Modeling and Identification of Technically Premix Flame Dynamics

技术上预混火焰动力学的建模和识别

基本信息

批准号：
393001638
负责人：
Professor Dr. Michael Pfitzner
金额：
--
依托单位：
Institut für Thermodynamik (LRT-10)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/393001638?language=en
关键词：
Modeling Identification Technically Premix Flame

项目摘要

In order to study self-excited combustion instabilities, it is essential to characterize the response of the flame of interest to relevant flow perturbations. In the proposed study, the dynamic response of technically premixed flames to perturbations of upstream velocity and equivalence ratio will be modelled and quantified simultaneously. This will be achieved by combining validated Large Eddy Simulation (LES) of turbulent, reacting flow with advanced System Identification (SI) in order to generate reduced order models of flame dynamics that properly respect the Multiple-Input / Single-Output (MISO) structure of technically premixed flames. Two main challenges will be addressed: 1) Advanced SI methods, employing Box-Jenkins models with MISO structure, will be used to identify reduced order response functions from LES time series data. Unlike models based on traditional identification schemes, the resulting flame models will be independent of the acoustic properties of the fuel injection system. In addition, combustion noise resulting from resolved turbulent fluctuations will not be disregarded in the advanced SI framework, as was done previously, but instead will be modelled as colored noise. This enhances the quality of the overall identification and allows to quantify uncertainties that result from finite time series length. 2) Reduced order models determined with System Identification (SI) can only be as accurate as the time series data that they are deduced from. Furthermore, MISO identification requires time series of considerable length. Thus a turbulent combustion model for LES of technically premixed flames that is both accurate and efficient must be employed, or developed and validated with respect to mean and fluctuating quantities. Furthermore, the capability of LES combustion models to predict flame dynamics will be validated. The model must be reliable even for coarse meshes and at elevated pressure, where sub-grid flame wrinkling can be considerable. The MISO models determined with validated LES/SI can be combined with acoustic models to study, for example, the impact of location and acoustic impedance of fuel injectors on the thermoacoustic stability of combustors in a flexible and efficient manner.

为了研究自激发的燃烧不稳定性，必须表征感兴趣的火焰对相关流动扰动的反应。在拟议的研究中，将同时建模和量化上游速度和等效比率的技术对上游速度和等效比率的扰动的动态响应。这将通过结合湍流的大型涡流模拟（LES）来实现这一目标，从而与高级系统识别（SI）进行反应，以生成降低的火焰动力学订单模型，以适当尊重多重输入 /单输出（MISO）结构技术预混合的火焰。将解决两个主要的挑战：1）使用具有味o结构的框 - 詹金斯模型的高级SI方法将用于识别LES时间序列数据中减少的订单响应函数。与基于传统识别方案的模型不同，所得的火焰模型将独立于燃油喷射系统的声学特性。此外，由分辨的湍流波动产生的燃烧噪声不会像先前的SI框架中无视，而是将其建模为有色噪声。这提高了整体识别的质量，并允许量化由有限的时间序列长度导致的不确定性。 2）用系统识别（SI）确定的减少订单模型只能与从中推导的时间序列数据一样准确。此外，误差识别需要相当长的时间序列。因此，必须采用或开发和验证既准确又有效的技术预混合火焰LE的湍流燃烧模型。此外，将验证LES燃烧模型预测火焰动力学的能力。该模型即使对于粗网格，在升高的压力下，该模型也必须是可靠的，在较高的压力下，亚电网火焰皱纹可能是可靠的。用经过验证的LES/SI确定的味iso模型可以与声学模型结合使用，例如研究燃料注射器对燃料对燃烧器对燃烧器热声稳定性的影响，以灵活而有效的方式进行。