化工原理Ⅰ习题及解答.docx
- 文档编号:6113763
- 上传时间:2023-01-03
- 格式:DOCX
- 页数:13
- 大小:78.83KB
化工原理Ⅰ习题及解答.docx
《化工原理Ⅰ习题及解答.docx》由会员分享,可在线阅读,更多相关《化工原理Ⅰ习题及解答.docx(13页珍藏版)》请在冰豆网上搜索。
化工原理Ⅰ习题及解答
«化工原理
»习题
一、填空题
1.Whenthetemperatureofthegasincreases,theviscositiesofgaseswill(),whiletheviscositiesofliquidswill().
2.Aturbulentflowisconsideredtoconsistofthreezones:
(),(),().
3.Twoclassesofmetersareusedtomeasuretheflowrateoffluid.Withtheincreaseofflowrate,thepressuredropof()and()willincrease,whilethepressuredropof()willmaintainconstant.
4.Thegagepressureofanequipmentis100kPa,sotheabsolutepressureofitis()kPa;Thevaccumpressureofanotherreactoris400mmHg,thentheabsolutepressureofthereactoris().(theatmosphericpressureis101.33kPa)
5.Basedonmechanicalconstruction,theimpellerofcentrifugalpumpscanbeclassifiedas(),(),andanenclosedimpeller.
6.Generally,therearethreeperformancecurvesforacentrifugalpump,whichare(),(),().
7.Theoperatingpointofthecentrifugalpumpistheintersectionof()and().
8.(),()and()areexamplesofreciprocatingpumps.
9.Forthepumppriming,thedischargelineofa()pumpcannotbeclosedwithoutstallingorbreakingthepump,whilethedischargelineof()pumpscanbecompletelyclosedwithoutdamage.
10.Inordertoavoid(),thecentrifugalpumpsshouldbefilledwithliquidsbeforepriming(启动).
11.Inadouble–pipeheatexchanger,theairisheatedbysaturatedsteam.Thetemperatureoftheheat-exchangertubewallisclosetothetemperatureof()andtheoverallcoefficientisclosetothefilmcoefficientof().(saturatedsteamorair).
12.Manymetersareusedtomeasuretheflowrateoffluid,listthreetypesofmetersusedindustrially:
(),(),().
13.Ingravitationalsettling,theparticlequicklyreachesaconstantvelocity,whichisthemaximumattainableunderthecircumstancesandwhichiscalled().
14.Ifthevelocityofthedust-ladenairisincreased,theefficiencyofthecyclonewill(),thepressuredropwill().
15.Intheory,thecapacityofthesettlingchamberisinrelationto(),(),andhasnothingtodowith().
16.Bythefiltrationoperations-basicequation.Listthemeasurementsofincreasingthecapacityofthefilters(atleastthreeitems):
(),(),().
17.Whencurrentsinafluidresultfrombuoyancyforcescreatedbydensitydifferences,andthedensitydifferencesarecausedbytemperaturegradientsinthefluid,theactioniscalled().Whenthecurrentsareduetoapump,theflowiscalled().
18.Avapormaycondenseonacoldsurfaceinoneoftwoways,whicharewelldescribedbytheterms()and().
19.Heatflowunaccompaniedbyanyobservablemotionofmatteriscalled(),while()canrefertotheflowofheatassociatedwiththemovementofafluid,()isatermgiventothetransferofenergythroughspacebyelectromagneticwaves.
20.Atsteadystate,theheatflowratethroughacylinderis(),theheatfluxis().(aconstant,notaconstant)
21.Theheattransferredaccompanyingcondensationis(),andtheheattransferfromtheriseorfallinthetemperatureofafluidwithoutphasechangeis().
二、判断题
1.Fluidfrictionisinterconvertible(可互相转换的)withthemechanicalenergyquantities.()
2.Thefluidisflowinginapipe.Ifitisturbulent,thevelocitydistributionwith
respecttotheradiusisaparabola(抛物线).()
3.Absolutepressuresarealwayspositive,butgagepressurecanbeeitherpositive(正的)ornegative(负的).()
4.Thefluidstreamcanbeconsideredastwoparts,theboundarylayerandtheremainingfluid.
5.Whenenerthevelocityofafluidischanged,formfrictionwillbegenerated.()
6.Thethinnertheviscoussublayeris,thelowerthefrictionlossis.()
7.Gasviscositiesaregenerallygreaterthanliquidviscosities.()
8.Theflowwithoutlateralmixingislaminarflow.()
9.Thethinnertheviscoussublayeris,thelowerthefrictionlossis.()
10.Thedischargelineofacentrifugalpumpcanbecompletelyclosedwithoutdamage.()
11.Anenclosedimpellerhasasolidspassingcapability.()
12.Plungeranddiaphragmpumpsarewidelyusedas“meteringpump”.()
13.Positive-displacementmachines,ingeneral,handlesmallerquantitiesoffluidsathigherdischargepressuresthandocentrifugalmachines.()
14.Thevoluteistherotatingpartthatconvertsdriverenergyintothekineticenergy.()
15.Inheatconvection,heatflowisassociatedwiththeflowofafluid.()
16.Asforafluid,thefilmcoefficienthwithphasechangeisgreaterthanthatwithoutphasechange.()
17.Gaseshavethesmallestthermalconductivities,soporousmaterialsbyentrappingaircanbeusedtoeliminateconvection.()
18.Formostliquids,thethermalconductivitykishigherthanthatforsolids.()
19.Inordertoobtainalargerfilmcoefficientontheshell-sidefluid,multipassheatexchangersshouldbeused.()
20.Fourier’lawisthebasiclawofconvection.()
21.Whenquenching(急冷)ahotfluidfromachemicalreactortostopfurtherreactions,parallelflowshouldbeused.()
22.Inordertoobtainalargerfilmcoefficientonthetube-sidefluid,multipassheatexchangersshouldbeused.()
23.Inconstant-pressurefiltration,boththepressuredropandtheflowrateallowedareheldconstant.()
24.Bothhydrocloneandcycloneareusedtoseparatesolidsfromgases.()
25.Inthegravitysedimentationprocess,iftheresidencetimeofasolidisgreaterthanitssedimentationtime,thesolidwillbeseparatedfromthegases.()
26.Thelargertheparticlediameterandtheparticledensityare,thesamllertheterminalvelocityis.()
27.Alarge-diametercyclonehasamuchlowerseparationfactoratthesamevelocity.()
28.Thecakeresistanceincreaseswithtimeinbothconstant-ratefiltrationandconstant-pressurefiltration.()
29.Inconstant-pressurefiltration,boththecakeresistanceandthepressuredropareheldconstant.()
30.Inthesettleingchamber,thegasstreamshouldbelaminar,andReofwhichislessthan2100.()
三、选择题
1.Waterwithρ=1000kg/m3,μ=0.001Pa.sflowingatanaveragevelocityof1m/sina200mmpipe,()
ATheflowislaminar;BTheflowisturbulent;
CTheflowistransition;DTheflowisuncertain.
2.Incompressiblefluidsflowinahorizontalpipe(theflowissteady),theenergyconsumedbyfrictioncomesfrom().
AkineticenergyBpotentialenergy
CpressureenergyDuncertain
3.Incompletelyturbulentflow(Re>106)throughasteelpipe,thefanningfrictionfactorisrelatedto().
AReonlyBReandk/DCk/DDReandk
4.Foradouble-pipeexchanger,thedimensionofinnertubeisΦ19×2.5mm,andthedimensionofoutertubeisΦ38×3mm,theequivalentdiameteroftheannularspaceDeqis().
A13mmB19mmC24mmD18mm
5.TheIntrinsicdistinctionbetweenthelaminarflowandtheturbulentflowis().
Avelocityofturbulentflowisgreaterthanthatoflaminarflow
BReoflaminarflowislessthanthatofturbulent
Clargercross-sectionalareaisturbulent,whilesamllercross-sectionalareaislaminar.
Dlaminarflowwithoutlateralmixing,whileturbulenthaslateralmixing.
6.Forarotameter,whentheflowrateofwateris1m3/h,thepressuredropthroughitis20Pa.Iftheflowratedoubles,thepressuredropthroughtherotameterwillbe().
A40PaB20PaC10PaD60Pa
7.Fluidsflowthroughtwoparallelpipes,flowsinbothpipesarelaminar.IfthelengthofthetwopipesL1=L2,innerdiameterd1=2d2,thevolumetricflowrateq2/q1willbe().
A1/2B1/4C1/8D1/16
8.Fluidflowsthroughastraightpipe,whentheflowiscompletelyturbulent,withtheincreaseofRethefrictioncoefficientλwill().
AincreaseBdecreaseCnearlyremainaconstantDuncertain
9.Ifthereadingsofavacuumgauge(真空表)atthesuctionconnectionofthecentrifugalpumpis700mmHg,andtheatmosphericpressure is101.33kPa,thevaporpressureof42℃wateris8.2kPa,cavitation().
AmusthappenBisimpossible
CperhapshappenDuncertain
10.Twopumpsoperating()willbemoreeffectivewithalowresistancepipesystem.
AinseriesBinparallel
CintheparallelpipesystemDinbranchingpipesystem
11.Inordertoavoid(),thecentrifugalpumpshouldbefilledwithwaterbeforepumppriming.
AairboundBcavitation
CbeingbrokenDpipeblock(堵塞)
12.Efficincyofacentrifugalpumpwill()withtheincreaseoftheflowrate,
AincreaseBdecrease
Cincreaseuntilreachingamaximumvalue,thendecrease
Ddecreaseuntilreachingaminimumvalue,thenincrease
13.()cannotchangetheoperatingpointofthecentrifugalpump.
AchangingtheimpellerspeedBchangingtheimpellerdiameter
CoperatinginparallelDchangingthesuctionlift
14.Aflatwallisconstructedoftwolayers.Thethicknessesandareasofthetwolayersarethesame.Theaveragethermalconductivitiesarek1andk2respectivelyandthetemperaturedifferencesare
and
.Theheattransferissteady.Ifk1>k2,()
A
>
B
<
C
=
Duncertain
15.Waterisflowinginapipe(Re>104)atanaveragevelocityV.Itsfilmcoefficentish1.Iftheaveragevelocityisincreasedto3V,assumingotherconditionsarenotchanged,itsfilmcoefficenth2=()
A3h1B0.33h1C2.41h1D1.73h1
16.Inacondenser,acoldfluidisheatedbysaturatedstreamfrom15℃to40℃.Iftheflowiscountercurrent,theLMTD=
Iftheflowisparallel,theLMTD=
.()
A
=
B
>
C
<
Duncertain
17.Thehotfluidiscooledby20℃waterfrom85℃to40℃.Ifthetemperatureoftheleavingwaterisrequirednottobehigherthan40℃,()mustbeused.
AcountercurrentflowBbaffleflow(折流)
CparallelflowDcrossflow
18.Airisheatedbysaturatedsteaminashell-and-tubeexchanger,()isthemosteconomicmethodtoincreasethe
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 化工 原理 习题 解答