64 Re 22590 10 0.903 10 i d u ???? ?? ? ??? 3 3 4.18 10 0.903 10 Pr 6.229 0.606 pc???? ??? ? ?? i =0.023( λ/d)Re 0.8 Pr 0.4 =0.023 × (0.606/0.015) × (22590) 0.8× 6.229 0.4 =5875.0 W/( ㎡· K) 1/K 1 =1/ ? 1+d 2 /(? i·d 1 )=1/1400+19/(5875 × 15) K 1 =1075.4 W/( ㎡· K) m1 28 20.7 55.5 80 20.7 ln 80 28 t ?? ? ???℃ 2 11 1 m1 140000 2.35 1075.4 55.5 Q A m K t ? ? ?? ? 1/K 2 =1/ ? 2+d 2 /(? i·d 1 )=1/1200+19/(5875 × 15) K 1 =953.3 W/( ㎡· K) ?? m2 (80 20.7) 60 20 49.0 80 20.7 ln 60 20 t ? ??? ? ???℃ 2 22 2 m2 12600 0.27 953.3 49.0 Q A m K t ? ? ?? ? 2 1 2 2.35 0.27 2.62 A A A m ? ????需22 3.14 0.019 2.5 19 2.83m A d l n ?? ???? ????实?AA 实需??此换热器可满足生产要求。
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