论文标题
数据驱动的数据驱动分析对湍流引起的喷气燃料的重新变异性分析
Data-driven Analysis of Relight variability of Jet Fuels induced by Turbulence
论文作者
论文摘要
出于安全目的,在火焰爆发时可靠重新点燃飞机发动机是一项至关重要的要求。通常,使用火花形式的外部点火源用于在燃烧器中实现稳定的火焰。但是,这种强制性的湍流点火可能并不总是成功地重新确认燃烧器,这主要是因为燃烧器的状态无法精确确定。燃烧器内部湍流,流入条件和火花放电特征的不确定性也可能导致火花的变化,即使对于名义上相同的工作条件也是如此。先前的研究表明,在所有不确定的参数中,湍流通常是主导的,并且可以大大改变点火行为。例如,即使不同的燃料具有相似的点火延迟时间,它们在实际系统中的点火行为也可能完全不同。在实际的操作条件下,了解为什么点火失败以及预期结果有多少变化是一项挑战。这项工作的重点是了解两种不同的飞机燃料的湍流引起的重新变异,即JET-A和一个名为C1的变体。一种详细的,先前开发的仿真方法用于生成大量成功和失败的点火事件。使用这些数据,根据判别分析来评估失火的原因,该分析描述了导致点火或失败的湍流初始条件之间的差异。据确定,两种燃料的点火故障原因是不同的。虽然发现JET-A受燃料夹带的影响,但发现C1对小型湍流特征更敏感。在C1的点火模式中发现了更大的可变性,这可能会受到内核分解引起的极端事件。
For safety purposes, reliable reignition of aircraft engines in the event of flame blow-out is a critical requirement. Typically, an external ignition source in the form of a spark is used to achieve a stable flame in the combustor. However, such forced turbulent ignition may not always successfully relight the combustor, mainly because the state of the combustor cannot be precisely determined. Uncertainty in the turbulent flow inside the combustor, inflow conditions, and spark discharge characteristics can lead to variability in sparking outcomes even for nominally identical operating conditions. Prior studies have shown that of all the uncertain parameters, turbulence is often dominant and can drastically alter ignition behavior. For instance, even when different fuels have similar ignition delay times, their ignition behavior in practical systems can be completely different. In practical operating conditions, it is challenging to understand why ignition fails and how much variation in outcomes can be expected. The focus of this work is to understand relight variability induced by turbulence for two different aircraft fuels, namely Jet-A and a variant named C1. A detailed, previously developed simulation approach is used to generate a large number of successful and failed ignition events. Using this data, the cause of misfire is evaluated based on a discriminant analysis that delineates the difference between turbulent initial conditions that lead to ignition or failure. It was determined that the cause of ignition failure is different for the two fuels. While it was found that Jet-A is influenced by fuel entrainment, C1 was found to be more sensitive to small scale turbulence features. A larger variability is found in the ignition modes of C1, which can be subject to extreme events induced by kernel breakdown.