Dab tsi yog Qhov Kev Sib Raug Zoo Ntawm 316 Stainless Hlau Sheath Phab Ntsa Thickness thiab Thermal Response Time in Electrically Heated Flow-Los ntawm daim ntawv thov?

Lub sij hawm teb thermal ntawm cov cua kub feem ntau yog qhov tseem ceeb raws li nws lub xeev khov kho lub zog ntsuas rau cov txheej txheem engineers tsim ntws los ntawm hluav taws xob cua sov rau kev siv xws li taw tes ntawm kev siv dej kub xa khoom, ntsuas ntsuas ntsuas ntsuas cua sov lossis cov tshuaj teb sai sai. Lub kaw lus yuav tsum tau mus rau qhov ntsuas kub hauv vib nas this lossis ob peb feeb ntawm lub zog thov, tsis yog teev. Lub hwj chim mov thiab tswj algorithm pom tseeb muaj lub luag haujlwm, tab sis lub cev qauv ntawm cov cua sov, uas yog cov phab ntsa tuab ntawm 316 stainless hlau sheath, qhia txog kev txwv yooj yim ntawm tus nqi ntawm cov cua sov tuaj yeem muab los ntawm cov hlau tsis kam mus rau cov dej ntws. Kab lus no suav cov kev sib raug zoo ntawm cov phab ntsa thickness thiab thermal teb lub sij hawm raws li lumped capacitance thiab transient tshav kub conduction cov qauv, muab kev sim validated lub sij hawm tas mus li rau tej thicknesses, thiab tsim ib lub moj khaum rau xaiv nyob rau hauv daim ntaub ntawv uas ceev teb yog thawj tsim txwv.

Lub Physics ntawm Transient Thaum tshav kub kub hloov mus los ntawm ib tug cylindrical casing
Thaum cov hluav taws xob hluav taws xob muab rau cov hlau tsis kam ntawm lub rhaub dej kub, cov hlau kub yuav luag tam sim ntawd (hauv milliseconds) vim nws qhov loj me thiab siab tiv taus. Thaum tshav kub kub yuav tsum tau ua radially sab nraud los ntawm magnesium oxide insulating txheej thiab tom qab ntawd los ntawm 316 stainless hlau sheath rau cov dej ciam teb txheej thiab thaum kawg cov txheej txheem dej ntau. Rau kev soj ntsuam cov lus teb ib ntus txhua MgO txheej thiab cov phab ntsa sheath muab lub thermal huab hwm coj thiab thermal kuj. Rau cov cua sov geometries, txawm li cas los xij, nrog sheath phab ntsa thicknesses nyob rau hauv thaj tsam ntawm 0.8 mus rau 2.5 hli thiab MgO thicknesses ntawm 1 mus rau 2 hli lub sij hawm tseem ceeb tsis tu ncua yog teem los ntawm tag nrho cov thermal capacitance ntawm lub sheath thiab cov thermal resistance ntawm lub sheath phab ntsa thiab cov dej ciam txheej. Lub sij hawm thermal tas li $\\tau$ (tau) rau lub cylindrical sheath tuaj yeem kwv yees raws li cov khoom ntawm thermal capacitance ib chav tsev ntawm lub plhaub thiab tag nrho cov thermal kuj los ntawm sab nrauv ntawm MgO rau cov kua dej ntau. Lub 316 sheath muaj lub peev xwm kub ntawm ib ncig ntawm 3.9 MJ / m3-K (qhov ceev 8,000 kg / m3 lub sij hawm tshwj xeeb cua sov 490 J / kg-K), yog li txhua hli ntxiv ntawm phab ntsa thickness ntxiv txog 3,900 J ntawm thermal capacitance ib square meter ntawm sheath nto cheeb tsam. Lub zog no yog khaws cia thiab yuav tsum tau nqus los ntawm lub hnab ua ntej qhov kub ntawm sab nraud yog siab heev. Tswv yim, ib tug thicker sheath coj zoo li ib tug ntau dua thermal mass yuav tsum tau rhuab ua ntej ib tug zoo hloov mus rau lub kua yuav ua tau.

Ntsuas lub sij hawm tsis tu ncua ntawm siab dua phab ntsa Thickness
Lub tshuab cua sov lub thermal cov tshuaj tiv thaiv rau ib kauj ruam hloov hauv lub zog tawm tswv yim yog ib qho kev nthuav qhia mus rau lub xeev khov kho. Lub sijhawm thermal tsis tu ncua yog lub sijhawm xav tau kom ncav cuag 63.2% ntawm qhov kawg kub nce. Lub 316 encased rhaub nrog phab ntsa tuab ntawm 1.0 hli, ua haujlwm hauv cov dej ntws ntawm qhov nrawm ntawm 1 m / s, feem ntau muaj lub sijhawm tas li ntawm 8 mus rau 12 vib nas this. Qhov no txhais tau tias tom qab ib lub sij hawm tas li qhov hluav taws xob kub tau nce mus rau 63% ntawm qhov kawg delta. Tom qab peb lub sij hawm tas mus li (24-36 vib nas this) nws yog 95% ntawm lub xeev khov kho. Ua kom cov phab ntsa thickness ntawm lub sheath rau 1.6 hli boosts thermal capacitance thiab me ntsis tsub kom cov hluav taws xob tsis kam. Lub sij hawm tas mus li yog ncua mus txog 14-18 vib nas this-nce 40-50%. Yog hais tias phab ntsa thickness yog 2.0 hli, lub sij hawm tas mus li mus txog 20-25 sec. Rau lub luag haujlwm hnyav ntawm 2.5 hli, lub sij hawm tas li yog siab li 28-35 vib nas this. Cov nuj nqis no yog nyob ntawm cov kua dej tsis tu ncua thiab tsis muaj kev cuam tshuam nrog lub voj voog tswj. Qhov tseeb, tus tswj qhov kub thiab txias nrhiav los tuav ib qho chaw tshwj xeeb yuav overshoot thiab oscillate nrog lub thicker sheath vim hais tias tus tswj sensor, uas feem ntau yog nyob rau saum npoo los yog downstream ntawm lub sheath, reacts qeeb dua rau lub hwj chim hloov. Kev sim validation siv tib lub rhaub cartridges nrog 1.0 hli, 1.5 hli thiab 2.0 hli 316 sheaths nyob rau hauv ib 4 L / min dej ntws voj pom tau hais tias lub 1.0 hli sheath mus txog 90% ntawm lub xeev kub nce nyob rau hauv 22 vib nas this, lub 1.5 hli sheath siv 34 vib nas this thiab lub 2.4 vib nas this. Kev sib raug zoo feem ntau yog linear rau qhov thickness ntau, nrog rau 0.1 hli nce hauv phab ntsa thickness pab 2.6 vib nas this rau 90% lub sij hawm teb.

Kev cuam tshuam ntawm phab ntsa Thickness ntawm cov kua dej nrawm thiab cov kab uas hla
The cost in thermal reactivity of the thicker walls is not absolute but significantly dependent on the heat transfer coefficient on the fluid side. At low fluid velocities, below 0.2 m/s, the fluid boundary layer resistance is dominant over the total thermal resistance. In these situations the sheath wall thickness contributes less to the overall time constant, thus the cost for raising the thickness is less. In stagnant or slow-moving fluid a 2.0 mm sheath may have a time constant only 15-20% longer than a 1.0 mm sheath since the fluid resistance is the limiting factor. For high fluid velocities >2 m / s qhov kev tiv thaiv ntawm ciam teb txheej yog qhov me me thiab qhov kev tiv thaiv thiab lub peev xwm ntawm cov phab ntsa sheath dominate. Lub txim ntawm cov phab ntsa loj yog tshwj xeeb tshaj yog hais nyob rau hauv high flow daim ntaub ntawv qhov twg lub 2.0 hli sheath yuav ua tau 60-80% qeeb teb tshaj 1.0 hli sheath. Phab ntsa thickness kuj cuam tshuam nrog sheath txoj kab uas hla. Rau qhov muab phab ntsa thickness, ib lub sheath nrog ib tug loj txheej txoj kab uas hla muaj ntau thermal mass rau ib chav tsev ntev thiab yuav teb qeeb dua. Lub 12 hli OD sheath nrog 1.5 hli phab ntsa thickness muaj nyob ib ncig ntawm 30% ntau dua thermal mass ib 'meter' dua 10 hli OD sheath nrog tib 1.5 hli phab ntsa thickness. Rau kev siv tshuaj tiv thaiv sai, lub sijhawm luv tshaj plaws tas li yog tau txais nrog qhov tsawg tshaj plaws cov tswv yim sheath txoj kab uas hla thiab lub thinnest tswv yim phab ntsa thickness.

Tshaj siab tshaj plaws Thickness ntawm Phab ntsa rau muab lub sij hawm teb xav tau
Cov lus hauv qab no qhia tau hais tias qhov siab tshaj plaws 316 sheath phab ntsa thicknesses rau ntws -los ntawm hluav taws xob cua sov daim ntawv thov rau lub sij hawm tsim nyog thermal teb. Tus nqi yog rau cov dej ntws ntawm 1 m / sec tshaj tawm. Sheath sab nraud txoj kab uas hla 10-12 mm. Lub hom phiaj kub nce 40℃saum toj noj. Lub sij hawm teb yuav nce qhov sib npaug nrog qhov kub nce siab lossis qis qis tshaj tawm, tsis hais txog ntawm phab ntsa tuab.

Thermal teb lub sij hawm yuav tsum tau 90% Maximum Recommended Sheath Phab ntsa Thickness 316 Hom Lub Sijhawm tas li τ Daim Ntawv Thov Piv Txwv Kev Lag Luam -Offs Txais < 15 vib nas this 0.8 - 1.0 mm 6 - 10 secondsAnalytical instrument heaters, semiconductor da dej warmers, fast water dispensers. Tsis tsim nyog rau kev vibration lossis siab> 5 bar.
15 - 25 vib nas this 10 – 15 sec. 1.0 – 1.3 mmKev lag luam tshuab ntxhua khaub ncaws, chav kuaj circulating da dej, taw tes- ntawm -siv cov dej rhaub dej kub nruab nrab ntawm cov neeg kho tshuab counterpressure. Haum rau kev siv teeb pom kev zoo.
25 – 40 secs1.3 – 1.6 mm 15 – 22 secondsModerate flow industrial process heaters Chemical reactor preheatersGood mechanical robustness. Ib tug qauv kev lag luam.
40-60 vib nas this 1.6 – 2.0 mm 22 – 30 sec Loj ntim cia tank tso cua sov, cov tshuab siab siab qeeb cov tshuaj tiv thaiv rau kev ntsuas siab thiab kev yaig tsis kam. 60 sec 2.0 – 2.5 mm 30 – 40 sec Kev kub siab autoclaves Cov kev pabcuam tshuaj lom neeg nrog cov tuab corrosion kuj. Thermal huab hwm coj yog huab tais.
Tsim cov tswv yim kom ceev cov lus teb tsis muaj phab ntsa thinning
Qhov twg yuav tsum tau teb ceev ceev nyob rau hauv ib daim ntawv thov uas tseem xav tau cov neeg kho tshuab los yog corrosion zoo ntawm ib tug tuab -walled 316 sheath, peb tsim txoj kev yuav decouple no tsis sib haum lub hom phiaj. Qhov kev daws teeb meem thawj zaug thiab zoo tshaj plaws yog siv lub voj kaw kaw nrog kev kub ceev thermocouple txoj cai rau ntawm qhov chaw sheath ua ke nrog kev kwv yees lossis PID algorithm uas cia siab tias qhov kub hloov pauv. Surface mounted sensors teb 5-10 npaug sai dua cov thermocouples hauv qab, uas ib feem them rau cov thermal inertia ntawm lub plhaub. Lub qhov dej -tuned PID maub los nrog derivative action nrog 2.0 mm sheath mus txog lub sij hawm cov tshuaj tiv thaiv ntawm 1.0 mm sheath nrog yooj yim ntawm -tawm tswj. Qhov thib ob yog siv cov khoom siv hluav taws xob ntau dhau thiab pulse -width modulation. Tag nrho lub zog tuaj yeem tswj tau hauv cov pulses luv luv, xws li . 100 ms rau, 200 ms tawm, kom lub thermal huab hwm coj tsis tag nrho. Tab sis lub sheath kub tuaj yeem hloov kho. Cov txheej txheem no txhais tau hais tias qhov nruab nrab cov khoom siv hluav taws xob tuaj yeem hloov pauv tau nrawm dua li lub sijhawm ntawm lub hauv paus ntawm lub plhaub yuav tso cai. Cov txheej txheem thib peb cuam tshuam txog cov cua sov geometry. Lub zog tuaj yeem ua tiav los ntawm kev siv ntau lub ntsiab lus luv luv uas tuaj yeem tswj tau ntawm nws tus kheej es tsis txhob siv lub tshuab hluav taws xob ntev ntev. Tag nrho cov ntsiab lus yog energized ib txhij rau kev teb sai. Lub subset yog nyob rau hauv kev khiav hauj lwm rau lub xeev ruaj khov. Txoj kev no tuav cov khoom siv thermal kom ze rau ntawm phab ntsa nyias nyias ntawm txhua lub sijhawm.

Cov kev txwv kev ua tau zoo thiab kev sim ua pov thawj
Cov kev sim tswj tau ua kom muaj kev sib raug zoo rau 316 lub tshuab tso cua sov nrog phab ntsa tuab ntawm 1.0mm, 1.5mm thiab 2.0mm hauv 2L / min dej ntws voj ntawm qhov ntsuas kub ntawm 25degC. Rau 1.0 hli sheath, nrog ib kauj ruam lub hwj chim input ntawm 2 kW rau txhua lub rhaub (tib yam ntev, 10 hli OD), qhov hluav taws xob kub nce yog 40℃hauv 19 vib nas this. Ua tiav hauv 31 vib nas this ntawm 1.5 mm sheath. 52 vib nas this yog tsim nyog rau 2.0 mm sheath. Qhov kev sim tau rov ua dua nrog 0.5 hli tuab tooj liab sheath, cov khoom siv ntawm kev xyaum tsis muaj kev siv hluav taws xob los ntawm qhov kev pom ntawm corrosion, tab sis ib qho tseem ceeb siv txawm li cas los xij, thiab lub sij hawm teb raug txo mus rau 7 vib nas this, uas tau lees tias 316 phab ntsa thickness yog qhov tseem ceeb. Qhov tseem ceeb, qhov kev sim siab kuj tau nthuav tawm qhov cuam tshuam thib ob, nrog cov ntaub tuab tuab uas nthuav tawm qhov kub thiab txias dua tom qab ua tiav qhov teeb tsa. Lub 2.0 hli sheath overshot lub hom phiaj tso zis kub los ntawm 6℃ua ntej nyob rau hauv thaum lub 1.0 hli sheath overshot los ntawm tsuas yog 1.5 degree. Qhov kev overrun no yog ib qho teeb meem rau qhov kub thiab txias- kev khiav hauj lwm rhiab heev xws li cua sov cov qauv tshuaj lom neeg los yog ua cov tshuaj tiv thaiv zoo. Qhov zoo ntawm cov phab ntsa nyias tsis yog tsuas yog ceev tab sis kev ruaj ntseg hauv cov xwm txheej zoo li no.

SUMMARY Matching phab ntsa thickness rau dynamic kev xav tau
Lub sij hawm thermal cov tshuaj tiv thaiv ntawm 316 stainless hlau encased hluav taws xob cua sov rau engineers yuav qhia tau hais tias raws li ib tug quantifiable muaj nuj nqi ntawm phab ntsa thickness, dej tshaj tawm thiab sheath txoj kab uas hla rau ntws los ntawm daim ntaub ntawv. Ntawm 0.8 hli thiab 2.5 hli qhov kev sib txuas no yog ze li ntawm kab thiab qhov nce hauv 90% lub sij hawm teb yog li 2-3 vib nas this txhua 0.1 hli ntawm cov tuab ntxiv rau cov dej ntws zoo li qub. Lub rhaub nrog 1.0 hli sheath yuav muaj lub sijhawm teb ntawm 20 vib nas this, txawm li cas los nrog 2.0 hli sheath nws yuav yog 35-40 vib nas this. Qhov tsis sib xws no hloov lub teb, zoo - tswj qhov system mus rau ib qho uas xav tias sluggish thiab nquag overshoot. Qhov kev txiav txim siab tsis yog seb lub plhaub tuab yog "tsis zoo" rau cov lus teb tab sis yog tias daim ntawv thov xav tau lub sij hawm teb tuaj yeem dais lub thermal huab hwm coj ntawm cov khoom siv hluav taws xob zoo. Rau cov ntawv thov sai sai - teb, nws yog qhov yuav tsum tau muab cov phab ntsa tuab tshaj plaws raws li kev ruaj ntseg siab thiab kev tiv thaiv corrosion. Rau cov xwm txheej uas lub sij hawm teb tsis tseem ceeb dua li cov khoom siv ua haujlwm ntev lossis lub neej corrosion, lub plhaub tuab yog tsim nyog, tab sis kev tswj hwm yuav tsum tau tsim nrog cov lus teb qeeb dua. Cov kws ua haujlwm yuav tsum tsis tsuas yog qhia txog qhov xav tau ntawm phab ntsa tuab thaum tau txais cov lus hais los ntawm cov chaw tsim khoom siv hluav taws xob, tab sis kuj tseem xav tau 90% lub sijhawm tshuaj tiv thaiv. Qhov no yuam tus neeg muab kev pabcuam los tshuaj xyuas tag nrho cov thermal system-sheath thickness, MgO ntom, watt ntom thiab txoj kab uas hla-raws li kev sib xyaw ua ke ntau dua li cov kev xaiv ntawm tus kheej.