1、五、数据处理室温:18.5 压强:102.31Kpa由 ;210()()()pwmiwmVCtATAt而 ; ;121()()()lnwmwTT121()()()lnwwmttt 且 密度 ;12;wwtt152310496tt平均比热: );./(pCkJg则: ; ;210()wmVtAT21()piiwmVCtA又 紫铜管规格:直径 长度.8,0L则; 203.1402659dL 2(.)1.48iiA表 1 实验测得的数据V(m 3/h) ()T()2()1wT()2w()1t()2t22.5 103.0 97.9 97.5 89.4 72.1 37.619.01 103.0 98.7
2、 97.5 91.6 73.2 37.515.01 103.1 99.1 97.7 93 74.2 37.010.03 103.2 99.8 97.8 95.5 75.3 35.87.5 103.1 99.8 97.7 96.4 75.5 35.0表 2 实验计算各物理量的数值()()wmT()wmt3(/)kg( )0/2mW( )i/26.891513 37.0453 1.019134 662.7223 123.28586.265991 37.23335 1.015782 635.1473 106.88885.742892 37.42725 1.012756 568.4748 87.227
3、64.829138 38.12191 1.009451 478.1089 60.5654.32317 38.53271 1.008853 409.2181 45.91215从表 2 中可看出冷流体的流量越大,蒸汽给热系数越大,冷流体给热系数也越大。即蒸汽给热系数和冷流体给热系数随着冷流体的流量的增大而增大。50下空气的物理性质: 698.0Pr),./(1083.2,.1096. 25 CmWsPa4.rRemANuRelgl/lg.0表三 冷流体的相关数据流速 u(m/s) 雷诺数 Re 努塞尔数 Nu 4.0Pr/lgNuRelg33.57136 26882.21 67.08838 1.8
4、89104 4.42946528.36407 22637.78 58.16563 1.827123 4.35483422.39583 17821.19 47.46661 1.738845 4.25093714.96537 11869.63 32.95763 1.580413 4.07443711.19045 8870.334 24.984 1.460119 3.947943.94.04.14.24.34. 4.51.41.51.61.71.81.93.94.04.14.24.34. 4.51.41.51.61.71.81.9lgNu/Pr0.4Re图 1 关系图4.0Pr/lgNulg作图得出直线方程: = 1.75156 + 0.89058 4.0r/l Relg由此可知 ;7516.lgA18.A9058.m