某建筑暖通空調(diào)工程的水系統(tǒng)水力計算過程案例1.1空調(diào)水系統(tǒng)的水力計算(1)該建筑空調(diào)水系統(tǒng)采用機(jī)械循環(huán)雙管下供下回異程式系統(tǒng)。確定系統(tǒng)最不利環(huán)路，依次對各管段進(jìn)行編號；(2)根據(jù)各立管流量確定各管段總流量，標(biāo)注各管段的長度；(3)根據(jù)流量及推薦平均比摩阻60~120Pa/m，確定各管段的比摩阻，管徑和流速。根據(jù)該表查取比摩阻和流速時需用插值法；(4)確定沿程阻力損失。確定比摩阻后將所得比摩阻乘以相應(yīng)管長即為該管段的沿程阻力損失ΔPy=RL(Pa)；(5)確定局部阻力系數(shù)ζ，根據(jù)各管段的實(shí)際情況，再根據(jù)各個局部阻力部件的ζ值，確定各管段的局部阻力系數(shù)∑ζ；確定局部阻力損失。由流速確定動壓頭ΔPd=ρv2/2，其與∑ζ的乘積即為該管段的局部損失，ΔPj=ΔPdΣξ(Pa)；(7)確定總阻力損失。沿程阻力損失與局部阻力損失之和即為該管段的總阻力損失：ΔP=ΔPy+ΔPj=RL+ΔPj(9-1)式中：ΔP——計算管段的壓力損失，Pa；ΔPy——計算管段的沿程損失，Pa；ΔPj——計算管段的局部損失，Pa；R——每米管段的沿程損失，Pa/m；L——管段長度，m。(8)把環(huán)路中各管段的阻力損失求和確定最不利環(huán)路的總阻力損失?？傋枇p失必須小于資用壓頭，而且應(yīng)該留有資用壓頭5%以上的富裕值；(9)校核各環(huán)路的不平衡率；(10)對其他各立管進(jìn)行水力計算；1.2空調(diào)水系統(tǒng)水力計算實(shí)例以立管1樓層1為例，進(jìn)行空調(diào)水系統(tǒng)水力計算，首先繪制軸測圖，并進(jìn)行管段編號，標(biāo)注各管段的長度及其負(fù)荷，結(jié)果如下圖：圖9-1立管1一層水系統(tǒng)圖軸測圖確定最不利環(huán)路，根據(jù)管道流量和比摩阻范圍選取管段管徑，再根據(jù)所選管徑求出該管段實(shí)際比摩阻和水的流速，并進(jìn)行阻力計算。其中最不利環(huán)路為立管6樓層4，其計算結(jié)果如下：表9.1空調(diào)水系統(tǒng)立管1樓層1最不利環(huán)路計算編號Q(W)G(kg/h)L(m)D(mm)υ(m/s)R(Pa/m)ΣξΔPy(Pa)ΔPj(Pa)ΔP(Pa)FG16226010708.725.91650.82142.4828416711513FG2309545324.0914.3500.67134.011.119162472164FG3284764897.872.3500.62114.380.126319282FG4259984471.665.22500.5696.280.150216518FG5233084008.982.26400.84289.90.165636691FG6206183546.35.24400.75229.360.11202281229FG7179283083.622.26400.65175.80.139821419FG8152382620.945.24320.76289.760.11518291547FG9125482158.262.26320.62200.320.145319472FG1098581695.585.24320.49127.10.166612678FG1171681232.92.26250.56216.890.149015506FG124478770.224.98250.3590.113.1449187636E32985513.427.8200.41181.265.514144046641881FH16226010708.725.46650.82142.482.57778391616FH2309545324.0914.85500.67134.011.119902472237FH3284764897.872.1500.62114.380.124119260FH4259984471.665.42500.5696.280.152216537FH5233084008.982.06400.84289.90.159836634FH6206183546.35.44400.75229.360.11247281275FH7179283083.622.06400.65175.80.136321384FH8152382620.945.44320.76289.760.11575291604FH9125482158.262.06320.62200.320.141319433FH1098581695.585.44320.49127.10.169112703FH1171681232.92.06250.56216.890.144715463FH124478770.224.89250.3590.111.644197537由上可知最不利環(huán)路阻力為63218Pa，接著對立管1樓層1其余管段進(jìn)行水力計算，并平衡阻力。計算結(jié)果如下表：表9.2空調(diào)水系統(tǒng)立管1樓層1水力計算編號Q(W)G(kg/h)L(m)D(mm)υ(m/s)R(Pa/m)ΣξΔPy(Pa)ΔPj(Pa)ΔP(Pa)不平衡率F634.06500.68136.931.555634590116.70%F484.68500.64121.780.1570205900.00%F324.09500.6107.510.1440184580.00%FG16248844280.053.26500.5488.640.1289153040.00%F759.72400.72211.640.120562620820.00%F434.22400.57138.380.1584166009.90%F634.36500.68136.931.559734594216.70%F484.38500.64121.780.1533205540.00%F324.34500.6107.510.1467184850.00%FH16248844280.053.06500.5488.640.1272152860.00%F759.97400.72211.640.121092621350.00%F433.97400.57138.380.1550165669.90%E12690462.6814.56200.37149.4382176305513272725.70%E22690462.6814.56200.37149.4382176305513272724.00%E41493256.812.32150.35198.627.52448304723292021.40%E52690462.6814.56200.37149.4382176305513272727.90%E62690462.6814.56200.37149.4382176305513272729.30%E72690462.6814.56200.37149.4382176305513272733.80%E82690462.6814.56200.37149.4382176305513272734.90%E92690462.6814.56200.37149.4382176305513272738.00%E102690462.6814.56200.37149.4382176305513272739.50%E112478426.2214.97200.34128.481922404684239023.10%E122478426.2214.97200.34128.481922404684239023.90%E131873322.1610.36200.2676.8812797304013119735.30%E1478931357.618.06250.61260.177.2470031351360500.00%E1579061359.837.76250.61260.987202631318333447.50%E163967682.3211.53250.3172.071083140474413050.00%E175118880.31.57250