A Numerical Study on the Hydro-elastic Behavior of Composite Marine Propeller

Transcription

1 Fourth International Sympoium on Marine Propulor mp 15, Autin, Texa, USA, June 2015 A Numerical Stuy on the Hyro-elatic Behavior of Compoite Marine Propeller Hyounguk Lee 1, Min-Churl Song 2, Jung-Chun Suh 3, Myung-Chan Cha 1, Bong-Jun Chang 1 1 Maritime Reearch Intitute, Hyunai Heavy Inutrie, Co., Lt., Ulan, Korea 2 Inutrial Technology Intitute, Hyunai Heavy Inutrie, Co., Lt., Ulan, Korea 3 Department of Naval Architecture & Ocean Engineering, Reearch Intitute of Marine Sytem Engineering, Seoul National Univerity, Seoul, Korea ABSTRACT The topic of thi tuy i the numerical invetigation of hyro-elatic effect on a compoite marine propeller that account for the lamination of fiber material. For the propeller blae, BEM/FEM-bae teay an unteay tranient two-way iterative coupling flui-tructure interaction (FSI) analye are conucte. The teay an tranient FSI analyi methoologie are verifie by comparion with publihe moel tet from the author previou tuy. A imple tack finite-element (FE) moel that conier the effect of ply lamination an reuce the computation an moeling time i evie to be ue in the eign of the propeller. To evaluate the applicability of the moel, the tapere compoite material beam in the imple FE moel i compare with the actual layere tructure that reflect a real FE moel. The uability of revere engineering with teay analyi an the poibility of performance optimization at off-eign conition i confirme by applying the imple ply tack moel to the well-known KP458 benchmark propeller. Keywor Compoite Marine propeller; Hyro-elatic Analyi, Fluitructure interaction (FSI), Bounary element metho (BEM, Panel metho), Finite element metho (FEM), Steay tate analyi, Unteay tranient analyi, Acoutic meium, Ply, Lamination, Stack 1 INTRODUCTION Unlike ingle-material metal, compoite material have been wiely ue ue to their uperior propertie, uch a their light weight, high egree of tiffne an oun aborption. Depite the high cot, the excellent manufacturing an maintenance ability of an aitive prouction proce increae the ue of compoite material in many inutrial area, incluing aviation, environment/energy, information, electricity, automobile an houehol upplie. In aition to thee avantage, the application of compoite material in marine propeller coul alo offer many potential benefit: lighter weight, lower noie level, better maintainability, etc. In particular, the characteritic of the material, uch a flexibility an eformability, i better coniere at the eign tage. It i poible for the compoite propeller to reuce fuel oil conumption in it operating profile againt NAB (Nickel- Aluminum-Bronze alloy) metallic propeller which o not change their hape. To preict the propulion performance an tructural afety accurately, variou tuie have been conucte to analyze compoite marine propeller. Lin an Lin (1996) imulate the elatic behavior of marine propeller with a VLM FEM FSI analyi. Chen et al. (2006) an Young (2007, 2008) tuie teay an unteay hyro-elatic behavior of a compoite propeller with an FSI analyi an moel tet. Young alo conucte a BEM analyi to preict the hyroynamic amping effect for unteay behavior in the wake fiel. Aitionally, Motley et al. (2009) an Blaque et al. (2010) tuie optimum ply lamination for improving propulion performance. In thi paper, the BEM/FEM-bae FSI teay an unteay algorithm for flexible marine propeller i valiate by comparion with former tuie. In aition, the imple compoite ply-tacking FE moel i propoe, which i a practical application for moeling compoite blae with complex internal lay-up an core hape. Thi imple FE moel i alo valiate with a real FE moel. After valiation, a numerical invetigation of the compoite propeller with KP458 geometry at eign an off-eign conition i carrie out. 2. FORMULATION The flow aroun the propeller, tructural eformation of the blae an correlation of the interface are formulate to perform the hyro-elatic analyi for the performance preiction of a compoite propeller. The propeller i aume to be in incompreible, invici an irrotational

2 flow. Therefore, the perturbe velocity potential, ϕ, atifie the Laplace equation an the preure acting on the blae urface can be obtaine by uing velocity potential erive from the bounary element metho (BEM). The governing equation of oli eformation can be repreente a follow: coe, an implicit FEM olver (Abaqu Stanar) an a 2- way iterative interface. The rotational force uch a the Corioli an the centrifugal force, an the hyroynamic amping effect of the unteay conition, uch a ae ma, are calculate by Abaqu. M C K F ST (1) where M, C, K an FST are ma, amping, tiffne matrice an loa acting on the blae, repectively. The value of the ma, amping an tiffne in the valiation were obtaine from publihe experimental reult. An, an are noal acceleration, velocity, an iplacement vector, repectively. The total loa force F ST conit of the hyroynamic preure on the blae urface ( ), rotational boy force ( Fcori : Corioli force an Fcent : centrifugal force) an coupling component ( ). F f FST Fhp Fcori Fcent Ff F F f (2) Accoring to Young (2008), becaue the amount of blae eformation i not mall enough to aume linear, a twoway iterative coupling FSI analyi that inclue a tructural nonlinear analyi mut be introuce. To analyze trictly the elatic vibration repone ue to the changing flow fiel in a hip wake, the acoutic flui meium finite element moel i aapte to conier thi fluttering effect. The equation of flui preure that conier the coupling term of the bounary between the flui an the tructure interface i a follow: F hp Mfp Cf p Kfp Sf 0 (3) M f C f K f S f where,, an are hyroynamic ae ma, hyroynamic amping, hyroynamic pring an coupling matrix, repectively. An p i flui noe preure vector an i iplacement vector on the flui-tructure interface. The equation (4) can be repreente by (1) an (2). From equation (3) an (4), the ytem equation for the FSI problem can be expree a an equation (5). M C K S p F (4) T f M 0 0 C 0 S M f f p Cf p T K S F f 0 K p 0 f 3. HYDRO-ELASTIC ANALYSIS METHODOLOGY Bae on the evelope mathematical moel, the teay an unteay FSI analyi algorithm wa implemente. The funamental FSI algorithm tructure i hown in Figure 1. The hyro-elatic analyi coe inclue the BEM panel (5) Figure 1: Schematic iagram of a propeller blae FSI The eformation of a compoite propeller blae epen not only upon the loa acting on the blae urface, but alo the propertie of the compoite material, the ply tacking equence, the lamination orientation, etc. Therefore, to preict the initial blae geometry, the revere engineering proce i require in the eign of the blae. Figure 2 repreent the revere engineering algorithm for the initial eign of the blae. For more accurate performance preiction an tructural aement of the compoite propeller, a time omain-bae FSI analyi accounting for the blae poition in the hipwake fiel i require. Rotating blae in non-uniform inflow have a ynamic vibration behavior calle fluttering. Thi fluttering i caue by blae eformation in repone to preure loa change over time. Due to the

3 enity of the water, a marine propeller cannot iregar the amping effect of the ae ma on the blae urface which vibrate in the hip wake, unlike an aviation propeller or win turbine blae. Figure 2: Revere engineering algorithm for the initial eign of the blae Thu, the hyroynamic amping effect of the ae ma mut be coniere by applying the acoutic meium aroun the propeller blae. The evelope 2-way iterative coupling FSI algorithm for a compoite material propeller i hown in Figure 3. To valiate the propoe tatic FSI analyi methoology, a comparative analyi i performe with Young (2008) experimental an analytical reult for the P5479 propeller, a ix-blae, 610-mm iameter carbon-fiber reinforceplatic propeller that wa manufacture at A.I.R. Fertigung- Technologie, GmbH in Hohen Luckow, Germany. The FSI analye are conucte for two RPM operating conition: 909 an 454 RPM. The analyi reult are compare to a tet at the Naval Surface Warfare Center, Carerock Diviion (NSWCCD) an to Young (2008) calculation with the avance ratio (J) of 0.5~0.9. Figure 4 how that the reult of the preent tuy an Young (2008) analyi agree with the full-cale moel tet. The accuracy of the preent algorithm i ufficient, a hown in Figure 4. Figure 3: Tranient FSI algorithm for a compoite propeller The propeller ue in thi analyi i a P5475 propeller, which eform in actual conition ubtantially enough to valiate the analyi algorithm, the laer Doppler velocimetry (LDV) meaure reult of the pitch eformation publihe in Chen et al. (2006), an the preente unteay tranient FSI algorithm. A wake creen i aapte to imulate the 4-cycle wake flow in orer to meaure the hyro-elatic behavior in the unteay flow fiel at NSWCCD, an the 4-cycle wake flow conition i applie to the FSI analyi. The mean velocity of the tunnel inflow wa 5.03 m/, an velocity itribution meaure by LDV i inicate by the re otte line in Figure 5. The wake applie in thi tuy i inicate by the blue line, an thi applie wake ha only minor ifference from the meaure velocity. The pitch variation were meaure by vieo camera at two point: 10 an 55. The propeller rotation wa 750 RPM, an the meaure ifference of the pitch angle at the blae tip between the eforme an uneforme hape (accoring to blae poition) i repreente by the re quare in Figure 6. Aitionally, the calculate reult are plotte from Chen et al. (2006), which ue the VLM FEM FSI metho, an from the BEM FEM FSI metho of thi tuy uner ientical conition.

4 Figure 6: Pitch change for P5475 (meaure, preicte by Chen et al. an preicte by the preent tuy) (a) RPM = 909 Coniering that the purpoe of the unteay FSI analyi of a marine propeller in a wake fiel i to accurately preict the performance an tructural afety, the propoe unteay tranient analyi can provie a more accurate an realitic preiction for eforme geometrie an variation. (b) RPM = 454 Figure 4: Comparion of the moel tet an the BEM-FEM FSI preiction for the P5479 propeller 4. PLY STACK FINITE-ELEMET (FE) MODEL A marine propeller blae ha complex 3D geometry mae up of a combination of variou eign parameter itribution: pitch, kew, rake, chor length, thickne an camber. It take a lot of time an effort to moel the blae tructure ue to the ply heet morphology itelf. On the other han, the homogeneou iotropic aumption ha been applie to implify the complex tructure. However, it i ifficult to accurately ae the performance an afety with the homogeneou moel. Thu, the imple analyi methoology which conier the ply lamination effect i require. In thi tuy, the imple FE moel i introuce with the blae tructure having fixe element number in 40 ⅹ40 ⅹ 4 to the irection of chor, pan an thickne. The imple tructure element reflect propertie of compoite ply heet in the irection of the thickne of the element. The continuum hell element of Abaqu (SC8R) i applie to the preent imple moel. Prior to the application of propeller blae, a tapere beam moel i ue to verify the utility of the imple FE moel by comparion with the FE moel that reflect the real lay-up of compoite plie. The ifference in tructural moel are hown in Figure 7. A ingle material, without itinction of core an kin, i applie to the ply, an the ply rop pace in the real FE moel wa fille with rein. Figure 5: Inflow meaure by LDV (NSWCCD) an applie to the FSI analyi (a) (b) Figure 7: The comparion of a material beam between (a) the real FE moel an (b) imple ply tack moel

5 A ply tack angle i applie to two layer per compoite heet with a [0 o /60 o /-60 o /90 o ] equence. The thickne of the beam root i 18 mm an the tapere angle of the beam i 11.3 o. The loa conition i 10 MPa uniform preure acting on the upper ie. The material propertie of the applie compoite ply are E 1 = 131,600 MPa, E 2 = 8,200 MPa, ν = an G = 4,500 MPa. Thoe of the epoxy which i fille in the rein pocket are E = 3,900 MPa, ν = The ifference between the real FE moel an the imple FE moel i 1% for the von Mie tre (422 MPa an 427 MPa), 3% for the iplacement at the tip (0.29 mm an 0.30 mm) an 23% (0.43 an 0.33) for the Tai-Hill failure inex in which exceeing 1 inicate failure. Thi ifference in the Tai-Hill failure inex can be ue to the exitence of the rein pocket. Although the ifference of the failure inex i not mall, the imple moel i till ueful for hyro-elatic analyi of compoite marine propeller becaue the eformation ifference i inignificant an i within the error range of the hyroynamic analyi. Table 1: Geometry of propeller KP458 Skew r / R P / D x m / D C / D f (eg) 0 / C t 0 / D Table 2: Operation conition of KVLCC2 Deign Off-eign Ship pee (knot) RPM Ship wake (w ) Figure 8: Comparion of the tructural analyi between the real FE moel an imple-tack moel 5. HYDRO-ELASTIC ASPECTS OF COMPOSITE MARINE PROPELLER The confirmation of the ifference in flexible eformation behavior accoring to ply tack pattern i carrie out with the application of the preent imple FE moel to the compoite propeller blae. The target i a well known benchmark propeller KP458 for KRISO VLCC (KVLCC2). The eign an off-eign operating conition are hown in Table 2. The CFRP material of E 1 = 117 GPa an E 2 = 7.8 GPa for both core an kin i applie to the ply lamination of propeller KP458. Ply tacking parameter are efine a ply tack angle (θ) an orientation angle (α). Ply tack angle refer to the angle between each ply when laminate with combination ply an it can be repreente a [±θ 1 / ±θ 2 / / 0], which i a combination of ply heet angle +θ 1, -θ 1, +θ 2, -θ 2,, 0. Orientation angle refer to the amount of rotation of thi compoite heet relative to a propeller center line: a line connecting the mipoint of each mean-line. Axial Velocity / Ship Spee r/r 0.5 r/r 0.6 r/r 0.8 r/r 1.0 r/r Poition (eg.) Figure 8: Axial inflow velocity of propeller KP458 at propeller plane To invetigate the hyro-elatic behavior ue to ply lamination lay-up, three ply tack angle equence are compare by varying orientation angle at off-eign conition. Initial blae geometrie for each ply tack angle an orientation angle combination are reefine by the revere engineering algorithm (Figure 2) in orer to have the ame geometry an performance at eign conition. The applie ply tack angle equence are [±60 o / 0 o ], [±30 o

6 / 0 o ], [±15 o / 0 o ] an orientation angle are from -36 o to 24 o. The compoite heet with ply angle [±60 o / 0 o ] ha an iotropic-like (quai-iotropic) material property an [±30 o / 0 o ] an [±15 o / 0 o ] have in-plane orthotropic material property. It can be expecte that the orthogonality of tructural propertie woul be enhance an the ben-twit behavior woul be change when the ply angle change from 60 o to 15 o. The inflow conition i hown in Figure 8 a well a the effective wake incoming to the propeller plane, which i preicte with meaure nominal wake by Huang metho (1980). Since the initial geometrie of each ply lamination combination are ifferent an have the ame geometry at eign conition, the geometry an performance at offeign conition woul change entirely. If it i poible to aume that propeller thrut an effective wake for each ply lamination combination are the ame at ientical hip pee conition, the comparion of open water efficiency can be performe by uing the thrut ientity metho: fining RPM that ha the ame thrut a that of the rigi propeller. Figure 9: Comparion of efficiency accoring to the combination of ply tack angle an orientation angle at off-eign conition Alo are hown in Figure 9, open water efficiencie varying accoring to a combination of ply tack angle an orientation angle at off-eign conition. The range of efficiency variation i enlarge a tructural orthogonality i increae. Ply equence [±60 o / 0 o ] i expecte to have 0.5~1% efficiency gain for the whole orientation angle, an [±15 o / 0 o ] i expecte to a 3% efficiency gain for an orientation angle of aroun 30 o. 6. CONCLUSIONS AND FUTURE WORK In thi tuy, a BEM/FEM-bae FSI analyi algorithm for a compoite marine propeller with a imple ply tack moel i eigne for practical ue in performance etimation an tructural analyi. A ummary of the key propertie an fining of thi methoology i a follow: 1. The BEM/FEM-bae FSI algorithm i propoe for the hyro-elatic analyi an eign of a compoite marine propeller becaue of it computational efficiency an accuracy. 2. BEM panel coe i ue for flow analyi, an a commercial implicit FEA olver (Abaqu 6.12 Stanar) i ue to etermine the tructural behavior, incluing the hyroynamic ae ma. In aition, an interface coe i evie to link the flui an tructure olver. 3. A finite element moel of acoutic flui meium i introuce in orer to conier hyroynamic amping effect uch a the ae ma ue to blae vibration in water. A ytem of equation that capture the preure on the blae urface an the tructural eformation of the blae are compoe to olve for the hyroynamic repone. 4. The analye for orthotropic homogeneou material elatomer propeller are compare with the icloe tet an reult of analye from previou tuie. The accuracy of the preent methoology i evaluate through comparion with the teay an unteay FSI analyi. 5. For a more elaborate analyi of the compoite marine propeller, a imple ply tack methoology i propoe. Thi metho i aapte to a 3D continuum hell element of the tapere beam tructure moel which moele the propeller blae. The applicability of the imple ply tack metho i confirme by a comparion with the oli FE moel which reflect the real lamination tructure. 7. An analyi of the hyro-elatic behavior ifference for variou ply lamination cae i performe for the CFRP ply tructure of the target propeller, KP458 of KRISO VLCC. 8. The applicability of the revere engineering methoology i confirme by uing the teay FSI algorithm to etimate the initial geometry. 9. Opportunitie to improve the propulion performance uring off-eign operating conition are ientifie by aapting the compoite material of the marine propeller. REFERENCES Blaque, J. P., Berggreen, C. an Aneron, P. (2010), Hyro-elatic analyi an optimization of a compoite marine propeller, Marine Structure, vol. 23, pp Chen, B. Y-H., Neely, S. K., Michael, T.J., Gowing, S., Szwerc, R.P., Buchler, D. an Schult, R. (2006), Deign, fabrication an teting of pitch-aapting (flexible) compoite propeller, SNAME

7 Propeller/Shafting Sympoium. He, J. L. an Valarezo, W. O. (1985), Calculation of Steay Flow About Propeller by Mean of a Surface Panel Metho, 23r Aeropace Science Meeting, Reno, Nevaa. Hohino, T. (1989), Hyroynamic Analyi of Propeller in Steay Flow Uing a Surface Panel Metho, Proceeing of the Spring Meeting, No.1-6, The Society of Naval Architect of Japan. Hin, C-Y (1990), Development an Analyi of Panel Metho for Propeller in Unteay Flow, PhD thei, MIT, Dept. of Ocean Engineering. Huang, H. H. an Grove, N. C. (1980), Effective Wake: Theory an experiment, 13th Symp. on Naval Hyroynamic, Office of Naval Reearch, pp Kerwin, J. E., an Lee, C-S (1978), Preiction of Steay an Unteay Marine Propeller Performance by Numerical Lifting Surface Theory, Tran. SNAME, vol. 86. Kröger, H. an Fröhlingorf, W. (2012), Simulation-bae optimization of the manufacturing proce for a compoite marine propeller, Proceeing of CFK-Valley Stae Convention. Lee, H., Song, M-C, Suh, J-C an Chang, B-J (2014), Hyro-elatic analyi of marine propeller bae on a BEM-FEM couple FSI algorithm, International Journal of Naval Architecture an Ocean Engineering, vol. 6, pp Lee, J-T (1987), A Potential Bae Panel Metho for the Analyi of Marine Propeller in Steay Flow, PhD thei, MIT, Dept. of Ocean Engineering. Lin, H., an Lin, J. (1996), Nonlinear hyroelatic behavior of propeller uing a finite element metho an lifting urface theory, Journal of Marine Science an Technology 1, vol. 2, pp Motley, M. R., Liu, Z. an Young, Y. L. (2009), Utilizing flui-tructure interaction to improve energy efficiency of compoite marine propeller in patially varying wake, Compoite Structure, vol. 90, pp Paik, K. J. (2010), Simulation of flui-tructure interaction for urface hip with linear/nonlinear eformation, PhD thei, Univerity of Iowa. Young, Y. L. (2007), Time-epenent hyroelatic analyi of cavitating propulor, Journal of Flui an Structure, vol. 23, pp Young, Y. L., an Liu, Z. (2007), Hyroelatic tailoring of compoite naval propulor, Proceeing of the 26th International Conference on Offhore Mechanic an Arctic Engineering, OMAE Young, Y. L. (2008), Flui-tructure interaction analyi of flexible compoite marine propeller, Journal of Flui an Structure, vol. 24, pp DISCUSSION Quetion from Eckhar Praefke While the potential benefit of flexible propeller are well known an eaily comprehenible, I woul like to know more about the compoite material reitance againt cavitation. I am aking becaue I have een everal compoite propeller uffering from cavitation eroion or even elamination alreay after the firt ea trial. So my quetion refer to the progre mae in thi regar (gelcoat). Author Cloure Thank you for your comment about potential problem of compoite material marine propeller. I fully agree with you that there are worriome about cavitation eroion an ply elamination problem becaue of it material characteritic, even though flexible compoite propeller reuce cavitation volume an retar cavitation inception. Even though thi tuy i focue on the hyro-elatic behavior of the flexible propeller, the application of coating material having enough cavitation eroion reitance an (ea) water proof ability i require to ucceful evelopment of the compoite propeller. Thank you again for your icuion.