LES Of The Cavitation Characteristics Of The Sidewall Of A Sudden Lateral Enlargement And Bottom Drop Section In Gate Chamber With Arch Sluice

With the flow rate in the discharge structure continuously improving, the cavitation problem of Side wall has become more apparent, becoming critical issues that need urgent solution in high-speed flow project. Although the issue of side wall cavitation research has achieved certain results, its still far from fully. On the basis of reviewing and summarizing previous studies, using CFD software-Fluent, with Jiudianxia Hydro Project atmospheric model results, by the combination of LES and the VOF free surface simulation technology, a numerical simulation study was conducted on hydraulic characteristics of a sudden lateral enlargement and bottom drop section in gate chamber with arch sluice. Main research contents and results are as follows:(1) From the N-S equation, we pointed out that the Turbulence-Shear is a strong pulse of the source side wall combining with The basic mechanical properties of water of a sudden lateral enlargement and bottom drop section in gate chamber with arch sluice. Intermittent pulse will lead to the occurrence of cavitation because of reflex low pressure area of sidewall, which indicated the direction of this study.The theory of large-eddy simulation was elaborated and constant of the Smagorinsky subgrid model was calibrated by the classic backward-facing step flow.(2) By the combination of smagorinsky subgrid model of shear turbulence model and the VOF free surface simulation technology, a numerical simulation study was conducted on hydraulic characteristics of a sudden lateral enlargement and bottom drop section in gate chamber with arch sluice and gained flow pattern, velocity, pressure, bottom-side cavity and other mechanical properties of water. By the comparison with Experimental results of hydraulic model, we can acquire that LES for the simulation the flow field of a sudden lateral enlargement and bottom drop section in radial gate had a strong reliability.(3)There is more concentrated low-pressure area in side wall, and the location of low-pressure area had no significant change in water depth, the relative pressure fluctuation intensity of low pressure area up to 0.33; measuring point along the flow direction of the correlation coefficient of fluctuating pressure is not a linear relationship with the distances, the overall trend was decrease with the increase of the distance; from the analysis of the spectrum can be seen, the fluctuating pressure of measuring points was belonging to low-frequency pulse.(4)Studies have shown that:the average number of cavitation the sidewall of a sudden lateral enlargement and bottom drop section in gate chamber with arch sluice is not low.However, due to the impact of pulse, there was relatively large intermittent cavitation coefficient on some measuring points, thus becoming the cavitation source of the sidewall of a sudden lateral enlargement and bottom drop section in gate chamber with arch sluice and causing damage.