城市燃气管网的水力计算方案

城市燃气管网的水力计算方案1.1管材的选定普通无缝钢管、聚乙烯PE管1.2管线布置管线布网沿城市道路布置燃气管网，并与城市气源相连，根据城市道路的分布情况，布置8个环路区域，并以此对管网进行编号，编号后所形成的8个环路区域分别是AIBCDJA、BCEFB、DCEGKD、EFHGE对以上8种区域分别定为I、II、III、IV、V、VI、VII、VIII回路。1.3环路的面积及周长的统计根据CAD命令对以上区域进行统计和计算各自的面积和周长环路的面积及周长统计如下表：表1.1环路面积及周长统计表环路名称环路面积（m2）环路周长（m）I12546005248III4947003106IV11016004855V10888504355VI9945503998VII10238254355VIII153255055691.4每人每小时的高峰小时用气量=0.041Nm3/(人·h)1.5计算各环单位长度的途泻流量计算各环内的最大小时用气量（以面积、人口密度和每人每小时的最大用气量相乘）然后除以环周长。各环管段单位长度途泻流量见下表表1.2中压管道单位长度途泄流量表环号面积（㎡）居民数（人）平均的最大小时用气量〔m3/(人·h)〕本环供气量（m3/h）环周边长（m）单位长度途泄流量〔m3/(m·h)〕I1385925296400.041121560330.201II1254600267900.041109852480.209III494700106400.04143631060.140IV1101600235600.04196648550.199V1088850233700.04195843550.220VI994550212800.04187239980.218VII1023825218500.04189643550.206VIII1532550328700.041134855690.2421.6计算各管段的计算流量1)在管网的计算简图上将各管段依次编号，在供气点最远处，假定零点位置H点，同时决定气流方向2)计算各管段的途泻流量。3)计算各管段的转输流量，计算由零点开始，与气流相反的方向推算到供气点4)计算各管段的计算流量：Q=0.55Q1+Q2表1.3中压管网各管段计算流量表环号管段号管段长度L（m）管段长度途泄流量〔m3/(m·h)〕流量附注途泄流量Q10.55Q1转输流量Q2计算流量QI1-26430.20112971230923802-322850.201459253205623091-621420.201+0.209=0.4108784834539366-73930.201+0.140=0.341134744715453-75710.201+0.199=0.400228126471597II1-621420.209+0.201=0.4108784834539361-46780.209142787328104-515350.2093211765567325-68930.209187103453556III6-73930.140+0.201=0.341134744715457-99640.140+0.199=0.3393271807629429-106430.140+0.218=0.3582301274355626-1011070.14015585435520IV3-75710.199+0.201=0.4002281264715977-99640.199+0.140=0.3393271807629428-914990.199+0.220=0.41962834576211073-818210.19936219912601459V8-914990.220+0.199=0.41962834576211079-148210.220+0.218=0.43836019876396114-1513210.220+0.242=0.462610336674038-157140.2201578667153VI9-148210.218+0.220=0.4393601987639619-106430.218+0.140=0.35823012743556210-1314990.218+0.206=0.4246363509844814-1310350.218+0.242=0.46047626298360VII10-1314990.206+0.218=0.4246363509844810-116430.2061327334942211-1212500.20625814220734912-139640.20619910998207VIII14-1310350.242+0.218=0.4604762629836014-1513210.242+0.220=0.4626103366740313-162860.242693825729516-1719280.242467257025715-1710000.2422421330133从气源至1点距离为1595m，计算流量为4162Nm3（h）1.7初步选择各管段管径局部阻力损失取沿程摩擦阻力损失的10％。中压压燃气管道水力计算公式：式中，P1--燃气管道起点的绝对压力（kpa）；P2--燃气管道终点的绝对压力（kpa）；L--燃气管道计量长度（km）；Z--压缩分子，本设计燃气压力小于1.2Mpa，Z取1。（参考燃气工程设计手册）根据指导书，门站出站压力为0.4Mpa，燃气管道为次高压B燃气管道，管道末端压力为0.46Mpa。预定沿程阻力的单位长度计算压力降，取局部阻力损失为沿程阻力损失的10％，经计算，由气源至零点的平均距离为9469m。则沿程阻力的单位长度计算压力降为：查【燃气工程设计手册】，根据初步流量分配及沿程阻力的单位长度计算压力降选择各管段的管径。选定管径后，根据内插法求出该管段的实际沿程阻力单位长度压力降。然后计算各环的闭合差，即闭合差的允许值在10％以内，超过10％的应进行校正计算。因为天然气的密度为0.7424kg/Nm3，故在查燃气管道水力计算图表时，需进行修正，即选定管径后，由图查得管段的值，求出全部列于中压环网水力计算表中。根据公式计算式中—环网内各管段压力平方差(（)；—环网内各管段压力平方差绝对值(（)；—工程计算的精度要求，一般<10%。代入数据，计算结果见水力计算表。表1.4中压环网水力计算环号管段初步计算管段号邻环号长度管段流量管径单位压力降管段压力降△p/QI1-2-6432380D219×72.818130.762-3-22852309D219×72.864212.781-6II2142-9361251.5-963910.36-7III393-5451001.1-16112.963-7IV571597100634265.7441022.5417.90%II1-6I2142-9361251.5-963910.31-4-678810125427193.364-5-1535732125345596.235-6-893556100544387.98207727.879.70%III6-7I3935451001.116112.967-9IV9649421251.745121.799-10VI643562100532025.76-10-1107-5201001.3-47719.18455422.6232.30%IV3-7I571597100634265.747-9III9649421251.745121.798-9V1499-11071502.5-37773.413-8-1821-14591503.9-70291.82-286918.7615.30%V8-9IV149911071502.537773.419-14VI8219611252.822992.3914-15VII836999.188-15-714-153703.6-257016.8720531.858.40%VI9-14V821-9611252.8-22992.399-10III643562100532025.710-13VI4512711.4414-13VIII1035-3601002.2-23086.41377225.9428.80%VII10-13VI1499-4481003.4-512711.4410-11-6434221002.918651.4211-12-12503491002.126007.4512-13-964207803286313.83220137.417.70%VIII14-13VI10353601002.223086.4114-15V1321-4031002.8-36999.1813-16-286295805.916995.7616-17-1928257804773130.0815-17-1000-133702.8-275020.68546972.1130.10%1.8校正流量计算根据公式计算(4-05)式中—邻环校正流量的第一个近似值；—与该邻环共用管段的值。代入数据，计算结果见水力计算校正表。一次流量校正计算一次校正计算二次流量校正计算二次计算△Qˊ△Q"△Q=△Qˊ+△Qˊ管段校正流量△Qn校正后管段流量Qˊ△pˊ/L管段压力降△pˊ考虑局部阻力后压力损失1.1△pˊ∆Q'∆Q"∆Q管段校正流量校正后管段流量△pˊ/L管段压力降考虑局部阻力后压力损失1.1-10.39-12.32-22.71-22.712357.292.71736.11909.71-9.493.12-6.37-6.372350.922.71736.11909.71-22.212286.792.76169.56786.45-6.372280.422.76169.56786.4521.22-911.781.4-9421.8-10367.2811.44-897.341.1-8782.2-9660.42-18.92-563.921.2-1650.6-1815.66-10.04-573.961.8-1886.4-2075.0433.38630.386.23540.23891.22-39.04591.34528553140.5370.4921.60%0.43%-42.59-3.84-46.43-21.22-960.221.7-10067.4-11071.14-17.27-3.54-20.81-11.44-971.661.8-10281.6-11309.76-46.43763.573.82576.42831.04-20.81742.762.972013.662215.026-46.43685.572.74141.54558.95-20.81661.762.383653.34018.63-46.43509.571.74197.14616.81-20.81488.761.083643.444007.784850.6-971.21.10%1.96%-115.04-3.79-118.8318.92563.921.21650.61815.66-5.579.243.6710.04573.961.351709.551880.505-150.13791.872.72602.82863.08-29762.872.542448.562693.41627.01589.015.13279.33607.23-22.88566.131.883137.843451.624-118.83-638.836.6-7306.2-8036.823.67-635.166.58-7281.06-8012.466226.511.891.50%0.08%87.39-56.0931.3-33.38563.625.83311.83642.9847.08-11.4132.6739.04602.665.993420.293762.319150.131092.135.14916.45408.04291121.135.375176.685691.348170.16-936.842-2998-3297.878.27-858.571.63-2443.37-2687.70731.3-1427.73.7-6737.7-7411.4732.67-1395.033.17-5772.57-6349.827-1507.5381.038.40%2.27%-129.47-9.39-138.86-170.16936.841.82698.22968.02-57.1411.54-45.6-78.27858.571.532293.472522.8176.98967.982.82298.82528.68-72.15895.832.331912.932101.223-71.65331.351.72245.72470.27-60.53270.821.341770.141947.154-138.86-291.866.3-4498.2-4948.02-45.6-337.466.95-4962.3-5458.532741.51011.2423.40%9.27%-83.09-62.75-145.84-6.98-967.982.9-2380.9-2618.9915.7310.8226.5572.15-895.831.1-3366.1-3702.71-27.01531.991.12636.32899.9322.88557.871.452861.353147.485-86.79361.211.72548.32803.1355.58416.792.974452.034897.233-78.63-438.633.3-3415.5-3757.0511.62-427.013.03-3136.05-3449.655-611.8811.235.60%5.87%-33.63-25.42-59.0586.79-361.211.7-2548.3-2803.13-33.681.6-29.08-55.58-416.792.6-3897.4-4287.14-59.05362.951.71093.11202.41-29.08333.871.861195.981315.578-59.05289.951.316251787.5-29.08260.871.191487.51636.25-59.05147.951.31253.21378.52-29.08118.871.191147.161261.8761423-66.7621.80%0.85%-43.34-23.87-67.2178.63438.633.33415.53757.0521.21-6.2811.93-11.62427.012.973073.953381.34571.65-331.352.6-3431.6-3778.0660.53-270.821.23-1621.83-1787.313-67.21227.792.7772.2849.4211.93242.721.231209.781330.758-67.21189.791.83470.43817.4411.93201.722.975726.166298.776-67.21-200.217-7000-770011.93-185.286.57-6570-7227-2776.51815.0615.30%9.97%1.5水力计算校正管段号额定流量同时工作系数计算流量管段长度L1管径d局部阻力系数∑ξl2当量长度L2计算长度L单位长度压力损失△p/L△P管段终始端标高差△H附加压头管段实际压力损失管段局部阻力系数计算及其他说明1/20.710.71.2157.70.2581.98663.18661.8582.2296-1.2-6.39248.62290°直角弯头ξ=2.2，三通分流ξ=1.5，旋塞=ξ1.02/32.712.70.9156.60.9956.5677.46715.76511.18850011.188590°直角弯头ξ=2.2*33/42.712.70.8158.40.9958.3589.15815.76512.6120012.61290°直角弯头ξ=2.2*2，旋塞ξ=44/52.712.73251.350.9951.343251.343251.1923.576315.981-12.405三通直流ξ=15/65.40.563.02432511.1151.1151.1151.4611.383315.981-11.598三通直流ξ=16/78.10.443.56432511.3141.3141.3141.7075.121315.981-10.86三通直流ξ=17/810.80.381.10432511.5131.5131.5131.95.7315.981-10.281三通直流ξ=18/913.50.351.72532511.7421.7421.7421.925.76315.981-10.221三通直流ξ=19/1016.20.315.02232511.8511.8511.8511.965.88315.981-10.101三通直流ξ=110/1118.90.295.48132512.022.025.0226315.981-9.981三通直流ξ=111/1221.60.275.83232512.152.155.151.985.94315.981-10.041三通直流ξ=112/1321.30.266.31832512.3292.3295.32926315.981-9.981三通直流ξ=113-14270.256.7532512.4882.4885.4883.29.6315.981-6.381三通直流ξ=114-1529.70.247.12832512.6272.6275.6273.39.9315.981-6.081三通直流ξ=115-1632.40.247.77632512.8662.8665.8663.811.4315.981-1.581三通直流ξ=116-1735.10.238.0733321.352.9761.01767.01761.8565.568315.981-10.413三通直流ξ=1，管道变径17-1837.80.238.69433213.2053.2056.2051.9345.802315.981-10.179三通直流ξ=118-1940.50.228.9133213.2843.2846.2842.0116.033315.981-9.948三通直流ξ=119-2043.20.229.50433213.5033.5036.5032.2566.768315.981-9.213三通直流ξ=120-2145.90.2210.09833213.7223.7226.7222.5597.677315.981-8.304三通直流ξ=121-2248.60.2210.69233213.9413.9416.9412.6758.025315.981-7.956三通直流ξ=122-2351.30.2110.77333213.9713.9716.9712.8218.463315.981-7.518三通直流ξ=123-24540.2111.343401.351.185.6438.6431.935.79315.981-10.191三通直流ξ=1，管道变径24-2556.70.2111.90734011.3891.3897.3892.1126.336315.981-9.645三通直流ξ=125-2659.40.2112.47434011.5981.5987.5982.1326.396315.981-9.585三通直流ξ=126-2762.10.212.4234011.5781.5787.5782.336.99315.981-8.991三通直流ξ=127-2861.80.212.9634011.7771.7777.7772.567.68315.981-8.301三通直流ξ=128-2967.50.213.534011.9761.9767.9762.7728.316315.981-7.665三通直流ξ=129-3070.20.211.