Cov ntsuas dej Doppler, siv cov nyhuv Doppler los xam qhov ceev ntawm cov kua dej los ntawm kev ntes cov suab nrov los ntawm cov khoom me me uas txav mus los, tau dhau los ua qhov kev daws teeb meem rau kev ntsuas cov kua dej tsis ua hluav taws xob, cov khoom me me uas muaj cov khoom me me, lossis cov kua dej turbulent hauv kev lag luam xws li kev kho dej khib nyiab, kev khawb av, thiab kev ua liaj ua teb. Txawm li cas los xij, lawv cov kev ua tau zoo yog nyob ntawm cov khoom siv lub cev thiab tshuaj ntawm cov kua dej ntsuas. Tsab xov xwm no piav qhia txog cov kev cai tseem ceeb uas cov kua dej yuav tsum ua tau raws li - lossis cov yam tseem ceeb uas yuav tsum suav nrog - kom ntseeg tau tias Doppler flowmeters xa cov ntaub ntawv raug, ruaj khov, thiab ntev mus ntev.
1. Muaj Cov Khoom Me Me Los Yog Npuas: Qhov Yuav Tsum Tau Ua "Reflective Medium"
Lub hauv paus ntawm kev ua haujlwm ntawm Doppler flowmeter yog qhov xav tau cov khoom siv reflective hauv cov kua. Tsis zoo li cov ultrasonic transit-time flowmeters, uas vam khom kev xa suab ntawm ob lub transducers, Doppler meters vam khom cov suab nrov uas dhia tawm ntawm cov khoom txav mus los lossis cov npuas hauv cov kua. Yog tsis muaj cov reflectors no, lub meter tsis tuaj yeem ntes tau lub teeb liab uas siv tau, ua rau kev ntsuas tsis ua haujlwm lossis nyeem tsis raug.
Cov Kev Cai Tshwj Xeeb:
- Qhov Tsawg Kawg Nkaus: Feem ntau, cov kua yuav tsum muaj tsawg kawg yog 10–50 cov khoom me me hauv ib milliliter (lossis qhov sib npaug ntawm cov npuas dej), txawm hais tias qhov no txawv ntawm cov qauv ntsuas. Piv txwv li, cov dej khib nyiab uas muaj cov khoom khov kho (piv txwv li, cov khoom siv organic, cov av xuab zeb) lossis cov khoom siv hauv kev khawb av (nrog cov khoom siv ore) ua tau raws li qhov yuav tsum tau ua no, thaum cov dej ntshiab heev (piv txwv li, dej deionized rau kev tsim khoom siv hluav taws xob) tsis ua tau - tshwj tsis yog tias muaj cov khoom siv dag (piv txwv li, cov khoom siv hauv qib zaub mov) ntxiv rau.
- Qhov Loj ntawm Cov Khoom Me Me/Npuas: Qhov loj ntawm cov khoom me me lossis cov npuas uas zoo tshaj plaws yog txij li 50 micrometers (μm) mus txog 1 millimeter (mm). Cov khoom me me dua 50 μm tej zaum yuav tsis cuam tshuam lub zog suab txaus, ua rau cov teeb liab tsis muaj zog; cov loj dua 1 hli tuaj yeem ua rau cov teeb liab tawg lossis txhaws lub transducer ntawm lub ntsuas, tshwj xeeb tshaj yog hauv cov kav dej me me.
- Kev Faib Tawm Sib Npaug: Cov khoom me me lossis cov npuas dej yuav tsum tau faib sib npaug thoob plaws hauv cov kua. Cov khoom me me uas tau muab faib ua pawg lossis sib sau ua ke (piv txwv li, cov av noo uas nyob hauv cov kav dej qis) ua rau lub zog teeb liab tsis sib xws, ua rau kev xam qhov ceev tsis sib xws.
2. Kev Ua Kua: Tsis Muaj Qhov Yuav Tsum Tau Ua, Tab Sis Muaj Kev Cuam Tshuam Tsis Ncaj Qha
Tsis zoo li cov ntsuas hluav taws xob electromagnetic, uas xav kom cov kua muaj qhov conductivity tsawg kawg nkaus (feem ntau >5 μS/cm), Doppler flowmeters tsis yog cov kua uas tsis conductive. Lawv ua haujlwm raws li cov ntsiab cai acoustic, tsis yog electromagnetic induction, yog li lawv tuaj yeem ntsuas cov kua uas tsis conductive xws li roj, cov kuab tshuaj, lossis dej deionized (yog tias muaj cov reflectors).
Cov Kev Xav Txog Tsis Ncaj Qha:
- Rau cov kua dej uas muaj hluav taws xob (piv txwv li, cov dej khib nyiab, dej hiav txwv), kev hluav taws xob tsis cuam tshuam rau kev ntsuas Doppler. Txawm li cas los xij, yog tias cov kua dej muaj xeb heev (ib yam khoom uas qee zaum txuas nrog kev hluav taws xob siab, xws li cov kua qaub lossis alkaline), nws yuav ua rau lub tsev transducer ntawm lub ntsuas puas tsuaj - xav tau kev hloov kho cov khoom siv (piv txwv li, titanium lossis PTFE coatings) es tsis txhob cuam tshuam rau lub hauv paus ntsiab lus Doppler nws tus kheej.
3. Viscosity: Kev Sib Npaug ntawm Cov Txheej Txheem Nqus thiab Kev Xa Xov Tooj
Qhov viscosity ntawm cov kua dej cuam tshuam rau ob qho tib si qhov ceev ntawm cov dej ntws thiab kev sib kis ntawm cov suab nrov los ntawm cov kua dej, uas ua rau muaj kev cuam tshuam rau qhov tseeb ntawm Doppler meter.
Cov Kev Ntsuas Tseem Ceeb:
- Qhov Viscosity Qis Mus Rau Nruab Nrab (≤100 cP): Cov kua xws li dej (1 cP ntawm 20°C), dej khib nyiab, lossis roj sib dua (piv txwv li, diesel, 2–5 cP) yog qhov zoo tagnrho. Lawv qhov viscosity qis ua kom muaj kev ruaj khov, turbulent lossis transitional flow regime (Reynolds number >2300), uas sib haum nrog Doppler meters tsim kev xav ntawm qhov ceev sib npaug thoob plaws hauv cov yeeb nkab hla-section.
- Qhov Viscosity Siab (>100 cP): Cov kua xws li cov roj hnyav, cov kua qab zib, lossis cov nplaum ua rau muaj teeb meem. Qhov viscosity siab tsim cov txheej txheem ntws laminar (Reynolds tus lej <2300), qhov twg qhov ceev siab tshaj plaws ntawm qhov chaw ntawm cov yeeb nkab thiab qis tshaj plaws ze ntawm phab ntsa. Doppler meters, uas kuaj qhov ceev ntawm ib qho chaw (lossis thaj chaw me me), tej zaum yuav tsis ntes qhov ceev nruab nrab kom raug - ua rau tsis ntsuas txaus. Tsis tas li ntawd, qhov viscosity siab ua rau cov nthwv dej suab qeeb dua, txo qhov muaj zog ntawm lub teeb liab. Rau cov ntawv thov zoo li no, cov meters nrog cov zaus hloov kho tau (qhov zaus qis dua, 200–500 kHz, nkag mus rau hauv cov kua tuab dua) lossis ntau qhov kev kuaj pom zoo.
4. Kub: Kev Ruaj Ntseg rau Kev Ua Haujlwm Transducer
Qhov kub ntawm cov kua dej cuam tshuam rau ob qho tseem ceeb ntawm kev ua haujlwm ntawm Doppler flowmeter: qhov ceev ntawm lub suab hauv cov kua dej thiab qhov ruaj khov ntawm lub transducer.
Cov Lus Qhia Txog Kev Ua Haujlwm:
- Qhov Ntau Yam: Feem ntau cov ntsuas Doppler kev lag luam raug ntsuas rau qhov kub ntawm cov kua ntawm -40 ° C thiab 120 ° C. Hauv qhov ntau yam no, qhov ceev ntawm lub suab hauv cov kua sib txawv raws li qhov kwv yees tau (piv txwv li, lub suab mus ncig ~ 1482 m / s hauv dej ntawm 20 ° C vs. ~ 1531 m / s ntawm 100 ° C), thiab cov ntsuas niaj hnub no suav nrog cov txheej txheem them nyiaj kub kom kho rau qhov sib txawv no.
- Kub Heev: Qhov kub sab nraum qhov ntsuas uas ntsuas tau yuav ua rau lub transducer puas tsuaj (piv txwv li, lub foob puas thaum kub siab, cov khoom siv tsis khov thaum kub qis) lossis kev them rov qab kub tsis raug. Piv txwv li, kev ntsuas cov kua nitrogen (-196 ° C) lossis cov ntsev molten kub siab (> 300 ° C) xav tau cov ntsuas Doppler tshwj xeeb nrog cov transducers tiv taus kub siab (piv txwv li, cov khoom siv ceramic) thiab cov txheej txheem them rov qab siab heev.
5. Kev Sib Piv Tshuaj: Tiv Thaiv Transducer thiab Vaj Tse
Cov tshuaj lom neeg ntawm cov kua txiav txim siab qhov kev xaiv cov khoom siv rau Doppler meter lub transducer thiab lub tsev yeeb nkab. Cov kua tsis sib xws tuaj yeem ua rau xeb, tawg, lossis o - ua rau cov khoom siv tsis ua haujlwm thiab nyeem tsis raug.
Cov Xwm Txheej Sib Xws Feem Ntau:
- Cov Kua Uas Muaj Tshuaj Tua Kab (piv txwv li, cov kua qaub, alkalis, dej hiav txwv): Cov transducers thiab cov tsev yuav tsum ua los ntawm cov khoom siv tiv taus tshuaj tua kab xws li 316L stainless hlau, titanium, lossis PTFE. Piv txwv li, kev ntsuas hydrochloric acid (HCl) xav tau cov transducers uas muaj PTFE los tiv thaiv kev puas tsuaj ntawm cov hlau.
- Cov Kua Uas Siv Tau (piv txwv li, cov xuab zeb uas muaj xuab zeb, cov pob zeb sib xyaw): Cov khoom siv uas tiv taus kev hnav (piv txwv li, cov taub hau tungsten carbide, cov transducers ceramic) yog qhov tsim nyog kom tsis txhob muaj kev puas tsuaj ntawm qhov chaw ntawm lub transducer, uas yuav ua rau kev sib kis suab tsis zoo.
- Cov tshuaj yaj (piv txwv li, ethanol, acetone): Cov khoom siv tsis ua haujlwm xws li polypropylene lossis PVDF tiv thaiv kev o lossis kev tawg ntawm cov khoom ntawm lub 'meter'.
6. Kev Nqus Ceev: Sib phim Qhov Ntsuas Ntau Yam rau Daim Ntawv Thov
Cov ntsuas dej Doppler muaj cov qhov ceev tshwj xeeb uas lawv tuaj yeem ntsuas tau raws li qhov tseeb, thiab qhov ceev ntawm cov kua dej yuav tsum poob rau hauv lub qhov rais no kom tsis txhob muaj qhov yuam kev ntsuas.
Cov Kev Cai Ceev:
- Qhov Ceev Tsawg Kawg Nkaus: Feem ntau cov Doppler meters xav tau qhov ceev tsawg kawg nkaus ntawm 0.1–0.3 m/s. Hauv qab qhov txwv no, cov khoom me me lossis cov npuas dej yuav poob (hauv cov kua uas muaj viscosity tsawg) lossis qhov ntws dhau los ua laminar dhau (hauv cov kua uas muaj viscosity siab), ua rau cov cim tsis muaj zog lossis tsis sib xws.
- Qhov Ceev Tshaj Plaws: Qhov txwv siab tshaj plaws feem ntau yog li ntawm 5–10 m/s. Tshaj qhov no tuaj yeem ua rau muaj suab nrov los ntawm kev cuam tshuam lossis kev puas tsuaj rau lub transducer (piv txwv li, los ntawm kev cuam tshuam ntawm cov khoom me me uas muaj zog heev hauv cov slurries).
- Kev Sib Npaug Ceev: Txawm tias nyob hauv qhov ntau thiab tsawg ntawm lub 'meter' los xij, qhov sib txawv ntawm qhov ceev (piv txwv li, vim yog cov yeeb nkab khoov, cov qhov dej, lossis cov khoom thaiv sab saud) tuaj yeem ua rau cov nyeem tsis sib xws. Kev teeb tsa lub 'meter' nrog cov yeeb nkab ncaj txaus (piv txwv li, 10x txoj kab uas hla ntawm cov yeeb nkab sab saud, 5x sab hauv qab) pab ua kom muaj kev ntws sib npaug.
Xaus lus
Cov ntsuas dej Doppler muaj kev ywj pheej zoo heev rau kev ntsuas cov kua dej uas muaj ntau yam sib txawv, tab sis lawv qhov tseeb nyob ntawm kev sib phim cov khoom ntawm cov kua dej nrog cov kev txwv tsim ntawm lub ntsuas. Los ntawm kev soj ntsuam cov yam xws li cov ntsiab lus ntawm cov khoom me me, viscosity, kub, kev sib raug zoo ntawm cov tshuaj lom neeg, thiab qhov ceev ntawm cov dej ntws, cov neeg teb xov tooj tuaj yeem xaiv lub ntsuas Doppler zoo, ua kom zoo dua kev teeb tsa, thiab xyuas kom meej tias muaj kev ua haujlwm ntev-txawm tias hauv kev kho dej khib nyiab, kev khawb av, lossis kev saib xyuas cov txheej txheem kev lag luam. Rau cov ntawv thov tshwj xeeb (piv txwv li, dej ntshiab heev, cov kua dej viscosity siab), kev sab laj nrog cov chaw tsim khoom kom kho cov khoom siv transducer lossis cov txheej txheem ua cov teeb liab yog qhov tseem ceeb rau kev kov yeej cov teeb meem cuam tshuam nrog cov kua dej.
Lub sijhawm tshaj tawm: Cuaj hlis-17-2025