Yuav Ua Li Cas Qhov Kawg Cap Tsim (Cas vs. Domed) ntawm lub qhov rooj kaw Titanium cua sov Tube cuam tshuam rau nws lub peev xwm los tiv thaiv sab hauv siab tsim-Txawm li cas los xij ntawm cov dej noo decomposition ntawm 200 degree?

Qhov Kev Lag Luam Yooj Yim - tawm hauv Titanium Heater End Cap Tsim
Cov hlua khi titanium cua sov yog rwb thaiv tsev nrog magnesium oxide (MgO) uas tuaj yeem nqus cov kab ya raws thaum tsim khoom lossis khaws cia. Thaum lub tshuab ua kom sov rau qhov kub ntawm 200℃ntawm phab ntsa sab hauv, cov dej noo vaporizes thiab tuaj yeem tawg mus rau hauv hydrogen thiab oxygen. Qhov no tuaj yeem ua rau lub siab sab hauv tsim thiab tuaj yeem ua rau lub hau kawg ua tsis tiav. Kev tsim ntawm lub hau kawg, txawm tias tiaj tus lossis domed, ncaj qha cuam tshuam li cas lub raj tiv thaiv lub siab sab hauv. Lub hau tiaj tiaj muaj khoov cov kab mob uas muaj kev ntxhov siab ntawm qhov sib koom ua ke. Lub domed cap yog nyob rau hauv daim nyias nyias. Phab ntsa thickness yog qhov ua haujlwm ntawm lub hau kawg. Lub phab ntsa tuab tuaj yeem txhawb nqa lub hau npog ntawm qhov siab dua. Lub hau domed tuaj yeem ua rau tib lub siab ntsuas nrog lub phab ntsa nyias. Qhov kev tshuaj ntsuam no ntsuas lub peev xwm ntawm lub tiaj tus piv rau domed kawg lub kaus mom ntawm titanium cua sov raj thiab muab cov lus qhia xaiv rau kev pabcuam kub kub qhov twg hauv qhov kev kub ntxhov yog qhov txaus ntshai.

Qhov cuam tshuam rau Mechanical Integrity: Stress Distribution in Flat and Domed Caps
Peb txiav txim siab tias qhov kev ntxhov siab tshwm sim los ntawm qhov siab ntawm qhov nruab nrab ntawm qhov kawg ntawm lub hau welded rau lub titanium raj ntawm sab hauv vojvoog r thiab phab ntsa thickness t yog muab los ntawm $\\sigma_{flat}=0.31*P*r^2/t^2$, qhov twg P sawv cev rau sab hauv siab. Rau ib tug raug 20 hli OD raj ( puab vojvoog 8 hli rau 1.0 hli phab ntsa) ntawm lub internal siab ntawm 10 bar (1 MPa), sigma_flat=(0.31 * 1e6 * 0.008^2) / (0.001^2)=198 MPa. Qhov no tsuas yog me ntsis siab dua qhov kev tawm dag zog ntawm Qib 2 titanium (275 MPa) thiab yog li muaj qhov kev nyab xeeb tsawg heev. Rau lub domed cap (hemispherical), qhov kev ntxhov siab yog σdome=P r 2 t qhov twg lub vojvoog ntawm lub dome yog suav tias yog tib yam li lub vojvoog ntawm lub raj. Raws li cov xwm txheej zoo ib yam, σ_dome=(1e6 × 0.008) / (2 × 0.001)=4 MPa-50 qis dua lub tiaj tiaj. Lub domed cap bears lub strain yuav luag tag nrho hauv daim nyias nyias, tsis khoov; nws yog deb tshaj resistant rau sab hauv siab. Rau cov kaus mom tiaj tus, hom tsis ua haujlwm cuam tshuam nrog yielding thiab bulging nyob ib ncig ntawm qhov chaw, ces weld tear-out. Domed lub kaus mom feem ntau ua tsis tiav los ntawm kev tawm dag zog ntawm 10 mus rau 20 npaug siab dua li lub kaus mom tiaj tus nrog tib phab ntsa tuab.

Kev cuam tshuam rau Kev Ua Haujlwm Thermal: Kev Hloov Kub Kub thiab Kev Txwv Kev Tsim Khoom
Qhov kawg cap tsim tsuas yog cuam tshuam ncaj qha rau kev ua haujlwm thermal. Lub hau tiaj tiaj muaj thaj chaw loj dua nyob rau hauv kev sib cuag nrog cov txheej txheem nruab nrab thiab qhov no tuaj yeem txhim kho kev xa hluav taws xob ntawm qhov kawg ntawm lub rhaub. Tab sis qhov txawv yog tsawg (feem ntau<5% of total heating area). More importantly, there is the question of manufacturability. The dome caps are made by pressing or spinning, which is an additional manufacturing process and adds 10–20% to the cost over flat caps. Thin walls (≤1.0 mm) Dome caps Dome caps are easier to successfully weld, since the dome absorbs thermal expansion during welding, thus minimizing the residual stress. Flat caps can be welded with sufficient strength for thick walls (≥1.5 mm) if the tube diameter is small (<16 mm OD). The heat gradient across the end cap in operation is similar for both types, as the cap thickness is normally matched to the tube wall.

End Cap Xaiv Matrix: Kev Sib Txuas Kev Lag Luam -tawm
Tube OD & Phab ntsa Thickness Max Safe Internal Pressure (pav ca, Qib 2) Max Safe Internal Pressure (domed cap) End Cap Recommendation (Core Engineering Rationale)
12 hli × 0.8 hli 4 bar > 50 bar Domed Thin phab ntsa tsis tuaj yeem tuav lub hau bending kev ntxhov siab.
16 hli × 1.0 hli 6 bar> 40 bar Domed Flat cap tsawg heev; domed muab kev nyab xeeb margin
20 hli x 1.2 hli 8 bar> 35 bar Domed Ideal rau Kev Ntseeg. Post weld kev ntxhov siab txo qis tsuas yog lub hau tiaj tus txais tau.
20 mm × 1.6 mm 14 bar> 45 bar Ob lub hau tiaj tiaj yog txaus rau ntau lub hom phiaj; domed muab cov npoo ntxiv.
2.0 hli x 25 hli 18 bar > 50 bar Pav ca (txuag nqi) Cov phab ntsa tuab muab txaus khoov lub zog. Tshaj - specification yog domed.
Engineering Beyond the Cap: Moisture Control thiab Venting
Txoj hauv kev zoo tshaj plaws los tswj lub siab sab hauv- yog kom tsis txhob muaj dej nkag mus rau tag nrho. Lub tshuab cua sov yog purged nrog nitrogen thaum lub sij hawm MgO filling thiab lub tshuab nqus tsev sealing kom txo cov seem seem kom tsawg dua 0.1% los ntawm qhov hnyav, yog li tiv thaiv kev siab tsim - nce txawm tias ntawm 300℃. Rau cov tshuab cua sov tam sim no lossis cov qauv tsim nqi qis, lub qhov me me (0.2-0.5 hli txoj kab uas hla) nyob rau hauv lub hau kawg muab txoj hauv kev khiav tawm rau hauv cov pa roj uas tsis muaj kev cuam tshuam corrosion vim lub qhov feem ntau yog submerged thiab brine tsis nkag mus rau vim qhov zoo sab hauv siab. Xwb, qhov tawg tawg tau ntsuas rau 10 bar tuaj yeem muab tso rau hauv lub hau tiaj tus, muab cov kev tswj hwm tso tawm.

Xaus: Flat Caps yog OK rau cov phab ntsa tuab, Domed Caps zoo dua rau cov phab ntsa nyias
The heating tube is titanium sealed and it runs at 200C and even trace moisture decomposes and the end cap design is essential to how much pressure it can take. A flat cap experiences bending strains proportional to P x r(squared) / t(squared) whereas a domed cap experiences membrane stresses proportional to P x r / t - a factor of r/t lower. For thin wall (≤1.2mm) on standard 20mm OD tube a domed cap is necessary to safely bear pressures above 5 bar. For thick walls (>=1.6 mm) lub hau tiaj tiaj zoo li lub sijhawm t² hauv tus lej txo cov kev ntxhov siab khoov mus rau qib siab. Yog tias pom tias muaj kev kub ntxhov sab hauv yog qhov txaus ntshai (xws li, cov khoom siv cua sov khaws cia hauv qhov chaw ntub dej ua ntej kev teeb tsa), ces lub hau domed lossis lub qhov cua tsim yuav tsum tau teev tseg tsis hais txog ntawm phab ntsa tuab. Muab cov chaw tsim khoom nrog qhov siab tshaj plaws kev ua haujlwm kub thiab cia cov av noo kom tso cai rau cov chaw tsim khoom tsim lub hau kawg kom ntseeg tau ntev - kev pabcuam.