Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics最新文献_第6页

An Improved Hybrid Alternative WENO Scheme for High Mach Number Flows 一种改进的高马赫数流混合备选WENO格式

Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics Pub Date : 2021-08-10 DOI: 10.1115/fedsm2021-65717

U. S. Rajput, K. Singh

引用次数: 1

Fractal and Convolutional Analysis for Deep Atmospheric Turbulence Using Machine Learning 基于机器学习的深层大气湍流分形和卷积分析

Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics Pub Date : 2021-08-10 DOI: 10.1115/fedsm2021-65798

Nicholas Dudu, Arturo Rodríguez, Gael Moran, Jose Terrazas, Richard Adansi, V. Kotteda, Christopher Harris, Vinod Kumar

{"title":"Fractal and Convolutional Analysis for Deep Atmospheric Turbulence Using Machine Learning","authors":"Nicholas Dudu, Arturo Rodríguez, Gael Moran, Jose Terrazas, Richard Adansi, V. Kotteda, Christopher Harris, Vinod Kumar","doi":"10.1115/fedsm2021-65798","DOIUrl":"https://doi.org/10.1115/fedsm2021-65798","url":null,"abstract":"\u0000 Atmospheric turbulence studies indicate the presence of self-similar scaling structures over a range of scales from the inertial outer scale to the dissipative inner scale. A measure of this self-similar structure has been obtained by computing the fractal dimension of images visualizing the turbulence using the widely used box-counting method. If applied blindly, the box-counting method can lead to misleading results in which the edges of the scaling range, corresponding to the upper and lower length scales referred to above are incorporated in an incorrect way. Furthermore, certain structures arising in turbulent flows that are not self-similar can deliver spurious contributions to the box-counting dimension. An appropriately trained Convolutional Neural Network can take account of both the above features in an appropriate way, using as inputs more detailed information than just the number of boxes covering the putative fractal set. To give a particular example, how the shape of clusters of covering boxes covering the object changes with box size could be analyzed. We will create a data set of decaying isotropic turbulence scenarios for atmospheric turbulence using Large-Eddy Simulations (LES) and analyze characteristic structures arising from these. These could include contours of velocity magnitude, as well as of levels of a passive scalar introduced into the simulated flows. We will then identify features of the structures that can be used to train the networks to obtain the most appropriate fractal dimension describing the scaling range, even when this range is of limited extent, down to a minimum of one order of magnitude.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125787636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Prediction of Combustion Performance of Biodiesel in Gas Turbine Combustor 生物柴油在燃气轮机燃烧室的燃烧性能预测

Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics Pub Date : 2021-08-10 DOI: 10.1115/fedsm2021-66282

P. Yadav, N. Yadav

{"title":"Prediction of Combustion Performance of Biodiesel in Gas Turbine Combustor","authors":"P. Yadav, N. Yadav","doi":"10.1115/fedsm2021-66282","DOIUrl":"https://doi.org/10.1115/fedsm2021-66282","url":null,"abstract":"\u0000 This paper focuses the computational fluid dynamics analysis inside the gas turbine combustor for the combustion of biodiesel and air mixture. The biodiesel (methyl soyate) is made from the vegetable oil (soybean oil). ANSYS fluent is used for Numerical simulation and model adapted Eddy dissipation concept for turbulence, discrete model, k-epsilon (standard), and the species transport. The model was validated and the combustion performance of biodiesel is predicted with an air-assist injector. The fuel spray is created by commercially available airblast atomizer in this study. The strength of recirculation increases with increased in equivalence ratio. The strong corner recirculation was observed at 0.75 equivalence ratio. The higher turbulence kinetic energy is found at the middle of the combustor. The temperature increases with the increase in the equivalence ratio in the flame stable region while it decreases with increases in the equivalence ratio. It was observed that an increase in the equivalence ratio, flame length increases. The profiles of carbon monoxide (CO) and nitric oxides (NOx) emissions can be obtained at 15% atomizing airflow rates, while the total airflow rate kept constant. The NOx and CO emissions are effected mainly by the fuel-air mixing process that the fuel-air mixing process and atomization have the great impact on CO and NOx emissions.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121686286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A New RANS Correction to Account for Varying Viscosity Effects 一种新的RANS校正来解释不同的粘度效应

Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics Pub Date : 2021-06-10 DOI: 10.1115/fedsm2021-65823

V. Leite, E. Merzari

{"title":"A New RANS Correction to Account for Varying Viscosity Effects","authors":"V. Leite, E. Merzari","doi":"10.1115/fedsm2021-65823","DOIUrl":"https://doi.org/10.1115/fedsm2021-65823","url":null,"abstract":"\u0000 It has previously been shown that by increasing the Reynolds number across a channel by spatially varying the viscosity does not cause an immediate change in the size of turbulent structures and a delay is in fact observed in both wall shear and friction Reynolds number (Coppo Leite, V, & Merzari, E., Proceedings of the ASME 2020 FEDSM, p. V003T05A019). Furthermore, it is also shown that depending on the length in which the flow condition changes, turbulence bursts are observed in the turbulence field. For the present work we propose a new version of the standard Reynolds Averaged Navier Stokes (RANS) k–τ model that includes some modifications in the production term in order to account for these effects. The new proposed model may be useful for many engineering applications as turbulent flows featuring temperature gradients and high heat transfer rates are often seen in heat exchangers, combustion chambers and nuclear reactors. In these applications, thermal and viscous properties of the working fluid are important design parameters that depend on temperature; hence it is likely to observe strong gradients on these scalars’ fields. To accomplish our goal, the modifications for the k–τ model are implemented and tested for a channel flow with spatial varying viscosity in the streamwise direction. The numerical simulations are performed using Nek5000, a spectral-element code developed at Argonne National Laboratory (ANL). Finally, the results considering a turbulence channel using the proposed model are compared against data obtained using Direct Numerical Simulations from the earlier work.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"242 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121330715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0