机械能转化演示实验

学习资料收集于网络，仅供参考验报告纸五、数据记录与分析温度：25℃管路内经d1=30mm节流件变截面管内径d2=15mmh4和h5之间管径长L=61cm表1原始数据记录V（L/h)h1(cm)h2(cm)h3(cm)h4(cm)h5(cm)h6(cm)400105.5102.4104.136.936.537.3520105.3101.9103.936.435.936.6640104.899.7102.535.134.435.4760104.598.2102.234.433.534.5880104.196.1101.233.232.633.61000103.492.6100.131.330.531.61120103.390.599.430.229.830.61240102.787.697.828.728.029.11．h1和h2分析表2h1、h2变截面连续性方程序号V(L/h)h1(cm)h2(cm)流速u(m/s)流速u(m/s)2-4ud2x10-42121121400105.5102.40.160.801.411.792520105.3101.90.200.841.841.893640104.899.70.251.032.262.324760104.598.20.301.152.692.595880104.196.10.351.303.112.9261000103.492.60.391.513.543.3971120103.390.50.441.643.963.7081240102.787.60.491.794.394.02分析：流体为均质、不可压缩流体，连续性方程成立学习资料学习资料收集于网络，仅供参考数据处理实例：以第一组数据为例验报告纸学习资料学习资料收集于网络，仅供参考u1V4000.16900πd210009000.032由p12p22u1u2g2gg2gu2g（h1229.8（105.5102.4）1020.1620.80h2）u21据式（5）知：ud20.160.0321.4110411ud20.800.01521.7910422则u1d12u2d122．h1和h3的分析表3h1、h3流体经节流件后压头损失关系序号V(L/h)流速u1(m/s)h1(cm)h3(cm)压头损失hf（cm）14000.16105.5104.11.425200.20105.3103.91.436400.25104.8102.52.347600.30104.5102.22.358800.35104.1101.22.9610000.39103.4100.13.3711200.44103.399.43.9812400.49102.797.84.9分析：流速增大，压头损失增大，压头损失和速度的平方成正比数据处理实例：以第一组数据为例流速计算同 1中的相同hf =h1-h3=105.5 -104.1 =1.4cm学习资料学习资料收集于网络，仅供参考验报告纸3．h3和h4的分析表4 h3、h4流体经弯头和流量计件后压头损失和位能变化关系序号V(L/h)流速u1(m/s)h3(cm)h4(cm)位能差（cm）14000.16104.136.967.225200.20103.936.467.536400.25102.535.167.447600.30102.234.467.858800.35101.233.268.0610000.39100.131.368.8711200.4499.430.269.2812400.4997.828.769.1分析：流体经3到4处，受弯头和转子流量计及位能的影响且随流量的增大，单管压力计3和4的读数差变大，流体局部阻力导致的能头损失增大。数据处理实例：以第一组数据为例流速计算同1中的相同位能差 =h3-h4=104.1-36.9 =67.2cm4．h4和h5的分析表5h4、h5直管段雷诺数和流体阻力系数关系序号V(L/h)流速u1(m/s)h4(cm)h5(cm)阻力系数λRehf14000.1636.936.50.165267.110.425200.2036.435.90.126847.240.536400.2535.134.40.118427.370.747600.3034.433.50.1010007.500.958800.3533.532.60.0711587.640.9610000.3931.330.50.0513167.770.8711200.4430.229.80.0214747.900.5812400.4928.728.00.0316328.030.7学习资料学习资料收集于网络，仅供参考验报告纸分析：Re足够大时，λ与Re无关，只与流体流速平方成正比数据处理实例：以第一组数据为例 （25℃，水的粘度μ=0.8937x10-3pa·s）流速计算同1中的相同Hf=h4-h5=36.9-36.9=0cmdu0.030.16998.25267.11Re0.89371032hfdg20.40.039.80.16u2L1020.1620.611025．h5和h6的分析表6h5、h6单管压力计h5处中心点速度序号V(L/h)流速u(m/s)h5(cm)h6(cm)hu（m/s）平均u（m/s）114000.1636.537.30.80.4025200.2035.936.60.70.3736400.2534.435.41.00.4447600.3033.534.51.00.440.4358800.3532.633.61.00.44610000.3930.531.61.10.46711200.4429.830