Thaum tshav kub kub hloov khoom ntawm qhib cell hlau foams

Hlau ua npuas ncauj yog ib hom ntawm cov khoom siv sib xyaw ua ke hlau uas muaj qee tus lej, qee qhov loj ntawm qhov pores, thiab qee qhov porosity hauv cov hlau matrix. Ua npuas ncauj hlau muaj cov yam ntxwv tshwj xeeb xws li thaj chaw loj tshwj xeeb, porosity loj, thiab qhov ntom ntom me me, thiab muaj cov yam ntxwv sib xyaw ua ke xws li cua sov dissipation (qhib-cell), rwb thaiv tsev kub (kaw-cell), suab nqus thiab kev co damping, lub teeb yuag. , siab tshwj xeeb lub zog, electromagnetic shielding, thiab lwm yam, thiab nws yog ib yam ntawm cov qauv thiab haumxeeb khoom integrating cov khoom ntawm thermophysics, mechanics, acoustics, thiab hluav taws xob.
Rauqhib-cell hlau ua npuas ncauj, lub siab porosity thiab complex peb-dimensional mesh qauv ua rau nws muaj zoo heev tshav kub dissipation thiab high tshav kub hloov efficiency, uas muaj ib tug heev daim ntawv thov kev cia siab nyob rau hauv lub tshav pob ntawm compact tshav kub exchangers, microelectronic ntaus ntawv txias, thiab hais txog. Rau cov khoom siv hluav taws xob hloov hluav taws xob ntawm lub xov tooj ntawm tes ua npuas dej, nws cov xwm txheej tshawb fawb tau tshawb xyuas thiab tshuaj xyuas los ntawm daim ntawv thov ntawm cov khoom siv hluav taws xob sib txuas.
Hlau ua npuas ncaujrau compact tshav kub exchangers
Cov khoom siv hluav taws xob ua kom zoo dua qub ntawm cov hlau ua npuas ncauj feem ntau tau lees paub. Thaum cov pa roj los yog kua ntws los ntawm lub qhov, cov cua sov tau hloov pauv thiab hloov pauv hauv daim ntawv ntawm kev quab yuam convection ntawm cov hlau ua npuas ncauj nrog cov qauv qhib thiab cov kua dej. Ntawm qhov tod tes, lub complex peb-dimensional mesh qauv ntawm cov hlau ua npuas ncauj ua rau cov nonlinear nyhuv ntawm cov kua, thiab cov degree ntawm turbulence kuj ntxiv dag zog rau, yog li txhawb cov khoom nto rau cov kua nyob rau hauv lub high kub hloov lwm lub tsev; ntawm qhov tod tes, cov hlau ua npuas dej loj tshwj xeeb ntawm thaj chaw kuj yog ib qho tseem ceeb vim li cas cov hlau muaj kev ua haujlwm zoo thaum tshav kub kub. Tam sim no, txoj kev tshawb fawb ntawm cov hlau ua npuas ncauj rau kev sib hloov pauv hloov pauv hloov pauv kev ua tau zoo feem ntau tsom rau huab cua-sab txhim kho cov cua sov hloov pauv thiab cov tub yees-sab txhim kho cov cua sov.
Rau cov huab cua-sab txhim kho cov khoom siv hluav taws xob hloov hluav taws xob ntawm cov hlau ua npuas dej, hlau ua npuas dej yog siv los hloov cov fins rau cov cua sov dissipation nyob rau hauv cov ntaub ntawv siv cov fins ib txwm siv, xws li cua txias cov khoom hluav taws xob, phaj kub exchangers, thiab finned heat exchangers. Hauv cov khoom siv hluav taws xob sib txuas, cov khoom siv hluav taws xob hloov pauv tam sim no tau kawm tshwj xeeb rau tooj liab thiab txhuas ua npuas ncauj hlau nrog pore ntom feem ntau tsawg dua 40% thiab porosities ntawm 70% lossis ntau dua.
Ntawm ib qho pore loj, qhov kub hloov pauv nce nrog qhov nce ntawm porosity thiab dominates. Ntawm qhov tod tes, rau qee qhov porosity, qhov siab dua qhov pore ntom, qhov qis dua qhov kev hloov pauv cua sov, uas yuav yog vim qhov pore loj heev. Lub pore qauv tsis muaj porosity, pore ntom, thiab pore txoj kab uas hla yog lub ntsiab yam tseem ceeb cuam tshuam rau lub tshav kub hloov kev ua tau zoo ntawmhlau ua npuas ncauj. Rau kev siv hlau ua npuas dej hauv cov khoom siv hluav taws xob ua kom txias, cov teebmeem ntawm cov hlau ua npuas ncauj porosity thiab pore txoj kab uas hla ntawm cov cua kub dissipation nyhuv tau tshawb xyuas los ntawm kev sim orthogonal. Cov txiaj ntsig tau pom tias nyob rau hauv kev quab yuam convection, lub tshav kub dissipation kev ua tau zoo ntawm cov hlau ua npuas ncauj muaj feem xyuam rau lub pore qauv, nyob rau hauv uas lub pore loj muaj lub zog loj tshaj plaws.
Qee qhov kev tshawb fawb pom tau hais tias txawm hais tias cov hlau ua npuas dej muaj lub luag haujlwm tseem ceeb hauv kev txhim kho cov cua sov, kev loj hlob ntawm kev tiv thaiv tsis muaj qhov tsis txaus ntseeg nrog rau kev loj hlob ntawm cov khoom siv hluav taws xob. Lub tshav kub hloov ua haujlwm ntawm cov hlau ua npuas dej tau txhim kho zoo ntawm qhov poob qis, thiab qhov poob siab nce nrog qhov nce ntawm qhov pore ntom. Cov txiaj ntsig ntawm txoj kev tshawb fawb no yog cov lus qhia rau kev tsim thiab kev tsim khoom ntawm lub teeb yuag thiab compact high-efficiency heat exchangers. Kev tshawb fawb txog kev ua npuas dej hlau kub exchangers thiab finned heat exchangers ntawm tib qhov loj tau nqa tawm, thiab nws tau pom tias nyob rau hauv tib yam kev sim, cov npuas hlau kub exchanger yog tsawg npaum li finned heat exchanger, thiab lub siab poob thiab Kev sib txhuam coefficient yog siab dua li cov finned heat exchanger. Cov hlau ntxeem tau muaj qhov pom tseeb ntxiv dag zog rau kev hloov pauv cua sov, thiab cov nyhuv ntxiv zog txo nrog qhov nce ntawm Reynolds tus lej; Cov hlau nplaum ua npuas dej ua rau cov dej tsis kam ua kom pom tseeb, tab sis qhov sib npaug ntawm kev tiv thaiv nce qis nrog qhov nce ntawm Reynolds tus lej. Kev ua kom muaj zog ntawm kev hloov pauv hluav taws xob convective thiab nce siab hauv cov dej ntws ntawm ob yam tuaj yeem pom,ntxeem tau ua npuas ncauj hlauyog qhov tsim nyog rau cov kua dej me me nrog lub sijhawm me me ntws. Ua npuas ncauj hlau muaj lub luag haujlwm ntawm huab cua-sab txhim kho cov cua sov hloov pauv, tab sis kev hloov pauv kev ua haujlwm tau zoo nyob rau tib lub sijhawm, kev ua haujlwm kuj nce ntxiv, thiab kev ua tau zoo tag nrho yog qhov phem dua li cov tsoos fins. Kev tshawb fawb qhia tau hais tias ua npuas ncauj hlau yog haum rau tsawg-flow tsawg zaus. Yog li ntawd, ua npuas ncauj hlau cua-sab txhim kho cua sov hloov pauv yuav tsum tau xav txog lub sijhawm thov, thiab tsis tuaj yeem ua qhov muag tsis pom kev siv cov tsoos fin heat dissipation lwm txoj kev tshawb fawb.

Cov hlau ua npuas dej kuj tuaj yeem ua lub luag haujlwm hauv kev txhim kho cov cua sov hloov ntawm cov tub yees los ntawm theem hloov. Cov txiaj ntsig tau pom tias thaum lub porosity yog qhov tseeb, qhov kev hloov pauv ntawm cov cua sov ua kom zoo dua qub vim qhov pore ntom ntawm 20 mus rau 40 PPI thiab qhov pore loj yuav txo qis, vim cov qauv ntawm tes zoo dua nrog thaj chaw loj dua thiab muaj kev ntxhov siab ntau dua. Nyob rau hauv high flow rates, lub boiling heat transfer coefficient tswj ib tug khov kho thiab maj mam nce nrog nce dryness. Nrog rau kev nce siab hauv kev khiav hauj lwm siab, qhov kub kub hloov pauv tshwm sim ntawm qhov qhuav qhuav zoo ib yam li hauv av boiling, piv txwv li, lub tshav kub hloov mus rau qhov siab ntxiv, tab sis lub siab nce mus rau qee yam ua lub luag haujlwm tsis zoo hauv lub boiling. hloov kub. Lub tshav kub hloov coefficient ntawm tooj liab ua npuas ncauj raj yog li peb zaug siab dua li ntawm lub teeb raj. Nyob rau hauv cov ntaub ntawv ntawm ntshiab refrigerant, lub xub ntiag ntawm ua npuas ncauj hlau ua rau lub ndlwg ntawm boiling tshav kub hloov lwm lub tsev, thiab lub tshav kub hloov coefficient yog nce mus txog 185%. Nyob rau hauv cov ntaub ntawv ntawm cov roj-muaj tej yam kev mob, cov nyhuv ntawm hlau ua npuas ncauj kom ntxiv dag zog rau lub tshav kub hloov yog tsis muaj zog; Raws li cov xwm txheej zoo ib yam, piv nrog 5PPI ua npuas dej hlau, 10PPI ua npuas ncauj hlau tuaj yeem ua kom cov cua sov hloov pauv mus txog 0.6 npaug, thiab qhov pore me me tuaj yeem txhim kho cov dej ntws kub hloov coefficient.
Cov teebmeem ntawm huab hwm coj tus nqi thiab ob-theem kua dryness ntawm ntws condensation siab poob thiab tshav kub hloov coefficient raug txheeb xyuas. Cov txiaj ntsig tau pom tias lub siab poob ntawm cov phab ntsa sab hauv uas muaj cov hlau ua npuas dej yog qhov loj dua li ntawm lub teeb lub raj, thiab lub siab poob siab tuaj yeem nce sai thiab tsis yog linearly nrog qhov nce ntawm huab hwm coj txaus thiab dryness. Lub condensation tshav kub hloov coefficient ntawm lub puab phab ntsa-filled annular hlau ua npuas ncauj raj yog loj dua li ntawm lub teeb lub teeb, thiab lub tshav kub hloov coefficient nce nrog rau qhov nce ntawm huab hwm coj tus nqi thiab dryness, thiab ntws condensation tshav kub hloov coefficient ntawm hom no. ntawm cov hlab ntsha muaj zog yog li ob zaug ntau npaum li lub teeb lub raj. Vim tias nws cov nyhuv capillary yog qhov pom tseeb, qhov pore ntom ntawm 130PPI lub raj txuas ntxiv yog qhov zoo tshaj plaws cov nyhuv, rau lub teeb raj 3.06 npaug, 40PPI raj feem ntau zoo ib yam li cov qauv ntawm cov raj qis qis raws li ib qho kev txhawb zog.
Nyob rau hauv lub compact tshav kub exchanger,hlau ua npuas ncaujtuaj yeem siv tag nrho los ntxiv dag zog rau lub luag haujlwm ntawm kev hloov hluav taws xob, tab sis txoj kev tshawb fawb tau pom tias cov yam ntxwv ntawm cov hlau ua npuas dej loj hlob kuj tseem ceeb heev, qhov kev xav tau ntawm kev ua tau zoo los ntsuam xyuas daim ntawv thov ntawm foam hlau nyob rau hauv compact heat exchanger. Nyob rau hauv tas li ntawd, nyob rau hauv lub xub ntiag ntawm cov roj lubricants, ua npuas ncauj hlau yuav ua rau deterioration ntawm tshav kub hloov lwm lub tsev, thiab txhim khu kev qha tshav kub hloov ntawm hlau foams rau theem hloov tshav kub hloov ntawm cov tub yees yuav tsum tau xav txog nyob rau hauv lub teeb ntawm cov teebmeem ntawm lubricants.