directional163

StudyofLackingPicksonShearerHelicalVaneonDrumLoadInfluenceLiXiaohuo1,a,YaoTianyu2,b,MuYongcheng3,c,HuYantao4,d1,2,3,4MechanicalEngineeringCollegeofLiaoningTechnicalUniversity,Fuxin123000,Chinaalixiaohuo@163.
com,byaotianyu85833@sina.
com,cmuyongcheng2006@sina.
com,dhuyantao1982@163.
comKeywords:Drumshearer;Helicalvane;Cuttingpick;Load;MatlabAbstract.
Inordertomasterloadmagnitudeadrumanditschangesunderlackingpickscondition,findouttheinfluenceondrumloadswhenlackingpicksonhelicalvanes,explorefailurereasonsofashearerdrum,amathematicalmodelofshearerdrumloadswasanalyzedandestablishedinthepaper,usingMatlabcomputeranalysisprogram,drumloadsandtheirchangesunderseveralconditionsweresimulatedwhenlackingpicksonhelicalvanes,andtheinfluencetoshearerdrumloadoflackingpicksondifferentpositionswasanalyzed.
Theresultsindicatethat,thecloserlackingpickpositiontotheseamexposedsurface,thesmallerdrumloadfluctuationiswhenexistingonelackingpickonhelicalvane;theloadfluctuationandpositionangleoftwolackingpicksonthedruminverselyproportionalwhenexistingtwolackingpicksonhelicalvane,whichisroughlyinaccordwiththeactualsituation.
IntroductionDuetoabadworkingenvironment,alackingpickphenomenonoftenhappensduringashearerworks,ashearerunderlackingpickconditionwillaffectdrumworkreliability,servicelife,cuttingperformanceandproductivity[1,2].
Researchforthedrumloadsandtheirchangeruleswhenashearernormalworkinghavealreadyexisted[3-5],butdidnotseethereportaboutloadsandinfluenceswhenlackingpicksonashearer.
Soitisimportanttofindoutdrumloadsandtheirinfluencesonashearerperformancewhenlackingpicksonashearer.
CalculationmethodofloadsonshearerdrumPickforcesondrum.
Theworkingprocessofshearerdrumisshownasfigure1.
Atanymoment,theloadsofithpick(positionAngleisγi)[3-5]areasfollowsFig.
1Forcedanalysisofpickonshearerdrum(1)Cutresistance0.
50.
1750.
31101000.
5cosizycotqjyddZAhtKKKKKKfkSdBhσθ++.
(1)(2)Tractionresistance0.
50.
1750.
31101000.
5cosizycotqjyddYAhtKKKKKKkSdBhσθ++.
(2)(3)Lateralresistance132[]iiChXZCCht=++.
(3)Where,Aiscoalseamaveragecuttingimpedance;h,tisrespectivelyaveragecuttingthicknessandaveragetransversaldistance;σyispickunidirectionalcompressivestrength;Kφ,Kc,Kot,Kqarerespectivelypickfrontinfluencecoefficient,pickarrangementinfluencecoefficient,minepressureinfluencecoefficient,ratiocoefficientoftractionresistanceandcuttingresistance.
Instantaneousdrumloads.
Asshowninfigure1,instantaneousdrumloadsarevectorsumofeachforcecuttingcoalandrock.
Anymomentj,threedirectionalloadsofadrum(directionofvertical''a',directionoftraction'b',axialdirectionofdrum'c')are1(sincos)pnajiiiiiRYZγγ==Σ+,1(cossin)pnbjiiiiiRYZγγ==Σ+,1pncjiiRX==Σ.
(4)SimulationofdrumloadswhenlackingpicksSetaveragecuttingimpedanceofcoalandrockfor240N/mm.
Maingeometricparametersaboutashearerdrumare:haulingspeedis2.
3m/min,drumrevolvingspeedis60.
5r/min,drumdiameteris1.
8m.
Pickarrangementondrumisshowninfigure2,therearethreeheadhelicalvanes,installationanglesofpicksonhelicalvanesareallzero,theirtransversaldistancesare37mm.
Fig.
2PickarrangementsondrumLackingonepicksonthesamehelicalvane.
Importlackingpicksdataofdifferentpositionsonthehelicalvane(numberedΔ)intoMatlabtobesimulated,andvariationcoefficientsofdrumloadsareasshownintable1.
ΔCvaCvbCvcΔCvaCvbCvc20.
058750.
062330.
0576480.
049690.
054650.
0492930.
056230.
060820.
0560590.
049380.
053340.
0471040.
054770.
059730.
05519100.
048220.
051700.
0447050.
053960.
058620.
05386110.
046900.
050500.
0422860.
052430.
056770.
05236120.
045890.
047990.
0410870.
051300.
055680.
05036Non-lacking0.
042600.
043830.
03307Table1LoadvariationcoefficientsoflackingonepickLackingtwopicksonthesamehelicalvane.
ThereisresearchonvariationcoefficientofdrumloadwhenNo.
2or3andanotherpicklacking(numberedΔ,Δ=4-12),andvariationcoefficientsofdrumloadsareasshownintable2.
ΔCvaCvbCvcΔCvaCvbCvc2,40.
084840.
091250.
092663,40.
100480.
107740.
091632,50.
081300.
087140.
088873,50.
082310.
088150.
087612,60.
076780.
081540.
084283,60.
078610.
083620.
085802,70.
071570.
076730.
079113,70.
073890.
079070.
081032,80.
066200.
071130.
073693,80.
068720.
073920.
076282,90.
062160.
066020.
068793,90.
064600.
068740.
071252,100.
058300.
061510.
063123,100.
060270.
063610.
065332,110.
054970.
058070.
058363,110.
056130.
059420.
060122,120.
052970.
055170.
054803,120.
053270.
055430.
05587Table2LoadvariationcoefficientsoflackingtwopicksonsamehelicalvaneFigure3issimulationcurvesofloadswhennon-lackingpick;figure4andfigure5arerespectivelysimulatedcurvesofdrumloadswhenlackingNo.
10andlackingNo.
10&No.
3.
Fig.
3Non-lackingpickFig.
4Δ=10Fig.
5Δ=3&10Lackingtwopicksonadjacenthelicalvane.
ThereisresearchonvariationcoefficientofdrumloadwhenNo.
15or16andanotherpicklacking(Δ=4-12),andvariationscoefficientsofdrumloadsareasshownintable3.
ΔCvaCvbCvcΔCvaCvbCvc15,40.
056430.
060640.
0607516,40.
054760.
059530.
0567415,50.
057930.
061970.
0637316,50.
055370.
059700.
0592215,60.
059820.
063840.
0669316,60.
056240.
060380.
0620015,70.
062700.
066490.
0691416,70.
058390.
062450.
0640615,80.
065330.
070040.
0729716,80.
060610.
065360.
0677115,90.
068840.
072700.
0740116,90.
064110.
068040.
0691415,100.
070670.
074690.
0753316,100.
066260.
070580.
0710215,110.
071880.
076200.
0747316,110.
067990.
072650.
0710115,120.
071800.
075430.
0739816,120.
067050.
072650.
07092Table3LoadvariationcoefficientsoflackingtwopicksonadjacenthelicalvaneAnalysisofsimulationresultsComparingfigure4withfigure3findsobviousloadingfluctuations.
Figure3decreasesmoreobviouslythanfigure4inrange100-200,whilefigure3hasanobviousincreasingprocessin200-350°.
Analysisshowsthatlackingpicksshouldhavecutcoalintherange100-200,butlackingpickleadloadondrumtodecrease;thepicks,whichonthesametransversalandnexttothelackingpick,cutdoublethicknessesofcoalleadloadondrumtoincreaseintherange200-350°.
Thesamesituationcanbereflectedonthetendencybetweenfigure4andfigure5.
Asshownintable1,whenexistingonelackingpickondrum,thecloseroflackingpicktothecoalseamexposedsurface,thesmallercoefficientvariationsofdrumloadsis.
Analyzingindicatesthatthecloseroflackingpickpositiontothecoalexposedsurfaceis,thesmallerpressurecoefficientofcoalis.
Thenleadthedecreaseofinfluenceondrum.
Table2andtable3showthatlackingtwopicksonthesamehelicalvane,horizontalorlongitudinalcontrast,theloadvariationcoefficientdecreaseswiththepositionangleoflackingtwopicksincreases;whentwolackingpicksonadjacenthelicalvanes,longitudinalcontrast,thevariationcoefficientofloadfirstincreasesthendecreaseswiththepositionangleoflackingtwopicksdecreases.
Owingtotwolackingpicksonthehelicalvane,thesmallerpositionangleoflackingtwopicksis,themoreconsistentofnextpickschangingofcutthicknessis,whichonthesametransversalwiththelackingpicks,soitaddsthevariationcoefficientofdrumload;atthesametime,picksareclosertothecoalexposedsurfacewhenΔchangesfrom4to12,suchthesituationisasseenintable2andtable3.
ConclusionsThemainreasonofappearingabigloadfluctuationondrumwhenhelicalvaneislackofpicksisthatthelackingpicksdon'tcutcoalandrock,thenextpickonthesametransversalwillcuttwocuttingthicknessesofcoalandrock,thereforeloadschangetoomuchincertainranges.
Lackingonepickonhelicalvane,thecloserpositionoflackingpicktothecoalexposedsurfaceis,thesmallerloadfluctuationofdrumis.
Inaddition,whenlackingtwopicksonhelicalvane,threedirectionalloadfluctuationsofdrummainlydependontwofactors,oneisthelocationofthetwolackingpicksandtheotheristhepositionangle.
Thesmallerpositionangleofthelackingtwopicksis,thegreaterloadfluctuationcanbe;thecloserlackingtwopickstocoalseamexposedsurfaceis,thesmallerdrumloadfluctuationis.
Theresearchmethodcansimulateloadsonadrumandtheirchangesaccuratelyintheconditionoflackingpicks,whichlaysthefoundationofexploringtheinfluencetoloadchangesondrumwhenlackingpicks.
AcknowledgementsThisworkwassupportedby:1NationalNaturalScienceFoundation-fundedProject(59774033);2Sci.
&tech.
researchguidanceprojectsofChinaCoalIndustryAssociation(MTKJ2011-325).
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