Ntau tus kws tshaj lij uas koom nrog R & D lossis kev tswj hwm zoo yuav ntsib qhov teeb meem no thaum ua cov kev tswj xyuas zoo tuaj (IQC). Tom qab tshuaj xyuas nws ob zaug, kuv ntseeg tias nws yuav tsum muaj kev tshuaj xyuas kom ntxaws.
"kev tshwm sim" txhais li cas? Puas yog nws xa mus rau nws txoj kev xav thaum lub sij hawm tsim kho lossis rau lub zog siv tshuab tom qab kev kho zaum kawg?
Qhov txawv yog dab tsi? 5% lossis 50%?
Yog tias tsis muaj ntau thaj tsam thiab cov xwm txheej tshwj xeeb, cov lus nug no tsis tuaj yeem teb tau yooj yim li "yog" lossis "tsis yog." Yog li ntawd, peb yuav mus ncaj qha los ntawm engineering foundations kom huv si soj ntsuam qhov teeb meem ntawm "kua nplaum viscosity variation." Dab tsi peb yuav tsum tau ntsuas yog seb qhov kev hloov pauv no tshwm sim los ntawm kev sib txawv ntawm cov qauv kev sim lossis qhov hloov pauv ntawm cov khoom siv hauv lub cev- thiab qhov tsis ua haujlwm txaus ntshai li qhov kev hloov pauv tuaj yeem ua rau ntawm cov kab ntau lawm.
01 Qhov Zoo Ntawm Viscosity
Tab sis yog tias peb txais kev pom txawv thiab xav txog lub ntiaj teb microscopic lub cev ntawm polymers, viscosity yog qhov tseem ceeb ntawm cov txheej txheem tsis tshua muaj zog. Lub viscosity ntawm polymer cov ntaub ntawv tshwm sim los ntawm ob yam: thawj, theem nrab kev sib cuam tshuam ntawm molecular chains (xws li van der Waals rog, hydrogen bonds, thiab txawm instantaneous dipole lub sij hawm tshwm sim los ntawm transient uneven electron huab faib); Thib ob, lub cev kev sib koom ua ke muaj nyob rau hauv qhov ntev - cov qauv saw ntawm cov polymers, uas zoo li lub vev xaib tangled interwoven thoob plaws hauv qhov chaw. Thaum peb siv lub zog macroscopic-xws li lub zog los ntawm lub tshuab xa tawm lossis lub zog shear ntawm lub viscometer rotor- txhawm rau ua kom ntws, peb tseem ceeb heev rau kev siv tshuab ua haujlwm kom kov yeej cov khoom siv hluav taws xob sib txawv thiab tawg los ntawm cov pob hauv lub cev.
Lub "sab hauv kev sib txhuam quab yuam" tsim los ntawm cov saw molecular no thaum zawv zawg yog qhov macroscopic manifestation ntawm viscosity. Yog li ntawd, viscosity tsis yog ib qho kev sib cais ntawm cov kua nplaum tab sis yog ib qho kev xav ntawm nws cov qauv molecular thiab kev sib cuam tshuam ntawm cov tshuaj.
Qhov no kuj piav qhia tias vim li cas viscosity thiaj li nkag siab zoo rau cov xwm txheej xws li qhov kub thiab txias, shear npaum li cas, thiab lub sij hawm-vim cov kev txwv no ncaj qha hloov cov kev txav mus los ntawm cov molecules thiab lawv lub xeev entanglement.
02 Cov ntaub ntawv tsis ncaj ncees feem ntau tshwm sim los ntawm misalignment ntawm kev xeem ciam teb.
Rov qab mus rau cov npoj yaig cov lus nug, ob pawg ntawm cov nplaum ua pov thawj sib txawv viscosities. Ua ntej xav tias muaj cov khoom tsis xws luag, peb yuav tsum xub txiav txim tsis cuam tshuam los ntawm cov txheej txheem kuaj. Txij li cov kua dej polymer feem ntau tsis yog -Newtonian kua, lawv ua rau muaj kev txwv nruj heev rau kev sim.
Kev sib raug zoo ntawm qhov kub thiab txias thiab kev txav mus los ntawm cov khoom siv hluav taws xob ua raws li tus qauv exponential (raws li Arrhenius empirical txoj cai). Feem ntau, qhov nruab nrab kub ntawm qhov chaw nplaum nplaum yog 20 degree, hos qhov ntsuas kub ntawm chav kuaj yog 25 degree.
Yog tias tus qauv tsis raug rau qhov sib npaug ntawm qhov sib npaug ntawm qhov kub thiab txias tom qab kuaj (uas feem ntau xav tau ntau tshaj 30 feeb), cov ntaub ntawv ntsuas yuav ua rau muaj qhov sib txawv tseem ceeb. Qhov kub hloov pauv ntawm 1℃yuav ua rau muaj kev hloov pauv viscosity ntawm 5% mus rau 10%.
Shear Rate: Ntau cov txheej txheem tswj tau zoo saib xyuas qhov sib xws ntawm cov qauv rotor thiab kev sib hloov ceev thaum sib piv cov khoom siv. Cov kua dej polymer muaj cov yam ntxwv ntawm "shear-kev coj tus cwj pwm thinning."
Qhov siab dua qhov kev sib hloov ceev, qhov ntau dua qhov uas cov saw hlau molecular raug yuam kom taw qhia thiab tsis muaj mob, ua rau qhov ntsuas qis dua qhov pom tseeb viscosity. Qhov tseem ceeb, thaum ntsuas cov tsis yog -Newtonian kua, qhov viscosity point ntawm ib qho kev sib hloov ceev feem ntau tsis muaj qab hau; dab tsi yuav tsum tau muab piv yog "shear stress–viscosity curves" tau txais ntawm cov nqi sib txawv.
Lub Sijhawm (Thixotropy): Hauv cov tshuab uas muaj cov tshuaj thixotropic xws li fumed silica, hydrogen bond network tsim nyob rau hauv lub sijhawm so (ua rau siab viscosity), thaum lub network no cuam tshuam nrog kev ntxhov siab (ua rau qis viscosity).
Qhov no zoo ib yam li muaj ob tus neeg sib tw hauv 100-meter kev sib tw: ib tus tau ua tiav sov- nce thiab tswj lub cev zoo, thaum lwm tus twb tau khiav tsib sib tw sib tw thiab lawv lub cev lub cev tseem tsis tau zoo ua ntej sim thib rau. Qhov pom qhov sib txawv hauv cov txiaj ntsig kawg yuav tsis tas yuav cuam tshuam qhov sib txawv ntawm qhov muaj peev xwm tab sis tuaj yeem tsuas yog los ntawm kev hloov pauv hauv lawv qhov kev xeem ua ntej -. Yog tias lub sijhawm ua ntej - txiav sijhawm lossis lub sijhawm so rov qab sib txawv ntawm ob pawg ntawm cov qauv ua ntej kuaj, cov ntawv nyeem yuav sib txawv. Yog li ntawd, nws yog ib qho tseem ceeb uas yuav tsum tau qhia kom meej meej ua ntej kuaj seb lub sij hawm txiav ua ntej yuav tsum ntev npaum li cas thiab lub sij hawm ntsuas qhov twg yuav tsum tau ntsuas. Yog tias tsis muaj sijhawm sib raug zoo, cov ntaub ntawv tsis tuaj yeem muab piv tau zoo.
03 Dab tsi yog qhov sib txawv tseem ceeb uas yuav suav tias yog qhov txawv txav? Thaum twg nws yuav cuam tshuam rau cov khoom?
Nws yuav tsum xub lees paub tias cov txheej txheem polymerization nws tus kheej yog inherently random, ua rau nws unrealistic xav tau kiag li uniform molecular hnyav faib thoob plaws tag nrho cov batch ntawm nplaum.
Cov lus qhia tshwj xeeb hauv kev lag luam qhia tau hais tias kev hloov pauv viscosity nyob rau hauv ± 10% mus rau ± 15% poob nyob rau hauv ib txwm kam rau ua.
Yog tias qhov sib txawv ntau dua 20% -30%, kev ceeb toom tau lees paub- qhov no qhia tau tias muaj teeb meem nrog lub hauv paus resin batch lossis tsis sib xws ntawm cov thixotrop. Cov txiaj ntsig zoo li cas yuav ua rau muaj kev sib txawv?
Nyob ntawm koj lub qhov rais txheej txheem. Yog tias koj siv cov nplaum los yog ib nrab- tsis siv neeg, 20% qhov sib txawv ntawm cov viscosity yuav cuam tshuam rau tus neeg teb xov tooj qhov kev xav ntawm kev ntxhib los mos tab sis tsis tas yuav cuam tshuam qhov kawg ntawm daim ntawv cog lus.
Rau cov kab xa tawm tsis siv neeg, kev hloov pauv hauv viscosity ncaj qha cuam tshuam rau tus nqi ntawm cov nplaum siv. Nyob rau hauv cov xwm txheej zoo sib xws thiab lub sijhawm, cov viscosity siab tuaj yeem tiv thaiv cov nplaum los ntawm kev ntws los yog ua rau txoj hlua; viscosity tsawg tuaj yeem ua rau sagging lossis tsis xav tau ntawm cov nplaum. Qhov no tuaj yeem cuam tshuam kev sib dhos ntau lawm. Qhov tseem ceeb tshaj plaws nyob rau hauv qhov zoo interface wetting.
Ntxiv viscosity txo cov kua dej, tiv thaiv cov nplaum los ntawm kev nkag mus rau hauv micro- ntxhib nto ntawm substrate. Thaum pom ntawm daim ntawv thov, ntau qhov chaw me me muaj nyob ntawm qhov interface. Raws li kev ntxhov siab, qhov kev pheej hmoo ntawm kev cuam tshuam kev cuam tshuam cuam tshuam nce. Ad: WorkBuddy AI Office Assistant - xa tawm -dawb thiab npaj tau-rau- siv. Sim WorkBuddy tam sim no. Tsis tas li ntawd, kev tsim npuas yuav tshwm sim. Ntxiv viscosity txo cov kua dej, tiv thaiv cov nplaum los ntawm kev nkag mus rau micro- ntxhib nto ntawm substrate. Thaum pom ntawm daim ntawv thov, ntau qhov chaw me me muaj nyob ntawm qhov interface. Raws li kev ntxhov siab, qhov kev pheej hmoo ntawm kev cuam tshuam kev cuam tshuam cuam tshuam nce. Ad: WorkBuddy AI Office Assistant – xa{14}}dawb thiab npaj tau{15}}rau- siv. Sim WorkBuddy tam sim no. Tsis tas li ntawd, kev tsim npuas yuav tshwm sim.
Thaum lub viscosity ntawm cov nplaum nplaum ntxiv, microbubbles entrained thaum stirring los yog filling ua nyuaj rau tshem tawm. Txawm tias nyob rau hauv lub tshuab nqus tsev, siab - viscosity systems yuav ntxiab cov npuas no. Thaum kho, cov npuas no hloov mus rau hauv cov ntsiab lus kev ntxhov siab, uas nyob rau hauv siab - cov ntawv thov hluav taws xob hluav taws xob yuav ncaj qha ua rau qee qhov tso tawm lossis tawg.
[Engineering-Txoj Kev Txiav Txim Siab-Kev Ua Haujlwm] Ntawm no yog peb yam - kauj ruam ua haujlwm rau engineering- raws li kev txiav txim siab:
1. Ua ntej, paub meej tias qhov tsis sib xws yog qhov tseeb
Ob pawg ntawm cov qauv tau ntsuas ib txhij siv tib lub viscometer, rotor, kev sib hloov ceev, qhov kub thiab txias, nrog rau qhov zoo tib yam so thiab shear lub sij hawm. Yog tias qhov sib txawv tsawg dua 15%, nws yog qhov yuav muaj qhov txawv txav. Yog tias qhov sib txawv tshaj 20%, kev tshuaj xyuas ntxiv yuav tsum tau ua.
2. Tam sim no cia peb saib lwm qhov ntawm koj lub qhov rais txheej txheem
Kev ntsuas ntawm cov kab ntau lawm: txiav txim siab tam sim no huab cua siab, lub sijhawm thov, koob txoj kab uas hla ntawm cov khoom siv, thiab cov viscosity tau txais.
Piv txwv li, yog tias koj lub cuab yeej ua haujlwm tsis tu ncua ua cov nplaum hauv qhov viscosity ntawm ± 15%, batch variations yuav tsis cuam tshuam rau kev ua haujlwm. Txawm li cas los xij, yog tias lub qhov rais kam rau ua nqaim, koj yuav tsum pom zoo nrog tus neeg muag khoom ntawm cov qauv tswj nruj dua.
3. Thaum kawg, tshuaj xyuas cov hom kev ua tsis tiav
Yog tias cov khoom kawg dhau qhov kev sim ua haujlwm (xws li, lub zog shear, kev ua haujlwm siab, kev laus) tom qab viscosity fluctuations, nws qhia tau hais tias qhov kev hloov pauv poob hauv qhov kev txwv. Yog hais tias ib lub batch nthuav tawm cov dej tsis zoo los yog cov npuas seem, tshuaj xyuas cov kev hloov pauv viscosity thiab tsim kom muaj kev tswj hwm sab hauv. Txawm hais tias qhov ruaj khov viscosity yog qhov xav tau, qhov tseem ceeb tshaj yog nws qhov ruaj khov txaus nyob rau hauv koj cov kev tsim khoom tshwj xeeb.
Txhawm rau txheeb xyuas qhov teeb meem zoo, ua ntej tshem tawm kev ntsuas qhov yuam kev, tom qab ntawd sib piv cov txheej txheem tsis pub dhau qhov kev pom zoo, thiab thaum kawg txheeb xyuas cov kev tshawb pom no nrog cov qauv tsis ua haujlwm tiag tiag - txoj hauv kev no tiv thaiv kev ua yuam kev los ntawm ib tus lej tus nqi. Yog tias koj kuj tau ntsib qhov tsis sib xws ntawm ob pawg ntawm cov ntaub ntawv nplaum lossis cov khoom ntim tsis sib haum ntawm cov kab ntau lawm, ua raws li cov txheej txheem no.