1、 1 VORTEX-TUNNEL SPILLWAYS AND HYDRAULIC OPERATING CONDITIONS M. A. Galant, B. A. Zhivotovskii,V. B. Rodionov,and N. N. Rozanova Executive Summary Spillway tunnel is widely used in high-pressure hydraulic engineering. Therefore, this type of spillway this study is an important and urgent task to hel
2、p in the use of these types of hydraulic construction of spillway can help develop the best and reliable spillway structure. This is confirmed by vortex spillway tunnel in the design of a pressure fluctuation and intensity of turbulent energy dissipation process Keywords: vortex spillway energy diss
3、ipation Tunnel spillways are widely used in medium- and high-pressure hydraulic works. It is therefore an important and pressing task to improve the constructions used in these types of spillways and to develop optimal and reliable spillway structures.With this in mind, we would like to turn the rea
4、ders attention to essentially novel (i.e., in terms of configuration and operating conditions) vortex spillways which utilize vortex-type flows. On the one hand, these types of spillways make possible large-scale dissipation of the kinetic energy of the flow on the initial leg of the tailrace segmen
5、t, and, as aconsequence, flow rates of slightly vortex-type and axial flows through the subsequent legs that do not produce cavitation damage. On the other hand, the dangerous effect of high flow rates on the streamlined surface decreases over the length of the initial tailrace leg as a consequence
6、of the increased pressure on the wall caused by the effect of centrifugal forces. A number of structural studies of tunnel spillways for hydraulic works such as the Rogunskii, Teri, Telmamskii, and Tupolangskii hydraulic works based on different operating principles have now been completed. These co
7、nstructions may be divided into the following basic groups: - vortex-type (or so-called single-vortex type) spillways with smooth dissipation of the flow energy throughout the length of the tunnel when L r (60 - 80)hT or (60 - 80)dT (where dT and hT are the diameter and height of the tunnel), while
8、the cross-section of the tunnel is either circular or near-circular throughout its length. - vortex-type spillways with increasingly greater dissipation of the energy of the vortex-type flow over a shorter length 2 Lr - (60 - 80)hT of a noncircular section river diversion tunnel (horseshoe-shaped, s
9、quare, triangular) which is connected to the eddy chamber either by means of an energy-dissipation (expansion) or by means of a smooth transition leg； - spillways with two or more interacting vortex-type flows in energy-dissipation discharge chambers or in specialenergy dissipators that have been te
10、rmed counter-vortex energy dissipators.The terminal portion of the tailrace tunnel of a vortex spillway may be constructed in the form of a ski-jump bucket, a stilling basin, or special structures depending on the flow rate at the exit from the tunnel and on the conditions in the channel downstream.
11、 The hydraulic system used to link the flow to the tailrace canal may involve the use of either overflowtype or free-fall type structures.Vortex spillways with smooth or accelerated dissipation of energy over the entire length of the water conduit represent the simplest and most promising types of h
12、ydraulic structures.Techniques of designing vortex spillways have now been developed and published in numerous studies； inparticular, techniques are now available for calculating the hydraulic resistance of individual legs of a route and the flow rates and pressures in vortex-type flow. However, for
13、 each actual hydraulic project a designed structure must also be evaluated by means of model investigations, since it is still not possible to evaluate all the elements of the operation of a spillway by means of calculations.Thus, let us turn our attention to a number of theoretically important prob
14、lems. A familiarity with these topics will be of assistance in the design and investigation of vortex spillways. Evaluation of the Design and Geometric Dimensions of the Elements of a Spillway. The selection of a particular type of spillway depends on a number of factors, such as the effective head,
15、 the magnitude of the escapage discharge, theconfiguration of the hydraulic project (for example, the use of a river diversion tunnel during the operational period or of the water conduits of hydroelectric power plants in the construction period), conditions in the discharge of the flow into the tai
16、lrace channel, topographic and geological features (in particular, the possible length of the tailrace leg), and the technical and economic characteristics.Inlet (entry segment in the form of surface or subsurface offtake). The inlet is designed on the basis of standard techniques to maintain its co
17、nveyance capacity when functioning in the free-fall regime. Shafts (vertical or inclined). The diameter of the shaft is made nearly equal to the diameter of the tailrace leg: It should be noted that the eddy node is designed so that A = Areq, where Are q is the value of the geometric parameter of the vortex generator needed to maintain the required
