-compress chamber and combustion chamber) also have been changed. So, we use the dynamic mesh model in FLUENT to define this motion.The result about pre-compress progress indicates that: at the end of pre-compress progress, although the fresh charge have the expected pressure, but path lines distributing is not so reasonable. So changing the pre-compress chamber's shape and recalculating is necessary to improve the path lines's distribution. We can see that the new structure is more benifite to use the fresh charge's inertia.The result about sweep and exhaust gas indicates that: MFPSE can work well in the stages of free exhaust,fore-sweep and obliged exhaust progresses. There exists mild back flow phenomenon in the back-sweep stage.For abtain the better effect about sweep and exhaust gas, try to recalculate using new MFPSE'structure by adding the span between left and right exhaust vents and changing the pre-compress chamber's shape. Totally, the effect of new structure is better than the old one, although the back flow phenomenone is still occur.The researches of the thesis have done efficient work in the flow field numerical simulation calculation of working process of the MFPSE and provided great theoretical valve and practical meaning to promoting the development of novel internal-combustion engine trade of our country.