期刊文献+
共找到10篇文章
< 1 >
每页显示 20 50 100
基于涡旋强度亚格子应力模型的湍流有旋流动大涡模拟 被引量:1
1
作者 夏朝阳 张宏达 +2 位作者 于洲 叶桃红 唐鹏 《中国科学技术大学学报》 CAS CSCD 北大核心 2018年第3期236-245,共10页
为了改进大涡模拟方法预测湍流有旋流动的能力,将一种基于涡旋强度构建的亚格子涡粘模型应用于悉尼旋流燃烧器的冷态场大涡模拟中.选取高雷诺数低旋流数和低雷诺数高旋流数两种工况,验证该模型在强剪切且有旋流场大涡模拟中的表现,并与... 为了改进大涡模拟方法预测湍流有旋流动的能力,将一种基于涡旋强度构建的亚格子涡粘模型应用于悉尼旋流燃烧器的冷态场大涡模拟中.选取高雷诺数低旋流数和低雷诺数高旋流数两种工况,验证该模型在强剪切且有旋流场大涡模拟中的表现,并与动态Smagorinsky(DSM)模型模拟结果以及实验结果进行比较.模拟结果表明,基于涡旋强度模型(SSM)的大涡模拟结果能够合理预测钝体回流区、二次回流区以及中心射流进动等重要特征,同时速度统计矩结果总体好于DSM模型结果.但在旋流剪切层处二阶矩预测较高,说明SSM模型在剪切层处可能耗散较大,需要改进. 展开更多
关键词 大涡模拟 涡粘模型 悉尼旋流燃烧器 涡旋强度
下载PDF
高雷诺数湍流非预混火焰及NO生成的大涡模拟 被引量:1
2
作者 于洲 黄立航 +1 位作者 叶桃红 朱旻明 《空气动力学学报》 CSCD 北大核心 2020年第3期629-640,共12页
采用两种亚网格湍流燃烧模型,即化学建表方法结合假定概率密度模型和稀疏拉格朗日过滤密度函数方法,对高雷诺数湍流非预混火焰Flame D进行数值研究,定量比较不同亚网格模型的差异,并对火焰特征、污染生物生成特性进行分析。结果表明,两... 采用两种亚网格湍流燃烧模型,即化学建表方法结合假定概率密度模型和稀疏拉格朗日过滤密度函数方法,对高雷诺数湍流非预混火焰Flame D进行数值研究,定量比较不同亚网格模型的差异,并对火焰特征、污染生物生成特性进行分析。结果表明,两类亚网格燃烧模型预测的温度及大组分分布相近,稀疏拉格朗日过滤密度函数方法可以更好地模拟CO质量分数分布。不同的假定概率分布均可合理描述湍流与火焰的相互作用,之间的差别主要体现在NO分布,Dirac函数远高估了NO生成,而Top-hat函数则略低估了NO生成,Beta函数表现最优。Flame D的高温区及NO质量分数均主要分布在当量混合线及富燃侧附近。受高温伴流的影响,NO质量分数与温度一直保持高度正相关,峰值主要集中在标量耗散率很小的区域。不同截面上,反应物中的O2和生成物中的H2O均与NO高度相关。 展开更多
关键词 化学建表方法 过滤密度函数方法 假定概率密度函数 湍流非预混火焰 氮氧化物
下载PDF
浓度分层下正庚烷自点火过程的直接数值模拟 被引量:1
3
作者 吴煜杨 叶桃红 朱旻明 《燃烧科学与技术》 EI CAS CSCD 北大核心 2019年第4期353-358,共6页
针对实际内燃机内存在浓度分层的情况,采用直接数值模拟,研究了浓度分层对正庚烷在空气中的自点火过程的影响.结果表明:在压力2.4MPa,初始温度860K(位于负温度系数区域)下,随着浓度分层的增加,整体着火时间提前,但是第1阶段点火延迟时... 针对实际内燃机内存在浓度分层的情况,采用直接数值模拟,研究了浓度分层对正庚烷在空气中的自点火过程的影响.结果表明:在压力2.4MPa,初始温度860K(位于负温度系数区域)下,随着浓度分层的增加,整体着火时间提前,但是第1阶段点火延迟时间几乎没有变化.第2阶段着火位置的混合物分数随着浓度分层的增加而变大,说明两阶段着火不存在统一的最易着火的混合分数.通过budget分析,揭示低温反应和高温反应阶段存在不同的火焰传播模式. 展开更多
关键词 自点火过程 点火延迟时间 浓度分层 直接数值模拟 负温度系数
下载PDF
基于RELAP5的气液相界面跨节点时压力峰修正方法的研究
4
作者 王小虎 赵平辉 +3 位作者 叶桃红 熊琰 谭超 陈云龙 《核动力工程》 EI CAS CSCD 北大核心 2024年第1期34-40,共7页
为减小或消除RELAP5在垂直分层流动计算时气液相界面跨节点的非物理压力峰,提高计算的稳定性,从动量方程的角度出发,研究造成垂直单管排放算例中出现压力峰的原因,并提出了直接对动量方程进行修正从而减小压力峰的方法。研究发现,液相... 为减小或消除RELAP5在垂直分层流动计算时气液相界面跨节点的非物理压力峰,提高计算的稳定性,从动量方程的角度出发,研究造成垂直单管排放算例中出现压力峰的原因,并提出了直接对动量方程进行修正从而减小压力峰的方法。研究发现,液相非稳态项是引起此类压力峰的主要原因。基于此,发展了用于修正液相非稳态项的数值方法,并且通过垂直单管的充排问题和压力计问题对该数值方法进行了验证。验证结果表明,该修正方法可以减小气液相界面跨节点时的非物理压力峰,有利于提高程序的计算稳定性。 展开更多
关键词 垂直分层流动 气液相界面 RELAP5 压力峰 动量方程
原文传递
Numerical study of methane/air jet flame in vitiated co-flow using tabulated detailed chemistry 被引量:7
5
作者 HAN Chao ZHANG Pei +1 位作者 ye taohong CHEN YiLiang 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第9期1750-1760,共11页
Two different combustion models,the autoignition(AI)model and flamelet/progress variable(FPV)model,have been applied to study the auto-ignition process of methane/air jet flame in vitiated co-flow.A priori study was c... Two different combustion models,the autoignition(AI)model and flamelet/progress variable(FPV)model,have been applied to study the auto-ignition process of methane/air jet flame in vitiated co-flow.A priori study was conducted to test the validity of the two models.Results show that the different range of predicted reaction rates is mainly responsible for their different performances in large eddy simulation(LES)studies.In this paper,beta PDF was used to model the mixture fraction distribution,while two different shapes of PDF,delta function and beta function,were applied for the reaction progress.Compared to the FPV model,the AI model combined with beta function for reaction progress could capture the auto-ignition process and predict the exact lifted height.Also the results indicate that the variance of reaction progress plays an important role in predicting the flame lifted height. 展开更多
关键词 喷射火焰 数值模拟 空气 甲烷 化学 表格 反应速率 点火过程
原文传递
Large eddy simulation of unconfined turbulent swirling flow 被引量:5
6
作者 ZHANG HongDa HAN Chao +2 位作者 ye taohong ZHANG JiMin CHEN YiLiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第10期1731-1744,共14页
Large eddy simulations(LES) were performed to study the non-reacting flow fields of a Cambridge swirl burner. The dynamic Smagorinsky eddy viscosity model is used as the sub-grid scale turbulence model. Comparisons of... Large eddy simulations(LES) were performed to study the non-reacting flow fields of a Cambridge swirl burner. The dynamic Smagorinsky eddy viscosity model is used as the sub-grid scale turbulence model. Comparisons of experimental data show that the LES results are capable of predicting mean and root-mean-square velocity profiles. The LES results show that the annular swirling flow has a minor impact on the formation of the bluff-body recirculation zone. The vortex structures near the shear layers, visualized by the iso-surface of Q-criterion, display ring structures in non-swirling flow and helical structures in swirling flow near the burner exit. Spectral analysis was employed to predict the occurrence of flow oscillations induced by vortex shedding and precessing vortex core(PVC). In order to extract accurately the unsteady large-scale structures in swirling flow, a three-dimensional proper orthogonal decomposition(POD) method was developed to reconstruct turbulent fluctuating velocity fields. POD analysis reveals that flow fields contain co-existing helical and toroidal shaped coherent structures. The helical structure associated with the PVC is the most energetic dynamic flow structure. The latter toroidal structure associated with vortex shedding has lower energy content which indicates that it is a secondary structure. 展开更多
关键词 旋流燃烧器 湍流模型 大涡模拟 侧限 螺旋结构 流动结构 环形结构 反应流场
原文传递
Large eddy simulation of hydrogen/air scramjet combustion using tabulated thermo-chemistry approach 被引量:6
7
作者 Cao Changmin ye taohong Zhao Majie 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2015年第5期1316-1327,共12页
Large eddy simulations (LES) have been performed to investigate the flow and combustion fields in the scramjet of the German Aerospace Center (DLR). Turbulent combustion is mod- eled by the tabulated thermo-chemis... Large eddy simulations (LES) have been performed to investigate the flow and combustion fields in the scramjet of the German Aerospace Center (DLR). Turbulent combustion is mod- eled by the tabulated thermo-chemistry approach in combination with the presumed probability density function (PDF). A/3-function is used to model the distribution of the mixture fraction, while two different PDFs, g-function (Model I) and //-function (Model II), are applied to model the reaction progress. Temperature is obtained by solving filtered energy transport equation and the reaction rate of the progress variable is rescaled by pressure to consider the effects of compressibil- ity. The adaptive mesh refinement (AMR) technique is used to properly capture shock waves, boundary layers, shear layers and flame structures. Statistical results of temperature and velocity predicted by Model II show better accuracy than that predicted by Model I. The results of scatter points and mixture fraction-conditional variables indicate the significant differences between Model I and Model II. It is concluded that second moment information in the presumed PDF of the reaction progress is very important in the simulation of supersonic combustion. It is also found that an unstable flame with extinction and ignition develops in the shear layers of bluff body and a fuel- rich partially premixed flame stabilizes in the central recirculation bubble. 展开更多
关键词 Large eddy simulation(LES) Presumed probability densityfunction (PDF) Scram jet Tabulated thermo-chemistry Turbulent combustion model
原文传递
Study of the mechanisms of the flame propagation and stabilization in porous media 被引量:3
8
作者 ZHAO PingHui ye taohong +1 位作者 JIANG Hai CHEN YiLiang 《Science China(Technological Sciences)》 SCIE EI CAS 2008年第7期871-881,共11页
The CH4/air premixed gas combustion processes in porous media were numerically studied using the two-temperature reacting fluid model with dispersions and detailed chemical reaction mechanism GRI 3.0. The mechanisms o... The CH4/air premixed gas combustion processes in porous media were numerically studied using the two-temperature reacting fluid model with dispersions and detailed chemical reaction mechanism GRI 3.0. The mechanisms of the propagation and stabilization of submerge flames and surface flames in porous media were illuminated distinctly by considering the magnitude of the terms in the two energy equations, analyzing the sensibility of flame propagation speed to flame location, heat exchange coefficient between gas and solid, thermal conductivity and radiative extinction coefficient of porous media. It was concluded that the propagation mechanism of a submerged flame is similar to that of a free flame with an additional preheat zone and that the surface-flame propagation mechanism in porous media is similar to that of a free flame with heat loss in reaction zone. 展开更多
关键词 POROUS media surface FLAME SUBMERGED FLAME FLAME propagation SPEED
原文传递
Continuum-based slip model and its validity for micro-channel flows 被引量:3
9
作者 ZHANG Genxuan LIU Minghou +3 位作者 ZHANG Xianfeng ye taohong CHEN Yiliang WANG Lu 《Chinese Science Bulletin》 SCIE EI CAS 2006年第9期1130-1137,共8页
In this paper, the low Mach number he- lium and nitrogen flows in micro-channels are inves- tigated numerically with variations of inlet to outlet pressure ratios, aspect ratios, out pressures and fluid mediums by usi... In this paper, the low Mach number he- lium and nitrogen flows in micro-channels are inves- tigated numerically with variations of inlet to outlet pressure ratios, aspect ratios, out pressures and fluid mediums by using different continuum-based slip models. Theoretical solutions based on perturbation expansions of the Navier-Stokes equations have been developed under different order slip conditions. The validity of slip models has been examined by the corresponding experiments and the DSMC method at different Knudsen numbers. Simulations have shown good predictions of the compressibility, rarefaction and thermal creep effects on micro-channel flows with the present slip models. The higher order slip models relatively decrease the rarefaction effects comparing with a first-order slip model. Both of the Knudsen number and the Reynolds number have been identified as key parameters, which govern the rarefaction effects and thermal creep effects, respec- tively. The present slip models have been also dem- onstrated to be appropriate for micro-channel nitro- gen flows with the Knudsen number less than 0.15, and the higher order slip conditions improve the Na- vier-Stokes predictions in the slip flow regime with Kn<0.08. However, the continuum-based slip models significantly under-predict the rarefaction effects in the transitional flow regime as the Knudsen number exceeds 0.2. 展开更多
关键词 微通道 滑移模型 扰动分析 稀疏效应 克努森数
原文传递
Calibration of a new very large eddy simulation(VLES)methodology for turbulent flow simulation 被引量:2
10
作者 HAN XingSi ye taohong CHEN YiLiang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第10期1905-1914,共10页
Following the idea of Speziale's Very Large Eddy Simulation(VLES) method,a new unified hybrid simulation approach was proposed which can change seamlessly from RANS(Reynolds-Averaged Navier-Stokes) to LES(Large Ed... Following the idea of Speziale's Very Large Eddy Simulation(VLES) method,a new unified hybrid simulation approach was proposed which can change seamlessly from RANS(Reynolds-Averaged Navier-Stokes) to LES(Large Eddy Simulation) method depending on the numerical resolution.The model constants were calibrated in accordance with other hybrid methods.Besides being able to approach the two limits of RANS and LES,the new model also provides a proper VLES mode between the two limits,and thus can be used for a wide range of mesh resolutions.Also RANS simulation can be recovered near the wall which is similar to the Detached Eddy Simulation(DES) concept.This new methodology was implemented into Wilcox's k-ω model and applications were conducted for fully developed turbulent channel flow at Reτ = 395 and turbulent flow past a square cylinder at Re = 22000.Results were compared with LES predictions and other studies.The new method is found to be quite efficient in resolving large flow structures,and can predict satisfactory results on relative coarse mesh. 展开更多
关键词 大涡模拟 校准方法 NAVIER-STOKES方程 湍流模拟 RANS 混合方法 湍流模型 LES
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部