Yuav Ua Li Cas Thermal Cycling Rate (2℃/min vs . 10℃/min) Ntawm 20℃thiab 200℃hauv Huab cua Hloov Lub Ncauj Lub Neej ntawm PFA (Perfluoroalkoxy) Sheath Heater los ntawm 50,000 txog 10,000 Cycles?
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Thermal cycling ntawm 20℃thiab 200℃ua rau qaug zog nyob rau hauv PFA sheath heaters nyob rau hauv cov huab cua vim qhov txawv expansion ntawm cov polymer thiab cov khoom hlau sab hauv. Lub neej qaug zog nrog kev caij tsheb kauj vab qeeb (2℃/ min) yog 50,000-100,000 cycles. Lub neej txo qis mus rau 10,000-20,000 cycles ntawm ceev ceev ntawm 10C / min. Tus nqi siab dua ua rau muaj qhov kub thiab txias dua nyob thoob plaws PFA phab ntsa, uas ua rau muaj kev ntxhov siab ntau ntxiv thiab ua rau qhov pib tawg sai dua. Thermal Fatigue Mechanism In Pfa Heaters Qhov nro tshwm sim los ntawm thermal cycling los ntawm qhov tsis sib haum xeeb hauv coefficient ntawm thermal expansion (CTE) ntawm PFA (120 × 10⁻⁶ / degree) thiab cov hlau tsis muaj zog (17 × 10⁻⁶ /℃). Qhov kev nyuab siab amplitude Δσ=Δ × ΔT × E, qhov twg Δ yog qhov sib txawv CTE, ΔT yog qhov kub thiab txias thiab E yog qhov elastic modulus. Qhov nrawm nrawm nrawm ua rau muaj qhov kub siab dua tam sim ntawd, uas ua rau muaj kev ntxhov siab ntau dua hauv zos. Quantitative Fatigue Life vs Ramp Rate Cov hauv qab no tau tsim los rau PFA siv kev tswj xyuas thermal cycling los ntawm 20℃mus rau 200 degree. Rau ramp tus nqi ntawm 1 deg C / min lub voj voog mus rau qhov tsis ua hauj lwm yog 100,000-200,000 thiab tsis ua hauj lwm tshwm sim los ntawm crazing. Ntawm 2℃/ min, muaj 50,000-100,000 cycles thiab tsis ua hauj lwm yog los ntawm nto tawg. Ntawm 5℃/ min, lub voj voog yog 20,000-40,000 thiab tawg yog qhov hnyav dua. Tus naj npawb ntawm cov voj voog yog 10,000-20,000 ntawm 10℃/ min, thiab los ntawm phab ntsa tawg. Ntawm 20℃/ min, lub voj voog yog 5,000-10,000 thiab tawg sai. Thermal Cycling Ramp Rate Xaiv Phau Ntawv Qhia Ramp Rate (degree / min) Cycles rau Kev Ua Haujlwm Tsis Ua Haujlwm Pom Zoo<2 >100,000 Crazing Yes 2-5 50,000-100,000 Surface cracking Yes 5-10 20,000-50,000 Cracking Acceptable 10-15 10,000-20,000 Through-wall cracking Limited >15 <10,000Rapid failure None Informed specification For a PFA heater exposed to thermal cycling between 20°C and 200°C, the ramp rate should be limited to 5°C/min or less for >50,000 cycles. Tus engineer muaj peev xwm ua kom lub neej thermal qaug zog los ntawm kev nce tus nqi ntawm cov cua sov.
