| [ sciEncE ] in KIDS 글 쓴 이(By): koma (김 민 준) 날 짜 (Date): 2000년 1월 25일 화요일 오후 05시 59분 58초 제 목(Title): Re: [Q]Quartz versus Aluminum Emissivity: Aluminum: Highly Polished plate, 98.3% pure 0.039-0.057 at T = 440-1070 F Commercial sheet 0.09 at 212 F Heavily oxidized 0.20-0.31 at 299-940 F Al-surfaced roofing 0.216 at 100 F Quartz, rough, fused 0.93 at 70 F (heat flux) = sigma (area) (emissivity) T^4 emissivity_Al < emissivity_quartz For the same heat flux, T_Al > T_quartz (for equillibirum state) Ref) J.P.Holman, "Heat Transfer" koma :) p.s. 맞게 계산한건가 ??? |