機械能轉化演示實驗[教育相關]

1、驗 報 告 紙五、數(shù)據(jù)記錄與分析溫度：25 管路內(nèi)經(jīng)d1=30mm 節(jié)流件變截面管內(nèi)徑d2=15mm h4和h5之間管徑長L=61cm表1 原始數(shù)據(jù)記錄V（L/h)h1(cm)h2(cm)h3(cm)h4(cm)h5(cm)h6(cm)400105.5102.4104.136.936.537.3520105.3101.9103.936.435.936.6640104.899.7102.535.134.435.4760104.598.2102.234.433.534.5880104.196.1101.233.232.633.61000103.492.6100.131.330.531.611201

2、03.390.599.430.229.830.61240102.787.697.828.728.029.11 h1和h2分析表2 h1、h2變截面連續(xù)性方程序號V(L/h)h1(cm)h2(cm)流速u1(m/s)流速u2(m/s)u1d12x10-4u2d22x10-41400105.5102.40.160.801.411.792520105.3101.90.200.841.841.893640104.899.70.251.032.262.324760104.598.20.301.152.692.595880104.196.10.351.303.112.9261000103.492.60.3

3、91.513.543.3971120103.390.50.441.643.963.7081240102.787.60.491.794.394.02分析：流體為均質(zhì)、不可壓縮流體，連續(xù)性方程成立數(shù)據(jù)處理實例：以第一組數(shù)據(jù)為例驗 報 告 紙由據(jù)式（5）知：2h1和h3的分析表3 h1、h3流體經(jīng)節(jié)流件后壓頭損失關系序號V(L/h)流速u1(m/s)h1(cm)h3(cm)壓頭損失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.

4、22.9 610000.39103.4100.13.3 711200.44103.399.43.9 812400.49102.797.84.9 分析：流速增大，壓頭損失增大，壓頭損失和速度的平方成正比數(shù)據(jù)處理實例：以第一組數(shù)據(jù)為例流速計算同1中的相同驗 報 告 紙3h3和h4的分析表4 h3、h4流體經(jīng)彎頭和流量計件后壓頭損失和位能變化關系序號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

5、.35101.233.268.0 610000.39100.131.368.8 711200.4499.430.269.2 812400.4997.828.769.1 分析：流體經(jīng)3到4處，受彎頭和轉子流量計及位能的影響且隨流量的增大，單管壓力計3和4的讀數(shù)差變大，流體局部阻力導致的能頭損失增大。數(shù)據(jù)處理實例：以第一組數(shù)據(jù)為例流速計算同1中的相同4h4和h5的分析表5 h4、h5直管段雷諾數(shù)和流體阻力系數(shù)關系序號V(L/h)流速u1(m/s)h4(cm)h5(cm)阻力系數(shù)Rehf14000.1636.936.50.16 5267.110.425200.2036.435.90.12 6847.

6、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驗 報 告 紙分析：Re足夠大時，與Re無關，只與流體流速平方成正比數(shù)據(jù)處理實例：以第一組數(shù)據(jù)為例（25，水的粘度=0.8937x10-3pas）流速計算同1中的相同5h5和h6的分析表6 h5、h6單管壓力計h5處中心點速度序號V(L/h)流速u1(m/s)h5(cm)h6(cm)hu（m/s）平均u（m/s）14000.1636.537.30.80.400.4325200.2035.936.60.70.3736400.2534.435.41.00.4447600.3033.534.51.00.4458800.3532.633.61.00.