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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 D =4.5m,n=100 /1min特征水头：H二 38.0m , H = 34.0m, H =36.0mmaxminr水轮机安装高程处海拔方程 =150m效率修正值Aq =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H = 38.0m,maxH= 34.0m， H =36.0mminr列表如下HL240型水轮机等效率曲线计算H= 38.0mmaxn= 73.00m1minN = 46.53qQ (MW)1H = 36.0mrfn = 75m1RN = 42.91q Q (MW)
2、1H = 34.0mminfn= 77.17m1minN = 39.38qQ (MW)1qm(%)fQ1 mSq =q +mVqN(mw)qm(%)fQ1 优q =q +mVqN(mw)qm(%)fQ1 吆q =q +mVqN(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
3、.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89.21.2490.845.52901.2
4、391.640.9790.41.239246.753）出力限制线绘制计算出1、HH时，数值直线r2、H HH连接（H N ）与H N 见附图1min r r r min min4）等吸出高曲线的计算与绘制：1吸出高度计算公式为H = 10 丄+Aq）HS 900式中气蚀系数修正值Ac由H = 36m查得Ac二0.032等析出高度计算表Hmn (rjmin、1 1cQ1 m 3/sNkwAcc + Ac(c + Ac) HHs38730.220.780.0300.259.50.3330.210.8529.60.249.120.7130.201.0036.20.238.741.0930.201.2
5、243.40.2311.4-1.5670.211.31450.249.120.7130.221.3550.259.50.3330.231.370.269.88-0.0470.240.2710.26-0.4271.393477.170.220.7850.0380.2588.7721.0610.210.84270.2488.4231.410.200.9631.650.2388.0921.7410.201.27541.40.2389.0440.7890.211.31420.2488.4321.4010.221.3642.50.2588.7721.0610.230.2689.1120.7210.241
6、.3742.650.2789.4520.381.3942.836750.220.790.0320.2529.0720.7610.210.8324.80.2428.7121.1210.200.9529.10.2328.3521.4810.201.29390.2328.3561.4770.211.32539.50.2428.7121.1210.220.2529.0720.7610.231.35539.90.2629.4320.4010.241.36840.10.2729.7920.0411.38540.32利用表计算结果，作每个水头下的N= f （Q）辅助曲线（见附图2）。将各Q11值的出力从图中
7、查出填入表中。3根据表中对应的H和N,绘制各水头下H f （N）的辅助曲线（见附图 sS4）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D =6350mm,D =5550mm b/a取为1.5，丫取为 ab142蜗壳包角9 的选择混凝土蜗壳包角9通常采用180270，故选择9 =270 003蜗壳进
8、口断面的平均速度VcV根据水轮机设计H，可从水轮机设计水头从水电站图2-8中的经 cr验曲线查取，查得V = 5 msc3）. 蜗壳的水力计算1 确定进口断面尺寸进口断面的面积为囚QQ 9125.63 x 270 18 84 2F = 0 = max 0 = 18 84m 20 V3600 V 3600 x 4.9cc2 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 ,. D二0.3650 1F = ab - mltgb 2 + (r - r )b12a b 0-二 1.6a解上面方程组得b = 1.6， a=3.56m， b=5.33m， m=5.73m，0由前面查表已知D
9、=6350mm,D =5550mm，所以 abr = D ：2 = 3.175m, r = D /2 = 2.775m , aa *bb故 R = r + a = 3.175 + 3.56 = 6.735m 0a3 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-申的关系过程见下表及附表7断面aibiR (m)iF (m 2)i申（。）i03.565.336.37519.1227010.867.334.0352.2130.2120.6886.193.8631.6423.1630.5165.0383.6921.1315.9640.3443.8923.5190.689.6050.1722.7463.3470.3094.36绘制蜗壳平面单线图，选定申（每隔30选一个）有公式R二丫 + 2P计算出相应Rii a ii而Pi飞器 =15兀其进口宽度B= R + D1 R円a + 2Pic查图得申（。）0306090120150180210240270Pi00.8221.1621.4231.6431.8372.0122.1742.3242.465R (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
