SPRINGER BRIEFS IN APPLIED SCIENCES AND TECHNOLOGY MULTIPHASE FLOW Mingyan Liu Zongding Hu Nonlinear Analysis and Prediction of Time Series in Multiphase Reactors SpringerBriefs in Applied Sciences and Technology Multiphase Flow Series editors Lixin Cheng, Portsmouth, UK Dieter Mewes, Hannover, Germany For furthervolumes: http://www.springer.com/series/11897 Mingyan Liu Zongding Hu • Nonlinear Analysis and Prediction of Time Series in Multiphase Reactors 123 MingyanLiu Zongding Hu School ofChemical Engineering School ofChemical Engineering and Technology and Technology TianjinUniversity TianjinUniversity Tianjin Tianjin People’s Republic ofChina People’s Republic ofChina and State KeyLaboratory ofChemical Engineering Tianjin People’s Republic ofChina ISSN 2191-530X ISSN 2191-5318 (electronic) ISBN 978-3-319-04192-6 ISBN 978-3-319-04193-3 (eBook) DOI 10.1007/978-3-319-04193-3 SpringerChamHeidelbergNewYorkDordrechtLondon LibraryofCongressControlNumber:2013956739 (cid:2)TheAuthor(s)2014 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation,broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionor informationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodology now known or hereafter developed. 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While the advice and information in this book are believed to be true and accurate at the date of publication,neithertheauthorsnortheeditorsnorthepublishercanacceptanylegalresponsibilityfor anyerrorsoromissionsthatmaybemade.Thepublishermakesnowarranty,expressorimplied,with respecttothematerialcontainedherein. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Acknowledgments TheauthorsaregratefultotheNaturalScienceFoundationofChina(contractNos. 20106012 and 20576091), the Open Foundation of State Key Laboratory of Mul- tiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences and the Cheung Kong Scholar Program for Innovative Teams of the MinistryofEducation(contactNo.IRT0641)forfinancialsupportofthework.The authorsalsowishtothankDr.KlarenD.G.,Profs.KwaukM.,LiJ.,andLiuC.for their helpful comments and suggestions. We want to thank the members of our researchgroup team for their great contributionsfor this work. v Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Experimental. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1 Apparatus and Set-ups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2 Data Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Analysis Tools of Time Series Data. . . . . . . . . . . . . . . . . . . . . . . . 13 3.1 Time Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2 Power Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.3 Attractor Reconstruction and Phase Plot. . . . . . . . . . . . . . . . . . 13 3.4 Correlation Dimension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.5 Kolmogorov Entropy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.6 The Largest Lyapunov Exponent. . . . . . . . . . . . . . . . . . . . . . . 15 3.7 Local Non-Linear Short-Term Prediction . . . . . . . . . . . . . . . . . 16 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4 Results and Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.1 Single-Orifice Bubbling Mechanism . . . . . . . . . . . . . . . . . . . . 19 4.1.1 Time-Domain and Power Spectrum. . . . . . . . . . . . . . . . 19 4.1.2 Phase Plane Plot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.1.3 Kolmogorov Entropy and Correlation Dimension . . . . . . 22 4.1.4 Local Non-Linear Short-Term Prediction. . . . . . . . . . . . 27 4.2 Multi-Orifice Bubbling Behavior. . . . . . . . . . . . . . . . . . . . . . . 29 4.2.1 Traditional Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.2.2 Chaos Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.2.3 Flow Regime Identification Method . . . . . . . . . . . . . . . 35 4.3 Gas–Liquid–Solid Fluidized Beds . . . . . . . . . . . . . . . . . . . . . . 37 4.3.1 Ordinary Gas–Liquid–Solid Fluidized Beds . . . . . . . . . . 37 4.3.2 Magnetized Gas–Liquid–Solid Fluidized Beds . . . . . . . . 39 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 vii Abstract This chapter reports our recent work on the nonlinear aspects or deterministic chaosissuesinthesystemsofmultiphasereactors.Thereactorsincludegas–liquid bubblecolumns,gas–liquid–solidfluidizedbeds,andgas–liquid–solidmagnetized fluidized beds.Pressurefluctuations inthemultiphasesystemswere takenastime series for nonlinear analysis, modeling, and forecasting. The qualitative and quantitativenonlinearanalysistoolsincludeattractorphaseplaneplot,correlation dimension,KolmogoroventropyandlargestLyapunovexponentcalculations,and local nonlinear short-term prediction. First, chaotic bubbling dynamics and transition mechanism in gas–liquid bubble columns with single orifice were investigated.Second,thechaoticcharacteristicsingas–liquidbubblecolumnswith multiorificedistributorwerepresented.Finally,nonlinearbehaviorsinothertypes of multiphase reactors were explored briefly. The main results are as follows. Bubbling process with single orifice exhibited deterministic chaotic behavior in a certain range of gas flow rate. With the increase of gas flow rate, the sequence of periodic bubbling, primary chaotic bubbling, advanced chaotic bubbling, and jettingwassuccessivelyfound.Thesuddenincreaseoflocalnonlinearforecasting errorofpressuresignalwithtimeprovidedanevidenceofthepresenceofchaotic bubbling.Multivaluephenomenaofchaoticinvariantsresultedfromthemultiscale behaviorexistingintheheterogeneousflowregimeinmultiorificebubblecolumns. Flowregimesandtheirtransitionscouldbecharacterizedeffectivelybythechaotic invariantsforthesemultiphasereactors.Forgas–liquid–solidfluidizedbeds,some new flow regimes were identified by chaotic analyses. For gas–liquid–solid magnetized fluidized bed, the values of chaotic invariants reduced with the increase of magnetic field strength at given superficial gas velocity and liquid velocity. Keywords Gas–liquid bubble column (cid:2) Gas–liquid–solid fluidized bed (cid:2) Time series (cid:2) Chaotic analysis (cid:2) Pressure fluctuation (cid:2) Prediction ix Notation B Magnetic induction, T C Correlation integral ðrÞ d Embedding dimension D Correlation dimension 2 f Frequency, Hz g Functional relationship between the current state and the future state G Predictor which approximates function g HðxÞ Heaviside function K Kolmogorov entropy, bit/s K Order-2 Renyi entropy, bit/s 2;m Lðt Þ Replacement length at evolution time t of k step, k k dimensionless m Embedding dimension M Total known number of data points n Total number of replacement steps N Length of restructured vector X i N Number of predicted points p P Pressure, p a P Experimentally measured pressure, p e a P Predicted pressure, p p a P Power spectrum ðfÞ Q Gas flow rate, ml/min r Radius of hyper-sphere, dimensionless X Restructured vector i x Component of restructured vector t Time, s U Superficial gas velocity, m/s g Greek Letters d Standard deviation or size of the attractor e Holdup, dimensionless g c Correlation coefficient k Largest Lyapunov exponent 1 s Time delay, s Dt Sample time interval, s xi Chapter 1 Introduction Understanding the hydrodynamics in the gas–liquid bubble columns with single- ormulti-orificeorinthegas–liquid–solidfluidizedbedsincludinggas–liquid–solid magnetizedfluidizedbedsisofgreatimportanceforprocessindustriesbutitisstill not well known due to the limitations of traditional analysis methods and the complexityofmultiphaseflowsystemsthemselves[1,2].Itisinterestingtostudy the bubbling hydrodynamics from the point of view of modern non-linear dynamics [3–10]. Regardingasthebubblinghydrodynamicswithsingleorifice,TrittonandEgdell [11] carried out a set of experiments in a beaker on bubbling from an upwardly pointing vertical tube of an internal diameter of 1.2 mm. A period-doubling sequence leading to chaotic behavior in the inter-pulse return maps was found by analyzingthesignalfromahot-filmanemometerprobeplacedintheliquidnearthe bubbleformationregion.Mittonietal.[12]performedasetofexperimentsovera slightly broader set of conditions than that of Tritton and Egdell [11]. Similar sequence was observed in the inter-pulse return maps by analyzing the gas inlet pressure signal in the gas chamber. Nguyen et al. [13] investigated the spatio- temporaldynamicsinatrainofrisingbubblesandfoundthattheanalogybetween the rising bubbles in fluids and an inverted dripping faucet is weak. Li et al. [14] studiedthein-linebubblecoalescenceinnon-Newtonianfluidsinabubblecolumn. Bubble generation was through an orifice of varying diameter, submerged in the non-Newtonianliquidatthecenterofthebottomsectionofthetank.Thesignalsof frequency of bubble passage at different heights in the tank were measured by optical probes of photodiodes placed at the external wall of the square duct. The nonlinearanalysesrevealedthatthecoalescencebetweenbubbles obeys achaotic and deterministic mechanism. Ruzicka et al. [15] studied the chaotic features of bubbling from a submerged orifice above a gas chamber using the simultaneous measurements of gas chamber pressure and liquid velocity fluctuations. Besides return maps analysis, mean and variance, intermittency factor, distribution of thelengthofjettingbursts,Kolmogoroventropy,K,correlationdimension,D ,the 2 Mann-Whitney statistic, power spectrum of signal were calculated to reveal the underlying structure of the data. Although the typical period doubling sequence leading to chaotic behavior was not found, the sequence of periodic bubbling, M.LiuandZ.Hu,NonlinearAnalysisandPredictionofTimeSeries 1 inMultiphaseReactors,SpringerBriefsonMultiphaseFlow, DOI:10.1007/978-3-319-04193-3_1,(cid:2)TheAuthor(s)2014 2 1 Introduction chaotic bubbling and random bubbling was observed. Luewisutthichat et al. [16] investigatedthepowerspectrum,KandD byanalyzingtherisevelocityandshape 2 fluctuations of single bubbles bubbling through an orifice in a two-dimensional bubble column and found that the signals of bubble velocity and shape exhibit chaos. Tufaile and Sartorelli [17] studied the dynamics of the formation of air bubblesinasubmergedorificeinawater/glycerinsolutioninsideacylindricaltube. Thedelaytimebetweensuccessivebubbleswasmeasuredwithalaser-photodiode system. The sequence of period-1, period-2, period-3, period-4, period-2 and chaotic bubbling was observed by analyzing the constructed bifurcation diagrams andfirstreturnmaps.TufaileandSartorelli[18]studiedtheformationofairbubbles in a submerged nozzle in a water/glycerol solution inside a cylindrical tube sub- mitted to a sound wave perturbation. They observed a route to chaos via period doublingasafunction ofthesound waveamplitude andestablishedrelationstoa Henon-likedynamicswiththeconstructionofsymbolicplanes.Theysuggestedthat the bubble formation be seen as an oscillator driven by a sound wave. They [19] also found aroute tochaos via quasi-periodicity. Mosdorf and Shoji [20] described nonlinear features and analytical results for the chaotic bubbling from a submerged orifice of 2 mm in diameter and micro- convection induced by the bubble generation was recorded using hot-probe ane- mometerlocatedclosetotheorifice.Theyperformedthenonlinearanalysisforthe time series data of hot-probe anemometer including the calculation of the largest Lyapunov exponent and proposed a simple model to simulate the process of interactionbetween theelastic bubble walland liquid. Theyfound thatone ofthe reasons for chaos appearance is the nonlinear character of interaction between an elastic bubble wall and the liquid stream. Sarnobat et al. [21] studied the effect of an applied electric potential on the dynamicsofgasbubbleformationfromasinglenozzleinglycerolexperimentally. Theyfoundthatatconstantgasflow,bubble-formationexhibitedaclassicperiod- doubling route to chaos with increasing potential. Although electric potential and gas flow appeartohave similar effects on theperiod-doublingbifurcation process forthissystem,therelativeimpactofelectrostaticforcesissmaller.However,the relative impact of electrostatic forces for the case of insulating liquid and con- ducting gas phases is comparable to flow forces. Li et al. [22] studied the dynamics of a chain of bubbles rising in polymeric solutions by stimulus-response simulation, birefringence and particle image ve- locimetry. They identified two aspects as central to interactions and coalescence: stress creation by bubble passages and their relaxation. The competition displays complex nonlinear dynamics and can be described by a simple but explicit mathematical model. Recently, Frank and Li [23] investigated the chaotic dynamicsofabubblechainrisinginapolymericfluidbycognitivemodelingand analytical analysis. Good agreement of the cognitive simulation results with experimental data was obtained and this reveals that the period doubling bifur- cation sequence is the route to chaotic behavior. CieslinskiandMosdorf[24]discussedthenonlinearfeaturesoftheairbubbling fromasubmergedglassnozzlessubmergedindistilledwaterinacylindricaltank.