Le viscosity olutshintshayo kulwelo. Yintoni intsingiselo yaso emzimbeni mechanical?

Ulwelo uchazwa umzimba wenyama, ukukwazi ukutshintsha imilo yayo nempembelelo lokungavinjwa ezincinane kuyo. Kukholisa ukuba kubekho iintlobo ezimbini eziphambili ezilulwelo kunye neegesi idriphu. Uvuza fluid - ulwelo ngengqiqo yesiqhelo: amanzi, ioli separafini, ioli njalo njalo. ulwelo sukube - iigesi leyo phantsi kweemeko eziqhelekileyo na, umzekelo, izinto sukube ezifana umoya, initrogen, propane, ioksijini.

Ezi zinto zahluka kubume ezinto eziphilayo kunye nohlobo impefumlelwano iimolekyuli omnye komnye. Noko ke, ukususela kwinqanaba umbono ukukhanda, ukuba eendaba oluqhubekayo. Nangenxa yoko, kuba bachonge ezinye iimpawu ezifana zomatshini: lexinene nondiliseko ethile; kunye ezingundoqo iimpawu ngokwasemzimbeni: compressibility, ukwanda thermal, uqine, amandla uxinzeleko komhlaba kunye viscosity.

Phantsi viscosity ukuqonda ipropati le into engamanzi ukumelana etshebelezayo okanye shift maleko yayo omnye komnye. Kakuhle eli ingqiqo xa kukuvela imikhosi zochuku phakathi maleko ezahlukeneyo ngaphakathi kulwelo ngexesha zazihamba isihlobo. Ukwahlula phakathi ingqiqo ka "viscosity olutshintshayo kulwelo" yaye "viscosity entshukumo 'yayo. Emva koko, thatha sihlolisise, yintoni umahluko phakathi kwezi ngongoma.

nezimaphambili ezingundoqo kunye lobukhulu

amandla Viscous F, obuvela ihamba xa kuthelekiswa omnye maleko osecaleni kulwelo nolahlo ngokubanzi kuba umlinganiselo ngqo uqina ezi zoleko kunye indawo yazo zoqhagamshelwano S. La mandla izenzo kwicala aa Incopho isindululo, necaciswa Newton inxaki is ngokucophelela

F = μS (ΔV) / (Δn),

apho (ΔV) / (Δn) = GV - le ithambeka Velocity kwicala eqhelekileyo inxalenye ezihambayo.

Le ukulingana lomlingani μ - lo viscosity esinamandla, okanye nje viscosity nolahlo ngokubanzi ulwelo. Ukususela zibalo Newton ngayo

μ = F / (S ∙ GV).

Kwiyunithi inkqubo womlinganiselo emzimbeni viscosity ichazwa viscosity medium, apho kwi unit Velocity ithambeka GV = 1 cm / umzuzwana sentimitha sikwere maleko izenzo amandla frictional nganye ngo-1 dyne. Ngako oko, imilinganiso weyunithi kule nkqubo okuvakaliswa dynes ∙ s ∙ cm ^ (- 2) = r ∙ cm ^ (- 1) ∙ s ^ (- 1).

Le ndlela yokulinganisa kuthiwa viscosity ngokulula olutshintshayo (P).

1 P = 0.1 Pas ∙ c = 0,0102 kgf ∙ kunye ∙ m ^ (- 2).

Faka kunye neeyunithi ezincinane, ezizezi: P 1 = 100 centipoises (CPS) = 1000 elenziwa zii (millipuaz) = 1000000 INC (mikropuaz). Kwinkqubo yobugcisa ukuba iyunithi yexabiso viscosity ukuthatha kgf ∙ kunye ∙ m ^ (- 2).

Kwiyunithi inkqubo ngamazwe viscosity ichazwa viscosity medium, apho kwi unit Velocity ithambeka GV = 1 m / s to m 1 square metre yamanzi maleko lenze zochuku amandla 1 N (Newton) nganye. Amaxabiso isici μ kwi SI luboniswa kg ∙ m ^ (- 1) ^ ∙ kunye (- 1).

Ezinye iimpawu ezifana isigama nezakhi viscosity ulwelo kuqaliswa lulwahlulo viscosity lomlingani kinematic μ ku lexinene fluid. Ixabiso le viscosity kinematic kulinganiswa e Stokes (Class 1 = 1 cm ^ (2) / c).

Le lomlingani viscosity kukuba ngamanani lilingane inani kwezithuthi zivezwa irhasi ihamba nganye kwexesha unit kwicala aa Incopho na intshukumo, per unit ndawo xa isantya intshukumo yohlukile ngeyunithi Velocity nganye kwi kweemaleko irhasi ezahlulwe nganye kwiyunithi ubude. Viscosity lomlingani ixhomekeke uhlobo kunye nemeko umbandela (iqondo lobushushu kunye noxinzelelo).

viscosity Dynamic kunye viscosity kinematic olwelo kunye neegesi, ubukhulu becala kuxhomekeka lobushushu. Kuye kwaqatshelwa ukuba zombini ukuhla ukungavumelani ne ukwandisa lobushushu zokuyeka ulwelo, icala, ukunyuka njengoko ubushushu - for iigesi. Ngokungafaniyo oku kuxhomekeka kungachazwa nohlobo ebonakalayo impefumlelwano molecule e ulwelo kwamathana kunye neegesi.

Intsingiselo ebonakalayo

Kweli qela ingcamango lwalusanda kwikinetiki yeegesi viscosity isenzeko silele yokuba eliphakathi ihamba ngenxa isindululo random neemolekyuli kwenzeka layers ulungelelwaniso ngezantya ezahlukeneyo. Ngoko ke, ukuba lo maleko wokuqala kwicala ihamba ngokukhawuleza ngaphezu ezikufutshane apho kukho umaleko yesibini, umaleko wokuqala nowesibini ihamba molecule ngokukhawuleza, kwaye vice versa.

Ngoko ke, lo maleko wokuqala idla ukukhawulezisa intshukumo umaleko yesibini, kwaye eyesibini - isantya i nentshukumo yokuqala. Ngenxa yoko, inani lilonke intshukumo umaleko yokuqala iza kuncipha, kwaye eyesibini - ukwandisa. Ukutshintsha iziphumo kweli ubuninzi sentshukumo lubonakala ngokuba viscosity ingumlingani ku igesi.

Obhulowu ngokungafaniyo neegesi, usukuzwano lwangaphakathi a kakhulu sisenzo imikhosi aphakathi. Ke, ekubeni umgama phakathi molecule obhulowu ilulwelo encinane xa kuthelekiswa ne-bume sukube, imikhosi intsebenziswano beemolekyuli ngelixa - ebalulekileyo. Le molecule kulwelo, kwakunye molecule eziqinileyo, ukusukela kufuphi amanqaku kuvuselele. Noko ke, ukuzala, la malungiselelo nto zokubhala. Emva kwexesha elithile imolekyuli engamanzi umngena kwindawo entsha. Kwangaxeshanye, ngexesha apho ukuma molecule e ulwelo ayitshintshi, ixesha wayibiza ngokuba "ubomi yokuhlala".

amandla aphakathi baxhomekeke kakhulu kuhlobo ulwelo. Ukuba viscosity ukwimo nto incinane, ibizwa ngokuba "flowable", njengoko ngumlingani kwemali kunye viscosity enefuthe ngayo kulwelo - na bomzimba ngokulinganayo. Kwelinye icala, kukho izinto kunye viscosity phezulu ibe lukhuni ngomatshini, njengoko, umzekelo, nentlaka. Le viscosity osisiqu ngelixa kakhulu ixhomekeke nokwakhiwa nezingcoliso kunye neemali zabo kunye lobushushu. Njengoko ubushushu ukunyusa ubungakanani "ubomi omdala 'ixesha lifinyele, ukuze kwandiswe ukusebenza nokuncipha viscosity fluid nokushukumisa kwento.

Le ngxaki yokusetyenziswa viscosity, kwakunye nezinye izenzakalo zothutho molekyuli (kwe- kunye conductivity thermal) yinkqubo vuhlayiseki leyo ekhokelela nempumelelo karhulumente lizama ehambisana entropy kwelona qondo ezamahala amandla.