Feed-back control of the precessing vortex core in swirl-stabilized flames to exploit its direct impact on flame dynamics, thermoacoustic instabilities and emissions.

进动涡核作为旋流中一种典型的拟序结构，自发现以来，人们对其在反应流和非反应流中的特性进行了大量的研究。直到今天，这种流体动力学现象在工业燃气轮机中的应用对涡流稳定燃烧的直接影响还没有明确的证据。造成这种知识差距的主要原因是缺乏精确控制PVC的可能性。本研究项目旨在开发一种反馈控制系统，该系统允许以有针对性和精确的方式在原产地对聚氯乙烯进行实验控制。在上述项目的基础上，将关于聚氯乙烯形成的线性水动力稳定性分析的结果应用于此。在普通燃烧室试验台上建立、实施和标定了主动流量控制系统后，将进行湍流旋流稳定火焰的实验。将控制系统应用于开环测量，可以深入了解PVC的锁定行为，并有助于找到最佳的致动位置。采用反馈控制的下列研究允许有效地抑制聚氯乙烯。聚氯乙烯可以描述为一个稳定的极限环，因此，可以通过反馈控制将系统动力学带到其不稳定的不动点。为此，可以研究聚氯乙烯的不同状态，以便这种类型的主动流动控制能够将聚氯乙烯用作反应性和非反应性旋流稳定流动的性质的附加控制参数。在接下来的项目过程中，将研究聚氯乙烯对旋流稳定燃烧中火焰动力学、热声不稳定性和污染物形成的明显影响。

Since the discovery of the precessing vortex core (PVC), as a typical coherent structure in swirling flows, numerous investigations have been conducted to study its properties in reacting and non-reacting flows. Until today, there is no clear evidence concerning directly usable effects of this fluid dynamic phenomenon on swirl-stabilized combustion as it is applied in industrial gas turbines. The primary reason for this knowledge gap is connected to the lack of possibilities to control the PVC precisely. The present research project aims to develop a feed-back control system, which allows for experimental control of the PVC at its point of origin in a targeted and precise way. Based on the foregoing project, findings of the linear hydrodynamic stability analysis about the formation of the PVC are applied in this context. After construction, implementation and calibration of the active flow control system in the generic combustion chamber test rig, experiments on turbulent swirl-stabilized flames will be conducted. Applying the control system for open-loop measurements provides insight into the lock-in behaviour of the PVC and serves to find the optimal position for actuation. The following investigations employing feed-back control allow for effective suppression of the PVC. The PVC can be described as a stable limit cycle; therefore, the system dynamics can be brought to its unstable fixed point by feed-back control. For this reason, different states of the PVC can be investigated so that this type of active flow control enables the chance to employ the PVC as an additional control parameter for the properties of reacting and non-reacting swirl-stabilized flows. In the following course of the project, the explicit influence of the PVC on flame dynamics, thermoacoustic instability and pollutant formation in swirl-stabilized combustion will be investigated.