A PDF-Based Model for Full Cycle Simulation of Direct Injected Engines
A PDF-Based Model for Full Cycle Simulation of Direct Injected Engines
复制标题
基于 PDF 的直喷发动机全循环仿真模型
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
H. Bensler
中科院分区：
文献类型：
--
作者：
M. Tunér;M. Pasternak;F. Mauss;H. Bensler
在一维发动机模拟程序中，为了使模拟结果与实验数据相吻合，发动机性能的模拟大多采用参数拟合的方法。对于排放物的形成--CO、HC、NO、碳烟--的模拟尤其需要广泛的拟合程序。
这种方法的另一种选择是，根据详细的动力学模型计算排放量。然而，这要求能够准确地对缸内燃烧-流动相互作用进行建模，并且该模型所需的CPU时间仍然可以接受。基于概率密度函数的随机反应堆模型提供了一种可能的解决方案。他们通常只引入一个(与时间相关的)参数--混合时间--来模拟流动对化学的影响。在给定最佳混合时间的情况下，它们提供了热释放的预测，以及所有排放的形成。因此，适用于多个动力学过程的参数(也取决于缸内流动条件)被适用于湍流混合时间的单个参数所取代。
在这项工作中，实现了一个基于PDF的模型，并耦合到全循环发动机仿真工具WAVE，并将计算结果与发动机试验进行了比较。建模结果与试验结果吻合较好，表明基于PDF的DL模型可以快速、准确地模拟DL发动机的排放和性能。
In one-dimensional engine simulation programs the simulation of engine performance is mostly done by parameter fitting in order to match simulations with experimental data. The extensive fitting procedure is especially needed for emissions formation - CO, HC, NO, soot - simulations.
An alternative to this approach is, to calculate the emissions based on detailed kinetic models. This however demands that the in-cylinder combustion-flow interaction can be modeled accurately, and that the CPU time needed for the model is still acceptable. PDF based stochastic reactor models offer one possible solution. They usually introduce only one (time dependent) parameter - the mixing time - to model the influence of flow on the chemistry. They offer the prediction of the heat release, together with all emission formation, if the optimum mixing time is given. Hence parameter fitting for a number of kinetic processes, that depend also on the in cylinder flow conditions is replaced by a single parameter fitting for the turbulent mixing time.
In this work a PDF based model was implemented and coupled to the full cycle engine simulation tool, WAVE, and calculations were compared to engine experiments. Modeling results show good agreement with the experiments and show that PDF based Dl models can be used for fast and accurate simulation of Dl engine emissions and performance.