圆筒壁的稳态热传导 △t Q b R S.=2丌rL 2L(2-1)_A2-A 2丌r;L 2TrL q R R2 R3 iq1=242=7343=圆筒壁的稳态热传导 1 2 2 1 2 1 2 2 1 1 1 2 1 2 3 1 2 3 1 1 2 2 3 3 2 ( ) 2 2 ln ln 2 m m m m t t t Q b R S L r r A A S r L r L A r L A Q t t q S b t t t Q R R R r q r q r q       −  = = − − = = = − = =    = = = = = = =