Yuav ua li cas Dimpled los yog Corrugated PTFE Tubes Txhim Kho Thaum tshav kub kub hloov tsis muaj ntxiv Inserts?

Cov dimples, corrugations, lossis spirals tuaj yeem tsim ncaj qha rau ntawm lub raj nws tus kheej, tsis yog ntxiv cov khoom sib cais. Cov ntsiab lus sib xyaw no pab cuam tshuam kev ntws thiab nce kev xa hluav taws xob tsis muaj kev pheej hmoo ntawm kev ntxig ntxig los yog tsim kev cuam tshuam.

Vim li cas Passive Enhancement los ntawm Tube Geometry yuav tsum tau txiav txim siab
Hauv ntau cov txheej txheem tshuaj thiab tshuaj, kev ntseeg siab ntawm cov khoom siv hluav taws xob sib txawv yog qhov tseem ceeb ntawm lawv cov thermal ua haujlwm. Cov txheej txheem kev txhim kho ib txwm muaj xws li cov kab xev sib tw lossis cov xaim coil inserts muaj cov khoom siv sab hauv uas ua rau muaj kev tsiv teb tsaws chaw, qaug zog, lossis qhov chaw fouling. Lwm txoj hauv kev yog hloov lub raj phab ntsa nws tus kheej. Dimpled los yog corrugated PTFE tubing muaj ib tug nto roughness los yog waviness uas yog intrinsic rau lub raj. Tsis muaj qhov sib txawv txhais tau hais tias lub peev xwm ntawm kev ua haujlwm tsis ua haujlwm, ntxig nkag los yog ntws blockage yuav luag tsawg.

Txoj kev no yog qhov tshwj xeeb tshaj yog txaus nyiam los daws cov kua dej uas muaj cov khib nyiab tshem tawm, crystalline slurries los yog cov khoom siv los ua polymerization. Rau cov ntawv thov uas xav tau, ib qho dimpled lossis corrugated du hauv lub raj yog siv los tsim kev kub ntxhov yam tsis muaj qhov tawg qhov twg cov khib nyiab tuaj yeem sau.

Yuav ua li cas Dimples thiab Corrugations Mess nrog Flow
Lub dimpled los yog corrugated PTFE raj yog ib lub raj uas muaj ib tug series ntawm periodic indentations los yog dimples los yog alternations ntawm expansions thiab contractions los yog corrugations raws nws ntev. Raws li cov kua dej ntws los ntawm qhov sib txawv ntawm cov duab geometric, cov ciam teb nyob ib sab ntawm phab ntsa tau txuas ntxiv cuam tshuam thiab rov ua dua -tsim. Swirling vortices yog los tom qab txhua qhov dimple los yog corrugation ridge kom induce radial mixing ntawm cov tub ntxhais cov kua thiab cov phab ntsa. Qhov sib xyaw ua kom zoo thins cov txheej txheem thermal ciam teb thiab yog li txhim kho cov cua sov hloov pauv coefficient.

Qhov kev txhim kho mechanism yog txawv kiag li ntawm cov ntaub ntawv twisted ntxig. Daim kab xev sib tw muab ib qho helical swirl tsis tu ncua, tab sis cov dimples thiab corrugations ua rau thaj chaw muaj kev kub ntxhov. Qhov tshwm sim dimpled corrugated PTFE raj kub hloov pauv kev ua tau zoo yog feem ntau nruab nrab- ntawm qhov kev txhim kho ntawm 20-60% kev txhim kho ntawm lub raj du-tab sis nrog rau qhov sib npaug me me siab poob, feem ntau ntawm 30-100%.

Hauv kev xyaum, cov geometric tsis (dimple qhov tob, corrugation pitch thiab qhov siab) tuaj yeem raug teeb tsa ua lag luam -tawm ntawm kev hloov hluav taws xob nce thiab kev sib txhuam poob. Shorter pitch corrugations los yog ntxaum ntxaum ua kom muaj zog turbulence ntau dua, tab sis kuj muab kev tiv thaiv ntau dua. Ntev ntev, ntiav cov qauv muab ib tug smoother ntws nrog ib tug nruab nrab boost.

Qhov zoo ntawm Kev Sib Cais Sib Nqus
Dimpled los yog corrugated PTFE hlab muaj ntau yam zoo tshaj li twisted daim kab xev los yog lwm yam xoob inserts:

tsis tu ncua tsim ntawm insert geometry nyob rau hauv lub raj phab ntsa. Tsis muaj kev pheej hmoo ntawm kev txav mus los: Tsis muaj lub caij nyoog rau kev ntxig rau kev hloov pauv hauv qab, qhov chaw raug mob, lossis kov cov ntawv raj.

Tsis muaj kev tiv thaiv kev tiv thaiv ntxiv: Nrog rau qhov sib cais ntawm qhov kev tiv thaiv thermal yog nyob nruab nrab ntawm qhov ntxig thiab lub raj phab ntsa. Tsis muaj kev tiv thaiv ntxiv yog muaj vim tias tsis muaj qhov cuam tshuam nrog ib qho dimples lossis corrugations.

Kev kuaj xyuas yooj yim thiab ntxuav Cov hauv lub raj corrugated tseem yog ib qho qhib, tsis muaj kev cuam tshuam. Feem ntau txoj kev ntawm kev tu npua los yog txhuam yog txaus. Kev ntxuav lub raj nrog cov ntaub nplaum yuav tsum tau tshem tawm ntawm qhov ntxig.

Txo kev phom sij ntawm kev siv tshuab: Swirling inserts tuaj yeem ua rau muaj kev vibrations thiab abrasion ntawm PTFE raj phab ntsa nyob rau lub sij hawm, tshwj xeeb tshaj yog nyob rau hauv siab khiav ceev. Integral geometry tsis muaj qhov txheeb ze ntawm lub raj thiab qhov kev txhawb nqa.

It should be pointed out that even for very high heat transfer enhancement objectives (>100%) cov ntaub nplaum ntxig yog zoo dua li cov dimpled lossis corrugated hlab. Txawm li cas los xij, cov qauv tsim ib lub raj yog ib qho kev xaiv nrov rau cov ntawv thov uas qhov kev txhim kho me me tau txais thiab kev ntseeg siab yog qhov tseem ceeb tshaj plaws.

Kev ua haujlwm ntawm PTFE
Corrugated thiab dimpled hlab yog feem ntau ua hauj lwm nyob rau hauv cov hlau kub exchangers (xws li stainless hlau, cooper). Qee qhov tshwj xeeb extrusion lossis thermoforming txheej txheem yog xav tau rau lawv daim ntawv thov rau PTFE. PTFE tsis tuaj yeem ua tiav zoo li cov thermoplastics. PTFE feem ntau yog ram extruded los yog paste extruded. Ib txoj kev sib hloov-punch txoj kev tuaj yeem siv rau PTFE tom qab sintering los muab qhov tseeb dimples los yog corrugations, los yog ib tug succession ntawm rhuab tuag yuav siv tau los kos lub raj. Nruam corrugated PTFE hlab yog muag los ntawm cov kws tsim khoom tshwj xeeb rau cov kab me me (feem ntau 6-25mm).

Kev tswj ntawm phab ntsa thickness yuav tsum nruj heev. Phab ntsa yuav nyias dhau thiab tuaj yeem tawg nyob rau hauv lub siab sab hauv ntawm cov corrugations; phab ntsa tej zaum yuav tuab heev thiab cov flexural ua raws li xav tau los tsim kom muaj qhov nruj corrugation raug txo. Phab ntsa thicknesses ntawm corrugated PTFE tshav kub exchanger raj feem ntau nyob rau hauv thaj tsam ntawm 0.8 mus rau 2.0 hli nyob ntawm txoj kab uas hla thiab siab ntsuas.

Qhov cuam tshuam ntawm Flow Regime thiab Pressure Poob
Hauv laminar ntws (Re < 2000) muaj qhov dimples thiab corrugations muaj qhov cuam tshuam loj. Txawm tias tsawg Reynolds cov lej lawv ua rau muaj kev hloov pauv thaum ntxov mus rau qhov tsis ruaj khov, sib xyaw - tswj hwm kev tswj hwm, uas ua rau Nusselt tus lej nce 40-80% piv rau lub raj du. Tsis tas li ntawd, qhov kev nplua ntawm kev poob siab yog qhov tseem ceeb vim tias cov dej ntws tau raug yuam kom nrawm thiab decelerate tsis tu ncua.

Nyob rau hauv turbulent flow (Re > 4000) tus txheeb ze txhim kho yog tsawg dua - nquag 20-40% - txij li thaum lub ntuj turbulence twb ua kom zoo sib tov. Txawm li cas los xij qhov feem pua ​​​​nce hauv siab txo qis qis dua. Lub raj dimpled ua kom zoo tuaj yeem muaj qhov ua tau zoo thermal (qhov sib piv ntawm kev hloov pauv ntawm tshav kub hloov mus rau qhov kev sib txhuam nce mus rau 1/3 lub zog) zoo dua li 1.2, uas qhia tau hais tias kev txuag hluav taws xob piv rau lub raj du rau tib lub zog siv.

Cov lus hauv qab no qhia txog cov kev ua tau zoo ib yam rau cov dimpled lossis corrugated PTFE hlab nyob rau hauv kev sib raug zoo rau cov PTFE leeg raws li cov dej zoo li cov kua dej ntawm Re=2000-5000.

Parameter Hom Kev Txhim Kho Ntau Yam Kev Txhim Kho ntawm Nusselt tooj (kub hloov coefficient) ++20% rau +60%
Kev sib txhuam yam (siab poob) nce +30% rau +100%
Thermal performance factor (η) 1.1-1.3 Cov ntsiab lus
Dimpled los yog corrugated PTFE hlab muab ib qho yooj yim, passive txoj kev los txhim kho cua sov kis tau tus mob nrog zoo heev dependability. Cov hlab ntsha yog tsim los tsim cov txheej txheem saum npoo av uas rhuav tshem cov ciam teb txheej thiab txhawb kev sib xyaw radial, ua rau me me (20-}60%) cov cua sov hloov mus rau qhov tsis muaj peev xwm nkag mus rau hauv kev tsiv teb tsaws, tiv thaiv kev tiv thaiv, lossis kev tu cov teeb meem. Cov duab yog tshwj xeeb tshaj yog pab tau nyob rau hauv daim ntawv thov uas muaj hais, muaju los yog fouling kua uas cais inserts yuav muaj teeb meem. Tube geometry tseem yog ib qho tseem ceeb hauv kev tsim hluav taws xob hloov hluav taws xob - thiab nrog PTFE, dimpled los yog corrugated duab muab ib qho kev sib xyaw zoo ntawm kev ua tau zoo, kev huv thiab kev ua haujlwm ntev.