水輪機(jī)運(yùn)轉(zhuǎn)特性曲線的繪制

1、水輪機(jī)運(yùn)轉(zhuǎn)特性曲線的繪制1）基本資料轉(zhuǎn)型式：HL240型及模型綜合特性曲線轉(zhuǎn)輪直徑 Di=4.5m,n=100.rmin特征水頭：H max - 38.0m， H min = 34.0m， H r =36.0m水輪機(jī)安裝高程處海拔方程i =150m效率修正值厶=1.6%2）等效率曲線計(jì)算與繪制由于電站水頭變化范圍小現(xiàn)取3個(gè)水頭，即Hmax = 38.0m，Hmin = 34.0m， H r =36.0m列表如下HL240型水輪機(jī)等效率曲線計(jì)算H max = 38.0mFn1min = 73.00mFN =46.53壯(MW )H r = 36.0mFn 但=75mFN =42.91g (MW

2、)H min = 34.0mFn1min = 77.17mFN =39.381Q1 (MW )nm(%)FQ1嘆n =n +mvnN(mw)m(%)FQ1吆n =n +mN(mw)nm(%)FQ1吆n =n + mvnN(mw)870.8488.634.61870.8588.632.31870.8788.630.35880.8789.636.25880.8989.629.14880.9289.632.46890.9290.638.76890.9490.631.16890.9690.634.25900.9691.640.89900.9791.632.53901.0091.636.07911.00

3、92.643.06911.0292.634.27911.0692.637.20911.2192.652.10911.2192.641.54911.2292.644.49901.2391.652.39901.2491.642.16901.2591.645.09891.2690.653.08891.2790.642.67891.2890.645.67881.2989.653.75881.3089.642.03881.3089.645.87871.3288.654.38871.3288.642.52871.3488.646.755%出力限制到線上的點(diǎn)89.21.2490.845.52901.2391

4、.640.9790.41.239246.753）出力限制線繪制計(jì)算出1、H Hr時(shí)，數(shù)值直線2、Hmin H Hr 連接（HNQ 與 Hmin Nmin 見附圖 14）等吸出高曲線的計(jì)算與繪制：V1吸出高度計(jì)算公式為Hs =10（一 *）H900式中氣蝕系數(shù)修正值厶二由H =36m查得.u = 0.032等析出高度計(jì)算表H mn rjmi n)CTQ1 m3/sNkwcr + Act( +g)HHs38730.220.780.0300.259.50.3330.210.8529.60.249.120.7130.201.0036.20.238.741.0930.201.2243.40.2311.4

5、-1.5670.210.249.120.7131.31450.220.259.50.3331.3550.230.269.88-0.0470.241.370.2710.26-0.4271.393477.170.220.7850.0380.2588.7721.0610.210.84270.2488.4231.410.200.9631.650.2388.0921.7410.200.2389.0440.7891.27541.40.210.2488.4321.4011.31420.220.2588.7721.0611.3642.50.230.2689.1120.7210.241.3742.650.278

6、9.4520.381.3942.836750.220.790.0320.2529.0720.7610.210.8324.80.2428.7121.1210.200.9529.10.2328.3521.4810.201.29390.2328.3561.4770.210.2428.7121.1211.32539.50.220.2529.0720.7611.35539.90.230.2629.4320.4010.241.36840.10.2729.7920.0411.38540.3II2利用表計(jì)算結(jié)果，作每個(gè)水頭下的N=f（QJ輔助曲線（見附圖2）。將各Qi值的出力從圖中查出填入表中。3根據(jù)表中對(duì)應(yīng)

7、的Hs和N，繪制各水頭下Hs二f （N）的輔助曲線（見附圖4）繪制等吸出高曲線（見附圖4）六、蝸殼的設(shè)計(jì)1）、蝸殼型式選擇由于本水電水頭高度小于40m,所以采用混凝土蝸殼2）、蝸殼主要參數(shù)的確定1斷面形狀的確定由于水輪機(jī)為中型，因此混凝土蝸殼的斷面做成平頂梯形，以便施工見笑其徑向尺寸，降低廠房的土建投資根據(jù)水電站規(guī)模本電站采用平頂梯形斷面混凝土蝸殼， 由水力機(jī)械附表 以及附表二查得 HL240型水輪機(jī) Da=6350mm,lb=5550mm b/a取為1.5 ， 取為 142蝸殼包角;：0的選擇混凝土蝸殼包角；0通常采用180 270 ,故選擇0=2703蝸殼進(jìn)口斷面的平均速度VcVc根據(jù)水輪

8、機(jī)設(shè)計(jì)Hr，可從水輪機(jī)設(shè)計(jì)水頭從 水電站圖2-8中的經(jīng)驗(yàn)曲線查取，查得Vc -5m s3）.蝸殼的水力計(jì)算1確定進(jìn)口斷面尺寸進(jìn)口斷面的面積為Vc3600Vc125.63 2703600 4.92二 18.84 m2根據(jù)幾何關(guān)系確定進(jìn)口斷面尺寸如下 進(jìn)口斷面面積應(yīng)滿足下式且b D1 =0.365mftg丄b =1.6a解上面方程組得 bb =1.6，a=3.56m, b=5.33m, m=5.73m由前面查表已知Ca=6350mm,E=5550mm所以嘉=Da .；2 = 3.175m,厲=D 2 = 2.775m ,故 Rq =嘉 a =3.175 3.56 = 6.735m表73中間斷面尺寸的確定斷面aibiR(m)Fi(m2)巒）03.565.336.37519.1227010.867.334.0352.2130.2120.6886.193.8631.6423.1630.5165.0383.6921.1315.9640.3443.8923.5190.689.6050.1722.7463.3470.3094.36頂角的變化規(guī)律采用直線軌跡，采用圖解法來求得R八的關(guān)系過程見下表及附繪制蝸殼平面單線圖，選定叫（每隔30選一個(gè)）有公式尺=+2片計(jì)算出相應(yīng)RI q 9.,_而吒冷360T0.15押，其進(jìn)口寬度R7W查圖得0