Vim li cas lub rhaub Titanium tuab nrog qhov tsawg Watt ntom (5 W / cm²) Muaj lub neej ua kom sov siab ntev dua li lub rhaub nyias nyias nrog siab Watt ntom (15 W / cm²)?

Thaum tus txheej txheem engineer xaiv lub titanium immersion rhaub rau cyclic thermal kev pab (ntau zaus rau / tawm mus), lub rhaub tuab nrog tsawg watt ntom (5 W / cm^2) muaj lub neej ntev thermal qaug zog dua li lub rhaub nyias nrog siab watt ntom (15 W / cm^2). Lub thermal qaug zog lub neej yog tswj hwm los ntawm cyclic yas strain amplitude (Δε pl ) ntawm lub rhaub dej, uas yog dictated los ntawm kub viav vias (ΔT) thiab kub gradient los ntawm phab ntsa thickness. Lub tshuab cua sov tuab (2.5 hli) ntawm 5 W / cm 2 muaj qhov ntsuas kub qis (feem ntau yog 110-120℃rau cov cua sov dej) thiab qhov tsawg kawg ΔT hla phab ntsa (< 5℃). Lub qhov cub nqaim (1.2 hli) ntawm 15 W / cm2 qhia tau hais tias muaj qhov kub siab (140{20}}160 degree) thiab ntau dua ΔT hla phab ntsa (10-15 degree). nce ΔT ua rau muaj zog cyclic yas lim thiab txo lub neej qaug zog. Ntau cov qauv qhia tau hais tias cov tuab tuab tuab -watt- qhov kub kub ceev muaj lub thermal qaug zog lub neej ntawm 50,000-100,000 cycles, hos lub nyias nyias high-watt-density heater tsis nyob rau hauv 10,000-20,000 lub neej ntev dua-watt-thickness 3-1000 watt-thickness cycles-- 10000-10000 watt-thickness ntev-10000000000000000 amp; tsim.

Thermal Fatigue Mechanism Associated with Watt Density and Phab Ntsa Thickness
Thermal qaug zog tawg pib thaum cyclic thermal loads tshaj qhov endurance txwv ntawm cov khoom. Qhov kev ntxhov siab amplitude yog proportional rau qhov kub ntawm lub viav vias (ΔT_cycle) thiab kub gradient hla phab ntsa (ΔT_wall). Rau ib tug muab kub flux (watt ntom), qhov kub ntawm lub sheath saum toj no cov kua kub yog txhais los ntawm ΔT sheath=q / h qhov twg q yog watt ceev thiab h yog tshav kub hloov coefficient. Rau dej ntawm nucleate boiling h ≈ 5000-10,000 W/m 2 K. Ntawm 5 W/cm 2 (50,000 W/m 2) ΔT sheath=50,000/7,500 ≈ 7℃. 15 5 T²/m² (0,000 W/m²):=150,000 / 7,500 ≈ 20℃. Qhov siab dua watt ceev ua rau siab dua sheath kub thiab nce qhov kub ntawm qhov sib txawv ntawm phab ntsa. Thermal stress $\\sigma_{th} \\propto \\Delta T_{sheath}$ thiab kuj nyob ntawm phab ntsa thickness los ntawm Biot tooj. Rau cov phab ntsa nyias, cov gradient yog steeper thiab ntau dua cov kev ntxhov siab hauv zos yog tsim. Qhov kub thiab txias dua thiab gradient ntau dua hauv nyias, siab -watt-density heaters ua rau lub neej qaug zog.

Thermal Fatigue Life Quantified Raws li Kev Ua Haujlwm Ntawm Watt Ceev thiab Phab Ntsa Thickness
Phab ntsa Thickness (mm) Watt Density (W/cm2) Sheath Temp (C) rau Dej @ 100C ΔT Hla Phab Ntsa (C) Cyclic Plastic Strain (µε) Thermal Fatigue Lub Neej ( voj voog mus rau qhov tsis ua hauj lwm) Lub neej txheeb ze 1.2 5 107 2 20 > 100,000 10 × 1.2 10 114 5 60 40, {{6}×{6}, 1.5 5 107 3 25 80, 000 8 × 1.5 10 114 6 80 25, 000 2.5 × 1.5 15 120 12 200 8, 000 0.8 × (baseline) 2.0 5 107 4 30 60, 000 6 × 2.0 10 114 7 100 18, 000 1.8 × 2.5 5 107 5 35 50, 000 5 ×2.5 15 120 15 250 5 × {22}
Ib Daim Ntawv Qhia Txog Kev Xaiv Watt Density thiab Phab Ntsa Thickness raws li Cycle Life
Daim ntawv thov & Thermal Cycle RateRequired Cycles (xyoo ntawm kev pab cuam) Pom zoo phab ntsa (mm) Pom zoo Max Watt ceev (W/cm2) Cia siab tias qaug zog lub neej (kuj)
Kev ua haujlwm tsis tu ncua (tsis muaj kev caij tsheb kauj vab) N / A 1.5 15 > 100,000 (kev caij tsheb kauj vab tsis muaj kev txwv)
Kev caij tsheb kauj vab tsis tu ncua (1 lub voj voog / hnub, 350 cycles / xyoo, 10 xyoo=3,500 cycles) 5, 000 1.5 15 8,000 (tso cai)
Kev caij tsheb kauj vab nruab nrab (5 cycles / hnub, 1,800 / xyoo, 10 xyoo=18,000 cycles) 20, 000 1.5 8 40,000 (tau txais)
Kev caij tsheb kauj vab nquag (10 cycles / hnub, 3,600 / xyoo, 10 xyoo=36,000 cycles) 40, 000 2.0 6 60,000 (tau txais)
Kev caij tsheb kauj vab hnyav (20 cycles / hnub, 7,200 / xyoo, 5 xyoos=36,000 cycles) 40, 000 2.5 5 50,000 (tau txais)
Extreme cycling (50 cycles/day, fast on/off) > 50,000 2.5 4 >100,000 (siv tsawg watt ceev)
Engineering Considerations rau Heater Specification
Rau cov ntawv thov (> 50,000 cycles) xav tau lub neej ntev thermal qaug zog, cov phab ntsa tuab (2.0-2.5 hli) thiab qis watt ceev (3-5 W / cm2) yog qhov tsim nyog. Cov phab ntsa tuab faib cov thermal kev nyuaj siab tshaj qhov sib tshooj ntau dua thiab yog li txo qhov siab tshaj plaws ntawm qhov chaw. Qhov tsawg watt ntom ntom txo qhov kub ntawm lub viav vias thiab cov thermal gradient yog li cov sheath kub qis. Qhov kev sib xyaw ua ke ntawm cov khoom no txo ​​qis lub zog ceev ntawm lub tshuab cua sov (koj xav tau ntau qhov chaw kom tau txais tib lub zog tawm ntawm nws) tab sis kev ua kom ntev ntev feem ntau ua rau qhov loj dua ntawm lub rhaub. Piv txwv li, 10 kW rhaub ntawm 15 W / cm² xav tau thaj tsam ntawm 667 cm². Tib lub rhaub xav tau 2,000 cm² ntawm 5 W / cm², peb zaug ntawm thaj chaw saum npoo. Lub tshuab hluav taws xob tsawg watt, txawm li cas los xij, muaj lub neej 5 mus rau 10 npaug ntev dua hauv kev ua haujlwm tsis zoo. Rau cov ntawv thov tseem ceeb uas lub tshuab cua sov tsis ua haujlwm ua rau raug nqi poob qis, qhov loj dua, qis dua watt density heater yog tus nqi ntau dua rau lub neej ntawm cov khoom siv.

Cov ntsiab lus: Thick (2.5 mm) + Tsawg Watt Ceev (5 W / cm2) 10X Lub Neej Nyuaj Siab (1.2 mm) + High Watt Density (15 W / cm2)
Thick titanium heaters (2.5 mm wall) at low watt density (5 W/cm^2) have a thermal fatigue life of ~50,000 cycles, while thin heaters (1.2 mm wall) at high watt density (15 W/cm^2) have a life of ~5,000-12,000 cycles-a factor of 4-10 longer life for the thick, low-watt-density design. The reason for the longer life is the lower sheath temperature (107°C vs. 120°C), smaller temperature gradient across the wall (5°C vs. 15°C) and lower cyclic plastic strain (35 µε vs. 250 µε). For applications with frequent thermal cycling (>5 cycles ib hnub twg, > 1,800 cycles ib xyoos), ib tug tuab -walled rhaub (2.0-2.5 mm) nrog tsawg watt ceev (3-6 W / cm²) yog qhia kom paub tseeb tias 10+ xyoo kev pab cuam lub neej. Thaum qhia txog lub titanium rhaub rau cyclic thermal lub luag hauj lwm, tus neeg muag khoom yuav tsum tau qhia txog qhov kwv yees ntawm cov thermal cycles ib hnub twg thiab cov kev pab cuam lub neej yuav tsum tau, thiaj li hais tias qhov tseeb phab ntsa thickness thiab watt ceev yuav raug xaiv kom tsis txhob ntxov ntxov thermal qaug zog tsis ua hauj lwm.