The Study On The Hydraulic Characteristics Of Toothed Inner Energy Dissipater By Physical Model

Inner energy dissipater is a common form of inner energy dissipation in water pipe with pressure and tunnel, and has the advantages of simple layout, economic a nd practical nature,high ration of energy dissipation andso on. It has broad application prospects and good economic in hydraulic project and significant research value.Based on the previous tooth block innerdissipator preliminary study on hydraulic characterist ics of the tooth block. With the demonstration proof-test to analysis of the energy dissi pation mechanism of tooth block inner dissipation to do further research,Analysisthe fl ow capacity, head loss,the mean and pulsating pressure,the flow velocity of pipeline a n so on.Mainly discusses the influence of number and area contraction ratio to the ab ove characteristics,The main conclusions obtained by the analysis are:1.The flow capacity in pipeline decisioned by the type of energy dissipation, and has little to do with Re. Area shrinkage ratio is the main factor affecting the flow c apacity,the smaller the area shrinkage ratio and flow area,the worse the flow capacity in pipeline,when the area contraction ratio increased from0.375to0.625, the flow co efficient changes from0.35to0.8.2.With the increase of pipe flow capacity,the rate of energy dissipation also incr eased. At the same flow,the smaller the contraction ratio,the higher the rate of energy dissipation. In the test range, the energy dissipation rate can reach about80%.3.The head loss coefficient increases with the decrease of area contraction ratio i n the tooth pier inner dissipater,when the area shrinkage ratio as the same, little diff erence on the head loss coefficient of different numbers of teeth block. 4.The change regulation of mean pressure coefficient along the wall ofeach schem e is similar,and a sharp decline in the import of tooth block, and reached the minim um in the internal tooth block,then gradually recovered, pressure recovery length is mainly affected by the area contraction ratio, changes in the number of teeth on its in fluence on the tooth of a certain.5.In each test scenario, the smaller the area shrinkage ratio,the greater the range of the recirculation zone existed in front of the teeth pier segment, when aArea shri nkage ratio as the same, the more the number of teeth pier phase, the greater the s cope of the recirculation zone.6.Fluctuating pressure maximum of each scheme occurs in the range1.3D-1.6D af ter the tooth block segment.the smaller the area contraction ratio,the change of pressu re fluctuation is bigger,in the test range,the pulsating pressure amplitude can reach2ti mes the velocity head.7. The coefficients of fluctuating pressure of Energy dissipator on each test progr ams increases with the reduced of flow area contraction ratio,when aArea shrinkage r atio as the same,the impact with the increase of thenumber of teeth pier on fluctuati ng pressure coefficient is little.8.The probability density distribution of the fluctuating pressure coefficient of ske wness of each scheme at the range of-0.38to0.3, Kurtosis coefficient varied from2.92to4.06, which is close to normal distributionof basic...