华北理工环境工程原理习题及解答第4章 热量传递

14.1A0.02m2b0.01m2.8A140V3001002.28A114V20050)1(0aTTIUQQUIATQbdbddATQb0(1)ddaTATQbdbdT201(1)2QbaTCAa2202121[()()]2QabTTTTA22022.81400.01[(300100)(300100)]0.022AVamm22022.281140.01[(20050)(20050)]0.022AVamm2a2.24×10-3K100.677W/m·K0.6771+2.24×10-3T4.2)1(0aTW/(m·K)TqW/m21Tq·dT/dyq01TdT/dy100(1)ddTyTaTTqy220011()()2aTTTTqy220001122()20aTTTTqy4.3500mm380mm250mm1.40W/(m·K)0.10W/(m·K)0.92W/(m·K)A1m2100050122cm0.0459W/(m·)r1r2r31r1b110.51.4mWmK0.357m2·K/Wr23.8m2·K/W3r30.272·m2K/Wq123Trrr214.5W/m2T11000T2T1QR1923.4T3T1QR1R2108.3T4502r’0.436m2·K/WqT/r1r2r3r’195.3W/m24.460mm×3mm45W/(m·K)30mm30mm0.15W/(m·K)0.04W/(m·K)1-105525rm1rm2rm3rm1330ln27mm28.47mmrm23060ln30mm43.28mm4rm33090ln60mm73.99mm1R/L123112233222mmmbbbrrr33030Km/WKm/WKm/W24528.4720.1543.2820.0473.993.73×104K·m/W0.735K·m/W1.613K·m/W2.348K·m/WQ/L/TRL46.84W/m2R/L123112233222mmmbbbrrr33030Wm/KWm/KWm/K24528.4720.0443.2820.1573.993.73×104K·m/W2.758K·m/W0.430K·m/W3.189K·m/WQ/L/TRL34.50W/m4.510mm250mm250mm0.38W/m·K45W/m·K0.10W/m·K4003510W/m2·K600100W/m2·K2.0mA1A4Am1Am2Am3T1231111m12m23m324111m1600356001bbb11baaaTAAAAAAA400R=2.0m5T463.5400124.61m/s3m25×2.5mm204030d0.020mu1m/s995.7kg/m380.07×10-5Pa·s450.0201995.7Re2.491080.0710du5380.07104.17410Pr5.410.6176pC320.80.40.0234.5910/()RePrWmKd4.727mm10100250kg/h120()550.0287W/m·K1.99×105Pa·scp1.005kJ/kg·K1.077kg/m3uQ/A112.62m/sRedu0.027×112.62×1.077/1.99×1051.65×105Prcp1.99×105×1.005/0.02870.6970.023·/d·Re0.8·Pr0.4315.88W/m2·K6T2110KT120KTmT2T1/lnT2T1110K20K/ln110/2052.79KdLTmqmhcphThLqmcphTh/Tm250kg/h×1.005kJ/kg·K×90K/315.88W/m2·K·0.027m·52.79K4.44m4.850mmRe1×105100W/m2·K130.80.40.023RePrd0.80.4112110.80.4221220.023RePr0.023RePrdd0.81120.8221ReReddRedu0.80.211220.82211()dddddd19.635mm58.905mmd229.452mm0.20.222121250()()100/()111.17/()29.452dWmKWmKd74.919×2mm3490W/m2·K458W/m2·K0.000176m2·K/W0.00026m2·K/W45W/m·K1211212222223211110.0021mK/WmK/WmK/W0.00026mK/W0.000176mK/W3490454582.9510mK/WssbrrKK338.9W/m2·K21212100%10.1760.26100%17.34%2.950.1760.26ssssrrrrK54.10100503500kg/h180×10mm20302320W/m2·K4.18kJ/kg·K.121qmccpcTcqmhcphThqmc3500kg/h×50/1017500kg/h82T280KT120K2121802043.2880lnln20mTTKKTKTTKATmqmhcphThdLTmqmhcphTh23500/4.18/()503.582320/()0.1843.28mhphhmqcTkghkJkgKKLmKdTWmKmKT270KT130K2121703047.2170lnln30mTTKKTKTT23500/4.18/()503.282320/()0.1847.21mhphhmqcTkghkJkgKKLmKdTWmKmK4.111919×2mm1.2m350kg/h1535700W/m2·K100L2258.4kJ/kgT285KT165K2121856574.5585lnln65mTTKKTKTT9KATmqmL22350/2258.4/4.21700/()74.55mmqLkghkJkgAmKTWmKKA19×19mm××1.2m1.36m24.21m24.1213.2mmT2.9×1033362.9102.910219.7013.210mTK4.1370mm3m22712720.3×0.3m2270.80.931Q12C1212AT14T24/1004121C121C010.8Q121C0AT14T24/10040.8×5.67W/m2·K4×3m×0.07m××5004K43004K4/10041.63×103W2Q12C1212AT14T24/1004121C12C0/[1/1A1/A21/21]Q12C0/[1/1A1/A21/21]AT14T24/10045.67W/m2·K4[1/0.83×0.07×/0.3×0.3×31/0.931]×3m×0.07m××105004K43004K4/10041.42×103W4.14802m22044121212124()100CATTQ121AA1C12C01A12m211444401121244()5.672(353293)925.04100100CATTQW