Computational and Experimental Methods in Multiphase and Complex Flow X最新文献_第2页

LUBRICATION OF GEARBOXES: CFD ANALYSIS OF A CYCLOIDAL GEAR SET 齿轮箱的润滑:摆线齿轮组的CFD分析

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190101

F. Concli, L. Maccioni, C. Gorla

{"title":"LUBRICATION OF GEARBOXES: CFD ANALYSIS OF A CYCLOIDAL GEAR SET","authors":"F. Concli, L. Maccioni, C. Gorla","doi":"10.2495/MPF190101","DOIUrl":"https://doi.org/10.2495/MPF190101","url":null,"abstract":"In recent years, the increasing demand for more and more compact and efficient solutions has highlighted the need to have appropriate tools in order to optimize the internal design, to avoid thermal problems, ensuring proper lubrication and to increase the reliability of the systems. Typical high power density gearbox designs are based on planetary, harmonic and cycloidal architectures. Although many analytical and numerical models are already available for the prediction of the power losses related to gear meshing (sliding), bearings and seals, literature is lacking in terms of hydraulic power loss models (deep lubrication, churning, windage and squeezing). Some numerical multiphase CFD and experimental studies on parallel axis and planetary gear sets have been already performed by the authors in previous research. The aim of this paper is to extend the applicability of the previously developed numerical techniques to cycloidal architectures, taking into account the typical lubricants used for these type of drives. With respect to the load independent power losses (related to the interaction of the mechanical component and the surrounding lubricant), the cycloidal gear set has been numerically simulated with an especially developed CFD code implemented in the OpenFOAM® environment. A specific mesh handling technique allows us to manage the topological changes of the domain ensuring the numerical stability of the simulation and the correct calculation of the complex multiphase flows that take place in gearboxes. The results have been compared with those already available for other gear architectures with similar performances (dimensions, reduction ratios and loads).","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132189606","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: 21

PROTON RADIOGRAPHY OF EXPLOSIVELY DISPERSED METAL PARTICLES WITH VARYING CARRIER FLUID 带不同载体流体的爆炸分散金属颗粒的质子x线摄影

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190211

K. Hughes, K. Prestridge, N. Kim, R. Haftka, S. Balachandar

{"title":"PROTON RADIOGRAPHY OF EXPLOSIVELY DISPERSED METAL PARTICLES WITH VARYING CARRIER FLUID","authors":"K. Hughes, K. Prestridge, N. Kim, R. Haftka, S. Balachandar","doi":"10.2495/MPF190211","DOIUrl":"https://doi.org/10.2495/MPF190211","url":null,"abstract":"A series of experiments performed at Los Alamos National Laboratory aimed to provide validation data for numerical simulations performed at the Centre of Compressible Multiphase Turbulence at the University of Florida. Five explosive tests were performed. Approximately 2.8 g of PBX-9501 was initiated by a RP-80 detonator. A 13 x 6 mm cylindrical packet of 100 μm steel particles was dispersed by the explosive. Three ambient carrier fluids were investigated: air, xenon, and SF6. To penetrate the optically opaque explosive products at the early time and track the dispersed particle cloud, radiography was required. Proton radiography performed at the Los Alamos Neutron Science Centre allowed extraction of 21 radiograph images at 2 μs temporal resolution. Upstream and downstream particle fronts were extracted from the transmission radiographs. Centreline particle fronts for the three carrier phases demonstrated close agreement, suggesting the shock traversing the bed of particles provided little additional impulse to the dispersed particles in this regime. An additional shot was performed in vacuum and showed close agreement with the carrier phase shots, furthering this conclusion.","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123231324","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: 1

FULLY DEVELOPED BUBBLY TWO-PHASE FLOW THROUGH A PIPE: AN ANALYTICAL SOLUTION 完全发展的气泡两相流通过管道:一个解析解

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190141

W. Ali, M. Nazeer, A. Zeeshan

引用次数: 0

SWELLING DURING PYROLYSIS OF FIBRERESIN COMPOSITES WHEN HEATED ABOVE NORMAL OPERATING TEMPERATURES 当加热高于正常工作温度时，纤维-树脂复合材料在热解过程中膨胀

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190171

B. Houchens, Sarah N. Scott, Victor E. Brunini, E. Jones, M. Montoya, Wendy Flores-Brito, K. Hoffmeister

引用次数: 0

ANALYTICAL MODEL AND NUMERICAL STABILITY ANALYSIS FOR FALLING LIQUID FILM REGIMES IN VERTICAL PIPES 垂直管道降液膜流场的解析模型及数值稳定性分析

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190091

J. Muñoz-Cobo, S. M. Iglesias, D. S. Dominguez, A. Escrivá, C. Berna

{"title":"ANALYTICAL MODEL AND NUMERICAL STABILITY ANALYSIS FOR FALLING LIQUID FILM REGIMES IN VERTICAL PIPES","authors":"J. Muñoz-Cobo, S. M. Iglesias, D. S. Dominguez, A. Escrivá, C. Berna","doi":"10.2495/MPF190091","DOIUrl":"https://doi.org/10.2495/MPF190091","url":null,"abstract":"Gravity-driven falling film flows in vertical pipes are relevant in many industrial processes like evaporators, chemical reactors, and condensers. The wave formation and propagation processes, which continuously take place in the film, have a strong influence on the flow hydrodynamics and the heat and mass transfer phenomena. Several researchers have been studying the wave behaviour in these multiphase regimes through experimental works and computational fluid dynamics simulation techniques. In some simplified cases, like high viscosity fluids and infinity inclined plates, analytical solutions have been obtained. In this work, we propose an analytical model for falling film flow regimes in vertical pipes. Starting from the incompressible axisymmetric Navier–Stokes equations in cylindrical coordinates, we consider the force balance in the fluid, an asymptotic long-wave approximation and the first-order perturbation approximation for axial velocity. From this balance, we obtain a partial differential equation that describes the interface behaviour through the film thickness. The resulting equation can be solved using a numerical approach. The main resulting equation represents a stiff problem, thus, we perform a stability analysis using the fluid viscosity as a parameter. Finally, we set the model validity conditions and suggest some actions to improve the numerical strategy in order to better describe low viscosity fluids.","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130285426","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: 3

STUDY OF POLYMER ELASTIC BEHAVIOR IN THE DISPLACEMENT OF OIL DROPS AT PORE SCALE 孔隙尺度下油滴驱替过程中聚合物弹性行为的研究

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190161

L. Prada, A. Chaves, Julio Pedraza, Jose Gómez, S. Muñoz

{"title":"STUDY OF POLYMER ELASTIC BEHAVIOR IN THE DISPLACEMENT OF OIL DROPS AT PORE SCALE","authors":"L. Prada, A. Chaves, Julio Pedraza, Jose Gómez, S. Muñoz","doi":"10.2495/MPF190161","DOIUrl":"https://doi.org/10.2495/MPF190161","url":null,"abstract":"Polymeric liquids have been used in the oil industry, especially at enhanced oil recovery (EOR). From the rheological point of view, polymers have the particularity of being viscoelastic liquids. One of the most common and useful models to describe that behavior is the upper convected Maxwell model (UCM). The main characteristic of the polymer used in the EOR process is the increase in viscosity which pushes the oil outside of the reservoir. The elasticity could contribute to the drag of the oil that stays in the reservoir. Studying the elastic effect on the oil drop at the pore scale, brings an explanation if the addition of elastic force could mobilize the oil. This research explores if the contraction and expansion of the polymer in the pore-scale may increase the elastic behavior of this kind of fluid. For that reason, this work simplified the pore geometry and built two simple geometries with micrometer lengths. Using source terms with the user defined function this work introduces the UCM model in the ANSYS Fluent simulator with the purpose of evaluating the elastic effect of the polymer in a contraction and expansion geometry. Also, using the Eulerian multiphase model this research considers the possibility that extra elastic force will show a deformation effect on the oil, for that reason, this work considers an oil drop on the upper wall of the geometry. Finally, all the simulations exhibit that at pore scale conditions extra vortices exist in the UCM model but it is not possible to deform the oil completely and push it outside of the restrictions.","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124594265","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

MASS TRANSFER THROUGH FREE SURFACE BOUNDARY LAYERS USING A STATISTICAL APPROACH 用统计方法通过自由表面边界层传质

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190081

Francisco Antonio Loyola Lavin, H. Schulz

{"title":"MASS TRANSFER THROUGH FREE SURFACE BOUNDARY LAYERS USING A STATISTICAL APPROACH","authors":"Francisco Antonio Loyola Lavin, H. Schulz","doi":"10.2495/MPF190081","DOIUrl":"https://doi.org/10.2495/MPF190081","url":null,"abstract":"Mass exchange through gas–liquid interfaces, whose liquid side has a turbulent nature, are still difficult to quantify due to the unclosed set of turbulence equations, which are also nonlinear. This paper describes an efficient method to overcome this difficulty, by substituting the statistical variables of the original equations by statistical relationships furnished by the Random Square Waves (RSW) tool. Oscillatory records are simplified using random square waves (ideal and binary), which allow a theoretical statistical treatment of the signals. This tool was applied to the concentration boundary layer at the gas–liquid interface. Normalized mass fluxes and mean concentration profiles were obtained using Taylor-series-based solutions, which allow for consideration of transient situations through the successive calculation of the higher order coefficients (derivatives). Comparisons with experimental data available in open literature are presented as a first evaluation of the Taylor series, showing promising results. This method is a viable tool, and this study shows novel conclusions that reproduce general tendencies observed in one-dimensional mass transfer phenomena in boundary layers.","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133650079","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

INTERACTION OF A CAVITATION BUBBLE WITH AN ANTIBUBBLE 空化泡与反泡的相互作用

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190131

Bai Lixin, Xu. Weilin, Yan Jiuchun, Zeng Zhijie

{"title":"INTERACTION OF A CAVITATION BUBBLE WITH AN ANTIBUBBLE","authors":"Bai Lixin, Xu. Weilin, Yan Jiuchun, Zeng Zhijie","doi":"10.2495/MPF190131","DOIUrl":"https://doi.org/10.2495/MPF190131","url":null,"abstract":"ABSTRACT An antibubble is the opposite of a bubble: a thin spherical gas shell containing liquid inside and surrounded by liquid outside. Although antibubbles are rarely used in industry, they do have some potential applications, such as cleaning, lubrication, filtration and material transport. The dynamic behaviour of antibubbles and spark-induced cavitation bubbles is experimentally studied by using highspeed photography. It is found that when spark discharges occur between the electrodes and the cavitation bubble begin to expand, the antibubble splits into upper and lower parts. The upper parts with more gas produces annular liquid jet under the action of shock wave, and split into two bubbles in the next few cycles under the action of inertial force. The lower parts are composed of semi-spherical shell-like gas film. When the compression wave arrives, the gas film becomes thinner and contacts between the two sides of the gas film appear at some points. When the expansion wave arrives, the gas film becomes thicker and the contact point becomes larger to form holes. As the holes become larger and the gas film shrinks, many scattered microbubbles are formed. The secondary shock wave caused by the collapse of the cavitation bubble which occur a few milliseconds after the first shock wave (spark discharge) was observed by schlieren photography. The physical mechanism of interaction between cavitation bubble and antibubble is analysed.","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130971838","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

COMPUTATIONAL INVESTIGATIONS OF POLYMER SHEET BREAKUP FOR OPTIMIZATION OF DEVOLATILIZATION PROCESSES IN STEAM CONTACTORS 用于蒸汽接触器脱挥发过程优化的聚合物片分解计算研究

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190111

Bradley Shindle, A. Chandy

{"title":"COMPUTATIONAL INVESTIGATIONS OF POLYMER SHEET BREAKUP FOR OPTIMIZATION OF DEVOLATILIZATION PROCESSES IN STEAM CONTACTORS","authors":"Bradley Shindle, A. Chandy","doi":"10.2495/MPF190111","DOIUrl":"https://doi.org/10.2495/MPF190111","url":null,"abstract":"Polymer devolatilization is a vital process in polymer manufacturing and is significantly impactful on the successful creation of high quality polymers, meeting both rigorous product specifications and regulatory requirements. Polymers resulting from such processes have wide applications ranging from agricultural and biomedical solutions to aerospace components and even to modern day clothing and accessories. Although there are several popular methods used to accomplish the devolatilization process, this research focuses specifically on steam stripping, where superheated steam is used to remove any unwanted substances, such as volatiles and solvents, from the polymer mixture. This polymer mixture, referred to as ”cement” and comprised of polymer and a cyclohexane solvent, undergoes mixing with superheated steam in a contactor to evaporate and remove the cyclohexane. Between the heat and the aerodynamic forces caused by the mixing, the liquid polymer experiences sheet breakup. The objective of the current study is to create a computational fluid dynamics (CFD) model that solves for the initial breakup of the liquid mixture, and then use the resulting diameter distribution to simulate the trajectory and multiphase mass transfer of the cement as it forms into smaller and smaller droplets. A parametric","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126074464","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: 2

TWO-PHASE FLOW PHENOMENA IN A HORIZONTAL PIPE WITH A SUDDEN CONTRACTION: EFFECTS OF CONTRACTION RATIO ON FILM BEHAVIOUR 突然收缩水平管内两相流现象:收缩比对膜的影响

Computational and Experimental Methods in Multiphase and Complex Flow X Pub Date : 2019-07-23 DOI: 10.2495/MPF190061

T. Fujimatsu, M. Kito, K. Kondo

{"title":"TWO-PHASE FLOW PHENOMENA IN A HORIZONTAL PIPE WITH A SUDDEN CONTRACTION: EFFECTS OF CONTRACTION RATIO ON FILM BEHAVIOUR","authors":"T. Fujimatsu, M. Kito, K. Kondo","doi":"10.2495/MPF190061","DOIUrl":"https://doi.org/10.2495/MPF190061","url":null,"abstract":"Experimental studies were conducted on the behaviour of water films in a horizontal pipe with a sudden contraction to achieve a fundamental understanding of the film mechanisms of annular flow using high-speed video imaging analysis. The sudden contraction area ratios A C = (d 2 /d 1 ) 2 = 0.36 and 0.64, where d 1 is the inlet pipe diameter (50 mm) and d 2 is the contracted pipe diameter were examined. The experiments were carried out for various values of superficial gas and liquid velocities. The superficial gas velocity after mixing (j G1 ) ranged from 18.02 to 24.41 m/s (the calculated velocity from the cross-sectional at the sudden contraction was j G2 = 27.98–67.39 m/s) and the superficial liquid velocity (j L1 ) ranged from 8.62×10 -2 to 1.23×10 -1 m/s (j L2 = 1.35×10 -1 –3.42×10 -1 m/s). Four flow regimes were observed after the sudden contraction, namely, huge-wave (HW), two-dimensional disturbance wave (DW 1 ) which is formed perpendicularly to a pipe axis having a distinct coherence, three-dimensional disturbance wave (DW 2 ) which is formed obliquely to the pipe axis, and bow wave (DW 3 ) which is transitional wave to “Misty wave” from DW 2 . The disturbance wave occurrence frequencies were studied under various conditions of flow rate combination of air and water. DW 2 occurs over wide range of the superficial gas and liquid velocities. As the superficial gas velocity and the superficial liquid velocity increase, two-dimensional disturbance waves change into three-dimensional ones. The wave occurrence frequencies in the pipe with the sudden contraction ratio A C = 0.36 were mostly higher than those in the pipe with A C = 0.64.","PeriodicalId":399001,"journal":{"name":"Computational and Experimental Methods in Multiphase and Complex Flow X","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115056063","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