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turbulent combustion modeling using a flamelet generated manifold approach——a validation study in Open FOAM

Applied Mathematics and Mechanics(English Edition) 2019年第8期40卷 1197-1210页

作者： Tao LI Fanfu KONG4 Baopeng XU Xiaohan WANG Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou 510640China Key Laboratory of Renewable Energy Chinese Academy of Sciences Guangzhou 510640China Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou 510640China Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of TechnologyDalian 116024Liaoning ProvinceChina

An OpenFOAM based turbulence combustion solver with flamelet generated manifolds (FGMs) is presented in this paper. A series of flamelets, representative for turbulent flames, are calculated first by a one-dimensional (1D) detailed chemistry solver with the consideration of both transport and stretch/curvature contributions. The flame structure is then parameterized as a function of multiple reaction control variables. A manifold, which collects the 1D flame properties, is built from the 1D flame solutions. The control variables of the mixture fraction and the progress variable are solved from the corresponding transport equations. During the calculation, the scalar variables, e.g., temperature and species concentration, are retrieved from the manifolds by interpolation. A transport equation for NO is solved to improve its prediction accuracy. To verify the ability to deal with the enthalpy loss effect, the temperature retrieved directly from the manifolds is compared with the temperature solved from a transport equation of absolute enthalpy. The resulting FGM-computational fluid dynamics (CFD) coupled code has three significant features, i.e., accurate NO prediction, the ability to treat the heat loss effect and the adoption at the turbulence level, and high quality prediction within practical industrial configurations. The proposed method is validated against the Sandia flame D, and good agreement with the experimental data is obtained.

关键词： flamelet generated manifold turbulent combustion NO prediction

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turbulent intensity and its similarity function over an Inner Mongolian grassland during spring

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Science China Earth Sciences 2010年第5期53卷 773-780页

作者： YUE Ping1,2,3, NIU ShengJie2, HU YinQiao4 & ZHANG Qiang1 1 Key Laboratory of Arid Climate Change and Reducing Disaster of Gansu Province, Key Laboratory of Arid Climate Change and Reducing Disaster of CMA, Institute of Arid Meteorology, CMA, Lanzhou 730020, China 2 Nanjing University of Information Science and Technology, Nanjing 210044, China 3 Zhangye National Meteorological Observatory, Zhangye 734000, China 4 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou 730000, China Key Laboratory of Arid Climate Change and Reducing Disaster of Gansu Province Key Laboratory of Arid Climate Change and Reducing Disaster of CMA Institute of Arid Meteorology CMA Lanzhou China Nanjing University of Information Science and Technology Nanjing China Zhangye National Meteorological Observatory Zhangye China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Science Lanzhou China

Macroscopic reason for the development of turbulences in fluid is the conjunction action of velocity and temperature shears. We use the 2008 spring flux observations in the surface layer over Inner Mongolian grassland, obtain the similarity functions of turbulent intensity under different stratification stability conditions, and calculate the clear day turbulent intensity in the spring, which is then analyzed and compared with the observed values of turbulent intensity. The results show that in the Inner Mongolian grassland, under the condition of spring unstable stratification of the surface layer, dependence of the similarity function of turbulent intensity on stratification stability follows a "2/3 power law". The structural function is a constant under the neutral stratification condition, and complicated under the stable condition. The calculated turbulent intensity has a close correlation with the observed one, which verifies the accuracy of the similarity functions and the suitability of the theorem of turbulent intensity in the grassland region.

关键词： turbulent intensity variance of velocity similarity function grassland

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turbulent Inlet Conditions Modeling using Large-eddy Simulations

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Computer Modeling in Engineering & Sciences 2015年第2期104卷 105-132页

作者： M.M.R.Damasceno J.M.Vedovoto A.da Silveira-Neto UFU UberlandiaMGBrazil

Turbulence is a phenomenon which presents peculiarities when it is experimented or *** occurs due to its complexity and high sensibility to the inlet conditions of the turbulent flow fields,as well as the presence of a large range of time and length scales.A simplification for this situation is obtained with the use of approximations and turbulence *** the present work,the Largeeddy Simulations methodology was applied,aiming the modeling of the previously mentioned complexity,which consists in using a filter to resolve the large scales while the remaining scales were determined by classical and dynamic Smagorinsky *** different approximations for the inlet conditions were applied:white noise,Random Flow Generation(RFG)and Synthetic Eddy Method(SEM).It was possible to realize that the use of the dynamic Smagorinky model and the RFG or SEM methodologies resulted in a better characterization of the studied flow.

关键词： turbulent inlet conditions turbulence models large-eddy simulations

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turbulent Prandtl Number

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Science China Mathematics 1994年第11期37卷 1347-1353页

作者：钱俭 Department of Physics Graduate SchoolAcademia SinicaBeijing 100039PRC

The method of determining eddy transport coefficients of turbulence is utilized to study how the turbulent Prandtl number Prturb depends upon the molecular Prandtl number Pr and turbulence conditions.A comparison betw... 详细信息

关键词： turbulence spectral dynamics turbulent Prandtl number.

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turbulent flame image classification using Convolutional Neural Networks

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能源与人工智能(英文) 2022年第4期10卷 87-94页

作者： Rathziel Roncancio Aly El Gamal Jay P.Gore School of Mechanical Engineering Purdue UniversityWest LafayetteIN47907USA School of Electrical and Computer Engineering Purdue UniversityWest LafayetteIN 47907USA

Pockets of unburned material in turbulent premixed flames burning CHs,air,and CO_(2) were studied using OH Planar Laser-Induced Fuorescence(PLIF)images to improve current *** flames are ubiquitous in most natural gas air combustors running gas turbines with dry exhaust gas recirculation(EGR)for land-based power *** improvements continue in the charactenization and understanding of turbulent flames with EGR particularly for transient events like ignition and *** and/or islands of unburned material within bumed and unburned turbulent media are some of the features of these *** features reduce the heat release rates and increase the carbon monoxide and hydrocarbons *** present work involves Convolutional Neural Networks(CNN)based dassification of PIF images containing unburned pockets in three turbulent flames with 0%,5%,and 10%CO_(2).The CNN model was constructed using three convolutional layers and two fully connected layers using dropout and weight *** of 94.2%,92.3%and 89.2%were registered for the three flames,*** present approach represents significant computational time savings with respect to conventional image processing methods.

关键词： CNN Flame Neural network turbulent

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Two-point statistics of coherent structures in turbulent flow over riblet-mounted surfaces

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Acta Mechanica Sinica 2019年第3期35卷 457-471页

作者： Weipeng Li Hong Liu School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

Direct numerical simulations (DNS) of turbulent flow over a drag-reducing and a drag-increasing riblet configuration are performed. Three-dimensional two-point statistics are presented for the first time to quantify the interaction of the riblet surfaces with the coherent, energy-bearing eddy structures in the near-wall region. Results provide statistical evidence that the averaged organization of the streamwise vortices in the drag-reducing case is lifted above the riblet tip, while in the drag-increasing case the streamwise vortices are embedded further into the riblet cove. In the spanwise direction, the cores of the streamwise vortices over the riblet surfaces are shown to be closer to each other than those for flow over the smooth wall, and wider riblet spacing leads to more reduction on their spanwise distances. In the cases with riblets the streamwise vortices have longer streamwise lengths, but their inclination angles do not change much.

关键词： turbulent drag reduction Riblets Coherent structures

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Numerical Simulation on Gas-Solid Two-Phase turbulent Flow in FCC Riser Reactors(Ⅱ) Numerical Simulation on the Gas-Solid Two-Phase turbulent Flow

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Chinese Journal of Chemical Engineering 1998年第1期6卷 25-32页

作者：高金森徐春明林世雄郭印诚王希麟 State Key Laboratory of Heavy Oil Processing Petroleum University Department of Engineering Mechanics Tsinghua University

Numerical simulation on the flow,heat transfer and cracking reactions in commercial fluid catalyticcracking(FCC)riser reactors were carried out employing the developed turbulent gas-solid two-phase flow-reac-tion model for FCC riser reactors given in Part Ⅰ of the present *** information about the turbulentflow fields in the riser reactor obtained revealed the basic characteristics of the gas-solid two-phase turbulentflows when heat transfer and catalytic cracking reactions were co-existing in the *** showed that thedistributions of the flow,the turbulence kinetic energy and the catalyst particle concentration are not uniform inthe axial,radial and tangential *** most complicated part of the riser reactor is the feed *** complicated configuration of the turbulent gas-solid two-phase flows would exert a great influence onthe results of interphase heat transfer and cracking reactions.

关键词： commercial riser reactor flow-reaction model turbulent flow numerical simulation flow field

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Reflected shock/turbulent boundary layer interaction structure analysis based on large eddy simulation

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Chinese Journal of Aeronautics 2021年第5期34卷 364-372页

作者： Dongdong ZHONG Lixu WANG Ning GE College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Nanjing Engineering Institute of Aircraft Systems AVICNanjing 210016China

In order to understand the physical phenomenon of the reflected shock/turbulent boundary layer interaction,the Large Eddy Simulation(LES)is conducted to investigate shock wave and turbulent boundary layer interaction in a 12°compression ramp with inlet high Mach number of ***/recycling method is used as inflow turbulence generation technique and validated on a supersonic flat plate turbulent boundary *** flow field of recycling plane in the plate computation domain is obtained to give the inlet boundary condition for the LES *** paper focuses on the reflected shock/turbulent boundary layer interaction region,where the fine flow structure and instantaneous flow field are analyzed in *** is found that the unsteady motion of the shock wave leads to the increase of wall pressure fluctuation.

关键词： Large eddy simulation Reflected STBLI Rescaling/recycling method Shock motion turbulent

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Effects of the Reynolds number on the mean skin friction decomposition in turbulent channel flows

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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 331-342页

作者： Yitong FAN Cheng CHENG Weipeng LI School of Aeronautics and Astronautics Shanghai Jiao Tong University Engineering Research Center of Gas Turbine and Civil Aero Engine

As the Reynolds number increases, the skin friction has been identified as the dominant drag in many practical applications. In the present paper, the effects of the Reynolds number on the mean skin friction decomposition in turbulent channel flows up to Reτ= 5 200 are investigated based on two different methods, i.e., the FukagataIwamoto-Kasagi(FIK) identity(FUKAGATA, K., IWAMOTO, K., and KASAGI, *** of Reynolds stress distribution to the skin friction in wall-bounded *** of Fluids, 14(11), L73–L76(2002)) and the Renard-Deck(RD) identity(DECK,S., RENARD, N., LARAUFIE, R., and WEISS, P.′E. Large-scale contribution to mean wall shear stress in high-Reynolds-number flat-plate boundary layers up to Reθ= 13 *** of Fluid Mechanics, 743, 202–248(2014)). The direct numerical simulation(DNS) data provided by Lee and Moser(LEE, M. and MOSER, R. D. Direct numerical simulation of turbulent channel flow up to Reτ≈ 5 200. Journal of Fluid Mechanics,774, 395–415(2015)) are used. For these two skin friction decomposition methods, their decomposed constituents are discussed and compared for different Reynolds *** integrands of the decomposed constituents are locally analyzed across the boundary layer to assess the actions associated with the inhomogeneity and multi-scale nature of turbulent motion. The scaling of the decomposed constituents and their integrands are presented. In addition, the boundary layer is divided into three sub-regions to evaluate the contributive proportion of each sub-region with an increase in the Reynolds number.

关键词： drag decomposition mean skin friction turbulent channel flow Reynolds number effect

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MODELLING AND COMPUTATION OF UNSTEADY turbulent CAVITATION FLOWS

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Journal of Hydrodynamics 2006年第5期18卷 559-566页

作者： CHEN Ying LU Chuan-jing WU Lei Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

Unsteady turbulent cavitation flows in a Venturi-type section and around a NACA0012 hydrofoil were simulated by two-dimensional computations of viscous compressible turbulent flow model. The Venturi-type section flow proved numerical precision and reliability of the physical model and the code, and further the cavitation around NACA0012 foil was investigated. These flows were calculated with a code of SIMPLE-type finite volume scheme, associated with a barotropic vapor/liquid state law which strongly links density and pressure variation. To simulate turbulent flows, modified RNG k-ε model was used. Numerical results obtained in the Venturi-type flow simulated periodic shedding of sheet cavity and was compared with experiment data, and the results of the NACA0012 foil show quasi-periodic vortex cavitation phenomenon. Results obtained concerning cavity shape and unsteady behavior, void ratio, and velocity field were found in good agreement with experiment ones.

关键词： turbulent cavitation Venturi NACA0012

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