1、12FTM08AGMA Technical PaperCombined MarinePropulsion Systems:Optimization andValidation bySimulationBy B. Pinnekamp, F. Hoppe andM. Heger, RENK AGCombined Marine Propulsion Systems: Optimization andValidation by SimulationBurkhard Pinnekamp, Franz Hoppe and Moritz Heger, RENK AGThe statements and op
2、inions contained herein are those of the author and should not be construed as anofficial action or opinion of the American Gear Manufacturers Association.AbstractModernNavyandCoastGuardVesselsusuallyhavecombinedpropulsionsystemsusinggasturbines,dieselengines and electric motors as main propulsors.
3、Desired operating profiles demand for individualoptimization of the gear propulsion system with respect to efficiency, noise, operational flexibility and capitalcost.Combined systems are complex and therefore sensitive to dynamic excitation and resonance. To avoidunfavorabledynamiceffects,itisnecess
4、arytovalidatecandidatearrangementsusingmoderntoolslikemultibody simulation.The paper describes the evaluation process for optimized combined marine propulsion systems and systemvalidation by dynamic simulation.Copyright 2012American Gear Manufacturers Association1001 N. Fairfax Street, Suite 500Alex
5、andria, Virginia 22314October 2012ISBN: 978-1-61481-039-13 12FTM08Combined Marine Propulsion Systems: Optimizationand Validation by SimulationDr. Burkhard Pinnekamp, Dr. Franz Hoppe and Moritz Heger, RENK AGIntroductionThemaritimeworldexperiencessignificantchangesconcerningtasksandmissions;globalpro
6、tectionoftradesea ways plays an increasing role. Considering constraints with defensebudgets, futureNaval conceptsde-mand a reduction in the number of vessels and, at the same time, more efficiency and flexibility of propulsionsystems.Various alternatives of mechanical andelectric drive propulsionsy
7、stems may be considered for futureNavalshipbuildingprograms. Theselectionofthemostappropriatepropulsionsystemdepends onthe vesselplat-form and the intended mission profile. The most appropriate alternative enables optimum power manage-ment and minimum fuel oil consumption. A combinedsystem using die
8、sel engines forloitering, cruising,and-dependingonvesselsizeanddesiredspeed- gasturbinesforsprintspeedis theoptimum mechanicaldrivesystem. Formodernhybridmarinepropulsionsystems,electricmotorsmoreandmoretakeovertheroleofadiesel engine for cruise speed in a combined plant, adding operational flexibil
9、ity and other advantages. Theheart of a combined propulsion system is a reduction gear which enables the flexible arrangement of primemovers and can thereby support various vessel missions. The following list shows examples for combinedmarine propulsion systems:S CODAD (COmbined Diesel And Diesel);S
10、 CODELOD (COmbined Diesel-ELectric Or Diesel);S CODOG (COmbined Diesel Or Gas turbine);S CODAG (COmbined Diesel And Gas turbine);S CODELAG (COmbined Diesel-ELectric And Gas turbine).Thispaperprovidesanoverviewontheengineeringbackgroundfromagearmanufacturersperspective,andproposesconsiderationsforthe
11、optimizedpropulsion solution. Thetheoretical validationby advancedcalcu-lation methods is also described.Combined marine propulsion systemsOverviewTable 1 shows an overview of different propulsion system installations comparing hybrid mechanical andhybridelectricpropulsion. Mechanicalsystemswerecont
12、inuouslydevelopeduntilapproximatelyonedecadeago from simple CODAD solutions to highly complex CODAG arrangements with a cross connect gear. Inparallel, electric systems were increasingly accepted throughout the maritime world.Any of the listed configurations have their specific advantages and should
13、 be considered reflecting thevessels needs. Driving factor for the selection of a certain configuration is not only low investment cost butalsolifecyclecostconsideringspecificfuelconsumption,maintenance intensityand overhaulperiods aswellas reliability and redundancy.The missions determine the platf
14、orm, the platform determines the propulsion system and the propulsionsystemdeterminesthereductiongearsystem. Thepotentialprimemoversinapropulsionsystemaregiventheir weights, dimensions and performance are individually selected. The prime movers can be consideredblack boxes. A flexibly designed reduc
15、tion gear facilitatesS the matching and combining, if applicable, of the optimum prime movers with the propulsors,S the location of the prime movers in the machinery space, andS the optimum operation and maximum fuel efficiency of the prime movers.4 12FTM08Table 1. Propulsion system variants and exi
16、sting applications for surface combatantsPropulsiontypeDescriptionInstalled powerrange, MWTypical applicationCODELODCombined electric motor or dieselengineDE 5 . 10EM 0.3 . 0.6S Netherlands Navy OPVS Korean Coast Guard OPVCODELADCombinedelectricmotoranddieselengineDE 5 . 10EM 0.7 . 1.5No reference a
17、vailable yetCODOGCombined diesel engine or gasturbineDE 2.5 . 9GT 15 . 22S German Navy F123S ROKN FFXCODAGCombined diesel and gas turbine(with or without cross connectgear)DE 5 . 9GT 20 . 36With cross connect gear:S German Navy f124S U.S. Coast Guard NSCWithout cross connect gear:S U.S. Navy- Lockhe
18、ed Martin LCS- Austal LCSCODELOGCombined electric motor or gasturbineEM 2 . 3GT 20 . 32S Italian Navy FREMMCODELAGCombined electric motor and gasturbineEM 4 . 6GT 20 . 25S German Navy F125The reduction gear is a key determinant indevelopingapropulsionsystem that will meet the vesselsoperat-ing envel
19、ope and will fit the machinery space physical envelope. Theoverview presentedherein providesanoverview and trade-off analysis of principal mechanical drive systems and can serve as a reference andsample to identify the optimum propulsion system for a vessel. At least ten major parameters need to bec
20、onsidered in determining the optimum propulsion system:S MissionsS Operating profileS PowerS Efficiency and fuel consumptionS WeightS DimensionsS Maintenance and repair costS Location flexibilityS Survivability and redundancyS SignatureOncethepropulsionsystem has beenselected, thefinal arrangement c
21、an be further adjusted and optimizedto fit within the design parameters.Operating speed profileFor decades, different prime movers have been combined to allow for flexible operation of propulsion plants.As a basis for the layout, the assumed speed profile of the vessel needs to be known. In this con
22、text, thecomparison between former speed distribution assumptions and todays approach is interesting. The twographs in Figure 1 show typicaloperating profilesof frigates 20years agoand today. Thechange ofopera-tional demands is obvious: With a modern frigate concept, operation in slow speed or loite
23、r mode has almostdoubled,whereassprintspeedof30+knotsisrarelyconsidered,theUSNavyLCSisthemajorexceptionforasurface combatant with versatile mission deployments.5 12FTM08a) Frigate type CODOG F1235400 t (1990)b) Frigate type CODELAG F1256800 t (2010)Figure 1. Design operating profile (Source: German
24、Naval Headquarters)Why combined propulsion plants?A gasturbine is compact, light-weight and high-powered. It requires reasonable maintenance. However,when it operates at less than full or near-full load, its specific fuel consumption increases significantly.A high speed diesel engine has a high ther
25、mal efficiency over a broad range of loads and accordinglymaintains economic and level specific fuel consumption over those loads.Combined systems take consideration of the above mentioned aspects for an optimized combined system.Combined propulsion system examplesCODAGistheresultofafurtherdevelopme
26、ntinpropulsionsystems,mainlyderivedfromCODOG. AperfectCODAG system integration was performed in Germany in the late 1990s. The first German Navy F124Frigate with CODAG propulsion (Figure 2) was put in operation in 2001.The main factors in the successful development of the F124 CODAG plant are as fol
27、lows:S Experience derived from CODOG and CODAD applications, e.g., self synchronizing overrunningclutch;light weight fabricated casings and carburized double helical gears;S Optimized multi-disk clutch arrangement with hydraulic controls, lubrication and assembly on onecommon shaft;S Ship control sy
28、stem and gear sub-controls following latest electronic standards are perfectly integratedusing a programmable logic control unit (PLC) for operation, guarding and BUS data exchange. Localmonitoring and operation is facilitated comfortably via the PLC touch screen.The Lockheed Martin LCS monohull typ
29、e (Freedom class) of the US Navy features a completely differentpropulsion train technology. Four water jets are driven by two symmetrically arranged CODAG systems,where the high speed combining gear and the low speed splitter gear are separately installed, linked by longintermediateshaftseach,seeFi
30、gure 3. Gasturbinesanddieselenginescanbeengagedseparatelyincruiseorhigherspeedpropulsionmodes,orjointlydrivethewaterjetsachievingatopspeedinexcessof40knotsinthis CODAG mode. To match with different required water jet speeds, the diesel engine inputs are equippedwith two gear stages where the adequat
31、e gear ratio is selected via a multi disc clutch engagement.6 12FTM08Figure 2. F124 CODAG gear plant schematicFigure 3. U.S. Navy Lockheed Martin LCS CODAG gear plantMore examples for combined propulsion are given with the variants for the propulsion system of a samplefrigate in the following paragr
32、aphs.Sample for propulsion system variantsTodemonstratevariantsandevaluationofsuitablecombinedpropulsionsystems,a5200tonfrigateischosenas an example.Mission profile and power requirementThetotalrequiredprimemoverpowerisderivedfromtheaveragepowerpertonofcomparableNavalvesselsandexperience. Therequire
33、dinstalledprimemoverpowertoachieve29ktsfora5200 tonsfrigateisapprox-imately 40 MW. Figure 4 shows a simplified power vs. speed curve for acubic lawcorrelation. The frigateisassumed to operate underway approximately 150 days, i.e., 3600 hours per year.7 12FTM08Figure 4. Power requirement for a 5200 t
34、on frigate vs. speedBased on current ship programs and experience, the speed profile as shown in Table 2 is applied for theevaluation.Prime movers and basic propulsion system arrangementThe propulsion system is based on diesel engines of approximately 1000 to 1300 rpm and gas turbines of3300 to 3600
35、 rpm. Diesel engines provide better fuel efficiency across the load and speed spectrum thanother fossil fueled alternatives like gas turbines. Diesel engines maintain reasonable efficiency down to lowloadlevelsofapproximately15%. Gasturbinesfeaturelowdeadweightandvolumeatratedpowerandthere-foreprovi
36、dehigherpowerdensitythandieselengines. Acombinedpropulsionsystem,combiningtwoormoreprime movers to one or more propulsors, further optimizes speed and endurance.Diesel engines and gas turbines of different manufacturers are considered in this paper. However, for anypropulsion system configuration, a
37、lternative manufacturers can be adopted without major changes to thebasic features of the propulsion system performance.The frigate is assumed to have two propeller shafts with CPPs and will be operated using both propellersexcept in case of emergency.Requirements summaryTable 3showsanoverviewofthea
38、ssumedbasicspecsforthefrigate. Anychangestothesespecsmayhavean impact on the final selection of prime movers and referring gear specs but will basically not affect thecomparative aspects of the different propulsion system arrangements.Propulsion system arrangementsOverviewFive different propulsion s
39、ystem arrangements are investigated as potential solutions for the frigates powerplant. The featuresand performanceof eacharrangement areevaluated againstpertinent parameterslistedearlier. Table 4 shows an overview of the subject arrangements.Table 2. Frigate mission profileMode Speed, kts %oftime P
40、ropeller shaft power, MWIdle 0 5 0Loitering 6 5 0.35Low patrol 13 10 3.5High patrol 18 60 9.3Transit 24 15 22.1Sprint 29 5 39.08 12FTM08Table 3. Frigate basic specsDisplacement 5200 metric tonsSprint speed 28+ ktsOperating hours 3600 per yearPropulsion power approx. 40 MWPropulsors 2CPPPrime movers
41、High speed diesel enginesGas turbinesElectric motorsTable 4. Propulsion system variantsA: CODAD B: CODELOD C: CODOGD: CODELAGwith CCE: CODAGwith CCMW rpmFuel1),g/kWhNoPower,MWNoPower,MWNoPower,MWNoPower,MWNoPower,MWDE 20V 9.1 1150 195 4 36.4 4 36.4 0 2 18.2DE 12V 5.4 1000 195 2 (10.8)GT1 21 3600 225
42、 2 42 0 1 21GT2 32 3300 225 1 32Gen-set DE 12V 5.2 1000 2102)1 (5.2) 2 (10.4)Electric motor 1 2.4 1800 2283)2 (4.8)Electric motor 2 4.7 150 2283)2 9.4Total input shaftpower36.4 36.4 42 41.4 39.2Max speed, kts 28.0 28.0 29.4 29.2 29.0NOTES:1)At nominal load.2)Generator efficiency considered.3)Generat
43、or, converter, and electric motor efficiency considered.A final solution is not restricted to one of these proposed arrangements but could also be any combination ofindividualprimemovers,gearcomponents,andpropulsors. However,thebasicperformancefeaturescanbeclearly seen from the comparison and a sele
44、ction is hereby facilitated.Variant A: CODADThe CODAD system features more than one diesel engine per propulsor and offers significant flexibility inrunningeitheroftheenginesindividuallyorboth(ormore)simultaneously. Theproposedsystemcomprises4equaldieselengines,rated9.1MW,wheretwoofwhichareconnected
45、toeach,portandstarboardcombininggear. Figure 5showsoneofmanypossiblepropulsionsystems,Figure 6theprincipal geararrangement ofadifferent configuration.Figure 5. CODAD propulsion system9 12FTM08Figure 6. CODAD gear arrangement variantCODAD enables the propulsion system to run up to 80% of sprint speed
46、 (i.e., 22 kts) with only two of fourdiesel engines in operation, saving operating time and providing the opportunity formaintenance onnon-op-erating engines while underway. In case of damage to one of the diesel engines, up to three engines canstillbe used retaining a max speed of 25 kts and full m
47、aneuverability.Variant B: CODELODA fully integrated sole electric propulsion system (IEP) is not considered for the following reasons:S Acombinedpropulsionsystembringsprimemoversonlineasrequiredandcanminimizeoperatinghoursof individual units thereby reducing maintenance and repair.S With a well desi
48、gned system, a mechanical propulsion has a full load efficiency in the range of 98%whereas an electric drive has an efficiency of about 90-92%. This discrepancy would be even moresignificant considering operation at low loads.S Electric propulsion requires extensive electric and electronic equipment
49、 which easily compensates forany benefit with respect to required deck area, weight, survivability and reliability.S The overall investment cost for electric propulsion is higher than for a mechanical solution.A completely different approach is a combined mechanical and diesel electric system, often called a hybridpropulsion system. Such systems feature a main mechanical propulsion with diesel engines and a power-take-in (PTI) operated with an electric motor for loitering at low powerwith verylow noisegeneration andstillacceptable fuel efficiency, as the nomina
