Lub Plhaub li cas -Side Reynolds Number Influence the Onset of Flow-Induced Tube Vibration in a PTFE Exchanger?

Lub PTFE hlab nyob rau hauv lub tshav kub exchanger yog nyob ntsiag to thiab ruaj khov nyob rau hauv qis txaus tus nqi ntawm lub plhaub sab. Txawm li cas los xij, lub plhaub nce ntxiv - sab nrawm tuaj yeem hla qhov chaw kaw hydraulic. Cov dej nrawm nrawm, kev sib zog ua kom muaj zog, lub raj yooj yim thiab kev txhawb nqa qhov sib txuas ua ke kom tso cai rau cov kua ntws los ua kom muaj zog ua kom lub raj ntim khoom npaj txhij txog. Qhov tshwm sim yog ntws-vim kev vibration, thaum cov raj uas yav tas los zoo li qub pib sway, oscillate thiab qee zaum clatter nrog lub suab nrov tawm tsam lawv cov kev txhawb nqa.

Yog li ntawd, kev sib txuas ntawm lub plhaub sab ntawm Reynolds tus naj npawb thiab lub raj vibration yog ib qho tseem ceeb tshaj plaws ntawm kev siv tshuab -hydraulic kev sib cuam tshuam hauv kev tsim cov fluoropolymer kub exchangers thiab kev ua tau zoo ntawm PTFE exchanger kuj muaj feem xyuam rau qhov no.

Reynolds Number nyob rau hauv Plhaub Sab Flow yog dab tsi?
Reynolds tus lej yog tus lej tsis muaj qhov piav qhia qhov xwm txheej ntawm cov dej ntws. Nov yog qhov sib xyaw ntawm qhov cuam tshuam ntawm:

Kev nrawm ntawm cov kua dej

Qhov ntom ntom ntawm cov kua dej

viscosity ntawm cov kua

Hydraulic txoj kab uas hla

Hauv plhaub -sab exchanger ntws, Reynolds tus naj npawb yog siv los qhia seb cov kua dej feem ntau yog du, laminar flow los yog nquag, turbulent flow.

Ntau dua Reynolds naj npawb, Ntau zog turbulent
Rau ib lub raj tshwj xeeb pob geometry nce hauv lub plhaub -sab Reynolds tus lej feem ntau txhais tau tias:

Siab crossflow tshaj tawm

Siab zog turbulence

Loj oscillating siab zog

Ntau zog ntawm vortex shedding

Hauv qab qee qhov theem pib, lub zog hloov pauv me me dhau los hloov lub raj ntim hauv txhua txoj kev muaj txiaj ntsig. Lub kaw lus tseem mechanically damped thiab khov kho.

Txawm li cas los xij, tom qab lub ntsiab lus tseem ceeb tau dhau los lub zog ntawm cov dej ntws tuaj yeem pib ua ob peb lub zog nrog cov zaus ntawm kev co ntawm cov hlab ntsha.

Vim li cas PTFE Tubes rhiab heev rau kev vibration
Thaum PTFE muaj cov tshuaj tiv thaiv siab thiab tiv thaiv corrosion, nws yog mechanically ho tsis nruj dua li cov ntaub ntawv hlau raj.

PTFE raj yog muab piv nrog stainless hlau los yog titanium raj:

Txo Young's modulus

Ua kom yooj

Lowered natural zaus

Ntau dua deflection nyob rau hauv load

Raws li qhov tshwm sim, tus lej Reynolds tseem ceeb rau qhov pib ntawm kev vibration feem ntau yog nyob rau ntawm lub plhaub qis - sab nrawm dua li cov hlau sib piv.

Qhov no ua rau kev txiav txim siab ntawm kev vibrations tshwj xeeb yog qhov tseem ceeb hauv kev tsim cov fluoropolymer exchangers.

Flow Induced Tube Vibration Mechanism
Lub plhaub turbulent-sab kua dej ntws hla lub raj ntim induces hloov siab nyob ib ncig ntawm txhua lub raj.

Vortex Oscillation thiab Shedding
Alternating vortices tom qab cov hlab ntsha muab kev ntxhov siab rau sab nraud. Ntawm cov dej ntws qis, cov zog no tsis muaj zog thiab tsis muaj teeb meem loj.

Nrog nce Reynolds tus lej:

Turbulence theem nce

Kev hloov pauv siab tau dhau los ua kom pom tseeb

Ntau coherent oscillating rog Ntau coherent oscillating rog

Tube txav tau pib txhim kho

Yog hais tias qhov stimulation zaus nyob ze rau lub ntuj zaus ntawm lub raj, resonance phenomena yuav tshwm sim.

Tom qab ntawd qhov kev vibration amplitude tuaj yeem nce nrawm, tsis maj.

Fluid-Elastic Instability: Qhov tseem ceeb tshaj plaws
Qhov tseem ceeb tshaj plaws rau cov kua dej- elastic instability yog ib qho tseem ceeb tshaj plaws kev kuaj xyuas nyob rau hauv exchanger tsim.

Vim li cas qhov Risk nce mus
Kev txav mus rau qhov tsis ruaj tsis khov tsis yog txoj kab ncaj nraim. Hauv qab qhov tseem ceeb ntawm lub xeev ntws, cov txheej txheem damping yog qhov tseem ceeb thiab suppress lub raj txav. Saum toj no, cov kua nws tus kheej pib los pab txhawb lub zog rau hauv lub voj voog ntawm oscillation ntawm tus nqi nrawm dua li cov qauv tuaj yeem dissipate nws.

Tom qab ntawd txawm tias me me nce hauv qhov nrawm nrawm tuaj yeem ua rau muaj qhov tsis txaus ntseeg loj ntawm kev co amplitudes.

Lub raj nws tus kheej ua haujlwm raws li nws tus kheej lub zog kuaj lub tshuab, ncab dua thiab dhau ntawm lub voj voog siab kom txog thaum hnav, tawg lossis txhawb kev puas tsuaj.

Tej yam tshwm sim ntawm ntau dhau kev vibration
Flow-induced vibration yog tsis tswj yuav ua rau:

Kev qaug zog ntawm lub raj phab ntsa

Txhawb nqa

Abrasive hnav

Tube-rau- tube sib tsoo

Kev ua tsis tiav

Bundle puas tsuaj - kev puas tsuaj

Cov khoom muag muag hauv PTFE exchangers tuaj yeem yog qhov tshwj xeeb tshaj yog rau ntev -lub sij hawm oscillatory hnav ntawm qhov chaw txhawb nqa.

Kev soj ntsuam ntawm Tube Vibration hauv Plhaub Sab ntawm PTFE Exchanger los ntawm Reynolds Number
Nyob rau hauv kev sib pauv tsim, kev sib xyaw ua ke hydraulic thiab tshuab siv los ntsuas kev sib raug zoo ntawm lub plhaub sab Reynolds tus naj npawb, raj vibration thiab PTFE exchanger stability.

Parameters cuam tshuam rau qhov tseem ceeb
Ob peb yam cuam tshuam qhov tshwm sim ntawm instability.

Influence of Design Variables on Vibration
Kev nrawm ntawm plhaub sab Excitation quab yuam tsa
Tube span length Ntev spans txo nruj
Tube txoj kab uas hla Ntuj zaus hloov
Fluid density Zoo dua dynamic loading
Tube spacingVibration kuj tswj
Phab ntsa tawv (PTFE) cuam tshuam rau tus cwj pwm deflection
Kev sib cuam tshuam ntawm cov khoom no yog qhov nyuaj dua li txoj cai yooj yim - ntawm - tus ntiv tes xoo kwv yees thiab yuav tsum tau ua tib zoo tshawb fawb engineering.

Qhov tseem ceeb ntawm lub raj txhawb qhov sib nrug
Ib qho ntawm cov cuab yeej siv tau zoo tshaj plaws los tiv thaiv cov teeb meem kev co hauv PTFE exchangers yog raj txhawb kev sib nrug.

Qhov luv luv, lub ntuj zaus ntau dua.
Mechanically lub raj behaves raws li ib tug saj zawg zog beam. Lub inherent zaus ntawm kev vibration ntawm lub ncua yog heev cuam tshuam los ntawm nws unsupported ntev.

Ntxiv kev txhawb nqa ntxiv:

Tsis txhawb qhov ntev txo

Tube txhav tau ua tiav tiav

Deflection amplitude txo

Lub ntuj zaus nce ntau heev

Nws yog ib qho tseem ceeb uas lub ntuj zaus kev sib raug zoo yog rhiab rau lub ncua ntev. Raws li qhov tsis muaj kev txhawb nqa tau txo qis, lub ntuj zaus nce ntxiv raws li lub xwmfab ntawm qhov cuam tshuam txo qis, yog li kev txhawb nqa qhov sib txawv yog qhov kev ntsuas muaj zog tshwj xeeb.

Qhov no txav lub raj resonance zaus mus rau siab dua li thaj tsam tseem ceeb ntawm turbulent excitation tsim los ntawm lub plhaub -sab ntws.

Kev Lag Luam Kev Ua Haujlwm thiab TEMA Cov Lus Qhia
Flow induced vibration analysis yog ib qho kev ua haujlwm niaj hnub hauv plhaub - thiab - tube heat exchanger engineering raws li TEMA cov hauv paus ntsiab lus.

Kev txiav txim siab tsim los ntawm TEMA
Nyob rau hauv Tubular Exchanger Manufacturers Association (TEMA) lub moj khaum, cov kev ntsuam xyuas hauv qab no yog:

Transverse flow ceev

Kev vibration rhiab heev 1.

Ntuj frequencies ntawm ib lub raj

Kev txwv ntawm cov kua dej elastic instability

Teb rau vortex shedding

Tib lub tswv yim kev vibration yooj yim siv rau PTFE exchangers, txawm li cas los xij cov khoom siv ntxiv -kev txhawj xeeb tshwj xeeb yuav tsum tau muab rau hauv tus account.

Lawv yuav tsum xyuas kom meej tias cov kev khiav hauj lwm ntws nyob deb ntawm cov cheeb tsam tsis ruaj tsis khov tseem ceeb rau qhov kwv yees kev khiav hauj lwm ntawm cov exchanger.

Kev tsim qauv ntxiv kom txo qis kev vibration
Ntxiv nrog rau kev txhawb nqa qhov sib nrug, muaj ntau txoj hauv kev uas feem ntau siv los txwv qhov kev pheej hmoo ntawm kev vibration.

Lowered Plhaub Side Velocity
Txo lub plhaub- sab nrawm ncaj qha txo qis zog ua kom muaj zog thiab txo Reynolds tus lej.

Optimization ntawm Baffle Geometry
Baffle spacing thiab txiav geometry tuaj yeem cuam tshuam:

Flow Distribution: kab pheeb ces kaum

Kev siv turbulence

Kev nrawm peaks localized

Ua tib zoo ntsuas qhov ntsuas hydraulic yog siv kom tsis txhob muaj cov chaw ua kom muaj zog.

Bundle Kev Npaj ntawm Tube
Lub vortex tiam thiab sawv kev sib cuam tshuam yog sib txawv nyob rau hauv daim duab peb sab thiab square pitch kev npaj. Yog li ntawd, kev vibration susceptibility yog nyob ntawm qhov kev xaiv ntawm pob khoom.

Txhim kho cov qauv Damping
Nyob rau hauv ib co exchanger designs ntxiv damping ntsiab yog muab los pab dissipate oscillatory zog ua ntej resonance cov txheej txheem tau ua.

Exchangers ntawm PTFE yuav tsum tau ceev faj ntsuas
PTFE exchangers feem ntau raug xaiv rau lawv lub peev xwm los tswj cov tshuaj tiv thaiv kab mob uas cov tshuab hlau tsis haum.

Tab sis tib yam yooj yooj yim uas tso cai rau PTFE hlab nqus thermal stress ua rau lawv ntau mechanically rhiab heev rau turbulent flow rog.

Tsim optimization yog li yuav tsum tau sib npaug:

Kev tiv thaiv corrosion

Efficiency ntawm tshav kub kis

Poob siab

Mechanical stability

Txwv tsis pub khiav ceev

Lub plhaub sab nrawm nrawm tuaj yeem txhim kho kev ua haujlwm thermal tab sis ua rau muaj kev cuam tshuam kev vibration ib txhij.

Cov ntsiab lus
Ib qho tseem ceeb ntawm PTFE heat exchanger engineering yog qhov kev twv ua ntej ntawm qhov pib ntawm kev ntws tawm ntawm kev co. Lub zog turbulent ntws loj hlob zuj zus nrog kev nce ntawm lub plhaub - sab Reynolds tus lej. Thiab thaum kawg mus txog ib theem uas cov kua dej hloov pauv tuaj yeem ua rau muaj kev cuam tshuam ntawm qhov hloov pauv ntawm PTFE raj pob.

Kev sib cuam tshuam ntawm lub plhaub sab ntawm Reynolds tus naj npawb, lub raj vibration thiab PTFE exchanger kev ua tau zoo yog txiav txim siab los ntawm lub raj txhav, kev txhawb nqa luv, hla - ntws nrawm thiab cov dej tsis zoo. Ua tib zoo tsim kev suav, suav nrog kev tshuaj xyuas cov kua dej -elastic instability tshaj tawm raws li TEMA cov qauv, pab lav lub exchanger khiav qis dua qhov kev txwv tsis pub muaj kev co.

Cov kev txhawb nqa lub raj nruj nreem yog tseem yog ib qho kev tiv thaiv zoo tshaj plaws ntawm txhua qhov muaj, txij li lawv tau nce lub raj ntau zaus thiab txo qhov deflection amplitude. Nrog rau txoj cai hydraulic thiab mechanical tsim, PTFE exchanger tuaj yeem nyob ntsiag to thiab ntseeg tau ntau xyoo.

Silent flow feem ntau yog qhov pom tseeb tshaj plaws uas lub raj ntim tau khiav ruaj ntseg hauv nws cov kev txwv tsim hauv thermal ua tshuab.