Uketshezi, kokubili izinto eziwuketshezi kanye negesi zezinhlobo ezahlukene, zinamazinga ahlukene e-viscosity. I-Viscosity iwukungqubuzana phakathi kwama-molecule akha uketshezi. Ngakho-ke, ama-molecule akha ukungqubuzana koketshezi lapho uketshezi lugeleza. Kuketshezi, i-viscosity ibangelwa amandla okuhlangana (adonsa amandla phakathi kwama-molecule afanayo). Kanti ezintweni zegesi, i-viscosity ibangelwa ukungqubuzana phakathi kwama-molecule.
Uketshezi oluwuketshezi kulula ukulugeleza, isibonelo, amanzi. Ngokuphambene nalokho, uketshezi olujiyile kunzima ukulugeleza, isibonelo, uketshezi olugcotshwe. Ungafakazela ngokuthela amanzi kanye noketshezi endaweni ethambekele. Amanzi ageleza ngokushesha kunamafutha. Izinga lokuthamba koketshezi nalo lincike ekushiseni. Lapho izinga lokushisa loketshezi liphezulu, uketshezi luyancipha. Isibonelo, lapho umama ethosa inhlanzi ekhishini, uwoyela wokupheka oqala ukujiya uba uketshezi oluningi uma ushiswa. Ngokuphambene nalokho, lapho izinga lokushisa loketshezi oluwuketshezi luphakeme, kulapho uketshezi oluwuketshezi luba lukhudlwana.
I-Coefficient of Viscosity
Uphawu η lufanekisela ukujiya koketshezi (funda: eta). η = i-coefficient of viscosity. Ngakho-ke, izinga lokujiya koketshezi livezwa yi-coefficient ye-viscosity yoketshezi.
Ungqimba oluncane loketshezi lubekwa phakathi kwamapuleti amabili. Ukuhlangana kungamandla akhangayo phakathi kwama-molecule afanayo, kanti ukunamathela kungamandla okukhanga phakathi kwama-molecule ahlukene. Amandla okunamathela asebenza phakathi kwepuleti kanye nongqimba loketshezi olunamathele epuletini (ama-molecule oketshezi nama-molecule epuleti ayakhangana). Okwamanje, amandla okubumbana asebenza phakathi kwama-membrane oketshezi (uketshezi lukhanga ama-molecule).
Ekuqaleni, ipuleti kanye nesendlalelo soketshezi kuphumule (isithombe 1). Ngemva kwalokho, ipuleti elingaphezulu lidonswa ngakwesokudla (isithombe 2). Amapuleti angaphansi awadonswa (ipuleti elingezansi liphumule). Ubukhulu bamandla okudonsa buhlelwe ngendlela yokuthi ipuleti elingaphezulu lishintshele kwesokudla ngesivinini esingaguquki (v njalo). Ngenxa yokuthi kukhona amandla okunamathela asebenza phakathi komphetho wepuleti kanye nengxenye yoketshezi olunamathele epuletini, uketshezi olungaphansi kwepuleti nalo lushintshela kwesokudla. Ngenxa yokuthi kukhona amandla ahlangene phakathi kwama-molecule oketshezi, uketshezi oluya kwesokudla ludonsa uketshezi oluphansi.
Ingxenye yoketshezi engenhla idonsa uketshezi olungezansi ukuze lushintshe luye kwesokudla,
kanti ingxenye yoketshezi engezansi ibamba uketshezi olungaphezulu, ngakho-ke izinga loketshezi liyahlukahluka. Ingxenye yoketshezi engenhla ihamba ngesivinini esikhulu (v), uketshezi oluphansi luhamba ngesivinini esincane (v), njalo njalo. Ngakho-ke, i-v engezansi, incane. Ngamanye amazwi, ijubane lesendlalelo soketshezi lishintsha njalo kusukela phezulu kuya phansi kuze kufike ku-l.
Izinguquko ejubaneni lesendlalelo soketshezi (v) ezihlukaniswe ngebanga loshintsho (l) = v / l. I-V/l yaziwa ngokuthi i-speed gradient. Amapuleti aphezulu angahamba ngoba kukhona amandla okudonsa (F). Kwamanye amanzi, inani lokukhanga elidingekayo lilingana ngqo nendawo yoketshezi olunamathele epuletini (A), izinga loketshezi (v) kanye nokulingana okuphambene nebanga l. Ngokwezibalo, kungabhalwa kanje:
Ngaphambilini, kwachazwa ukuthi uketshezi oluncane luvame ukugeleza kalula, kanti uketshezi olujiyile lunzima ukugeleza. I-coefficient of viscosity iveza izinga le-viscosity yoketshezi. Uma uketshezi lukhuni, amandla okudonsa adingekayo nawo makhulu. Kulokhu, amandla okudonsa alingana ngqo ne-viscosity coefficient. Ngokwezibalo kungabhalwa kanje:
η = i-coefficient ye-viscosity, F = amandla, l = ibanga, A = indawo engaphezulu, v = isivinini, ∝ = ukuqhathanisa
I-International System Unit (SI) ye-coefficient of viscosity yi-Ns/m2 = Pa.s (isekhondi le-pascal). I-CGS unit (amasentimitha igremu lesekhondi) ye-coefficient viscosity yi-dyn.s/cm2 = poise (P). I-viscosity ivame ukuvezwa ku-centipoise (cP). 1 cP = 1/100 P. I-poise unit isetshenziswa ukuhlonipha usosayensi waseFrance, uJean Louis Marie Poiseuille (funda: pwa-zoo-yuh).
1 isikhundla = 1 dyn. s/cm 2 = 10 -1 Ns/m 2
