THEORETICAL INVESTIGATION OF TURBULENT COMBUSTION IN STRATIFIED INHOMOGENOUS MIXTURES USING DIRECT NUMERICAL SIMULATION

利用直接数值模拟对分层不均质混合物中的湍流燃烧进行理论研究

• 批准号: EP/E026516/1
• 负责人: Nilanjan Chakraborty
• 金额: $ 18.74万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE026516%2F1
• 关键词: THEORETICAL; INVESTIGATION; TURBULENT; COMBUSTION; STRATIFIED

The aim of this project is to understand the effects of turbulence on hydrocarbon fuel combustion where the fuel and oxidizer distribution form a highly stratified mixture at the time of ignition. For stratified charge combustion the reactants are neither homogeneously mixed (premixed) nor completely separated (non- premixed). Thus the analysis of this kind of combustion has special modelling needs in comparison to fully premixed or fully non-premixed flames. Turbulent combustion in a stratified fuel-air mixture is highly relevant in the context of both spark-ignition gasoline and compression-ignition Diesel engines and has the potential for reducing fuel consumption especially at low-speed, light- load operations in automobile applications. Stratified-charge combustion can also be found in the Lean Premixed Prevaporised (LPP) combustors in aircraft gas turbines where fuel and injected secondary air form an inhomogeneous fuel-air mixture ahead of the flame front. The capability of predicting accurately the flame propagation behaviour in the presence of mixture inhomogeneities and intense turbulence would facilitate the development of low-emission, energy-efficient devices, such as automotive engines and gas-turbine combustors. The proposed research project consists of three parts. In the first, three-dimensional (3-D) Direct Numerical Simulations (DNS) with simplified chemistry, appropriate for the combustion of realistic hydrocarbon fuels, will be performed for a variety of mixing fields and turbulence intensities to enhance the present state of fundamental understanding and to create a database for the assessment of existing combustion models and to develop new models wherever necessary. Three-dimensional DNS with a reasonable degree of detailed chemistry will be carried out based on the information gained from 3-D DNS with simplified chemistry. The second part of the project involves the development of a combustion model in the context of Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulations (LES). The model will be implemented with a view to future incorporation into industry-standard Computational Fluid Dynamics (CFD) packages, which can then be used for engineering design purposes.

该项目的目的是了解湍流对碳氢化合物燃料燃烧的影响，其中燃料和氧化剂分布在点火时形成高度分层的混合物。对于分层电荷燃烧，反应物既不是均匀混合（预混合）也不完全分离（未预混合）。因此，对这种燃烧的分析与完全预混合或完全未结的火焰相比，具有特殊的建模需求。在火花点燃汽油和压缩点击柴油发动机的背景下，分层燃料空气混合物中的湍流燃烧高度相关，并且有可能减少燃油消耗，尤其是在汽车应用中的低速，轻质负载操作下。在飞机燃气轮机中的瘦肉预燃料（LPP）燃烧器中也可以找到分层电荷燃烧，燃料和二级空气形成了火焰前方前方的不均匀燃油空气混合物。在存在混合物不均匀性和强烈的湍流的情况下，准确预测火焰传播行为的能力将有助于促进低发射，节能设备（例如汽车发动机和气动涡轮机燃烧器）的发展。拟议的研究项目由三个部分组成。在第一个具有简化化学的直接数值模拟（DNS）中，将进行适合于逼真的碳氢化合物燃料的燃烧，以进行各种混合场和湍流强度，以增强目前的基本理解状态，并为现有的燃烧而开发新的模型，以增强目前的理解状态。将根据具有简化化学的3-D DNS获得的信息，进行具有合理程度的详细化学性质的三维DNS。该项目的第二部分涉及在Reynolds平均Navier Stokes（RANS）和大型涡流模拟（LES）的背景下开发燃烧模型。该模型将进行实施，以期将未来的纳入行业标准计算流体动力学（CFD）软件包，然后可以用于工程设计目的。

项目成果

The relation between flame surface area and turbulent burning velocity in statistically planar turbulent stratified flames

统计平面湍流分层火焰中火焰表面积与湍流燃烧速度之间的关系

• DOI: 10.1063/5.0031291
• 发表时间: 2020
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: Brearley P