机械能转化演示实验.docx

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=15mm h4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2 h1、h2变截面连续性方程序号V(L/h)h1(cm)h2(cm)流速u1(m/s)流速u2(m/s)u1d12x10-4u2d22x10-41400105.5102.40.160.801.411.792520105.3101.90.200.841.841.893640104.899.70.251.032.262.324760104.598.20.301.152.692.595880104.196.10.351.303.112.9261000103.492.60.391.513.543.3971120103.390.50.441.643.963.7081240102.787.60.491.794.394.02分析：流体为均质、不可压缩流体，连续性方程成立数据处理实例：以第一组数据为例验 报 告 纸由据式（5）知：2h1和h3的分析表3 h1、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）14000.16105.5104.11.4 25200.20105.3103.91.4 36400.25104.8102.52.3 47600.30104.5102.22.3 58800.35104.1101.22.9 610000.39103.4100.13.3 711200.44103.399.43.9 812400.49102.797.84.9 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中的相同验 报 告 纸3h3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）14000.16104.136.967.2 25200.20103.936.467.5 36400.25102.535.167.4 47600.30102.234.467.8 58800.35101.233.268.0 610000.39100.131.368.8 711200.4499.430.269.2 812400.4997.828.769.1 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4h4和h5的分析表5 h4、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Rehf14000.1636.936.50.16 5267.110.425200.2036.435.90.12 6847.240.536400.2535.134.40.11 8427.370.747600.3034.433.50.10 10007.500.958800.3533.532.60.07 11587.640.9610000.3931.330.50.05 13167.770.8711200.4430.229.80.02 14747.900.5812400.4928.728.00.03 16328.030.7验 报 告 纸分析：Re足够大时，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=0.8937x10-3pas）流速计算同1中的相同5h5和h6的分析表6 h5、h6单管压力计h5处中心点速度序号V(L/h)流速u1(m/s)h5(cm)h6(cm)hu（m/s）平均u（m/s）14000.1636.537.30.80.400.4325200.2035.936.60.70.3736400.2534.435.41.00.4447600.3033.534.51.00.4458800.3532.633.61