Active control of the charge motion by fluidic vortex generators

现代内燃机利用设计的气缸装药运动来支持混合气的形成和/或燃烧。为了产生电荷运动，使用了形状适当的进气道。通常，电荷运动的增加会导致流动能力的降低，从而增加电荷交换功。在这个项目中，将研究一种产生涡流的替代方法。作为一个基础，使用一个端口，它产生很少的电荷运动。通过向靠近阀座的端口内切向脉冲注入空气，这种压力会增加。这使得它可以改变连续的漩涡，不同于开关端口打开和关闭通常。进一步的初步工作表明，产生压缩空气所需的功小于使用涡流口所增加的电荷交换功。该项目将在布伦瑞克工业大学流体力学研究所（ISM）和内燃机研究所（ivb）进行。在初步工作的基础上，将设计一系列的端口。这些将由ISM用固定的ranss模拟进行研究。结果是涡流与流量的帕累托前。从这个帕累托前三个端口与不同的漩涡水平将被选择。为了验证仿真结果，我们将在ivb的流动试验台上对它们进行实验研究。进一步的空气喷射试验将使用低和中涡流的端口进行。为了进行非定常研究，将建立一个机动发动机试验台。气缸盖的设计将使进气口易于更换。流量测量将使用热线风速计进行，因为使用这种技术可以比使用光学方法更快地获得结果。这一点很重要，因为由于空气喷射的可变性，参数空间很大。ISM将为非定常研究建立一个uRANS-和iddes -模拟链。将使用OpenFOAM作为仿真软件。使用这些工具将进行系统优化。目标是一个参数星座，它提供了一个理想的高涡流增加和一个理想的低工作，用于生产压缩空气。然后可以使用一个不需要空气注入而产生低旋流的端口，从而具有高的流动能力。最后将进行发动机仿真以进行评估。通过一种包括实验参数研究和尺度解析模拟的详细重新计算的联合调整方法，可以解释和描述空气喷射对涡流发展和相关灵敏度的影响。

Modern internal combustion engines utilize a designed motion of the cylinder charge to support mixture formation and/or combustion. For the generation of charge motion appropriately shaped intake ports are used. Generally an increase in charge motion causes a reduced flow capacity and thus an increased charge exchange work. In this project an alternative method of swirl generation will be investigated. As a basis a port is used which creates little charge motion. This will be increased by tangential pulsed injection of air into the port close to the valve seat. This makes it possible to vary the swirl continuously, different from switching ports on and off as usual. Further the preliminary work shows that the work needed to produce the compressed air is less than the increase of charge exchange work that would result from using a swirl port. The project will be carried out at the Institute of Fluid Mechanics (ISM) and the Institute of Internal Combustion Engines (ivb) at TU Braunschweig. Initially a series of ports will be designed, based on the preliminary work. These will be investigated by ISM with stationary RANS-simulations. The result is a pareto front of swirl vs. flow capacity. From this pareto front three ports with different swirl level will be chosen. They will be investigated experimentally on the flow test bench of ivb, in order to verify the simulation results. Further tests with air injection will be carried out using the ports with low and medium swirl. For unsteady investigations a test bed with a motored engine will be built up. The cylinder head will be designed such, that the inlet ports can be exchanged easily. The flow measurements will be carried out with hot wire anemometers, because with this technique the results are available much faster than with optical methods. This is important because of the large parameter space due to the variabilities of the air injection. The ISM will build up a simulation chain of uRANS- and IDDES-simulations for the unsteady investigations. OpenFOAM will be used as the simulation software. Using these tools a systematic optimisation will be carried out. The target is a parameter constellation, which gives a preferably high increase in swirl with a preferably low work for the production of compressed air. Then a port can be used which produces low swirl without air injection and has thus a high flow capacity. Finally engine simulations will be carried out for evalution. With a jointly adjusted approach involving experimental parameter studies and detailed recalculations with scale resolving simulations the effect of air injection on the development of swirl and the connected sensitivities can be explained and described.