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

本研究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变进行实验研究。基于这些流量测量，可以更详细地了解压缩后期循环间变化的性质和结构。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）可以克服透明发动机中光通道有限的问题，仅使用光路通过透明活塞头进行三维速度测量。除了3-5个实验子项目集中在压缩后期和点火阶段外，重点研究了流壁相互作用以及由此产生的翻滚涡位置和结构的波动不稳定性。此外，利用流场中流体旋转和流体变形张量的附加信息来限定压缩过程中的翻滚破碎过程，并在子项目7的LES模拟中进行了预测。

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.