蜗壳的型式及主要尺寸的确定

蜗壳的型式及主要尺寸的确定根据设计资料提供，水轮机型号为HL160—LJ—410及水电站工作水头H=118.5m40m，故采用金属蜗壳。金属蜗壳只承受内水压力，而机墩传下的荷载和水轮机层的荷载是由金属蜗壳外围的混凝土承受。为使金属蜗壳与其外围混凝土分开，受力互不传递，我国通常是在金属蜗壳上半部表面铺设沥青、麻刀、锯末或软木沥青、塑料软垫3——5cm厚的软垫层，靠近座环处不铺。使外压不传到金属蜗壳，内水压力不传到蜗壳外的混凝土上。蜗壳主要参数的选择①设计资料提供，每台机组的最大引用流量，则蜗壳进口处的流量smQQ300max00088.117123360345360②、蜗壳进口断面平均流速《水力机械》第二版P99图4—30(b)曲线得smVc9③、座环内、外径选择由水轮机的型号HL160—LJ—410，查到cmD4101的座环尺寸，当H=118.5m170m时，其座环内径mmDb5450,115mH=118.5m170m,其座环外径mmDa6450金属蜗壳的水力计算设i为从蜗壳鼻端起算至计算断面i的包角，则该计算断面处的max0360QQiiciiVQ0max360iairR2蜗壳断面计算表00003.23155.130.570.434.083010.251.140.604.434515.381.710.744.706020.502.280.854.937525.632.850.955.139030.753.421.045.3110535.883.991.135.4812041.004.561.205.6313546.135.131.285.7815051.255.691.355.9216556.386.261.416.0518061.506.831.486.1819566.637.401.546.3021071.757.971.596.4122576.888.541.656.5224082.009.111.706.6325587.139.681.766.7427092.2510.251.816.8428597.3810.821.866.94300102.5011.391.907.03315107.6311.961.957.13330112.7512.532.007.22345117.8813.102.047.31根据计算结果作蜗壳单线图