1、2023-1-2812023-1-282l导热导热l对流对流l辐射辐射 2023-1-283 2023-1-284 0 xt tw2 tw1 w1w 2ttA2023-1-285w1w 2ttqA热流密度热流密度 q导热热阻导热热阻w1w 2ttAw1w 2ttAw1w 2ttRRAtw1 tw2 R热阻网络热阻网络2023-1-2862023-1-2872023-1-2882023-1-289 50-415 W/mK 12-120 W/mK 1-40 W/mK 0.17-0.7 W/mK 0.03-0.12 W/mK 0.007-0.17 W/mK 2023-1-28102、对流、对流对流换
2、热对流换热 =Ah(tw tf)q=h(tw tf)2023-1-2811wf1ttAh1hRAhtw tfhR =Ah(tw tf)wfhttR2023-1-2812 2023-1-2813 h W/(m2K)225 501000 25250 5025000 2500100000 20001000002023-1-28142023-1-28152023-1-2816，2023-1-2817辐射换热的主要影响因素辐射换热的主要影响因素：2023-1-28182023-1-28191w1f1Ah ttw1f111ttAhw1f11httRw1w2ttAw1w2ttAw1w2ttR tw2 tw1 0 xt h1 tf1 h2 tf2 2023-1-28202w2f2Ah ttw2f221ttAhw2f22httRf1f 21211ttAhAAhf1f 2kttRf1f 212hhttRRR12khhRRRRtw1 R1hR2hRtw2 tf1 tf2 2023-1-2821f1f 2Ak ttAk t12111khhf1f2qk ttf1f21211tthh
