Volumetric measurements of internal flow in an IC engine during intake and compression

该研究项目的目的是对透明内燃机进气和压缩阶段内部流动拓扑的时空演化进行实验研究。基于这些流量测量，获得了关于后期压缩阶段循环间变化的性质和结构的更详细的知识。因此，最近开发的基于单视图方法的体积PIV测量方法（光场PIV，3D扫描PIV）被应用，这可以规避透明发动机中有限的光学访问的问题，仅使用通过透明活塞头的光路进行3D测速。研究的重点是流动-壁面相互作用和由此产生的滚流涡位置和结构的波动不稳定性，以及其他实验子项目3-5，这些项目集中在后期压缩和点火阶段。此外，在流场中的流体旋转和流体变形张量的附加信息被用来限定在压缩过程中的翻滚破裂的过程，在子项目7中由LES模拟预测。

The aim of the proposed research project is the experimental investigation of the spatio-temporal evolution of internal flow topology in a transparent IC engine during the intake and compression phase. Based on these flow measurements, more detailed knowledge is gained on the nature and structure of cycle-to-cycle variations in the late compression phase. Therefore, recently developed volumetric PIV measurement methods based on single-view approach (Light-field PIV, 3D Scanning PIV) are applied, which can circumvent the problems of limited optical access in transparent engines using only the light-path through the transparent piston head for 3D velocimetry. Focus of the studies are the flow-wall interactions and resulting fluctuation instabilities of position and structure of the tumble vortex in addition to the other experimental sub-projects 3-5, which concentrate on the late compression and ignition phase. Furthermore, the additional information of the fluid rotation and fluid deformation tensor in the flow field is used to qualify the process of tumble breakdown during compression, being predicted by the LES simulation in sub-project 7.