第六章 能量损失及管路计算

第六章 能量损失及管路计算 ,6-8 一旧铸铁管长l=30m，管径d=0.3m。管中水流速度v=1.5m/s，水温。t,20C 试计算沿程损失。 2lv0.3 解:根据谢维列夫公式:， ,,,0.021/0.03d,,,0.35mhf2dg ,62,,0.5mm6-9 直径d=250mm的铸铁管。当量粗糙度。用它输送,,，1.310m/s 的水。分别计算流动处于水力光滑区的最大输水量和阻力平方区时的最小流量。 d8/7 解:当流动处于水力光滑区时: Re26.98()32778,,max, vd,2max？Re,，，Qdv,,8.34L/s ？,v0.17m/smaxmaxmaxmax,4 d0.85当流动处于阻力平方区时:Re4160()454300,, min,2 vd,23min？Re,Qdv,,0.12m/s，， ？,v2.36m/sminminminmax,4 ,,,0.5mm615C-10 某水管直径d=0.5m，，水温。分别用公式法和查图法确定 333,流量分别为，，时的沿程阻力系数。 Q,0.005m/sQ,0.1m/sQ,2m/s132 ,,62t,15C,,，1.13910m/s 解:1)时， 3公式法:， v,0.025m/sQ,0.005m/s11 vdd8/71Re11178,,26.98()72379.1,，， ,, d8/7？,,4000Re26.98()位于水里光滑管区。 , ,0.237,,，,0.00320.221Re0.056 ,,0.06查图法: 3v,0.51m/s2)公式法:， Q,0.1m/s22 vdd58/72Re2.23610,,，26.98()72379.1,， ,, d8/7？,,4000Re26.98()，位于水力光滑区。 , ,0.237,,，,0.00320.221Re0.04 ,,0.03查图法: 3v,10.2m/sQ,2m/s3)公式法:， 33 development is limited by the handling capacity of the airport, not in-situ expansion. Jinsha River and minjiang rivers, the Yangtze River traverses northern border in Yibin city, with good conditions for development of water transport, but water with speed ... Rate of 10.9% per cent. In recent years, Yibin city, stepping up construction of transport infrastructure at the same time, increase the intensity of high-grade highway construction, and the overall technical levels improved significantly, which succeeds in improving road vddd68/70.8553，， Re4.510,,，26.98()72379.1,4160()8.210,，,,,2 dd8/70.85，位于第二过渡区。 ？,,26.98()Re4160(),,2 19.35,？,,0.025， ,,，1.142lg()dRe,, ,,0.025查图法: 6-14 如图6-22所示，用一直径d=20mm、长l=0.5m的管段做沿程阻力实验。当 ,62,33的水以通过时，两侧压管液面高差h=0.6m，,,，0.8910m/sQ,，1.210m/s ,试计算。若流动处于阻力平方区，确定当量粗糙度。 , 2Qlv？,,0.032v,,3.82m/s 解:，，，流动处于阻力平方区 ,,hfA2dg d,2？,,0.12mm,,，(1.142lg)， , 6-17 泵送供水管如图6-25所示。已知吸水管，，，d,225mml,7m,,0.025111,,4;排水管d,200mm，l,50m，,,0.028。H,45m。设水泵的扬程H211c1 2与流量Q的关系为。不计其他局部损失，该管路每昼夜的供水HQ,,652500 量是多少, development is limited by the handling capacity of the airport, not in-situ expansion. Jinsha River and minjiang rivers, the Yangtze River traverses northern border in Yibin city, with good conditions for development of water transport, but water with speed ... Rate of 10.9% per cent. In recent years, Yibin city, stepping up construction of transport infrastructure at the same time, increase the intensity of high-grade highway construction, and the overall technical levels improved significantly, which succeeds in improving road 2222lvvlvv2111222 解:由题意可得:H， ,,,,,，，，,HHQ，,,652500C112dggdgg222212 ,,,2223dvdvQ,,？,,Qdv0.081m/s，解得:， v,0.045m/s1122111444 3所以，供水量= Q，，,2436006975m development is limited by the handling capacity of the airport, not in-situ expansion. Jinsha River and minjiang rivers, the Yangtze River traverses northern border in Yibin city, with good conditions for development of water transport, but water with speed ... Rate of 10.9% per cent. In recent years, Yibin city, stepping up construction of transport infrastructure at the same time, increase the intensity of high-grade highway construction, and the overall technical levels improved significantly, which succeeds in improving road