International Journal of Spray and Combustion Dynamics最新文献_第4页

Improving droplet sizing methodology for spray dynamics investigation 改进喷雾动力学研究中的液滴尺寸测定方法

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716640244

J. J. Woo, V. Garaniya, R. Abbassi

{"title":"Improving droplet sizing methodology for spray dynamics investigation","authors":"J. J. Woo, V. Garaniya, R. Abbassi","doi":"10.1177/1756827716640244","DOIUrl":"https://doi.org/10.1177/1756827716640244","url":null,"abstract":"Spray modelling is one of the most useful techniques to characterize engine performance, efficiency and emissions. The size of droplets is one of the key variables that govern the efficiency of combustion of the liquid fuel. This study aims to develop an interactive tool using MATLAB codes that identifies the droplets and their sizes from the image taken with the long distance microscope in the spray chamber setup. In this developed method, firstly the background of the image was removed and then image processing techniques, dilation and erosion, were applied to the image file to refine the image files. Subsequently, circle detection method based on the Hough Transform algorithm with the function of imfindcircles was implemented. This function of the program allows the user to identify size droplets from the image files. A statistical study was conducted with the results automated from the MATLAB program using a different set of threshold values of black and white contrast. The results showed an optimal range for the threshold (black and white) values between 40 and 70. This optimal threshold range was established based on consideration of the correct and incorrect identification of the droplets. The results indicated that the program has the ability to identify the droplet providing size and numbers. The MATLAB program was developed using MATLAB compiler and can be used at different workstations.","PeriodicalId":49046,"journal":{"name":"International Journal of Spray and Combustion Dynamics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2016-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756827716640244","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65531866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

The effect of bend positions on premixed methane–air explosion overpressures in ducts 弯曲位置对管道内预混甲烷-空气爆炸超压的影响

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716645115

Chuan-jie Zhu, Zi-shan Gao, B. Lin, Zhong Tan, Yu-min Sun, Yidu Hong, Chang Guo

引用次数: 2

Theoretical investigation of the particle response to an acoustic field 粒子对声场响应的理论研究

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716641118

Javier Achury, W. Polifke

{"title":"Theoretical investigation of the particle response to an acoustic field","authors":"Javier Achury, W. Polifke","doi":"10.1177/1756827716641118","DOIUrl":"https://doi.org/10.1177/1756827716641118","url":null,"abstract":"In this paper, the problem of a particle subjected to an acoustic field is addressed theoretically. Once the fundamental equation of motion is obtained, two nonlinearities are identified: one related to the drag law and one associated with the excitation. In order to face the nonlinearities, two cases are constructed: the first corresponds to the parametric numerical solution of a particle with nonlinear drag in an oscillating flow field (infinite wavelength) and the second refers to the particle submitted to an acoustic standing wave (finite wavelength). For the latter, an approximated analytical solution is formulated. The system is linearized around an equilibrium point and the parameters of the equation are grouped in three nondimensional numbers: the Stokes number (St), the acoustic Mach number (Ma), and the densities ratio (γ). Conditions of parametric resonance in the particle response are deduced for this system by means of the analytical method here proposed, based on Hill’s determinants. Comparison with numerical solutions of the linearized and nonlinearized equations close to an equilibrium point corroborates the analysis for different combinations of parameters.","PeriodicalId":49046,"journal":{"name":"International Journal of Spray and Combustion Dynamics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2016-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756827716641118","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65531959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Modeling random combustion of lycopodium particles and gas 模拟石蒜颗粒和气体的随机燃烧

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716638963

M. Bidabadi, P. Aghajannezhad, M. Harati, E. Yaghoubi, Gholamreza Shahriari

引用次数: 6

Dynamic data-driven prediction of instability in a swirl-stabilized combustor 涡流稳定燃烧室不稳定性的动态数据驱动预测

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716642091

S. Sarkar, S. Chakravarthy, V. Ramanan, A. Ray

{"title":"Dynamic data-driven prediction of instability in a swirl-stabilized combustor","authors":"S. Sarkar, S. Chakravarthy, V. Ramanan, A. Ray","doi":"10.1177/1756827716642091","DOIUrl":"https://doi.org/10.1177/1756827716642091","url":null,"abstract":"Combustion instability poses a negative impact on the performance and structural durability of both land-based and aircraft gas turbine engines, and early detection of combustion instabilities is of paramount importance not only for performance monitoring and fault diagnosis, but also for initiating efficient decision and control of such engines. Combustion instability is, in general, characterized by self-sustained growth of large-amplitude pressure tones that are caused by a positive feedback arising from complex coupling of localized hydrodynamic perturbations, heat energy release, and acoustics of the combustor. This paper proposes a fast dynamic data-driven method for detecting early onsets of thermo-acoustic instabilities, where the underlying algorithms are built upon the concepts of symbolic time series analysis (STSA) via generalization of D-Markov machine construction. The proposed method captures the spatiotemporal co-dependence among time series from heterogeneous sensors (e.g. pressure and chemiluminescence) to generate an information-theoretic precursor, which is uniformly applicable across multiple operating regimes of the combustion process. The proposed method is experimentally validated on the time-series data, generated from a laboratory-scale swirl-stabilized combustor, while inducing thermo-acoustic instabilities for various protocols (e.g. increasing Reynolds number (Re) at a constant fuel flow rate and reducing equivalence ratio at a constant air flow rate) at varying air-fuel premixing levels. The underlying algorithms are developed based on D-Markov entropy rates, and the resulting instability precursor measure is rigorously compared with the state-of-the-art techniques in terms of its performance of instability prediction, computational complexity, and robustness to sensor noise.","PeriodicalId":49046,"journal":{"name":"International Journal of Spray and Combustion Dynamics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2016-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756827716642091","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65532079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 43

Helical modes in combined Rayleigh–Taylor and Kelvin–Helmholtz instability of a cylindrical interface 圆柱界面瑞利-泰勒不稳定性和开尔文-亥姆霍兹不稳定性的螺旋模态

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716642159

M. Vadivukkarasan, M. Panchagnula

{"title":"Helical modes in combined Rayleigh–Taylor and Kelvin–Helmholtz instability of a cylindrical interface","authors":"M. Vadivukkarasan, M. Panchagnula","doi":"10.1177/1756827716642159","DOIUrl":"https://doi.org/10.1177/1756827716642159","url":null,"abstract":"The effect of competing Rayleigh–Taylor and Kelvin–Helmholtz mechanisms of instability applied to a cylindrical two-fluid interface is discussed. A three-dimensional temporal linear stability model for the instability growth is developed based on the frozen time approximation. The fluids are assumed to be inviscid and incompressible. From the governing equations and the boundary conditions, a dispersion relation is derived and analyzed for instability. Four different regimes have been shown to be possible, based on the most unstable axial and circumferential wavenumbers. The four modes are the Taylor mode, the sinuous mode, the flute mode and long and short wavelength helical modes. The effect of Bond number, Weber number, and density ratio are investigated in the context of the mode chosen. It is found that Bond number is the primary determinant of the neutral stability while Weber number plays a key role in identifying the instability mode that is manifest. A regime map is presented to delineate the modes realized for a given set of flow parameter values. From this regime map, a short wavelength helical mode is identified which is shown to result only when both the Rayleigh–Taylor and Kelvin–Helmholtz instability mechanisms are active. A scaling law for the magnitude of the wavenumber vector as a function of Bond number and Weber number are also developed. A length scale is defined to characterize the interface distortion. Using this length scale, the set of conditions where the interface exhibits a maximum in surface area creation is identified. With the objective of achieving the smallest characteristic length scale of interface distortion, a criterion to optimally budget mean flow energy is also proposed.","PeriodicalId":49046,"journal":{"name":"International Journal of Spray and Combustion Dynamics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2016-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756827716642159","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65532248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

A numerical study of the propagation of organic gellant-based fuel-rich premixed spray flames 有机胶凝基富燃料预混喷雾火焰传播的数值研究

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716640709

J. Greenberg, LS Kagan, GI Sivashinsky

引用次数: 1

Numerical modeling of soot formation in a turbulent C2H4/air diffusion flame 湍流C2H4/空气扩散火焰中烟尘形成的数值模拟

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-04-21 DOI: 10.1177/1756827716638814

M. R. Busupally, A. De

{"title":"Numerical modeling of soot formation in a turbulent C2H4/air diffusion flame","authors":"M. R. Busupally, A. De","doi":"10.1177/1756827716638814","DOIUrl":"https://doi.org/10.1177/1756827716638814","url":null,"abstract":"Soot formation in a lifted C 2 H 4 -Air turbulent diffusion flame is studied using two different paths for soot nucleation and oxidation; by a 2D axisymmetric RANS simulation using ANSYS FLUENT 15.0. The turbulence-chemistry interactions are modeled using two different approaches: steady laminar flamelet approach and flamelet-generated manifold. Chemical mechanism is represented by POLIMI to study the effect of species concentration on soot formation. P1 approximation is employed to approximate the radiative transfer equation into truncated series expansion in spherical harmonics while the weighted sum of gray gases is invoked to model the absorption coefficient while the soot model accounts for nucleation, coagulation, surface growth, and oxidation. The first route for nucleation considers acetylene concentration as a linear function of soot nucleation rate, whereas the second route considers two and three ring aromatic species as function of nucleation rate. Equilibrium-based and instantaneous approach has been used to estimate the OH concentration for soot oxidation. Lee and Fenimore-Jones soot oxidation models are studied to shed light on the effect of OH on soot oxidation. Moreover, the soot-radiation interactions are also included in terms of absorption coefficient of soot. Furthermore, the soot-turbulence interactions have been invoked using a temperature/mixture fraction-based single variable PDF. Both the turbulence-chemistry interaction models are able to accurately predict the flame liftoff height, and for accurate prediction of flame length, radiative heat loss should be accounted in an accurate way. The soot-turbulence interactions are found sensitive to the PDF used in present study.","PeriodicalId":49046,"journal":{"name":"International Journal of Spray and Combustion Dynamics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2016-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756827716638814","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65531781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Experimental investigation of combustion instabilities in lean swirl-stabilized partially-premixed flames in single- and multiple-burner setup 单燃烧器和多燃烧器下稀旋流稳定部分预混火焰燃烧不稳定性的实验研究

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-03-01 DOI: 10.1177/1756827715627064

C. Kraus, S. Harth, H. Bockhorn

{"title":"Experimental investigation of combustion instabilities in lean swirl-stabilized partially-premixed flames in single- and multiple-burner setup","authors":"C. Kraus, S. Harth, H. Bockhorn","doi":"10.1177/1756827715627064","DOIUrl":"https://doi.org/10.1177/1756827715627064","url":null,"abstract":"In the present work, combustion instabilities of a modular combustor are investigated. The combustor operates with partially premixed, swirl-stabilized flames and can be operated in single- and different multiple-burner setups. The design parameters of the combustor prevent large-scale flame–flame interactions in the multiple-burner arrangements. The objective is to investigate how the interaction of the swirl jets affects the thermoacoustic stability of the combustor. Results of measurements of pressure oscillations and high-speed OH*-chemiluminescence imaging for the single-burner setup and two multiple-burner setups are discussed. Additionally, results of investigations with different flame characteristics are presented. These are achieved by varying the ratio of the mass flow rates through the swirlers of the double-concentric swirl nozzle. Several unstable modes with high pressure amplitudes are observed in the single-burner setup as well as in the multiple-burner setups. Numerical studies of the acoustic behavior of the combustor setups were performed that indicate that the different geometries show similar acoustic behaviors. The results lead to the conclusion that the interaction of the swirl jets in the multiple-burner setups affects the thermoacoustic response spectrum of the flame even in the absence of large-scale flame–flame interactions. Based on the findings in earlier studies, it is concluded that the differences in the flame response characteristics are induced by the reduction of the swirl intensity in the multiple-burner arrangements, which is caused by the exchange of momentum between the adjacent swirl jets.","PeriodicalId":49046,"journal":{"name":"International Journal of Spray and Combustion Dynamics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2016-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756827715627064","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65531202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Control authority over a combustion instability investigated in CFD 燃烧不稳定性控制权限的CFD研究

IF 1.6 4区工程技术

International Journal of Spray and Combustion Dynamics Pub Date : 2016-03-01 DOI: 10.1177/1756827715627071

R. Müller, J. Hermann, W. Polifke

引用次数: 3