Using the CFD Technique to Analyze Tire Tread Hydroplaning Effects

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1 Using he CFD Technique o Analyze Tire Tread Hydroplaning Effecs Min-Feng Sung *, Chin-Fu Chen, Chao-Jung Chen Kenda Rubber IND. CO., LTD, No.146, Sec. 1, Chung Shan Rd., Yuanlin, Chungha 51064, Taiwan. * Corresponding auhor s bigeyes [AT] kenda.com.w ABSTRACT---- Hydroplaning is a major cause of we-road accidens. The main conac elemen beween he ground and vehicle is he ire. Tire safey and performance are herefore criically imporan. We roads presen several unconrollable facors. This paper uses CFD (Compuaional Fluid Dynamics) o analyze we road hydroplaning effecs. Fluid dynamics canno be easily measured using normal experimens. Therefore he braking disance and record rolling vary by encoder. We propose anoher mehod o analysis i. By his resul, he large groove and ire deph can reduce hydroplaning effecs. A second mehod is modifying he ire void paern which can reduce he hydroplaning exen by 29%. Keywords--- Tire, CFD, Hydroplaning. 1. INTRODUCTION Recen developmens in high echnologies, new maerials and advanced manufacuring mehods in he moor vehicle indusry have ransformed he modern auomobile ino a universal ranspor. This populariy has also led lo raffic accidens, especially in winer. Acive safey sysems such as Elecronic Sabiliy Conrol (ESC) have considerably increased raffic safey. [1] Srandroh e al. [2] published an aricle invesigaing he performance of passenger cars wih or wihou ESC sysems in winer. This sudy examines he effecs of sudded ires in faal crashes on roads covered wih ice or snow in Sweden. The main sudy resuls showed ha 64% of faal crashes on roads covered wih ice or snow involved loss-of-conrol (LOC) as a major componen. More han 82% of LOC occurred due o over-seering. Tuononen e al. [3] published a paper ha poined ou how o measure he ires conac lengh on we-roads. Their resuls showed he ire conac lengh on dry roads was very sable, while he ire conac lengh became very unsable on we roads. The ire groove funcion is help remove waer film from he ire conac surface on we-roads. However, when he waer-film hickness becomes higher han groove's deph, hydroplaning effecs will occur. In 2013, Guo e al. [4] used Compuaional Fluid Dynamics (CFD) and Finie Elemen Mehod (FEM) echniques o solve he hydroplaning effec. Their resul showed ha he impac of sanding waer deph on hydrodynamic pressure is very apparen on a vehicle raveling 90 km/hr.. Sanding waer a dephs ranging from 5 mm o 8 mm presen hydrodynamic pressure increases a he mos apparen rae. I was suggesed ha a car should ravel a mid or low speed (65 o 85 km/h) on we roads. Nakajima e al. [5] used he CFD and FVM echniques o solve hydroplaning effecs. They poined ou ha simulaions could clarify he waer flow around he pracical read paern. The simulaion approach allowed developing new ire read paerns wihin a shor period based on he principle, make he sream line smooh. In 2013, Croner e al. [6] published an aricle indicaing ha numerical CFD and experimens could demonsrae he wake condiions in a single waer slick moving on he road. The simulaion resuls indicaed considerable changes in he conac area beween he ires and he road surface. Kim e al. [7] recommended using a simplified model o conduc flow field analysis on ire read paerns in conac wih a road surface and hen moving away from he road surface. Flow field analysis is hen used o analyze he noise. The main objec of his paper is herefore o sudy how o analyze ire hydroplaning effecs on we roads. 2. NUMERICAL SIMULATION 2.1 Model Srucure Many design parameers are necessary in producing high performance auomobile ires. These parameers include he ire groove paern, groove deph and widh, read geomeric layou, rubber maerials, noise level, rolling resisance, performance on boh dry and we roads. In order o invesigae he hydroplaning effecs his sudy designed five ypes of cases as lised in Table 1. Case 1 is simple design wih only four read ribs wih 8mm and 10mm deph, wihou read paern design. The hydroplaning resul is he reference base for he same layou design. Theoreically, a ire wih a read paern will increase he hydroplaning effecs bu he paern can improve manipulaion performance, because he paern can discharge more waer hrough he read grooves, improving he ire conac lengh and conac area. Case 2 is a paern wih groove deph of 8mm wih he void paern 31.7%. The groove deph for Case 3 is 10 mm wih he void paern he Asian Online Journals ( 151

2 same as case 2. We also know ha he groove deph has a oal deph limi. Therefore, in cases 4 and case 5 only he paern void is changed from 35% o 38%. Large voids can improve he groove crawl waer oal volume. 2.2 Simulaion model define We used he 205/65R18 ire size, he mos common passenger car ire in use o invesigae ire hydroplaning wih differen ire read designs. The calculaion domain is shown in Figure 1. The mesh is recangular wih nodes. A supercompuer wih 16 cores and 128G flash memory was used o calculae his problem. The simulaion flow char is shown in Figure 2. The firs sep is o draw he 3D geomery and modify he design paern for mapping o our simulaion requiremens. The second sep is oupuing he CAD ino he WRL forma and checking if he geomery scale is reasonable. The nex sep is loading he WRL file ino he CFD sofware and compleing he simulaion condiions. The final sep is simulaion and oupuing he hydroplaning force beween he waer and ire surface. 2.3 Simulaion Theory Subgrid geomery resoluion mehod A goal of a proposed sub-grid geomery resoluion mehod is o overcome he barrier beween CAD sysems and CFD code. Theoreically, common CAD sysems can generae he descripion of objec surface by se of plane faces. Using of his represenaion allows for CFD code o perceive geomery informaion from CAD. In his case he CFD code becomes compaible wih oher CAE sysems based on finie elemen analysis. Le he adapive locally refined grid (ALGR) has given in compuaional domain. A firs sage of algorihm he faces inersecing he grid cell (Figure 3) are being found. Then he grid cell is disjoined ino a se of finie volumes bounded by faces (or face spliners) and cell faces (or face spliners). If he cell does no have any faces inersec wih finie volume. Only allowable one siuaion is spliner face can bounded finie volume. A finie volume is indexed by i and is designaed as V i. Wih he help of his echnology, i can make program deal wih he ire wih complex hread paern rolling in compuaional domain wihou problem of disorion of compuaional grid Governing equaions solving In his sudy, he waer flow is inle from inpu and conac wih ires, herefore need consider governed by sysem of equaions for incompressible fluid which includes coninuiy and Navier-Sokes equaions. To consider he algorihm of he equaions solving again wrie ones in Lagrange inegral form for volume moved wih fluid during inermied ime duraion is: p V V 0 (1) P V V P eff F Equaions (1) and (2) were used o solve he velociy and pressure of fluid wih a decouple process called as pressurevelociy spli process [8-10]. Here, is he effecive shear sress ensor caused by viscosiy of fluid. The urbulence of eff waer flow around he rolling ire is also considered. The sandard K-ε model, expressed as (3) and (4) is used o solve he urbulen energy and dissipaion of fluid. ( pk) (3) Vk k G g T k Pr 2 ( p ) V (4) C1 G g T C2 k Pr k The model parameers and he expression for generaing erm G can be rewrien as (5), (6), and (7): D ij G V (2) i D (5) ij xj 2 k Sij V ij 3 (6) V V i j Sij x x (7) j i The objec of his sudy is o invesigae he resisance force of a rolling ires caused by fluid-dynamic, we will inroduced he similariy approach o experimenally measure he resisance of a ire rolling in an basin insead of wind unnel for he validaion of simulaion. Therefore, he working fluid in his simulaion is waer, and hea ransfer can be Asian Online Journals ( 152

3 negleced reasonably. The unis and numerical seings are lised in Table 2. Equaion (8) was used o solve he oal pressure of fluid, and he oal resisance force of a rolling ire is calculaed by Equaion (9) 1 2 Po P Phs V (8) abs 2 V F fluid ( P Phs ) nds ( ) ds (9) n 3. SIMULATION RESULT We used a smooh ire wih four groves o invesigae he basic hydroplaning effecs on he ire layou. The original design is shown in Figure 4, wih four grooves wih wo dephs; 8mm and 10mm. The simulaion resul is shown in Figure 5. When he inle waer fill wih he ire conac area and he ire has finished rolling one cycle. The sable hydroplaning effec for he 8mm groove is 2588(N) and 2336(N) for he 10mm groove. From his resul we can see ha he large groove deph can reduce he hydroplaning effec because greaer groove volume means he crawl waer volume is greaer wihin he same ime frame. Therefore, if he ire paern design is no changed bu he grooves are deeper, he hydroplaning effec can be reduced. In Figure 6 case 2 has 8mm deph and 31.7% paern void as he oher design for cases 3 and 4. Only he groove deph is changed from 8mm o 10mm and he paern void widh o 35% and 38%. The simulaion resul is shown in Figure 7. In his resul he hydroplaning effecs are 2394, 2491, 1646 and 1313(N). These simulaions permi idenifying when he groove deph presens no change (limi deph) and allows modifying he paern void o reduce he hydroplaning effecs. Large paern voids can also help he ire crawl more waer volume hrough he reads, reducing he waer force feedback ino he ire, mainaining more ire conac area wih he road surface. Figure 8 shows he waer splash simulaion resul in differen cases. We can see ha he waer splash in he original design mainains more road conac han he oher cases. In case 5 he waer splash has some rupures and does no remain inac, meaning he waer force feedback ino he ire is smaller. Therefore, his paern void design can improve he hydroplaning effec. 4. CONCLUSION In his paper presened CFD echniques used o simulae hydroplaning effecs. The hydroplaning effecs from differen ire read groove dephs and paern voids were analyzed. The simulaion resuls demonsrae ha ire read grove deph modificaion is he mos efficien way o reduce he hydroplaning effec. The ire read geomery is he limiing facor because finie limis o he ire read groove and paern deph exis. Therefore, we can modify he paern void o reduce he hydroplaning effec. Large read paern voids can also help he ire crawl more waer volume hrough he read, reducing he waer force feedback ino he ire, mainaining greaer ire conac area wih he road surface, improving ire safey performance on we roads. 5. REFERENCES [1] A. Lie, e al., The effeciveness of ESC in reducing real life crashes and injuries, Traff. Inj. Prev. 7, 2006, pp [2] J. Srandroh, M. Rizzi, M. Olai, A. Lie, C. Tingvall, The effecs of sudded ires on faal crashes wih passenger cars and he benefis of elecronic sabiliy conrol (ESC) in Swedish winer driving, Acciden Analysis and Prevenion, Vol.45, 2012, pp [3] M. Mailainen, A. Tuononen, Tyre conac lengh on dry and we road surfaces measured by hree-axial acceleromeer, Mechanical Sysems and Signal Processing, Vol.52-53, 2015, pp [4] Xin-xin Guo, Chi Zhang, Bu-Xin Cui, Di Wang, James Tsai, Analysis of Impac of Transverse Slope on Hydroplaning Risk Level, Procedia-Social and Behavioral Sciences, Vol.96, 2013, pp [5] Y. Nakajima, E. Sea, T. Kamegawa, H. Ogawa, Hydroplaning Analysis by FEM and FVM: Effec of Tire Rolling and Tire Paern on Hydroplaning, FISITA World Auomoive Congress, 2000, F2000G382. [6] E. Croner, H. Bézard, C. Sico, G. Mohay, Aerodynamic characerizaion of he wake of an isolaed rolling wheel, Inernaional Journal of Hea and Fluid Flow, Vol.43, 2013, pp [7] S. Kim, W. Jeong, Y. Park, S. Lee, Predicion mehod for ire air-pumping noise using a hybrid echnique, J. Acous. Soc. Am, Vol.119, 2006, pp [8] Aksenov, A.A., Gudzovsky, A.V., The sofware FlowVision for sudy of air flows, hea and mass ransfer by numerical mehods, Third Forum of Associaion of Engineers for Heaing, Venilaion, Air-Condiioning, Hea Supply and Building Thermal Physics, Vol.31-35, 1993, pp [9] Aksenov A.A., Dyadkin A.A., Gudzovsky A.V., Numerical Simulaion of Car Tire Aquaplaning, Compuaional Fluid Dynamics, 1996, pp [10] CAPVIDIA FlowVision HPC version , 2014 user manual. s s Asian Online Journals ( 153

4 APPENDIX Table 1 Simulaion iems for differen ire designs Iems Case1 Case2 Case3 Case4 Case5 Paen No Yes Yes Yes Yes Deph(mm) 8 / Void (%) Table 2 Unis and numerical seings. [10] Noaion Physical quaniy Dimension Noaion Physical quaniy Dimension C p specific hea= m 2 s -2 K -1 Q sum of he energy of differen naure m 2 s -2 F acceleraion of exernal ms -2 universal gas consan= R volume face A Jmole -1 K -1 G graviy acceleraion ms -2 T o oal emperaure K H oal enhalpy m 2 s -2 T ref reference emperaure = 273 K K urbulen energy m 2 s -2 T abs absolue emperaure K L characerisic lengh m T n emperaure value a ime layer n K M molar mass= kgmile -1 µ molecular dynamic viscosiy kgm -1 s -1 P relaive pressure Pa µ urbulen dynamic viscosiy kgm -1 s -1 P ref reference pressure= Pa V relaive velociy m/s P hs hydrosaic pressure Pa V n velociy value a ime layer n P abs absolue pressure Pa ρ n densiy value a ime layer n P o oal pressure Pa ρ n+1 densiy value a ime layer n+1 dissipaion rae of urbulen Pr urbulen prandl number ---- ε P n P n+1 pressure value a ime layer n pressure value a ime layer n+1 Pa β energy coefficien of hermal expansion m/s kg m -3 kg m -3 m 2 s -2 K -1 Pa T relaive local specific Kgs -2 Figure 1 Mesh defined for calculaion domain. Asian Online Journals ( 154

5 Figure 2 Skech of he simulaion sep. Figure 3 Sub-grid geomery resoluion; (a) finding of faces inerseced ALGR cell (b) disjoining of cell ino finie volumes Figure 4 Picure of he ire design: Case 1 Asian Online Journals ( 155

6 Figure 5 Hydroplaning resul for Case1 Figure 6 Picure of he ire design: Case2 Asian Online Journals ( 156

7 Figure 7 Hydroplaning resul for Case2 o Case5 Figure 8 Simulaion resul of he waer splash conour. Asian Online Journals ( 157