Numerical study of different models of an Agnew micro hydro turbine

Transcription

1 mme.modares.ac.ir * amirzaei@iust.ac.ir68464 * : 94 6 : : - NumericalstudyofdifferentmodelsofanAgnewmicrohydroturbine MohammadHasanShojaeefard * AmmarMirzaei, MohamadSadeghAbedinejad Yousef Yassi,-DepartmentofMechanicalEngineering,IranUniversityofScienceandTechnology,Tehran,Iran. -InstituteofMechanicalEngineering,IranianResearchOrganizationforScienceandTechnology(IROST),Tehran,Iran. P.O.B.68464Tehran,Iran,amirzaei@iust.ac.ir ARTICLEINFORMATION ABSTRACT OriginalResearchPaper Received04March05 Accepted05April05 AvailableOnline5April05 Keywords: Microhydroturbine Numericalsimulation Rotor-statorinteraction Turbulencemodel Inthisstudy,three-dimensionalfluidfieldofanaxialflowtypemicrohydronamedAgnewhas beeninvestigated.theturbineinstalledat thehydraulicmachineslaboratory(hml)ofiranian ResearchOrganizationforScienceandTechnology(IROST)hasbee designedtogenerate kw outputpower.allnumericalsimulationswereperformedusingansyscfx,computationalfluid Dynamic (CFD) code, to investigate the performance parameters such as efficiency and power, and results are validated against experimental data. Four different grid sizes are studied in accordance with the Grid Convergence Index (GCI) to investigate mesh independency of the solution. Results of several turbulence models were also examined to find out the Shear Stress Transport(SST)modelinordertotakeintoaccounttheturbulenceintheflow.Severalturbulence modelswerealsoexaminedtogetherwithwallfunctionsothattheturbulenceintheflowcouldbe takenintoconsideration.mixingplaneinterfaceplanewasusedtopassthedisturbanceof rotarydomaintostationarydomain.theobtainedresultsshowthathighresolutionadvection scheme,mixingplanetomodeltherotor-statorinteractiontogetherwithturbulenceintensityof I=6% at the inlet, best matches with the experimental results. The difference between the efficienciescomputedfrombothnumericalapproachesandexperimentalvaluesmaybeascribed tonumericalerror,modelerrororsystematicerror. 00 0/5 9.[] /9 -. Pleasecitethisarticleusing: : M.H.Shojaeefard,A.Mirzaei, M.S.AbedinejadY.Yassi,NumericalstudyofdifferentmodelsofanAgnewmicrohydroturbineModaresMechanicalEngineeringVol.5,No.6, pp.-0,05(inpersian)

2 ..[].[4]. 50 [5,4] Turbulenceintensity 79.[].[].[4] [].[5].[6] ( ( :. -.[7].[8]. 4..[9] -.[0].[] [].Agnew.k-.ShearStressTransport(SST) 4.ANSYSCFX 5.TaskFlow 6594

3 . 40.[5] [6] O.[7] H O. ) ( /. =.5 = ( ) ( ) Eff/Effexp 0/9 0/94 0/97 0/98.. () () W/Wexp /065 /064 /0 / () () - GridConvergenceIndex(GCI). / [5]..[4] - Staggerangle -Circumferentialdirection 6594

4 4/9 /4 pave 6594 p. /. 0/85 4/7 pave : / Mixingplane -Frozenrotor -Slidinginterface. (4) ().[9,8] / r = () = (4) h ( ) (5) ( ). h = ( ) (). (6) p() = (6) ln( ) ln + () (8) (7) q s =. sign( ) (7) () = ln (8). = =.[0].[8] () 4/9 /4 pave p. / (5) pave. 0/85 4/7. =Wout Q=47.04L/s (p<) / / /68 54/86 547/68 554/67 570/96 0/ 5/48 %/76 %4/8 %5/45 =Eff Q=47.04L/s / / /68 5/6 5/4 50/94 49/90 /7 5/75 %0/7 %/8 %/504 =Pin Q6.477L/s / / / /7 849/64 %0/5 %/68 %/06 N N N N4 r r r4 p 4

5 -.[7] -. -.[7] K cm SST SSG K-e BSL ERSAM 000.[] [] SST SSG K-e BSL ERSAM EXP EARSM - SSG 5 -k

6 6594 (0). 7.[6]. l 6. /54..[4] () = + () r 4...[6] 5...[6] - Blendfactor - Upwind 4- Robust 5- Highresolution(HR) [6] 0 5 I = = Re.[6] (0) (9) = 0.07 (0) U [J/kg] (Hrunaway/Hmax) 0/ 0/566 0/85 (9) (Q/Qmax) 0/557 0/700 0/98 (L/s) (bar) 88/ 88 87/7 - Lengthscale 6

7 () 0/750/5.... [6] I=6% I=0% I=5% EXP. B=0 0.5 B=0.5 B= B= HR [5]. / (9) I=6%. ().[6] (4) K = () K = (4) cm u I=6% I=0% 0. I=5% EXP Fullyimplicitmethod - Multigridacceleratedfactorizationtechnique HPWorkstationZ800 4-Intensity(I)

8 [7] 4 (%) /9 /84 /60 -/86 /7 5/49 / 5/47 6/55 8/96 (%) 6594 ( ) - /98 0/006 /68 - /44 0/004 /06 - /4 0/004 0/98-0/86 0/004 0/846-0/69 0/004 0/765-0/6 0/004 0/684 - /4 0/00 0/606-0/5 0/00 0/5-0/76 0/00 0/44 - /57 0/00 0/ [5] B= B=0.5 B= B= 0.0 HR () runawayspeed 8

9 (%) (%) /4 / - /5 /40 0/9 /94 / 5/ 4/ 5/55 4/8 6/5 (%) 5/4 5/7 /07 5/5 0/86 /8 4/05 /87 /66 /7 /58 5 (%) - /9 - /8-0/80 - /5 -/6 - /5 - / 0/05 - /57 /98 - /70 - /07 0/00 0/00 0/00 0/004 0/00 0/00 0/00 0/00 0/00 0/00 0/00 0/00 6 (%) - / - /58 - /9 - /98 - /5 -/6-0/6-0/45 - /00 - /5-0/9 0/00 0/00 0/00 0/00 0/00 0/00 0/00 0/00 0/00 0/00 0/00 ( ) /04 /066 0/996 0/9 0/86 0/789 0/78 0/657 0/599 0/50 0/470 0/407 ( ) /05 /009 0/959 0/908 0/860 0/8 0/76 0/74 0/668 0/67 0/ [9] (7-5) = (5) = (6) = 00 (7) [] [8]. 0/

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