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燃料燃烧的影响，在燃烧时，燃料和氧化剂的分布形成高度分层的混合物。对于分层充量燃烧，反应物既不是均匀混合(预混)，也不是完全分离(非预混)。因此，与完全预混或完全非预混火焰相比，这种燃烧的分析具有特殊的建模需求。分层燃料-空气混合物中的湍流燃烧在火花点火汽油发动机和压燃式柴油发动机中都是高度相关的，并且有可能降低燃料消耗，特别是在汽车应用中的低速、轻负荷运行时。在飞机燃气轮机的稀薄预混预汽化(LPP)燃烧室中也可以发现分层充气燃烧，其中燃料和注入的二次空气在火焰前沿形成不均匀的燃料-空气混合物。在混合气不均匀和强烈湍流存在的情况下，准确预测火焰传播行为的能力将有助于开发低排放、节能的设备，如汽车发动机和燃气轮机燃烧室。建议的研究项目由三个部分组成。首先，将对各种混合场和湍流强度进行适用于实际碳氢燃料燃烧的简化化学的三维(3-D)直接数值模拟，以加强对基本认识的现状，并创建用于评估现有燃烧模型的数据库，并在必要时开发新模型。根据从简化化学的三维域名系统获得的信息，进行具有合理详细程度的三维域名系统。该项目的第二部分涉及在雷诺平均纳维斯托克斯(RANS)和大涡模拟(LES)的背景下开发燃烧模型。该模型的实施将着眼于未来纳入行业标准的计算流体动力学(CFD)程序包，然后可用于工程设计目的。

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