挑流消能計(jì)算書挑流消能計(jì)算書

1、挑流消能計(jì)算書一、示意圖:一、基本設(shè)計(jì)資料1 .依據(jù)規(guī)范及參考書目:武漢大學(xué)水利水電學(xué)院水力計(jì)算手冊（第二版）計(jì)算參數(shù)：單寬流量q = 37.125 m3/s 上游水位高程E1 = 420.140 m 鼻坎出口水深h = 2.954 m 鼻坎頂點(diǎn)高程E3 = 412.080 m 壩面水平角 c = 3.43度抗沖系數(shù)K = 1.500三、計(jì)算過程下游水位高程E2 = 383.515 m 下游水深ht = 3.515 m鼻坎反弧半徑R = 14.600 m 鼻坎挑角。=21.00度1 .鼻坎至下游水面的挑距xp計(jì)算：計(jì)算公式：xp = v2sin0scos0s+vcos0sxv2sin20s+2

2、g（AS+hcos0s） 1/2/g （式 1.1）式1.1中鼻坎出口斷面的流速v可近似按下式計(jì)算：v = X（2gS）1/2 （式 1.2）式1.2中流速系數(shù)？可按下面的經(jīng)驗(yàn)公式計(jì)算：(p = 1-0.055/K1i/2i/3 (式 1.3)式 1.3 中流能比 K1 = q/(g1/2xZL5)(式 1.4)式1.4中上下游水位差Z = E1-E2 = 36.625m將Z代入式1.4得：K1 = 37.125/(9.811/2x36.6251.5) = 0.053將匕代入式1.3得：p = 1-0.055/0.0531/21/3 = 0.913式1.2中上游水位至鼻坎頂點(diǎn)高差S1 = E1

3、-E3 = 8.060m將p、S1代入式1.2得：v = 0.913X(2X9.8X8.060)1/2 = 11.481 m/s式1.1中水舌射出角。s = 0 -(P o-a )(式1.5)式1.5中溢流壩面與挑坎反弧末端切線的夾角P o = 0 +p cP o = 3.430+21.000 = 24.430 度式1.5中鼻坎出口斷面中點(diǎn)水流方向與溢流壩面間夾角a可由圖表查得從水力計(jì)算手冊圖4-3-4中根據(jù)P o與R/h的值查得a = 19.257度將P o、a代入式1.5得：0 s = 3.430-(24.430-19.257) = 15.827 度式1.1中鼻坎頂點(diǎn)與下游水位高差 S =

4、 E3-E2 = 28.565m將v、0 s、 S代入式1.1得：xp = 11.4812xsin15.83xcos15.83+11.481xcos15.83 x11.4812xsin215.83+19.6x(28.565+2.954xcos15.83)1/2/9.8=31.716 m沖刷坑深度t計(jì)算：計(jì)算公式：t = KXq1/2xZ0.25-ht (式 1.6)t = 1.500X37.1251/2x36.6250.25-3.515 = 18.969 m水面以下水舌長度的水平投影Lc計(jì)算：計(jì)算公式：Lc = T/tanP(式 1.7)式1.7中水舌外緣與下游水面的夾角P按下式計(jì)算:=tan215.83+19.6x(28.565+2.954xcos15.83)/(11.4812xcos20.28)i/2=2.264將tanp代入式1.7得：Lc = (t+ht)/tanp = (18.969+3.515)/2.264 = 9.931 m沖刷坑后坡計(jì)算：計(jì)算公式：i = t/L1 = t/(xp+Lc)(式 1.9)i= 18.969/(31.