Experimental Study On Pressure And Flow Field Characteristics Of Tooth Block Inner Dissipater

The energy dissipater is one of the effective energy dissipation way in the high head discharge structures. Teeth pier energy dissipater as a new energy dissipater proposed is try to overcome the lack of the hole plugs energy dissipater low flow capacity. Contents of this thesis are part of Shanxi Natural Science Foundation Project " The test studies for the hydraulic characteristics of tooth pier energy dissipation ". Based on the previous tooth pier energy dissipater preliminary, In this thesis, the hydraulic characteristics of the tooth pier energy dissipation is further researched, Tooth pier segment which is0.9times the length of the pipe diameter is evenly arranged in the pressure pipes. Ten schemes are established by changing the number of teeth pier and area shrinkage ratio.The physical model test method is used to research the teeth pier energy dissipation. Doppler ultrasonic flow meter and high-precision pressure sensor are used to measure pressures and flow rates of different schemes. After collation and analysis of data, variation of pressure distribution of schemes, flow coefficient, head loss coefficient,energy dissipation rate and the level of velocity distribution are obtained. At the same time it is analyzed the influence the number of teeth and the pier area contraction ratio to energy dissipation characteristics, the energy dissipation mechanism of energy dissipation tooth pier workers, the level of pressure pulsation velocity distribution properties and characteristics of the tooth pier energy dissipation workers. The main conclusions are listed in below:1. Under the guaranteed flow capacity situation, tooth pier energy dissipation rate of energy dissipation workers can reach a higher level. In the case of the flow coefficient is0.407,energy dissipation rate can reach80%, which is a potential for development of the energy dissipater.2. In the test, through the analysis, it is showed that each scheme have similar regular in the wall pressure coefficient variation along the pipeline. The average pressure is decline sharply in the beginning of the teeth and reach the lowest point in the internal of teeth pier segment, then gradually recovers to a stable value. The area shrinkage ratio mainly affect the length of the pressure recovery, On the contrary the number of teeth affect weakly.3. Through the analysis of the pressure data, variation along the distribution are obtained. Pulsating pressure are large in the teeth of the pier segments, with an area smaller than the larger contraction pressure pulsation changes in tooth pier segment, the largest pulsating pressure points are in the range of1.0D-1.6D after tooth pier segment. Along with the area shrinkage ratio increased, Pressure pulsation amplitude decreased.4.The probability density distribution of this pulsating pressure is close to normal distribution after analyzing coefficient of skew and coefficient of kurtosis.5. Through the analysis of the flow coefficient of energy dissipation within the tooth pier with Reynolds changing. It is that Reynolds get nothing to do with number flow capacity. The area shrinkage ratio mainly affect the flow capacity, On the contrary the number of teeth affect weakly.6. Teeth pier work with the decrease in the energy dissipation area shrinkage ratio increases in energy dissipation head loss coefficient segment.In the case of the same area shrinkage ratio, the pier head loss coefficient is not very different from number of teeth, the sudden expansion head loss coefficient and its theoretical value is relatively consistent.7. With analyzing flow velocity data in the front and back of teeth pier, typical cross-section horizontal velocity distribution, horizontal flow velocity vector and the typical depth of fluctuating velocity variation along the process are obtained.