The Preliminary Study For Characteristics Of Energy Dissipation And Pressure To Inner Dissipater Of The Tooth Block

It is a research priority to choose a way of energy dissipation reasonably for experts and scholars because energy dissipation is one of the important problems in hydraulic engineering. Plug or orifice 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 and practical nature, and high ration of energy dissipation and so on. It has broad application prospects in hydraulic project and significant research value of hydraulic characters.Combining the forms of inner dissipation way of the plug with free flow, it is proposed the new type of inner dissipater which is called the inner energy dissipater of tooth block on the basis of traditional types of inner dissipater. It is the researching object in paper and a new try for form of inner energy dissipation. It is conducted a primary research on hydraulic characters of the inner dissipater of tooth block which is adopted the method of physical model test. It is researched the regularity of head loss, energy dissipation rates, flow capacity, the distribution of time-averaged pressure and characteristics of fluctuating pressure to inner energy dissipater of tooth block in different numbers of tooth block and different sectional area contraction ratios. In this paper, the main research contents and conclusion is list in below.1. On the basis of the testing results of pressure in front and back of inner dissipater of tooth block, the main head loss is local head loss in testing tube which caused by sudden expansion and shrink of inner dissipater of tooth block. It is analyzed that the regularity of this part of head loss, Reynolds number, number of tooth block and area contraction ratio (ε).2. Within the scope of the test flow, it is analyzed and concluded the relationship of the energy dissipation ratio of inner energy dissipater of tooth block, area contraction of cross section and the head loss coefficient. It is also achieved the regularity between the head loss coefficient and numbers of tooth block.3. Within the scope of the test flow, the paper analyzes and studies the relationship between pipe discharge capacity and area contraction of cross section. The result shows that the discharge capacity of tooth block energy dissipater is mainly determined by the energy dissipater’s shape and size.4. Under different flow, it is achieved the results through the analysis of time-averaged pressure along the pipe for the testing schemes of inner energy dissipater of tooth block. The results show that the wall dimensionless pressure almost has no change with the change of Reynolds number. the general rule is the time-averaged pressure along the pipe has fallen sharply in section of tooth block, then increased gradually, and finally achieve smooth. And also it analyzes the various schemes of minimum pressure points and the recovering length of pressure.5. By analyzing the characteristics of fluctuating pressure in the inner energy dissipater of tooth block, the results shows that:the maximum points of fluctuating pressure for testing scheme of tooth block appear after the section of tooth block, after that points quickly reduce and gradually tend to be stable. But there are some differences in the change of fluctuating pressure along the pipe, the position of the maximum points of fluctuating pressure and the position of the steady pressure after the section of the tooth block. And also it is obtained the rule from the change of fluctuating pressure along the tube and in time domain, and the probability density distribution of the fluctuating pressure to the maximum points of fluctuating pressure.