0003. 双纽线流量计的计算公式.doc

双纽线流量计的计算公式【计算公式】GS = 1.0998*d2*sqrt(1000*p)柴油机试验测试与分析实用手册（一. 柴油机整机试验） 学苑出版社 2000.10 第1版，P194。柴油机试验测试与分析实用手册（二. 柴油机主要部件的试验、检测诊断仪器及试验室设计）内燃机与动力装置2011年增刊。 【参数说明】. 空气流量GS发动机增压器压气机的空气流量，kg/s. 流量系数 取常数0.99，无量纲. 节流装置前后的压差、压气机前真空度ppa：环境压力，kPap1：直管段处的绝对压力，pa p1，kPap = pa - p1 0，kPa。在许多的情况下，通过直接读取p/ (mmH2O) 值来获得p值；此时，p = 0.009807p/。. 膨胀校正系数 K：空气绝热指数，取常数1.41，无量纲 = sqrt ( (pa/p) * (K/(K-1) * ( (P1/Pa)(2/K) - (P1/Pa)(1+1/K) ) )表1 “p/ (mmH2O) ”对照表序号01234567891011pa (kPa)100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00p1 (kPa)100.0099.99099.01998.03997.05896.07795.09694.11693.13592.15491.17490.193p (kPa)00.00980.98071.96142.94213.92284.90355.88426.86497.84568.82639.8070p/ (mmH2O)011002003004005006007008009001000pa/pInf10197101.9750.9833.9925.4920.3916.9914.5712.7511.3310.20K1.4101.4101.4101.4101.4101.4101.4101.4101.4101.4101.4101.410K/(K-1)3.4393.4393.4393.4393.4393.4393.4393.4393.4393.4393.4393.439p1/pa1.000 1.000 0.990 0.980 0.971 0.961 0.951 0.941 0.931 0.922 0.912 0.902 (p1/pa)(2/K)1.000 1.000 0.986 0.972 0.959 0.945 0.931 0.918 0.904 0.891 0.877 0.864 (p1/pa)(1+1/K)1.000 1.000 0.983 0.967 0.950 0.934 0.918 0.902 0.886 0.870 0.854 0.838 (上2)-(上1)0.0000 0.0000 0.0028 0.0056 0.0083 0.0109 0.0135 0.0160 0.0185 0.0209 0.0233 0.0255 2NaN0.99990.98960.97910.96870.95830.94780.93740.92700.91650.90610.8956NaN0.99990.99480.98950.98420.97890.97360.96820.96280.95730.95190.9464应用Matlab 7.0分步骤求解值： % 测量值：pa、p/ % pa = 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00 % (kPa) deltapPrime = 0, 1, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 % p/ ，(mmH2O)%1% 计算：pa/p %1% deltap = 0.009807 * deltapPrime ; % (kPa) p1 = pa - deltap ; % (kPa) paDividedBydeltap = pa ./ deltap ; % (无单位) deltap, p1, paDividedBydeltap %2% 计算：K/(K-1) %2% K = 1.41 % (无单位) KDivideByK_1 = K/(K-1) % (无单位)%3% 计算：(P1/Pa)(2/K) - (P1/Pa)(1+1/K) %3% p1DividedBypa = p1 ./ pa ; % (无单位) power1 = p1DividedBypa . (2/K) ; % (p1/pa)(2/K)，(无单位) power2 = p1DividedBypa . (1+1/K) ; % (p1/pa)(1+1/K)，(无单位) power1_power2 = power1 - power2 ; % (p1/pa)(1+1/K) - (p1/pa)(1+1/K)，(无单位) p1DividedBypa, power1, power2, power1_power2 % (无单位)%4% 计算：2 = (pa/p) * (K/(K-1) * ( (P1/Pa)(2/K) - (P1/Pa)(1+1/K) ) %4% product = paDividedBydeltap .* KDivideByK_1 .* power1_power2 % (无单位)%5% 计算：最终值 %5% result = sqrt (product) % (无单位). 节流元件孔径d双纽线流量计的圆管段的内径，m. 节流装置前的气体密度t：节流元件前的空气温度， = 1.293 * (p1/101.333) * (273/(273+t) ，kg/m3表2 “p/ (mmH2O) ”对照表序号0123456789101112pa (kPa)101.333100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00p/ (mmH2O)0011002003004005006007008009001000t ()025.025.025.025.025.025.025.025.025.025.025.025.0 (kg/m3)1.29301.16891.16881.15751.14601.13461.12311.11161.10021.08871.07721.06581.0543应用Matlab 7.0分步骤求解值： % 测量值：pa、p/、t % pa = 101.333, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00 % (kPa) deltapPrime = 0, 0, 1, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 % p/ ，(mmH2O) t = 0.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0 % (kPa)%1% 计算：p1 %1% deltap = 0.009807 * deltapPrime ; % (kPa) p1 = pa - deltap ; % (kPa)%2% 计算： %2% result = 1.293 * (p1/101.333) .* (273./( 273+t) % (kg/m3)【GS之Matlab计算】表3 “p/ (mmH2O) GS”对照表序号01234567891011pa (kPa)100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00p/ (mmH2O)011002003004005006007008009001000t ()25.025.025.025.025.025.025.025.025.025.025.025.0Gs (kg/s)NaN0.03690.36490.51080.61910.70750.78260.84820.90630.95831.00521.0478. 应用Matlab 7.0分步骤求解GS的值 % 常量、常数 % coefficient_Gs = 1.0998 ; % (无单位) alpha_Gs = 0.99 ; % (无单位) d_Gs = 0.100 ; % 安装在增压器压气机进口处的空气流量计的直管段内径，是测量值，取决于具体的流量计 (m) K_Gs = 1.41 ; % (无单位)% 测量值：pa、p/、t % pa_Gs = 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00 ; % (kPa) deltapPrime_Gs = 0, 1, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 ; % p/ ，(mmH2O) t_Gs = 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0, 25.0 ; % ()%1% 计算：p、p1 %1% deltap_Gs = 0.009807 * deltapPrime_Gs ; % (kPa) p1_Gs = pa_Gs - deltap_Gs ; % (kPa)%2% 计算：膨胀校正系数(无单位) %2% epsilon_Gs_ProductTerm1 = pa_Gs ./ deltap_Gs ; % (无单位) epsilon_Gs_ProductTerm2 = K_Gs / ( K_Gs-1) ; % (无单位) epsilon_Gs_ProductTerm3 = (p1_Gs ./ pa_Gs) . (2/K_Gs) - (p1_Gs ./ pa_Gs) . (1+1/K_Gs) ; % (无单位) epsilon_Gs = sqrt (epsilon_Gs_ProductTerm1.*epsilon_Gs_ProductTerm2.*epsilon_Gs_ProductTerm3) ;%3% 计算：空气密度 %3% gamma_Gs = 1.293 * (p1_Gs/101.333) .* ( 273./(273+t_Gs) ) ; % (kg/m3)%4% 计算：发动机进气流量Gs %4% Gs_ProductConstant = coefficient_Gs * alpha_Gs * d_Gs2 ; % Gs_ProductConstant = 1.0998*d2 Gs = Gs_ProductConstant * epsilon_Gs .* sqrt(1000*gamma_Gs.*deltap_Gs) ; % (kg/s) epsilon_Gs, gamma_Gs, Gs . 在Matlab 7.0中编写“M-函数”，以此求解GS的值 . 在Matlab 7.0中，选择“File | New | M-File”菜单项，见图1。于是，弹出图2。. 在图2的代码编辑窗口中，手动键入如下代码function epsilon_Gs, gamma_Gs, Gs = Gs_Air (d_Gs, pa_Gs, deltapPrime_Gs, t_Gs)% 输入量d_Gs：安装在增压器压气机进口处的空气流量计的直管段内径，是测量值，取决于具体的流量计；m% 输入量pa_Gs：环境压力，kPa% 输入量deltapPrime_Gs：空气流量计的直管段处的真空度，mmH2O% 输入量t_Gs：空气流量计的直管段处的空气温度，图1 Matlab 7.0的“File | New | M-File”菜单项图2 Matlab 7.0的“M-函数”编辑器% 输出量epsilon_Gs：膨胀校正系数 ，无量纲% 输出量gamma_Gs：节流装置前的气体密度 ，kg/m3% 输出量Gs_Air：进气流量，kg/s% 常量、常数 %coefficient_Gs = 1.0998 ; % (无单位)alpha_Gs = 0.99 ; % (无单位)K_Gs = 1.41 ; % (无单位)%1% 计算：p、p1 %1%deltap_Gs = 0.009807 * deltapPrime_Gs ; % (kPa)p1_Gs = pa_Gs - deltap_Gs ; % (kPa)%2% 计算：膨胀校正系数(无单位) %2%epsilon_Gs_ProductTerm1 = pa_Gs ./ deltap_Gs ; % (无单位)epsilon_Gs_ProductTerm2 = K_Gs / ( K_Gs-1) ; % (无单位)epsilon_Gs_ProductTerm3 = (p1_Gs ./ pa_Gs) . (2/K_Gs) - (p1_Gs ./ pa_Gs) . (1+1/K_Gs) ; % (无单位)epsilon_Gs = sqrt (epsilon_Gs_ProductTerm1.*epsilon_Gs_ProductTerm2.*epsilon_Gs_ProductTerm3) ;%3% 计算：空气密度 %3%gamma_Gs = 1.293 * (p1_Gs/101.333) .* ( 273./(273+t_Gs) ) ; % (kg/m3)%4% 计算：发动机进气流量Gs %4%Gs_ProductConstant = coefficient_Gs * alpha_Gs * d_Gs2 ; % Gs_ProductConstant = 1.0998*d2Gs = Gs_ProductConstant * epsilon_Gs .* sqrt(1000*gamma_Gs.*deltap_Gs) ; % (kg/s). 在Matlab 7.0中，选择“File | Save”菜单项，于是弹出图3。图3 “File | Save”菜单项的弹出对话框. 保持此处的默认文件夹，将其保存为“D:MathworksworkGs_Air.m”。. 于是，图2变化为图4（见下）。图4 “D:MathworksworkGs_Air.m”文件. 在Command Window（命令窗口）中，键入下述代码% 测量值：pa、p/、t % d_Gs = 0.100 ; % 安装在增压器压气机进口处的空气流量计的直管段内径，是测量值，取决于具体的流量计 (m) pa_Gs = 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.00, 100.