水轮机运转特性曲线的绘制

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1、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=4.5m,n=100特征水头：，，=36.0m水轮机安装高程处海拔方程=150m效率修正值=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，，=36.0m列表如下HL240型水轮机等效率曲线计算(%)+N(mw)(%)+N(mw)(%)+N(mw)870.8488.634.61870.8588.632.31870.8788.630.35880.8789.636.25880.8989.629.14880.928

2、9.632.46890.9290.638.76890.9490.631.16890.9690.634.25900.9691.640.89900.9791.632.53901.0091.636.07911.0092.643.06911.0292.634.27911.0692.637.20911.2192.652.10911.2192.641.54911.2292.644.49901.2391.652.39901.2491.642.16901.2591.645.09891.2690.653.08891.2790.642

3、.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、时，数值直线2、连接（）与见附图14）等吸出高曲线的计算与绘制：1吸出高度计算公式为式中气蚀系数修正值由查得等析出高度计算表HmNkw38730.220.780

4、.0300.259.50.3330.210.200.200.210.220.230.240.851.001.221.311.3551.371.3929.636.243.4450.240.230.230.240.250.260.279.128.7411.49.129.59.8810.260.7131.093-1.5670.7130.333-0.047-0.4273477.170.220.210.200.200.210.220.230.240.7850.840.961.2751.311.361.371.392731.6

5、541.44242.542.6542.80.0380.2580.2480.2380.2380.2480.2580.2680.2788.7728.4238.0929.0448.4328.7729.1129.4521.0611.411.7410.7891.4011.0610.7210.3836750.220.210.200.200.210.220.230.240.790.830.951.291.3251.3551.3681.38524.829.13939.539.940.140.30.0320.2520.2420.23

6、20.2320.2420.2520.2620.2729.0728.7128.3528.3568.7129.0729.4329.7920.7611.1211.4811.4771.1210.7610.4010.0412利用表计算结果，作每个水头下的N=辅助曲线（见附图2）。将各值的出力从图中查出填入表中。3根据表中对应的和N，绘制各水头下的辅助曲线（见附图3）4）绘制等吸出高曲线（见附图4）六、蜗壳的设计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

7、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,Db=5550mmb/a取为1.5，取为14°2蜗壳包角的选择混凝土蜗壳包角通常采用180°~270°,故选择=270°3蜗壳进口断面的平均速度根据水轮机设计，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3).蜗壳的水力计算1确定进口断面尺寸进口断面的面积为2根据几何关系确定进口断面尺寸如下进口断面面

8、积应满足下式且解上面方程组得，a=3.56m，b=5.33m，m=5.73m，由前面查表已知Da=6350mm,Db=5550mm，所以，故.3中间断面尺寸的确定顶角的变化规律采用直线轨迹，采用图解法来求得R-的关系过程见下表及附表7断面03.565.336.37519.1227010.867.334.0352.2130.2120.6886.193.8631