1、8.管网设计计算(流量计算)8.1热水供应系统管路流量设计热水供应系统的管路流量按照给水系统的设计秒流量计算。(1)住宅建筑热水供应系统的设计秒流量 应按下列步骤和方法计算。根据住宅配置的卫生器具给水当量、使用人数、用水定额、使用时数及小时变化系数,按下式计算出最大用水时卫生器具给水当量平均出流概率:(%)式中: 热水供应管道的最大用水时卫生器具给水当量平均出流概率,%;最高日用水定额;每户用水人数;小时变化系数,冷水按下表计算表4取用,热水按表13取用;每户设置的卫生器具给水当量数;用水时数,h;0.2一个卫生器具给水当量的额定流量,L/s。1 住宅、别墅的热水小时变化系数Kh值居住人数(m
2、)100150200250300500100030006000Kh5.124.494.133.883.703.282.862.482.342 旅馆的热水小时变化系数Kh值居住人数(m)1503004506009001200Kh6.845.614.974.584.193.903 医院的热水小时变化系数Kh值床位数(m)50751002003005001000Kh4.553.783.542.932.602.231.954 住宅最高日生活用水定额及小时变化系数住宅类别卫生器具设备标准用水定额/L/(人d)小时变化系数Kh普通住宅有大便器、洗涤盆851503.02.5有大便器、洗脸盆、洗涤盆、洗衣盆、
3、热水器和淋浴设备1303002.82.3有大便器、洗脸盆、洗涤盆、洗衣机、集中热水供应(或家用热水机组)和淋浴设备1803202.52.0别墅有大便器、洗脸盆、洗涤盆、洗衣机、洒水栓,家用热水机组和淋浴设备2003502.31.8根据计算管段上的卫生器具给水当量总数,按下式计算得出该管段的卫生器具给水当量的同时出流概率:(%)式中: 计算管段的卫生器具给水当量同时出流概率,%;对应于不通的系数,查GB50015-2003建筑给水排水设计规范附表C中的表C;计算管段的卫生器具给水当量总数。根据计算管段上的卫生器具给水当量同时出流概率,按下式计算得计算管段的设计秒流量:(L/s)式中: 计算管段的
4、设计秒流量,L/s注:1.为了计算快速、方便,在计算出的后,即可根据计算管段的值,从GB50015-2003建筑给水排水设计规范附表D的计算表中直接查的给水设计秒流量。该表可用内插法。2.当计算管段的卫生器具给水当量总数超过GB50015-2003建筑给水排水设计规范附表D的计算表中最大值时,其流量应取最大用水平均秒流量,即。有两条或两条以上具有不同最大用水时卫生器具给水当量平均出流概率的给水支管的给水干管,该管段的最大时卫生器具给水当量平均出流概率按下式计算:式中: 给水干管的卫生器具给水当量平均出流概率;支管的最大用水时卫生器具给水当量平均出流概率;相应支管的卫生器具给水当量总数。(2)
5、集体宿舍、旅馆、宾馆、医院、疗养院、幼儿园、养老院、办公楼、商场、客运站、会展中心、中小学教学楼、公共厕所等建筑热水供应系统的设计秒流量应按下式计算:式中: 计算管段的给水设计秒流量,L/s;计算管段的卫生器具给水当量总数;根据建筑物用途而定的系数,应按下表采用。注:1.如计算值小于该管段上的一个最大卫生器具给水额定流量时,应采用一个最大的卫生器具给水额定流量作为设计秒流量。2.如计算值大于该管段上按卫生器具给水额定流量累加所得流量值时,应按卫生器具给水额定流量累加所得流量值确定。3.有大便器延时自闭冲洗阀的给水管段,大便器延时自闭冲洗阀的给水当量,均以0.5计,计算得到的附加1.10L/s的
6、流量后,为该管段的给水设计秒流量。4.综合楼建筑的值应按加权平均法计算。根据建筑物用途而定的系数值(值)建筑物名称值建筑物名称值幼儿园、托儿所、养老院1.2医院、疗养院、休养所2门诊部、诊疗所1.4集体宿舍、旅馆、招待所、宾馆2.5办公楼、商场1.5客运站、会展中心、公共厕所3学校1.8(3)工业企业的生活间、公共浴室、职工食堂或营业餐厅的厨房、体育场馆运动员休息室、剧院的化妆间、普通理化实验室等建筑热水供应系统的设计秒流量应按式下计算:式中: 计算管段的给水设计秒流量,L/s;同类型的一个卫生器具给水额定流量,L/s;同类型的卫生器具个数;卫生器具的同时给水分数,应按表1-3采用。注:1.如
7、计算值小于该管段上一个最大卫生器具给水定额流量时,应采用一个最大的卫生器具给水额定流量作为设计秒流量。2.大便器自闭式冲洗阀应单列计算,当单列计算值小于1.2L/s时,以1.2L/s计;大于1.2L/s时,以计算值计。表1 工业企业生活间、公共浴室、剧院化妆间、体育馆运动员休息室等卫生器具同时给水分数卫生器具名称同时给水分数/%工业企业生活间公共浴室剧院化妆室体育场馆运动员休息室洗涤盆(池)33151515洗手盆50505050洗脸盆、盥洗槽水嘴60100601005080浴盆50无间隔淋浴器100100100有间隔淋浴器806080608060100大便器冲洗水箱30202020大便器自闭式
8、冲洗阀2222小便器自闭式冲洗阀10101010小便器(槽)自动冲洗水箱100100100100净身盆33饮水器3060303030小卖部洗涤盆5050注:健身中心的卫生间,可采用本表体育场馆运动员休息室的同时给水分数。表2 职工食堂、营业餐厅厨房设备同时给水分数厨房设备名称同时给水分数%厨房设备名称同时给水分数%污水盆(池)50器皿洗涤机90洗涤盆(池)70开水器50煮锅60蒸汽发生器100生产性洗涤机40灶台水嘴30注:职工或学生饭堂的洗碗台水嘴,按比例100%同时给水,但不与厨房用水叠加。表3 实验室化验水嘴同时给水分数化验水嘴名称同时给水分数%科学研究实验室生产实验室单联化验水嘴203
9、0双联或三联化验水嘴3050(4)热水系统的热水循环流量计算。全天供应热水系统的循环流量,按下式计算:式中: 循环流量,L/h;配水管道系统的热损失,W,应经计算确定;初步设计式,可按设计小时耗热量的3%5%采用;配水管道的热水温度差,根据系统大小确定,一般可采用510;热水水密度,kg/L。定时供应热水的系统,应按管网中的热水容量每小时循环24次计算循环流量。9.管网的水力计算(扬程、流速)(1)管网热水流速的确定。热水管道内的流速,宜按下表选用。 热水管道内的流速公称直径DN/mm1520254050流速/(m/s)0.81.01.2(2)热水管道阻力的确定。热水管道的沿程水头损失可按下式
10、计算,管道的计算内径应考虑结垢和腐蚀引起过水断面缩小的因素。式中: 管道单位长度水头损失,kPa/m;管道计算内径,m;热水设计流量,m3/s;海澄-威廉系数,各种塑料管、内衬(涂)塑料;铜管、不锈钢管;衬水泥、树脂的铸铁管;普通钢管、铸铁管。 热水管道的配水管的局部水头损失,宜按管道的连接方式,采用管(配)件当量长度法计算。当管道的管(配)件当量长度资料不足时,可按下列管件的连接状况,按管网的沿程水头损失的百分数取值。a. 管(配)件内径一致,采用三通分水时,取2530;采用分水器时,取15%20%。b. 管(配)件内径略大于管道内径,采用三通分水时,取50%60%;采用分水器分水时,去30
11、%35%。c. 管(配)件内径略小于管道内径,采用三通分水时,取70%80%;采用分水器分水时,去35%40%。(注:螺纹接口的阀门及管件的摩阻损失当量长度可参照GB50015-2003建筑给水排水设计规范附表B选用。) 热水管道上附件的局部阻力可参照以下计算。a. 管道过滤器的局部水头损失,宜取0.01MPa。b. 管道倒流防止器的局部水头损失,宜取0.0250.04MPa。c. 水表的水头损失,应选用产品所给定的压力损失计算。在未确定具体产品时,可按下列情况取用:住宅的入户管上的水表,宜取0.01MPa;建筑物或小区引入管上的水表,宜取0.03MPa。d. 比例式减压阀的水头损失,阀后动水
12、压宜按阀后静水压的80%90%确定。(3) 热水供应系统的回水管管径计算。热水供应系统的回水管管径应通过计算确定,初步设计时,可参照下表确定。 热水回水管管径热水供水管管径/mm20253240506580100125150200热水回水管管径/mm202025324040506580100为了保证各立管的循环效果,尽量减少干管的水头损失,热水供水干管和回水干管均不宜变径,可按其相应的最大管径确定十、加压供水泵(水泵流量)采用加压泵供热水时,应根据系统总的花洒和水龙头数量及同时使用率(居民大约为0.2)来确定最大小时供水量,根据该用水量来选择水泵流量,DN15水龙头流量按0.2L/s,每个花洒
13、流量按0.15L/s计算。水泵扬程根据最不利的用水点来确定水压,一般集中使用的水龙头或花洒应有4m水柱压差。1自动加压泵 它由水泵、气压罐、压力开关组成。工作原理是:气压罐内注满空气,当用水点在用水时,供水管网压力下降,压力开关闭合,水泵启动加压给水。如用水量小于水泵流量,则水泵向气压罐内注水,将空气压缩,当达到压力开关设定的压力值时,水泵停止运行。当用水点在用水时,由于空气的膨胀作用,将气压罐内的水顶出供使用。在供水管网压力下降至压力开关的下限压力值时,压力开关闭合,水泵运行。这种装置能自动运行,且比较经济,但气压罐内的空气会慢慢地随水跑掉,如不及时补充空气,会造成水泵启动频繁,产生噪声,同
14、时损坏压力开关。因此,只能适于家庭及最大小时用水量小于2m3的全天候使用冷、热水的用户。(见图64)2变频加压系统该系统由变频器、控制器、水泵、隔膜气压罐、机架等组成,它由变频器根据供水压力调整水泵马达的电源频率来改变马达的转速,从而达到改变水泵流量的目的,同时可根据供水压力调整水泵的运行台数,从而达到经济和恒压运行的目的。(见图60) 水泵的总流量应大于最大小时用水量的20%。 水泵的台数一般为3台,其中2台型号相同,总流量应约等于最大小时用水量, 另1台可稍少,约为最大小时用水量的20%,以便用水量很少时开启。3加压给水装置由定时器、水泵及水泵控制装置组成。其工作原理是:在规定的用水时间内
15、,水泵启动向供水管网加压供水,它有两种方式: 3.1. 在水泵旁接旁通管,在用水过程中,由于用水量的 变化,使多余的水通过旁通管产生回流,有效防止用水点不用水时或水用量很少时使水泵损坏。调节旁通阀可调节水的回流量。(见图66)3.2. 在供水管的末端设回水管。(见图67)3.3. 水泵扬程选择:采用上行下给供水方式的其水泵扬程选择1015m即可,采用下行上给供水方式的其水泵扬程应进行水头损失计算。在水头损失的基础上再加10m扬程。4.4. 旁通管管径及回水管管径的确定:如果采取旁通回流时,当主管管径DN50时,旁通管管径比供水管管径小2。如采用供水管网末端回流时,回水管管径比主管管径小23。1
16、1.表格(管径大小查询)QDN15DN20DN25DN32DN40DN50DN70(L/h)(L/s)RVRVRVRVRVRVRV18365472900.0050.0100.0150.0200.0250.652.164.427.3911.040.040.070.110.150.180.120.410.831.372.030.020.040.050.070.090.040.120.230.380.560.010.020.030.040.050.010.030.050.090.130.010.030.050.090.13-0.010.030.040.07-0.010.010.020.02-0.01
17、0.010.02-0.010.010.01-0.010.01-0.010.011081261441621800.0300.0350.0400.0450.05015.3720.3726.0432.3639.350.220.250.290.330.362.813.694.695.807.010.111.131.140.160.180.771.011.281.581.900.060.070.080.100.110.180.230.300.360.440.030.040.050.050.060.090.120.150.180.220.030.030.030.040.040.030.030.040.05
18、0.060.020.020.020.020.030.010.010.010.020.020.010.010.010.010.021982162342522700.0550.0600.0650.0700.07547.0055.3164.5874.9085.980.400.440.470.510.548.349.7611.3012.9414.690.200.220.240.250.272.252.633.033.463.920.120.130.140.150.160.520.600.690.790.890.060.070.070.080.090.260.300.340.390.440.050.05
19、0.060.060.060.070.090.100.110.130.030.030.030.040.040.020.020.030.030.040.020.020.020.020.022883063243423600.0800.0850.0900.0950.10097.82110.43123.81137.94152.850.590.620.650.690.7316.5418.5020.5622.7325.000.290.310.330.340.364.404.915.456.016.600.170.180.190.200.211.001.111.231.351.480.090.100.100.
20、110.120.490.550.600.660.730.070.070.080.080.090.140.160.170.190.210.040.040.050.050.050.040.040.050.050.060.020.030.030.030.033964324685045400.1100.1200.1300.1400.150184.94220.10258.31299.58343.910.800.870.941.021.0929.8635.1341.0247.5754.610.400.430.470.510.547.859.2110.6712.2313.890.230.250.280.30
21、0.321.752.052.362.703.060.130.140.150.160.170.861.001.161.321.490.090.100.110.120.130.240.280.330.370.420.060.060.070.070.080.070.080.090.110.120.030.040.040.040.055766126486847200.1600.1700.1800.1900.200391.29441.73495.22551.78611.391.161.231.311.381.4562.1370.1478.6487.6297.090.580.620.650.690.721
22、5.6517.5219.4821.5523.720.340.360.380.400.423.443.844.264.705.160.180.200.210.220.231.681.872.072.282.500.140.150.15 0.160.170.470.520.580.640.700.080.090.090.100.100.130.150.160.180.200.050.050.050.060.0690010801260144016200.2500.3000.3500.4000.450955.291357.621872.622445.553095.151.812.182.542.903
23、.2651.70218.44297.32338.34491.500.911.091.271.451.6336.7552.9372.0494.09119.080.530.640.740.850.957.7610.8814.4918.6523.600.290.350.400.460.523.755.236.958.9011.080.210.260.300.340.391.041.441.902.433.010.130.150.180.200.230.290.400.530.670.830.080.090.110.120.14180019802160234025200.5000.5500.6000.
24、6500.700606.78734.21873.211025.471189.301.811.992.172.352.54147.01177.89211.70248.45288.151.061.171.271.381.4829.1435.2641.9649.2957.110.580.630.690.750.8113.4916.2119.2922.6426.260.430.470.520.560.603.654.345.105.916.780.250.280.310.330.361.001.191.391.611.840.150.170.180.200.2127002880306032403420
25、0.7500.8000.8500.9000.9501365.261553.371753.611965.982190.492.722.903.083.263.44330.78376.36424.87476.33530.721.591.701.801.912.0265.5674.5984.2194.40105.180.860.920.981.041.0930.1434.3038.7243.1448.360.640.690.730.770.827.718.709.7510.8612.100.380.410.430.460.482.082.342.622.913.910.230.240.260.270
26、.29360037803960414043201.0001.0501.1001.1501.200588.06648.33711.55777.71846.802.122.232.332.442.55116.55128.49141.02154.13167.831.151.211.271.321.3853.5959.0864.8470.8777.170.860.900.940.991.0313.4114.7916.2317.7419.310.510.530.560.590.613.533.874.214.584.950.300.320.330.350.36450046804860504052201.
27、2501.3001.3501.4001.450918.84993.821071.741152.601236.392.652.762.862.973.08182.11196.97212.41228.43245.041.441.501.551.611.6783.7390.5697.66105.03112.671.071.121.161.201.2520.9522.6624.4426.2928.200.640.660.690.710.745.345.756.176.607.050.380.390.410.410.44540055805760594061201.5001.5501.6001.6501.
28、7001323.131412.811505.131600.93-3.183.293.393.50-262.23280.01298.36317.30336.821.731.791.841.901.96120.57128.74137.18145.89154.871.291.331.371.421.4630.1732.2234.3336.5138.760.760.790.810.840.877.518.028.559.099.650.450.470.480.500.51630064806660684070201.7501.8001.8501.9001.950356.93377.62398.89420
29、.74443.172.022.072.132.192.25164.11173.62183.40193.45203.761.501.551.591.631.6841.0743.4545.9048.4151.000.890.920.940.970.9910.2210.8210.4312.0512.690.530.540.560.570.59720075607920828086402.0002.1002.2002.3002.400466.19513.98564.09616.54671.322.302.422.532.652.76214.35236.32259.36283.48308.461.721.
30、801.891.982.0653.6459.1464.9170.9477.251.021.071.121.171.2213.3514.7216.1617.6619.230.600.630.660.690.7290009360972010080104402.5002.6002.7002.8002.900728.43787.87849.64913.74980.172.882.993.113.223.34334.92362.25390.65420.12450.672.152.232.322.412.4983.8290.6697.77105.14112.791.271.321.381.431.4820
31、.8722.5724.3426.1728.080.750.780.810.840.8710800111601152011880122403.0003.1003.2003.3003.4001048.93-3.46-284.28514.97548.73583.56619.472.582.662.752.832.92120.70128.88137.33146.00155.081.531.581.631.681.7330.0532.0834.1936.3638.590.900.930.960.991.0212600129601332013680140403.5003.6003.7003.8003.90
32、0656.44694.49733.61773.80815.063.013.093.183.263.35164.28173.81183.60193.65203.981.781.831.88 1.941.9940.9043.2745.7148.2150.781.051.081.121.151.1814400147601512015480158404.0004.1004.2004.3004.400857.39-3.44-214.58225.44236.57247.97259.642.042.092.142.192.2453.4256.1258.8961.7364.631.211.241.271.30
33、1.3316200165601692017280176004.5004.6004.7004.8004.900271.57283.78296.25308.99322.002.292.342.392.442.5067.6170.6473.7576.2980.161.361.391.421.451.4818000183601872019080194405.0005.1005.2005.3005.400335.27348.82362.63376.71391.062.552.602.652.702.7583.4686.8490.2793.7897.351.511.541.571.601.63198002
34、01602052020880212405.5005.6005.7005.8005.900405.68420.57435.72451.14466.842.802.852.902.953.00100.99104.70108.47112.31116.221.661.691.721.751.7821600219602232022680230406.0006.1006.2006.3006.400482.79499.02515.52532.28549.313.063.113.163.213.26120.19124.23128.33132.51136.751.811.841.871.901.93234002
35、37602142024480248406.5006.6006.7006.8006.900566.61584.18602.02620.12-3.313.363.413.46-141.05145.43149.87154.38158.951.961.992.022.052.0825200255602592026280266407.0007.1007.2007.3007.400163.59168.30173.07177.91182.822.112.142.172.202.2327000273602772028080284407.5007.6007.7007.8007.900187.79192.8419
36、7.94203.12208.362.262.292.322.352.3828800291602952029880302408.0008.1008.2008.3008.400213.67219.04224.49229.99235.572.412.442.472.502.5330600309603132031680320408.5008.6008.7008.8008.900241.21246.92252.70258.54264.452.562.592.622.652.6832400345003492035280356409.0009.1009.2009.3009.400270.42276.47282.58288.75295.002.712.742.772.802.8334200345603492035280356409.5009.6009.7009.8009.900301.31307.68314.133