1、气-汽对流传热综合试验1. 光滑套管换热器传热系数旳测定数据记录与整顿表传热管内径di =0.020 m 有效长度Li =1.00 m 冷流体:空气(管内) 热流体:蒸汽(管外)数据项目12345孔板压差PkPa0.271.051.852.583.41空气入口温度t131.835.337.639.742.2空气出口温度t275.269.868.969.570.9壁面温度Tw99.999.9100.099.9100.0管内平均温度tm53.552.653.854.656.6空气密度mkg/ m31.0811.0851.0801.0781.071空气导热系数m*100W/ m2.8512.8442
2、.8532.8582.872空气定压比热容CpmkJ/ kg1.0051.0051.0051.0051.005空气粘度m*100000Pas1.981.971.981.981.99空气进出口温度差t43.434.531.329.828.7平均温差tm46.447.346.245.343.420时空气流量V20m3/ h11.79323.25630.87036.45541.911管内平均流量Vm3/ h12.88425.19433.44239.45645.456平均流速um/s11.3922.2729.5734.8840.19传热量QW168.74263.27315.59353.84390.06
3、对流传热系数iW/m257.8788.57108.70124.30143.02雷诺数Re1243624531322583798043260努赛尔准数Nu40.6062.2976.2086.9899.60Nu/Pr0.446.87971.00788.036100.549115.1372. 强化套管换热器传热系数及强化比旳测定数据记录与整顿表传热管内径di =0.020 m 有效长度Li =1.00 m 冷流体:空气(管内) 热流体:蒸汽(管外)数据项目12345孔板压差PkPa0.150.671.151.702.23空气入口温度t129.030.130.931.632.2空气出口温度t290.7
4、85.182.681.982.4壁面温度Tw99.699.799.899.999.9管内平均温度tm59.957.656.856.857.3空气密度mkg/ m31.0601.0681.0711.0711.069空气导热系数m*100W/ m2.8952.8792.8742.8742.877空气定压比热容CpmkJ/ kg1.0051.0051.0051.0051.005空气粘度m*10000Pas2.012.001.991.992.00空气进出口温度差t61.755.051.750.350.2平均温差tm39.742.143.043.142.620时空气流量V20m3/ h8.7918.58
5、24.3429.5933.89管内平均流量Vm3/ h9.83720.61326.90232.66637.432平均流速um/s8.7018.2223.7828.8833.09传热量QW179.60338.02392.16491.27560.77对流传热系数iW/m271.99127.77145.13181.39209.48雷诺数Re917619458255963108635373努赛尔准数Nu49.7388.76101.0126.23145.62Nu/Pr0.457.42102.49116.76145.92168.14Nu031.9854.3766.0475.7382.98强化比Nu/Nu01.561.631.531.671.753. 线性回归确定准数关联式由可得 由线性拟合成果可求得:光滑套管换热器 A= 0.0581 m=0.7074强化套管换热器 A= 0.0496 m=0,771