3通过肋壁的传热 肋壁面积:A=A1+A2 CA1 稳态下换热情况: A 2 Φ=h4(tr1-tmn) A, (twI-two) d=hoA(two-to)+hn A2(two-to) wO 肋面总效率 (41+742)3 通过肋壁的传热 肋壁面积： Ao = A1 + A2 稳态下换热情况： ( ) i i f 1 w1  = h A t −t ( ) i w1 wo  = A t −t   ( ) ( ) ( ) 1 2 o o o wo f o o wo f o o f wo f o h A t t h A t t h A t t = −  = − + −   o f o A (A A ) 1  2  + = A1 A A2 i 肋面总效率