機械能轉(zhuǎn)化演示實驗

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 =15mmh4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)400105.5102.4104.136.936.537.3520105.3101.9103.936.435.936.6640104.899.7102.535.134.435.4760104.598.2102.234.433.534.5880104.196.1101.233.232.633.61000103.492.6100.131.330.531.6112

2、0103.390.599.430.229.830.61240102.787.697.828.728.029.11h1 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)u1d12x10-4u2d22x10-41400105.5102.40.160.801.411.792520105.3101.90.200.841.841.893640104.899.70.251.032.262.324760104.598.20.301.152.692.595880104.196.10.351.303.112.92610001

3、03.492.60.391.513.543.3971120103.390.50.441.643.963.7081240102.787.60.491.794.394.02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p12p22由u1u2g2gg2gu22g（ h1h2）u22 9. 8 （105. 5102. 4） 10 20. 1620. 801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(guān)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、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，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(guān)系序號V(L/h)流速u1(m/s)h3(cm)h4(cm)位能差（ cm）14000.161

5、04.136.967.225200.20103.936.467.536400.25102.535.167.447600.30102.234.467.858800.35101.233.268.0610000.39100.131.368.8711200.4499.430.269.2812400.4997.828.769.1分析：流體經(jīng)3 到 4 處，受彎頭和轉(zhuǎn)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(dǎo)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(guān)系序號V

6、(L/h)流速 u1(m/s)h4(cm)h5(cm)阻力系數(shù)Rehf14000.1636.936.50.165267.110.425200.2036.435.90.126847.240.536400.2535.134.40.118427.370.747600.3034.433.50.1010007.500.958800.3533.532.60.0711587.640.9610000.3931.330.50.0513167.770.8711200.4430.229.80.0214747.900.5812400.4928.728.00.0316328.030.7驗報告紙分析： Re 足夠大時，與 Re 無關(guān)，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 =0.8937x10-3 pa· s）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）14000.1636.537.30.80.4025200.2035.936.60.70.3736400.2534.435.41.00.4447600.3033.534.51.00.440.4358800.3532.63