管道直径、流量、流速、压力之间的关系.docx
首先流量=流速X管道内径X管道内径xn÷4;所以流量和流速基本上知道一个就能算出另一个参数.但如果已知管道直径D,管道内压力P,能算出流量吗？答案是:还不能求管道中流体的流速和流量.你设想管道末端有一阀门,当关闭时,管内有压力P,可管内流量为零.所以:管内流量不是由管内压力决定,而是由管内沿途压力下降坡度决定的.所以一定要说明管道的长度和管道两端的压力差是多少才能求管道的流速和流量.如果从定性分析角度看,管道中压力与流量的关系是正比例关系，即压力越大，流量也越大.流量等于流速乘于断面.对管道的任何一断面，压力只来自一潴，也就是说压力的方向是单向的，在压力方向出口处被封闭时(阀门关闭)，管内流体处于禁止状态。一但出口打开，其流速起决于管道中压力.要定量分析，可以通过水力模型实验，安装压力计、流量计或测量流过容量.对于有压管流，也可以通过计算得到,计算步骤如下：1、计算管道的比阻S,如果是旧铸铁管或旧钢管，可用舍维列夫公式计算管道比阻s=0.001736d5.3或用s=10.3n2d5.33计算,或查有关表格；2、确定管道两端的作用水头差H=P(pg),如果有水平落差h(指管道起端比末端高出h),则H=P(pg)+h式中：H:以m为单位;P：为管道两端的压强差(不是某一断面的压强)，P以Pa为单位;3、计其流量Q:Q=(Hs1.)(l2)4、流速V=4Q(3.1416*dA2)式中：Q流量，以m3s为单位；H管道起端与末端的水头差,以m为单位;1.管道起端至末端的长度，以m为单位.钟径/流速/流H对照表(DN)值量-1Zh04msOtas0Sms1Omt12msI4ms16m,i1Sms2C*ns22ms2ns26m2Sms3Oms内曲枳r加0.S0.T0.91.J1.-JU6Ua工2-32-52.72.9X2X40.0003142S0.71.11.41.82.1X62.83.23.53.94.24.64.95.30.0004911.2I.T232964.14.65.25.86.4697.5Kl8.70.0008040.0012570.COl%340l.t2.T3.64.(*46.3T.26.19.010.01O9II.612.T1X6M2.e4.2,7.1KS9911.312.?14.115.11.018.419.921.24.87.29.611.9U.316.T19.121.523.926.328.731.)33.4.80.003318SOT.210.9!4.518.121.T2S.329.032-36.239.843.447.0W.TM.30.0O5(J271811.311.022.628.333.939.645.250.966.562.267.973.579.284.80.00785412S11.726.S35.344.253.0619T0.7T«-5B8.497.2106.0114.9123.7122.60.01227215025.43B.250.963.676.3W.Io.eM4.512?.2M0.0152.T166.411S-g90.0176712004$.267.9¢0.5119.1136.7159.3181.020e226.224S.27i.4雨I31473».30.0314160.CK9G370.0706S60.096211250?106.0Ml.4176.7212.1247.42牝731S.I353.4»6.a424.1364H.05l300101.9162.7203.6»4.5306.4取3Ml458.0608.9W9.4iO.Tl.6jruj59W.8T6143W138.520T.8277.1346.4416.64S4.95M.2623.4692.7762.0«1.3900.51039.1400181.0271.43l.9452.4M2.963K3T23.8814.3904.8996.31086.7H76.2126.T1»7.20.1256644229.0343.5458.0572.687.191.6916.11030.6114(.11259.61374.11488.6l03.21117.T0.159043S282.7424.1566.5706.9848.2曲6H3I.01272.3I417I55S.I1696.6137.81979.22120.60.1963496840T.t610.7U.31017.91221.4U25.0阳861832.22036.722».32442.92646.52860.03063.60.282743TOO54.116Ml.2641108.1389.44l42.531939.622216.712493.792770.”3047.91尔6M¾0213am.2341以320.384344640.50265422B723.221085.731447.M“工KU日UllTH蜗：1出：纲1逑1小，KlIMHMnKxEfU4TQ4.8450¼.7554次67KD916.«?1374.n1832.n*0,222X82632O&313664.354122394S80.44SO0e.41549652545T6<12.IGOO1130.97l96.4622l.947.433.92398.44523.895089.376664.846220.3S¢788.83T»l.32T9I6.81200628.6244X93257.2I4071.54885.85700.16514.47班？81438957.3977l6106S59I14OO.2I22N.51.130972注：最上面一行是流速以上表格中间大片数据的就是流量最左边一排是水管的公称直径何：那么多流速我选哪个别急看卜表（开式系统和闭式系统有区别哦）25tt406065»0181251502002503003W400o.e-0.1I9o.a-iOill.-.4.)-.e1.5-2.0.<-t2.a-2.5I.W.61l.e-2.50.6-0.4I80.790I.H.21.I-1.4i.1.e.1.5-2.01.6-2.31.T-2.41.7-2.4l-21I.S-2.3镀锌钢管外径内径DN1521.7516.25DN2026.7521.25DN2533.527DN3242.2535.75DN404841DN506053DN6575.568DN8088.580.5DNlOO114106DN125140131DN150165156DN200219203DN250273257
