水轮机运转特性曲线的绘制

水轮机运转特性曲线的绘制1）基本资料转型式：HL240型及模型综合特性曲线转轮直径Di=4.5m,n=100.rmin特征水头：Hmax-38.0m，Hmin=34.0m，Hr=36.0m水轮机安装高程处海拔方程i=150m效率修正值厶=1.6%2）等效率曲线计算与绘制由于电站水头变化范围小现取3个水头，即Hmax=38.0m，Hmin=34.0m，Hr=36.0m列表如下HL240型水轮机等效率曲线计算Hmax=38.0mFn1min=73.00mFN=46.53壮(MW)Hr=36.0mFn但=75mFN=42.91g(MW)Hmin=34.0mFn1min=77.17mFN=39.381Q1(MW)nm(%)FQ1叹n=n+mvnN(mw)^m(%)FQ1吆n=n+mN(mw)nm(%)FQ1吆n=n+mvnN(mw)870.8488.634.61870.8588.632.31870.8788.630.35880.8789.636.25880.8989.629.14880.9289.632.46890.9290.638.76890.9490.631.16890.9690.634.25900.9691.640.89900.9791.632.53901.0091.636.07911.0092.643.06911.0292.634.27911.0692.637.20911.2192.652.10911.2192.641.54911.2292.644.49901.2391.652.39901.2491.642.16901.2591.645.09891.2690.653.08891.2790.642.67891.2890.645.67881.2989.653.75881.3089.642.03881.3089.645.87871.3288.654.38871.3288.642.52871.3488.646.755%出力限制到线上的点89.21.2490.845.52901.2391.640.9790.41.239246.753）出力限制线绘制计算出1、HHr时，数值直线2、HminHHr连接（H「NQ与HminNmin见附图14）等吸出高曲线的计算与绘制：V1吸出高度计算公式为Hs=10（一*）H900式中气蚀系数修正值厶二由H=36m查得.u=0.032等析出高度计算表Hmn"rjmin)CTQ1m3/sNkwcr+Act(▽+g)HHs38730.220.780.0300.259.50.3330.210.8529.60.249.120.7130.201.0036.20.238.741.0930.201.2243.40.2311.4-1.5670.210.249.120.7131.31450.220.259.50.3331.3550.230.269.88-0.0470.241.370.2710.26-0.4271.393477.170.220.7850.0380.2588.7721.0610.210.84270.2488.4231.410.200.9631.650.2388.0921.7410.200.2389.0440.7891.27541.40.210.2488.4321.4011.31420.220.2588.7721.0611.3642.50.230.2689.1120.7210.241.3742.650.2789.4520.381.3942.836750.220.790.0320.2529.0720.7610.210.8324.80.2428.7121.1210.200.9529.10.2328.3521.4810.201.29390.2328.3561.4770.210.2428.7121.1211.32539.50.220.2529.0720.7611.35539.90.230.2629.4320.4010.241.36840.10.2729.7920.0411.38540.3II2利用表计算结果，作每个水头下的N=f（QJ辅助曲线（见附图2）。将各Qi值的出力从图中查出填入表中。3根据表中对应的Hs和N，绘制各水头下Hs二f（N）的辅助曲线（见附图4）绘制等吸出高曲线（见附图4）六、蜗壳的1）、蜗壳型式选择由于本水电水头高度小于40m,所以采用混凝土蜗壳2）、蜗壳主要参数的确定1断面形状的确定由于水轮机为中型，因此混凝土蜗壳的断面做成平顶梯形，以便施工见笑其径向尺寸，降低厂房的土建投资根据水电站规模本电站采用平顶梯形断面混凝土蜗壳，由《水力机械》附表以及附表二查得HL240型水轮机Da=6350mm,lb=5550mmb/a取为1.5，取为14°2蜗壳包角;：0的选择混凝土蜗壳包角；0通常采用180°~270°,故选择0=270°3蜗壳进口断面的平均速度VcVc根据水轮机设计Hr，可从水轮机设计水头从《水电站》图2-8中的经验曲线查取，查得Vc-5ms3）.蜗壳的水力计算1确定进口断面尺寸进口断面的面积为Vc3600Vc125.6327036004.92二18.84m2根据几何关系确定进口断面尺寸如下进口断面面积应满足下式且b^D1=0.365mftg©丄b=1.6a解上面方程组得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=3.1753.56=6.735m表73中间断面尺寸的确定断面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顶角的变化规律采用直线轨迹，采用图解法来求得R八的关系过程见下表及附绘制蜗壳平面单线图，选定叫（每隔30°选一个）有公式尺=»+2片计算出相应RIq9.,_而吒冷360^T0.15押，其进口宽度R7W查图得0306090120150180210240270p00.821.161.421.641.832.012.172.322.46223372445R(m)2.774.145.0910.56.066.446.797.127.427.705995199335依据上表绘制蜗壳单线图如附图5