孔板流量计算公式.docx

1、孔板流量计算公式孔板流量计的测定与计算在孔板流量计的前后端测出压差后可按以下两种方法进行计算； （一）、可按公式计算出瓦斯流量。计算公式：Q 混=Kb（h）1/2pT （1）Q 纯 = Q 混 X式中：Q 混抽放的瓦斯混合量，m3/min ；Q 纯抽放的瓦斯纯量， m3/min ；K实际孔板流量特性系数，计算见（2）式； b瓦斯浓度校正系数，计算见（3）式； p气压校正系数，计算见（4）式； T温度校正系数，计算见（5）式； h在孔板前后端所测之压差，mmH2O； X混合气体中瓦斯浓度，%。K=189.76a0mD2 （2）式中：a0标准孔板流量系数；m=（d1/D）2m截面比；D管道直径，米

2、； d1孔板直径，米；b=1/（10.00446X）1/2 （3）p=（PT/760）1/2 （4）式中：PT孔板上风端测得的绝对压力，mmHg；PT=测定当地压力（mmHg）+该点管内正压（正）或负压（负）（mmH2O）/13.6760标准大气压，mmHg；T=293/（273+t）1/2 （5）式中：t瓦斯管内测点温度，；293标准绝对温度，；四寸管路 d1=49.50mmD=98.28mm则：m=0.2536 查（表一）得 a0=0.6327K=0.3001六寸管路 d1=74.68mmD=151.20mm则：m=0.2439 查（表一）得 a0=0.6294K=0.6718二）、在计算

3、过程中为加快计算速度，可把公式中的各项数值表格化，查表得出 b 、 p、T。瓦斯浓度校正系数 b 值表二；0 1 2 3 41.001.021.041.071.101.131.161.201.241.001.021.051.071.101.131.171.211.251.001.021.051.081.101.141.171.211.251.001.031.051.081.111.141.171.221.265 6 7 8 91.0091.0321.0581.0851.1161.1481.1821.2221.261.0111.0351.0601.0881.1191.1511.1861.2251

4、.261.011.031.061.091.121.1541.1901.2291.271.0011.0401.0661.0951.1251.1581.1941.2341.2781.3281.011.041.061.091.121.1621.1981.2381.281.0211.0451.0711.1001.1311.1641.2021.2431.28瓦斯浓度(%)01020304050607080901007160394371.291.291.301.301.311.311.321.331.332728384491.344气压校正系数p值表三；压力(mmHg)p压力(mmHg)p压力(mmHg)

5、1500.442900.61743015542950.6234351600.453000.62944016523050.6334451700.453100.63945017583150.6434551800.463200.64946018563250.6544651900.473300.65947019523350.6634752000.483400.669480p压力(mmHg)p压力(mmHg)p0.7525700.8667100.9670.7565750.8707150.9700.7615800.8747200.9730.7655850.8787250.9770.7695900.8817

6、300.9800.7745950.8867350.9840.7786000.8897400.9870.7826050.8927450.9900.7866100.8967500.9930.7916150.9007550.9970.7946200.9037601.00020503450.6744850.7996250.9077651.0032100.483500.6784900.8036300.9107701.00621583550.6834950.8076350.9147751.0092200.493600.6895000.8116400.9187801.01322533650.6935050.

7、8156450.9227851.0162300.503700.6985100.8196500.9257901.01923503750.7025150.8236550.9287951.0232400.503800.7075200.8276600.9328001.02624563850.7125250.8316650.9358051.0292500.513900.7165300.8356700.9398101.03125533950.7205350.8396750.9428151.0342600.514000.7255400.8436800.9468201.03726594050.7295450.

8、8476850.9498251.0402700.524100.7345500.8506900.9538301.04327554150.7395550.8546950.9568351.0472800.534200.7435600,8587000.9608401.05028524250.7485650.8627050.9638451.0530.5380.5440.552温度校正系数T值表四；温度012345678940302010 0 -0 -1 0 -2 0 -3 0 -4 0096809831000101710351035105610761098112209660982099810161034

9、103710581078109911230964098009971014103310391059108011031126096309790995101210321041106110831105112909610977099310101029104310631085110811310960097509921008102710451066108611091133095809740990100710251047106810891115113909570972098810051023104910701091111511390955097109871003102110521072109411171141

10、0954096909851001101910541074109511191143i . DU254mm、llL 蒲mmdlnl27mm、m 料、 ls啡冲 30mmH2O、30% x-山Etl 1.01X105Pa 咂牙耳 ls007Mpa、团弩前岡冲 20oc、?耦-田AnQgDu*b*(Ah)98*136)607*10698*1362326mmHg- 6PU0.556 51 - 6TU0.983 淫 Q8ioHO019*lo74*30265566983UO06Irn3、minQ 游H Q8io*XHOo61*30%HO0183 r3n5举例）YD-2 型孔板流量计的应用与计算孔板流量计用以

11、测定瓦斯管路中的瓦斯流量（如下图）。一、 抽放瓦斯管路中孔板流量计的安装与使用：（1）、在抽放瓦斯管路中安装孔板时，孔板的孔口必须与管道同心，其端面与管路轴线垂直，偏心度1；（2）、安装孔板的管道内壁，在孔板前后距离 2D 的范围 内，不应有凸凹不平，焊缝和垫片等。（3）、孔板流量计的上游（前端），管道直线长度20D， 下游（后端）长度10D；（4）、要经常清理孔板前后的积水和污物，孔板锈蚀要更 换；（5）、抽放瓦斯量有较大变化时，应根据流量大小更换相 应的孔板。二、 应用孔板流量计与计算管道内的瓦斯流量时，必须同 时测量的参数：（1）、孔板前后端的压差值（h）；（2）、测量地点的大气压力（P

12、D）；（3）、管道内的气体压力（PG），D 正压或负压；（4）、管道内的气体温度（t）;（5）、管道内的瓦斯浓度（x）。三、 抽放的混合瓦斯量计算： QH=9.81-1/2Kb（h）1/2TP 式中：QH 抽放的混合瓦斯量，m3/min;KH 孔板系数，取实际校正值；0.3072b 瓦斯浓度校正常数；b=1/（1-0.00446x） 1/2x 混合瓦斯中的瓦斯浓度，%； h 孔板前后端压差；T 温度校正系数；T=293/（273+t） 1/2t 管道内的气体温度，；PD 测量地点的大气压力；PG 观测点管道内的压力，正压取(+),负压取(-),Kpa;101.325 标准大气压，Kpa。四、

13、抽放的纯瓦斯量计算 Qc=QHX/100 式中 Qc 抽放的纯瓦斯量，m3/min; 采面 钻场孔板测定数据记录表年 月时间钻场()孔板 前后 端的 压差 h(KPa)管道内的气体压力PG(KPa)测量 地点 的大 气压 力 PD (Kpa)管道内的气体温度(t)管道内的瓦斯浓度x(%)备注日班测定时间计算公式：QH=9.81-1/2Kb(h)1/2TP=9.81-1/2*0.3072*(1-0.00446)-1/2*( h)1/2* 293/(273+t) 1/2* (PD PG)/101.3251/2管道内的气体压力 PG 负压取负值；表一）实际孔板流量特性系数K 值表管径D ( mm )

14、m a 0K0.050.10.150.20.250.30.350.40.450.50.550.60.650.715a 00.61550.61920.62570.63350.64260.65320.66540.68150.69920.71920.74060.76730.79610.8223K0.00130.00260.00400.00540.00690.00700.00990.01180.01340.01540.01740.01970.02210.024620a 00.61510.61880.62520.63300.64230.65280.66470.68080.69840.71840.7398

15、0.76640.79530.8218K0.00230.00470.00710.00960.01220.01250.01770.02070.02390.02730.03090.03490.03930.043725a 00.61370.61840.62470.63250.64170.65240.66400.68010.69760.71760.73900.76550.79450.8215K0.00370.00730.01110.01500.01900.02320.02750.03220.03710.04250.04810.05440.06120.068138a 00.61370.61730.6234

16、0.63130.64020.65120.66240.67830.69540.71540.73710.76330.79230.8208K0.00840.01690.02560.02360.03290.04250.05250.06340.07480.08700.10010.11450.13010.146450a 00.61280.61620.62210.62930.63870.64920.66070.67640.69340.71340.73500.76100.79000.8200K0.01450.02920.03330.04870.06330.07990.09720.11590.13550.156

17、70.17930.20410.23110.259875a 00.61090.61400.61960.62610.63570.64600.65740.67270.68920.70920.73100.75650.78580.8185K0.03060.06550.09920.13370.16960.206220.24560.28720.33100.37850.42920.48450.54520.6116100a 00.60900.61170.61700.62380.63270.64280.65410.66900.68500.70500.72700.75200.78150.8170K0.05780.1

18、1610.17550.23660.30010.35470.42310.49650.57360.65760.74610.84360.95130.0726125a 00.60780.61050.61600.62230.63100.64110.65240.66750.68350.70320.72520.75000.77940.8145K0.09010.18100.27400.36900.46770.57030.67700.79170.91201.02451.18261.33431.50211.6905150a 00.60670.60930.61500.62090.62940.63940.65060.

19、66600.68200.70150.72350.74800.77730.8120K0.12930.26020.39390.53020.67180.81900.97221.13741.31031.49761.69901.91622.15722.4268175a 00.60550.60810.61340.61950.62770.63770.64880.66450.68050.69980.72180.74600.77510.8095K0.17600.35340.53470.72000.91201.11181.31971.54471.78002.03342.30712.60122.92793.2756

20、200a 00.60430.60690.61190.61800.62600.63600.64700.66300.67900.69800.72000.74400.77300.8070K0.22940.46070.69790.93821.18791.44831.71892.01302.31932.64913.00583.38843.81384.2651225a 00.60350.60590.61090.61720.62550.63550.64650.66220.67820.69720.71900.74300.77170.8057K0.28990.58120.88041.18581.50231.83

21、152.17382.54462.93183.34893.79904.28264.81885.3892250a 00.60270.60500.61000.61650.62500.63500.64600.66150.67750.69650.71800.74200.77050.8045K0.35750.71750.08521.46231.85312.25932.68163.13823.61594.13034.68355.28015.93986.6434275a 00.60180.60400.60900.61570.62450.63450.64550.66080.67680.69580.71700.74100.76930.8033K0.43180.86391.31091.77102.24062.73163.24223.79324.37064.99265.66636.38037.17608.0264300a 00.60100.60300.60800.61500.62400.63400.64500.66000.67600.69500.71600.74000.76800.8020K0.51320.02981.55762.10062.66423.24833.85554.50875.19535.93476.72557.58288.52559.5366