Purdue UniversityPurdue e-PubsI-3%1-!3).-!+ C.,/1%22.1 E-')-%%1)-' C.-&%1%-#% S#(..+ .& M%#(!-)#!+ E-')-%%1)-'1996Heat and Mass Transfer Calculation of theIntercooler With Spraying Water for AirCompressorY. KangNorth-West Institute of Textile Science and TechnologyL. YuShaanXi Blower FactoryF.++.6 3()2 !-$ !$$)3).-!+ 6.1*2 !3: (9/://$.#2.+)"./41$4%.%$4/)#%#8)2 $.#4,%-3 (!2 "%%- ,!$% !5!)+!"+% 3(1.4'( P41$4% %-P4"2, ! 2%15)#% .& 3(% P41$4% U-)5%12)37 L)"1!1)%2. P+%!2% #.-3!#3 %/4"2@/41$4%.%$4 &.1!$$)3).-!+ )-&.1,!3).-.C.,/+%3% /1.#%%$)-'2 ,!7 "% !#04)1%$ )- /1)-3 !-$ .- CD-ROM $)1%#3+7 &1., 3(% R!7 W. H%11)#* L!".1!3.1)%2 !3 (9/2://%-')-%%1)-'./41$4%.%$4/H%11)#*/E5%-32/.1$%1+)3.(3,+K!-', . !-$ 4, L., "H%!3 !-$ M!22 T1!-2&%1 C!+#4+!3).- .& 3(% I-3%1#..+%1 W)3( S/1!7)-' W!3%1 &.1 A)1 C.,/1%22.1" (1996).International Compressor Engineering Conference. P!/%1 1162.(9/://$.#2.+)"./41$4%.%$4/)#%#/1162HEATANDMASSTRANSFERCALCULATIONOFTHEINTERCOOLER WITHSPRAYINGWATER-FORAIRCOMPRESSOR KangYong*,YuLang"* *North-westInstituteof Textile Sci.andTech.,Xi' an,China **Dept.of Design,ShaanXi Blower Factory,LinTong,Xi' an,China ABSTRACT Thewayofheattransferwithexchangercoilbetweencoolingwater anddischargegasis nowincommonuseintheintercoolerofaircompressors.Buttheintercoolerwithspraying waterismore effectivethan that forheat transfer because the discharge gasisin directcontact withcooling water. Thispaperanalysestheprocessintheintercooler withspraying waterand deducesthecalculationformulasofmaindesigningparametersdependingonheatandmass transfer,two-phaseflowandenergyequations.Intheformulas,eachparametershows evidently itseffect totheefficiencyof heattransfer. Q cp T R D t F a (j Xo L y Nu Re A M N z s v H w Ro NOMENCLATURE heattranster constant-pressurespecificheatof gas temperature latent heat perunitmassof water containing watervapourinunitmassof drygas time totalsurface areaof drops heattransfer coefficient moisturetransfercoefficient length of spraying water passage averagediameterof drops containing water in per unitmassof gas Nusseltnumber Reynoldsnumber efficiencyof heattransfer mass number of drops density crosssection areaof passage velocity,volume specificenthalpy massflow thermalconductivity of gas 547 c B g w b a 0 calculating constant atomizating efficiency gas water SUBSCRIPTS saturation point ondropsurface mean value oil INTRODUCTION Intercoolerswithexchangercoiliscommonlyadoptedforaircompressor,butitsheat transferisnotmoreeffectivethantheintercooler, inwhichcoolingwaterisindirectcontact withdischargegas.Therefore,itisnecessarytoresearchheatandmasstransferofthe intercoolerwithsprayingwater,anddiscovertherelationshipsamongquantityofspraying water,watertemperature,airflowvelocity,averagediameterofdrops,relativevelocity betweenwaterdropsandgas,structure anddimensionofthedeviceandsoon.Depending on the foundationrelationships,the excellent design of the intercooler with spraying water can be found. BASICSTRUCTURE Therearethreebasicprocessestobecompletedifthedischargegasisindirectcontact with coolingwatertobecooled.Thefirstisthecirculatingsystem of coolingwater.Cooling waterisgotintheintercoolerbyapumpandspraysdischargegastobecooled.Thecooling waterwhichhascooleddischargegasentersacoolingtowerthrough apipeby theintercooler pressure,thenthecoolingwaterentersthepumpentranceafterbeingcooled.Thesecondis separatingprocess.Thedischargegaswhichhasbeencooledmustbeseparatedfromcooling waterto get into next sylinders tobe compressed.There are different separating methods,but in thisseparation,threeaspectsmust be guaranteed,steady flowto avoidwhirlpoolscarrying smallwater drops,low separating resistance,and smallvolume,so that the streamline baffles canbeadopted.Thedetaileddesignrefersto(4).Thethirdisheattransferprocess.This processcanbesimplifiedtoheatandmasstransferbetweenwaterdropsandgas.Through determinedcoefficientsofthecalculationformulaswhichwededuce,wecanobtainthemain parameterrelationship todesign the intercooler. INFERENCEOFCALCULATING FORMULA Wetakeainfinitesmalvolumeintheintercoolerwithsprayingwaterforstudyandgive out the heat andmass transfer formula dQ=[Cp(T-Tb)+R