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时间:2018-10-10
《管路沿程阻力系数测定实验》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、实验二管路沿程阻力系数测定实验一、实验目的1、掌握流体流经管道时沿程阻力损失的测定方法。2、测定流体经过直管时的沿程阻力,确定沿程阻力λ与Re的关系。3、学会压差计和流量计的使用。二、实验成果及要求1.有关常数。实验装置台号圆管直径d1=15cm,d2=20cm,d3=25cm,量测段长度L=85cm。及计算(见表1)。2.绘图分析绘制lgυ~lghf曲线,并确定指数关系值m的大小。在厘米纸上以lgυ为横坐标,以lghf为纵坐标,点绘所测的lgυ~lghf关系曲线,根据具体情况连成一段或几段直线。求厘米纸上直线的斜率将从图上求得的m值与已知各流区的
2、m值(即层流m=1,光滑管流区m=1.75,粗糙管紊流区m=2.0,紊流过渡区1.753、0.11.00316636.46067.350.217.10.0040.0044200044.944.428.83920.11.0034025.38980.276.83.40.0130.0165200019.810165.60220.11.0039156.85286.480.36.10.0050.0076200022.190.558.78220.11.0038204.90249.544.25.30.0050.0087200038.851.533.45120.11.0034669.08888.585.23.30.0100.014820005.13924、.2254.74520.11.00335557.59911990.528.50.0010.0029400039.1102.318.16220.11.0033440.38145.944.81.10.0150.01910400028.7139.4138.31020.11.00326200.33647.844.23.60.0010.00211400018.3218.636.07620.11.0036833.99946.742.44.30.0140.00912400050.978.649.16020.11.0039312.4096258.73.30.0065、0.00713400016.2246.977.09020.11.00314603.24761.155.95.20.0040.0041440009.8408.227.71820.11.0035250.7565148.32.70.0150.0121540007.8512.887.07020.11.00316493.78681.662.6190.0110.00416400047.484.49.69920.11.0032514.12443.643.10.50.0320.02517400029.6135.173.86120.11.00319146.400816、.179.41.70.0020.00318400014.3279.719.26620.11.0034994.07644.843.90.90.0150.0131940009444.426.25220.11.0036805.22231.129.81.30.0110.0092040007.8512.841.16820.11.00310671.6042017.42.60.0090.00621400015.9251.614.80220.11.0033837.0916261.20.80.0220.0172240006.462546.49720.11.003127、053.15223.420.13.30.0090.005图1λ与Re的关系图三、实验分析与讨论1.为什么压差计的水柱差就是沿程水头损失?如实验管道安装成倾斜,是否影响实验成果?答:在管道中的,水头损失直接反应于水头压力。测力水头两端压差就等于水头损失。如果管道倾斜安装,不影响实验结果。但压差计应垂直,如果在特殊情况下无法垂直,可乘以倾斜角度转化值。2.据实测m值判别本实验的流动型态和流区。答:~曲线的斜率m=1.0~1.8,即与成正比,表明流动为层流(m=1.0)、紊流光滑区和紊流过渡区(未达阻力平方区)。3.本次实验结果与莫迪图吻合与否?试分析其8、原因。答:钢管的当量粗糙度一般为0.2mm,常温下,,经济流速,若实用管径D=(20~100)cm,其~,相应的=0.00
3、0.11.00316636.46067.350.217.10.0040.0044200044.944.428.83920.11.0034025.38980.276.83.40.0130.0165200019.810165.60220.11.0039156.85286.480.36.10.0050.0076200022.190.558.78220.11.0038204.90249.544.25.30.0050.0087200038.851.533.45120.11.0034669.08888.585.23.30.0100.014820005.1392
4、.2254.74520.11.00335557.59911990.528.50.0010.0029400039.1102.318.16220.11.0033440.38145.944.81.10.0150.01910400028.7139.4138.31020.11.00326200.33647.844.23.60.0010.00211400018.3218.636.07620.11.0036833.99946.742.44.30.0140.00912400050.978.649.16020.11.0039312.4096258.73.30.006
5、0.00713400016.2246.977.09020.11.00314603.24761.155.95.20.0040.0041440009.8408.227.71820.11.0035250.7565148.32.70.0150.0121540007.8512.887.07020.11.00316493.78681.662.6190.0110.00416400047.484.49.69920.11.0032514.12443.643.10.50.0320.02517400029.6135.173.86120.11.00319146.40081
6、.179.41.70.0020.00318400014.3279.719.26620.11.0034994.07644.843.90.90.0150.0131940009444.426.25220.11.0036805.22231.129.81.30.0110.0092040007.8512.841.16820.11.00310671.6042017.42.60.0090.00621400015.9251.614.80220.11.0033837.0916261.20.80.0220.0172240006.462546.49720.11.00312
7、053.15223.420.13.30.0090.005图1λ与Re的关系图三、实验分析与讨论1.为什么压差计的水柱差就是沿程水头损失?如实验管道安装成倾斜,是否影响实验成果?答:在管道中的,水头损失直接反应于水头压力。测力水头两端压差就等于水头损失。如果管道倾斜安装,不影响实验结果。但压差计应垂直,如果在特殊情况下无法垂直,可乘以倾斜角度转化值。2.据实测m值判别本实验的流动型态和流区。答:~曲线的斜率m=1.0~1.8,即与成正比,表明流动为层流(m=1.0)、紊流光滑区和紊流过渡区(未达阻力平方区)。3.本次实验结果与莫迪图吻合与否?试分析其
8、原因。答:钢管的当量粗糙度一般为0.2mm,常温下,,经济流速,若实用管径D=(20~100)cm,其~,相应的=0.00
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