Noise Impact Of V-Groove Structure On NACA0012 Pump Blade

Water pumps are widely used in urban water supply,industrial production,and agricultural irrigation fields.The noise generated during the operation of water pumps can cause serious harm to people’s production and life.Therefore,researching the noise reduction of water pumps has important practical significance.The interaction between the water flow and the impeller and pump casing is one of the main sources of noise in water pumps.Many organisms in nature have excellent drag reduction and noise reduction effects due to the non-smooth surface structure of their bodies.This paper conducts research on noise reduction based on the V-shaped groove biomimetic drag reduction structure.This paper adopts numerical simulation methods to study the noise reduction effect of V-shaped groove bionic structures on the NACA0012 pump blade under different conditions.The specific research contents are as follows:(1)Numerical simulation methods were carried out on the flat plate,and the results were compared with the theoretical and numerical solutions under the same flow conditions to verify the reliability of the solution method and model used in this paper.(2)Different biomimetic denoising structure models were established.The calculation domain range and monitoring point positions were determined through numerical simulations,and grid independence verification was performed to ensure the accuracy of the calculation results.(3)Add six different V-shaped grooves with varying spacing to the front,middle,back,and full sections of the basic model,and investigate the effects of the spacing and position of the V-shaped grooves on its noise reduction performance under three different operating conditions using numerical simulation methods.(4)By comparing the differences and changes in velocity contour,turbulence kinetic energy contour,and vorticity contour between the model with added V-shaped grooves and the basic model,the noise reduction mechanism of the V-shaped grooves was analyzed.Numerical simulations indicate that the impact of V-groove structures on noise reduction varies depending on the speed conditions.At low speeds,adding V-groove structures at the front,middle,and full span of the baseline model doesn’t significantly reduce noise.However,incorporating V-groove structures at the rear section shows noticeable noise reduction,with a spacing of 1/1000 L being the most effective.Under medium speeds,noise reduction is observed when V-groove structures are added at the front,middle,rear,and full span of the baseline model.The most significant noise reduction occurs by adding V-groove structures with a spacing of 1/2000 L at the front,middle,and full span,resulting in maximum reductions of 6d B,5d B,and 12 d B respectively.Adding a V-groove structure with a spacing of 1/1500 L at the rear section achieves a maximum noise reduction of approximately 6d B.At high speeds,incorporating a V-groove structure with a spacing of 1/1000 L at the front of the baseline model leads to significant noise reduction,with a maximum reduction of 12 d B.The V-groove structure can reduce noise in several ways.Firstly,it increases the thickness of the low-speed boundary layer,making the transition between different velocity layers smoother and reducing noise.Secondly,it reduces turbulence and enhances fluid viscosity,which stabilizes turbulent changes near the wall and suppresses noise caused by turbulent dissipation.Additionally,the V-groove structure rectifies fluid flow,breaks up large-scale vortices,and reduces small-scale vortices,thereby reducing pulsating noise.Lastly,it forms a stable vortex flow that reduces the influence of the external flow field,suppresses the accumulation of low-speed fluid,reduces pressure fluctuations near the wall,and thus reduces noise.