dstandardizationofsafetyproduction,andstrivetoachieve\nsicallysafe\safetysectionandisaunitofsecurityofficersresponsibleforminesafetydutiesandsupervisetheimplementationofthefollow-upto,andimplementationofthesystem,prosecution.PartImanagementsystems...Youcanusebrazierswhen,2--3metersfromthegroundandputthefireoutbeforethework,confirmthenofirebeforetheycanleave;Highway11non-staffinthemarginwithin50m,radiusoftheexcavationwork,andworkingwithin6metresoftheedgeandstayundertheumbrellaheading;12,blastingintothepitpersonnelmustfollowtheshootingguard'scommand,hidetosafety;13non-miningvehicles(includingbicycles,animal-drawnvehicle,motorvehicles,etc)willbebannedfromenteringthepitsandotherproductionareaonpainofheavyfines,resultinginaccidentstobeinvestigatedforresponsibility;14shootingthefollowingmechanicalsafetydistancesasfollows:categorynamemechanicalcannonsshallowholesandpopshootingexposedblastingunits:metersdiggingmachinerigcargunpowderotherequipment-pitequipment,especiallyanelectricalswitchandavarietyofsafetydevices,inadditiontospecifyingtheuseofresponsiblepersonnel,bananytouchingofotherpersonnel;16foundthatpowerlinesorcablesbreakinggroundbeforewithoutascertainingwhetherthecharged,prohibitsanyonefromtouching,andshouldleave5metersaway,andimmediatelynotifythepersonchecking;17withouttheleadership'sconsent,arenotallowedtotakethestrippedtrucks,watertankers,oiltankers,asaresultoftheca《第二章流体输送机械》习题解答
1)某盛有液体的圆筒容器,容器轴心线为铅垂向,液面水平,如附图中虚线所示。当容器以等角速度ω绕容器轴线旋转,液面呈曲面状。试证明: ①液面为旋转抛物面。 ②
。
③液相内某一点(r,z)的压强。式中ρ为液体密度。
解 题给条件下回旋液相内满足的一般式为
(常量)
取圆柱坐标如图,当Z=0,r=0,P=P0,∵C=P0
故回旋液体种,一般式为① 液面为P=P0的等压面
,为旋转抛物面
②
又
即:h0=∴H=2h0
dstandardizationofsafetyproduction,andstrivetoachieve\nsicallysafe\safetysectionandisaunitofsecurityofficersresponsibleforminesafetydutiesandsupervisetheimplementationofthefollow-upto,andimplementationofthesystem,prosecution.PartImanagementsystems...Youcanusebrazierswhen,2--3metersfromthegroundandputthefireoutbeforethework,confirmthenofirebeforetheycanleave;Highway11non-staffinthemarginwithin50m,radiusoftheexcavationwork,andworkingwithin6metresoftheedgeandstayundertheumbrellaheading;12,blastingintothepitpersonnelmustfollowtheshootingguard'scommand,hidetosafety;13non-miningvehicles(includingbicycles,animal-drawnvehicle,motorvehicles,etc)willbebannedfromenteringthepitsandotherproductionareaonpainofheavyfines,resultinginaccidentstobeinvestigatedforresponsibility;14shootingthefollowingmechanicalsafetydistancesasfollows:categorynamemechanicalcannonsshallowholesandpopshootingexposedblastingunits:metersdiggingmachinerigcargunpowderotherequipment-pitequipment,especiallyanelectricalswitchandavarietyofsafetydevices,inadditiontospecifyingtheuseofresponsiblepersonnel,bananytouchingofotherpersonnel;16foundthatpowerlinesorcablesbreakinggroundbeforewithoutascertainingwhetherthecharged,prohibitsanyonefromtouching,andshouldleave5metersaway,andimmediatelynotifythepersonchecking;17withouttheleadership'sconsent,arenotallowedtotakethestrippedtrucks,watertankers,oiltankers,asaresultoftheca③某一点(r,Z)的压强P:
2)直径0.2m、高0.4m的空心圆桶内盛满水,圆筒定该中心处开有小孔通大气,液面与顶盖内侧面齐平,如附图所示,当圆筒以800rpm转速绕容器轴心线回旋,问:圆筒壁内侧最高点与最低点的液体压强各为多少?
解
取圆柱坐标如图,当Z=0,r=0, P=P0 ,∴C=P0
故回旋液体种,一般式为 B点:
Z=0,r=R=0.1m,C
点:Z=-0.4m,r=0.1m,
3)以碱液吸收混合器中的CO2的流程如附图所示。已知:塔顶压强为0.45at(表压),碱液槽液面与塔内碱液出口处垂直高度差为10.5m,碱液流量为10m3/h,输液管规格是φ57×3.5mm,管长共45m(包括局部阻力的当量管长),碱液密度
,粘度
,管壁粗糙度
。试求:①输送每千克
质量碱液所需轴功,J/kg。②输送碱液所需有效功率,W。
解 ①
dstandardizationofsafetyproduction,andstrivetoachieve\nsicallysafe\safetysectionandisaunitofsecurityofficersresponsibleforminesafetydutiesandsupervisetheimplementationofthefollow-upto,andimplementationofthesystem,prosecution.PartImanagementsystems...Youcanusebrazierswhen,2--3metersfromthegroundandputthefireoutbeforethework,confirmthenofirebeforetheycanleave;Highway11non-staffinthemarginwithin50m,radiusoftheexcavationwork,andworkingwithin6metresoftheedgeandstayundertheumbrellaheading;12,blastingintothepitpersonnelmustfollowtheshootingguard'scommand,hidetosafety;13non-miningvehicles(includingbicycles,animal-drawnvehicle,motorvehicles,etc)willbebannedfromenteringthepitsandotherproductionareaonpainofheavyfines,resultinginaccidentstobeinvestigatedforresponsibility;14shootingthefollowingmechanicalsafetydistancesasfollows:categorynamemechanicalcannonsshallowholesandpopshootingexposedblastingunits:metersdiggingmachinerigcargunpowderotherequipment-pitequipment,especiallyanelectricalswitchandavarietyofsafetydevices,inadditiontospecifyingtheuseofresponsiblepersonnel,bananytouchingofotherpersonnel;16foundthatpowerlinesorcablesbreakinggroundbeforewithoutascertainingwhetherthecharged,prohibitsanyonefromtouching,andshouldleave5metersaway,andimmediatelynotifythepersonchecking;17withouttheleadership'sconsent,arenotallowedtotakethestrippedtrucks,watertankers,oiltankers,asaresultoftheca
,查得
∴
②
4)在离心泵性能测定试验中,以2 泵汲入口处真空度为220mmHg,以孔板流量计及U形压差计测流量,孔板的孔径为35mm,采用汞为指示液,压差计读数
,孔流系数
,测得轴功率为1.92kW,已知泵的进、出口
截面间的垂直高度差为0.2m。求泵的效率η。
解
5)IS65-40-200型离心泵在V m3/h He m 7.5 13.2 时的“扬程~流量”数据如下: 12.5 12.5 15 11.8