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Shandongsteeltrawlerof104grosstonnagePropellerdesigndocumentInstructor：xunliliaoStudent’name:吕保达StudentID:u200816943Class:0803CompletionDate:2011/5/261.MainparametersofthehullShipType:SinglePropellerEnginesAfterwardSteelTrawlerLWL27.5mCb0.502LPP26.0mCp0.592Breadth5.40mB/Tm2.84Depth2.50mΔ137.35tAverageDraft1.90mXb-0.78mAftDraft2.40mZs0.35mEstimatethehulleffectivepowerbythemethodofAyreSpeedv（kn）91011SpeedlengthratioV/L1/20.971.081.19FroudenumbersVs/(gL)1/20.2900.3220.354StandardC0lookupthediagram7-3295243205StandardCbclookupthetable7-50.5930.560.546RealCb（fatterorthinner）（%）15.35，thinner10.36，thinner8.06，thinnerCb’samendment（%）11.217.1745.104Cb’samendedamount△1331710AmendedCb△1328260215B/Tamendment（%）=-10Cb（B/T-2）%-4.2168-4.2168-4.2168amountofB/T’amendment，△2-14-11-9C2afterAmendedB/TC2314249206StandardXc，%L，beforeorafteramidships1.838Afteramidships2.327Afteramidships2.495AfteramidshipsRealXc，%L，beforeorafteramidships3，afteramidships3，afteramidships3，afteramidshipsDifference%L，beforeorafterthestandardXc1.162，after0.6725，after0.5045，afterXc’samendment（%）lookupthetable7-7（b）0.220.50.96amountofXc’samendment，△3-1-1-2[Equation(7-24)]theC3afteramendXc313248204Amendmentofthelength（%）=（Lwl-1.025Lbp）/Lwl*100%3.23.23.2Amuontoftheamendmentoflength△4[Equation(7-25)]1087theC4afteramendlength323256211Vs372910001331Pe=△0.64*Vs3/C4*0.735(KW)39681092.theParametersoftheengineMainenginetype6160A-123Power（KW）136Rotationalspeed（rpm）850Gearboxtype2HC250Reductionratio1.97:13.Estimationofthepromotingfactors(1)WakeFractionThisshipisasinglescrewsteeltrawler,sowecanuseHankexieerformulatoestimatethewakefractionω:ω=0.77Cp-0.28Sothewakefractionωis0.176.(2)ThrustDeductionFractionTothesinglescrewsteeltrawler,thethrustdeductionfractiontcanalsobeestimatedbytheHankexieerformula:t=0.77Cp-0.30Sothethrustdeductionfractiontis0.156(3)RelativeRotativeEfficiencyBecauseofthelackofdata,weapproximatelyvaluetherelativerotativeefficiencyηR1.0.(4)HullEfficiencyηH=(1-t)/(1-ω)=(1-0.156)/(1-0.176)=1.024.NumberofBladesAccordingtothegeneralconditions,thenumberofthebladesofthesinglepaddleshipisusually4.What’smore,wehavemoredetailedchartsof4-bladepropeller,so,wechosethe4-bladepropeller.5EstimationoftheAE/A0EstimatetheAE/A0bytheformula:AE/A0=(1.3+0.3×Z)×T/(P0-Pv)D2+kAmongthis,inthedesignspeed,PE=71.5KW,V=10.1kn,T=PE/(1-t)V=71.5/((1-0.156）×10.1×0.5144)=16.31kN,Whenthetemperatureofthewateris15℃,thePv=1.705kN/m2.ThestaticpressureisP0=Pa+γhs=(10330+1025×(2.4-0.35))×9.8N/m2=121.83kN/m2Valuethek0.2GettheDis1.5mfromthehulllines.SotheAE/A0=(1.3+0.3×Z)×T/(P0-Pv)D2+k=（1.3+0.3×4）×16.31/((121.83-1.705)×1.52)+0.2=0.3516.IntroductiontothechoiceoftheimpellerAtpresent,inthedesigningofthecargoship,thedesignersmainlyusetheB-screwseriesandtheMAU-screwseries.Now,wechoosetheMAU-screwseries.7.Choosetwoorthreecharts,thencalculatethemaximumspeed.ChoosetheMAU4-40,MAU4-55,MAU4-70charts.Supposethereservepoweristenpercentoftheratedpower,theshafttransmissionefficiencyηS=0.98andthegearefficiencyηG=0.96.ThepowerthepropellerreceivedisPD0，PD0=Ps×0.9×ηS×ηG×ηR=115.14KW=156.67hp8.Goonwiththefinaldesignwiththechartschoseinthepreviousstep,andobtainthreegroupsofparametersofthepropellerandthemaximumspeed.inwhich,therotationspeedofthepropellerisN=n/i=850/1.97=431.47r/minWiththePB-δchartsoftheMAU4-40,MAU4-55,MAU4-70,weobtainthedatainthefollowingtable:ItemunitnumberAssumedspeedVkn9.00010.00011.000VA=（1-ω）*Vkn7.4168.2409.064Bp=N*PD0.5/VA2.536.05927.70921.835Bp1/26.0055.2644.673MAU4-40δ70.00063.00057.000P/D0.6800.7100.750ηO0.5800.6150.643PTE=PDOηHηOhp93.07798.693103.187MAU4-55δ68.50061.00055.000P/D0.7200.7600.810ηO0.5650.5950.630PTE=PDOηHηOhp90.67095.484101.101MAU4-70δ67.00060.40054.500P/D0.7300.7700.830ηO0.5450.5750.595PTE=PDOηHηOhp87.46092.27495.484Withthedatainthetable,wecandrawthefollowingdiagramthatthePTE,δandP/D,η0areasafunctionofVatdifferentnumbers.WecangettheconclusionthatthePTE-f(V)functiongraphintersectwiththeeffectivepowerofthehullatonepoint.wecanobtainthedesignedspeedandthebestparametersofthepropellersuchasP/D,Dandη0inthefollowingtableMAUVmax/knP/DδD/mη04-4010.14500.715262.07441.45950.61924-5510.07200.763360.52521.41290.59754-709.99420.769760.43631.39990.57509.CavitationcheckObtaintheminimumexpandedarearatioAE/A0thatisfreeofcavitationanditsmaximumspeedVs,P/D,η0andD.InaccordancewiththelinesthatisforthetrawlerandtugintheBurillchart,wecanobtaintheminimumexpandedarearatioAE/A0thatisfreeofcavitation.Theheadofeateratscrewcenterlinehscanbeobtainedfromthehulllines,hs=2.05.Thenwecanobtainthep0-pvp0-pv=pa+γhs-pv=(10330+1025*2.05-174)kgf/m2=12431.25kgf/m2Wheresupposethetemperatureis15℃andpv=174kgf/m2ThereceivedpowerPD0=156.67hp,theresultsofthecavitationcheckisinthefollowingtable:No.ItemUnitValueMAU4-40MAU4-55MAU4-701Vmaxkn10.14510.0729.9942VA=0.5144*Vmax(1-ω)m/s4.3004.2694.2363(0.7*π*N*D/60)2(m/s)2532.185498.743489.6084V0.7R2=VA2+(3)2(m/s)2550.676516.969507.5535σ=(p0-pv)/0.5*ρ*V0.7R20.4260.4530.4626τc(fromthediagram6-20)0.1350.1400.1427T=PD*η0*75/VAkgf1691.9901644.5271594.9198Ap=T/0.5*ρ*V0.7R2*τcm20.4350.434