Study On Internal Flow And Model Test Of Energy Dissipating Fixed Cone Valve

Energy dissipating fixed cone valve is a fluid machinery whose main function is to dissipate overlarge flow energy in hydraulic and hydropower projects, and reduce its impact on the waterworks and ecological environment along the lower reaches. Having complex internal flow conditions, the valve's design of its internal structure can directly influence its performance. Aimed at choosing the highly-efficient internal structure for valves, this thesis studies flow areas of fixed cone valves with different internal structures, and analyzes their performance of dissipating energy and controlling flow.This study combines numerical simulation computation and model hydraulic tests, the writer carries out simulation computing on the valve's internal flow area through numerical simulation, makes valve models and uses them to conduct hydraulic experiments in the same working conditions. Through numerical simulation computing, the writer also obtains distributions of pressure and speed in the flow area and flow line changes of the valve with different internal structures, works out energy dissipation rates in different working conditions,and studies dissipation rates of fixed cone valves with different internal structures. Through hydraulic model tests, the writer works out the valve's flow rate and pressure levels in its outlet and inlet in different working conditions, and analyzes their performance of dissipating energy and controlling flow, also verifies the accuracy of simulation computing with test results.This thesis draws the following conclusions. First, in order for the valve to perform its utmost to dissipate energy, its internal structure should be a core with both annular and cone perforated casings, of which the core plays the major role in dissipating energy, while adding annular and cone perforated casings can further improve that performance. Second, it is drawn from both simulation and test results that the valve's ability to control flow improves when the valve is turned from fully opened to 85% opened. Therefore, it is proposed that the valve be set as fully opened if it is 85% opened in real application, so as to optimize its ability to control flow. Finally, this thesis concludes that valve with a core and both annular and cone perforated casings as its internal structure can have the best performance, and can also meet the hydropower station's need to control flow.