Transcription of HUDSON
1 The Bas ics ofAXI AL FLOWFAN SHUDSONP roducts CorporationA Subsi diary of Hudso n Pro ducts Ho ldin gs, In ..?FIGURES..?NOMENCLATURE..? AxialFans..? EngineeringNomenclature..? EngineeringUnits..? versionFactors..? SelectionCriteria..? Equations- (I-P Unit s Only)..? PerformanceCalculation..? sumptions..? Clearance..? ..? Stacks..? istance..? ..? ..? ..? of Blades..? ..? ..? Fans(Auto-Variable ) ..? Variable-Speed..? ..? ..? Noise ..? ..? wer Noise ..? Noise ..? ..?REFERENCES..?DEDICATION..? -C ooledHeatExchangerFan..? Cur ve ..? HP SavingswithVelocity Recovery St ..? Fan Curv e ..? Vortex(Leakage).
2 ? Clearance..? InletBell ..? ..? ge CoolingTo wer Fan withVR Stack..?10 .Approximate Cos t of Power to Operate 8400hrs /yr..?11 .ASPvs. CFM for Air-CooledHeatExchanger ..?12 .VelocityPr ofiles- Taperedvs . ConstantChordBlade..?13 .TypicalSealDis c Priorto Ins tallation..?14 .TypicalAuto-Variable Fan ..?15 .InvertedActuator-VariablePitchFan ..?16 .AV ForceDiagram..?17 .Airflowvs. Signalfor Variable-PitchHub ..?18 .TypicalAuto-Variable Hub..?19 .ThrottledFlo w ThroughFan..?20 .Air Deli ver y vs. Temperature..?21 .PowerStudyRes ults ..?22 .WeightedSoundLev els ..?FOREWARDT hisma nualis designedto familiarizeuserswithapplicationsfor axialflowfans,velocityrecovery stacks,seal discs.
3 And providedfor estimatingfan powerconsumptionand shouldbe notedthat finalfan selectionshouldbe madeby usingHudson sTuf-Lite Fan Sele ctionProgramor by contactingHudsonProductsCorporationat 28 1-275-8100or lish LetterSymbolsACHE= air-cooledheatexc hangerACFM= actualcubicfeet per minuteACT= actualconditionsASP= actualstaticpressureATP= actualtotalpressureAV P = actualve locitypre ss ureBHP= brakehorsepowerBPF= beamor bladepass ing frequencyCS= currentsourceCFM= cubicfeet per minuteDR= densityratioEff= efficiencyD=fan diameterFPM= feet per minuteHP= horsepowerLP= soundpressure lev els (m etricunits)LW= soundpowerlevels (m etricunits)MSL= meansea levelN=numberof fansNF A= net free fan areaPWL= soundpo wer lev el (I-P uni ts )r=inl et bel l radiusPWM= pul se wide modul ati onR=feet from cent er of noisesourceRH= relat ive humidi tyRPM= revol uti ons per minut eSCFM= standardcubi c feet per mi nuteSF= speedfact orSP= stat ic pr es sureSPL= soundpres surelev el (I- P uni ts)
4 SR= soli di ty rati oSTD= standardconditionsEfftotal= tot al ef fi ci encyEffstatic= stat ic ef fi ci encyTP= tot al pres sureV=vel oci tyVFD= vari abl e-fr equencydriv erVP= vel oci ty pressur eVR= recoveredvelocity pressureVV I = vari abl e-voltageinv ert erGr eek LetterSymbols = densitySubs crip tsACT(act)= actualconditionST D (std)= standardconditionexit (ex)= velocityrecovery stackexitc=fan cur ve conditionat standarddensity1=inlet,condition12=outle t,condition2in= inletout= outletSL= sea le veldes= designeff= effectiv e51. 0 Def initionof Axial FansAn axialflowfan movesair or gas parallelto the axi sof comparison, a centrifugalor radi alflowfan movesair perpendicularto the axis w fansare bettersuitedfor lo w-resistance,high-flowapplications, whereascentrifugalflowfansapplyto high-pressureresistance,low-flow ,the typesof fansdiscussedin this manualcan handle resistances up to approximately1 in.
5 Of wat hav e widelyvariedoperatingcharacteristicsdepe ndingon bladewidth and shape,numberof bladesand tip mostcommontypeof fan for air- cooledheatexchanger(ACHE)is less than 14 ft. diameterandha s mostcom montypefor wetcoolingtowersis 28 ft dia meterand has eightbl typicalACHEfan is shownin Fig. CooledHeatEx changerFanFig. Fan Engineering NomenclatureAC FMActualcubi c feet per minute of ai r movedbythe fan .Act ual Condi ti onsResis tancesrel atedto act ual inl etor out let tem per at ure and fan elev at ion ab ove meansea lev el comparedto st andardcondition r Densi tyAir density at the planeof the fan basedon st andardor act ual si ng FrequencyNumberof tim es perrev olut ion that one fan bl ade pas ses ov er a beamorstr ut thoughtof as ho w the struct ure interactswiththe fan bl ade expressed in cycl es/ sec (H z).
6 Bl ade NaturalFrequencyFre que ncy at which a bla defre ely vib ra tes whe n it is stru ck in cyc les/sec(Hz ).Bl ade Passi ng FrequencyNumberof times perrev olut ion that a fan tip passesa pointon the fan ringexpressed in cycles/sec (H z) thoughtof as h ow th efan inter acts with the st ruct ure .Br ake Horsepower (B HP)Net pow er required bythe fan at act ual conditi ons to perf orm th e dSt raightli ne di st ancebet ween the lead ingand tr ail ing ai rf oil Di ameterWidth/ di stancebetween op po sit ebladetips. Fan La ws Set of law s that pr ed ictperformancechangesif one or moreparameter s ar echanged from one fan or operating conditio n e law s gov ern air fl ow, pr essu recapability and po wer requi red amongmanyotherpar Ri ng DiameterIns ide di ameter of fan hou sin g atthe pl ane of ModeResonantFrequencyFrequency atwhich a bladefreelyvibrateswhenstruck( natural frequency)in cycles/s ec (Hertz).
7 For ced DraftACHEFan is loc atedbe low the heattr ansfersurfaceforcingambient air th roughthebu of fan RPMand expressedas 1x, 2x and 3x fan speedincycles/second(Hertz). Harmonicfr equency isch eckedagainstresonantfrequenciesto prev entvibr ationand uce d DraftACHEFan is locatedabovethe heattr ansfersurfacedrawingambientair th roughthebu fan is exposedto the hea ted exhaust ai EdgeThickerportionof the air foil that is thefirst pa rt of the blad e to meetthe air .Net Fr ee AreaNet areaat the planeof the fanthr ou gh whichall air mustpas s. Us uallybasedonthe nominalfan diameterminusseal discareaor hubdiameter.
8 Notethat bladeareais not ch AngleBladetip anglebelo w the horizontalrequ ired to do the designwork and moveairup ns all rota te clockwiselookinginto the FrequencySafetyMar ginPer centdifferencebetweenthe closestres ona nt frequenciesof 1st moderesonantfrequency,bladeand bea mpassfr equencies,and 1x rate movedat standardconditions, instandard cubicfeet per ity RatioMeasureof a fa n s pr essurecapabilit ysolidity sumof the tip widthsdivided by the fancir PointFan operatingconditionwherethebo undarylayerof air separates fr om the s can be com paredto bo atpropeller or pum p cavi tati onsResi stancesrel at ed to thestandard density of ai r at 0.
9 075 lbs/ ft3, at 70 F drybulbtem per at ure and sea lev el (29. 92 in. Hg) .Stati c Eff ici encyFan ef fi ci encybasedon st aticpressure and fan brakehorsepower at the sa c PressureSumof al l the syst em resi st ancesagainstwhi ch the fan must work,expressedin inch esof H2O. Thi s is the usef ul work requiredfrom th efan.(Velocity pressur e excl uded).Tip ClearanceDi st ancebet ween the tip bl ad e andthe fan rin g or housing, som eti mes expressedas apercentof the fan di SpeedPeripheralspeedof the fan tip expr essedin feet per mi nut Eff ic ienc yFan eff ici enc y bas ed on the tot alpressure and fan brakehorsepower at the sa medensity for st andardor act ual conditi Pres sureSumof the stati c pr essureandvelocity ing EdgeThinnerport ion of the air foi Pr essureParasitic loss caus ed by wor kdoneto col lect all the ai r int o the fan s inlet ,expressed in in.
10 Of H2O. It is basedon the fan s netfree areaat the pl ane of the fan .Velocity Reco very StackDevicefr equently us ed incoolingtowers but rar ely in AC HEs. It captures thekinetic ener gy of the exi t ai r vel ocit y and con ver ts itto us eful reduces ai r vel ocit y anddecreasesthe tot al pres sureacti ng on the fan .WR2Fl yw heelef fect of fan that rel ates mas s mom entof iner tia aboutthe axis of rotat ion. in lb 1 Fan EngineeringUnitsI-P:inc h-pound temmetric:metricsystemSI:internationalsy stemof units LENGTHI-P:feet (ft)metric:meter(m)SI:meter(m) VOLUMEI-P:cubicfeet per minute(C FM)metric:cubicmetersper second(m3/s )cubicmeters per hour(m3/h)SI:cubiclitersper second(l3/s ) PRESSUREI-P:inchesof water(in.)