Viscosity ketshezi

Impahla noma yiluphi uketshezi, lokubonakala ikhono layo ukuvimbela displacement khulula noma shift izinhlayiya ayo, uchaza nomqondo viscosity uketshezi. Physico-chemical izakhiwo ukubaluleka kwalokhu itholakala lokuthi ukuthi uketshezi ezihambayo, kukhona abathile ngomshikisho yangaphakathi amandla phakathi amangqamuzana, okuyinto yena, osikweleta khona kwabo yokubakhona yamangqamuzana Luhambo amabutho.

Iqiniso liwukuthi e uketshezi ibanga inani eliphakathi amangqamuzana lincane kakhulu, kodwa ngenxa yokuthi mancane mobile kuka, bathi, amangqamuzana igesi. Penetration kwezinye ungqimba kungenzeka kuphela ukwakha therein isikhala esanele ketshezi ukuze akwazi ukufohla-molecule. Ukwakheka yeseli ezifana sisebenzisa amandla, okuyinto efanele incipha nge okwandisa izinga lokushisa kanye nokuncipha ingcindezi, noHezekeli.

Kuze kube manje, kufanele siqaphele ukuthi esiqinile umbono wesayensi owawuthandwa zalesi simo ingakamiswa aqine.

Izinkomba eyinhloko viscosity uketshezi, enze ashukumisayo Coefficient oboznachaemy - μ, futhi ngaphandle-ke, Coefficient kinematic, okhonjiswe - ν.

Sokulinganisa Coefficient ashukumisayo iyunithi poise (P) asetshenziswa GHS imethrikhi okuyinto ilingana 1 • x dyne / cm2 = 1 g / cm • x s). Uhlelo uhlelo adonsela phansi imethrikhi lokhu isilinganiso ulinganiswa kgf • s / m2; kanye SI ezivamile - e Pa • s. Ungasetha ubudlelwane zezibalo yalezi eziguquguqukayo nomunye. Kuyinto kanje: P 1 imayelana 0,0101 kgf • s / m2, okusisekelo 0.1 x Pa • s. Ngaphezu kwalokho, 1 x kgf • s / m2 = 98,1 n, futhi silingana 9,81 x Pa • s.

Ngu ifomula: ν = μ / ρ ungakwazi ukubala kinematic viscosity uketshezi, futhi iyunithi yalo iyona Stokes (Cm e CGS uhlelo), okuyinto ilingana 1 cm2 / s. Ngamanye izinhlelo - okudonsa ohlelweni imethrikhi futhi SI iyunithi isetshenziselwa ukukala lokhu isilinganiso elilingana 1 m2 / s, okuyinto 10000 Art.

Imithetho yemvelo yenza ukuthi nge okwandisa izinga lokushisa, viscosity uketshezi kuyehla. Lokhu kwencika ka Coefficient ashukumisayo kunqunywa kwesibalo μ = μ0 • e x a (t-t0), olukukhombayo: μ futhi μ0 - elihambisana Coefficient amagugu ngesikhathi kunikezwa okushisa t futhi t0, futhi - i-eksponenti ogama value kunqunywa izici uketshezi uqobo, futhi okuyinto oluyingozi, isibonelo, amafutha, ubukhulu bayo basukela 0,025 ukuze 0,035.

Kukhona ukwencika le nkomba futhi izimo lokushisa. Lokhu kubalulekile ikakhulukazi uma kuziwa emafutheni noma ezinye zokugcoba asetshenziswe ezihlukahlukene imishini, lokubolekwa, imishini. Ifomula lokhu kwencika ine uhlobo: νt = ν • x 50 x (50 / t0) n. It esiqokiwe: νt - ukubaluleka Coefficient kinematic ngesikhathi samanje lokushisa value, ν x 50 - ukubaluleka Coefficient ukubaluleka lokushisa 50 C, t - ukubaluleka izinga lokushisa lapho kudingeka sithole ukubaluleka Coefficient, n - izakhiwo sici uketshezi, lushintsha kuncike lokushisa, futhi ukubaluleka x ν 50.

Inani ingabalwa n kahle ngokwanele, uma sisebenzisa n ifomula = lg ν x 50 + 2.7. Ukuze hhayi ukwenza izibalo esimweni ngasinye, ukubaluleka n, elichaza viscosity kokuqala ketshezi at 50 C, ifinyeziwe itafula ekhethekile. Lokhu igijimisa kakhulu inqubo yokubala.

Ngaphezu kwalokho, kukhona itafula isifinyezo viscosity uketshezi, eveza kanye yonke idatha kanye izibalo kokubili izici ashukumisayo futhi kinematic sezinhlobo ezithile uketshezi.

ukuzimisela Lungile lamanani agcwele viscosity uketshezi inenani elikhulu esisebenzayo, okungukuthi inquma nekusebenta ukuqina izindlela eziningi ukuthi sisebenzisa kokubili emsebenzini nasekhaya.