Experiment And Numerical Simulation Research Of Vortex Flow Past Blades

The effects and harms of the ultrafine particles has been causing people’s concern. Particle aggregation technique is an effective method of controlling dust emissions of ultrafine particles. In order to fully understand the distribution of the turbulent flow field in turbulent coalescence apparatus, then improving the turbulent coalescence apparatus’ structure and reinforcing the coalescence effect to achieve the efficient removal of ultrafine particles, flow around vortex research and numerical simulation was conducted.In this paper, the blade flow around vortex test experiment platform was designed and built on the base of the size of the turbulence structure. The particle image velocimetry (P1V) system was applied to do flat three-dimensional experimental study of the blade flow around field in pipe. It was concluded based on time-averaged analysis the flow around blade generated a large-scale flow around vortex (recirculation zone), the recirculation zone and the blade downstream of the low velocity zone formed the blade wake region and the three-dimensional disturbance was violent; with the increase of wind speed, the wake region’s scale and the disturbance’s degree increased; the vortex generated by the multiple blades overlaid each other, enhancing the disturbance of the flow field. It was concluded from transient analysis:single blade flow around shear layer’s" entrainment" effect made the blade on both sides to form the large-scale vortex’s development and shedding alternately; while the multiple blades steaming around, by the effects of downstream blade, the upstream blade shear layer formed the large-scale vortex which was not able to fall off and enter into the downstream blade steaming around directly, and the flow around’s development was inverted.Using the large eddy model, Mathematical model was established based on the physical model of the experiment bench structure, and different conditions were simulated. Similar conclusions were gained with the experiment by analyzing the velocity profile. The simulation of the wake zone size was bigger compared with experimental results. The conclusions were verified by the vorticity field distribution that in the wake the vortex was larger and the disturbance was stronger. Compared with single-blade flow, the wake zone size in the multi-blades flow field decreased, but the vortex field size increased. It is suggested that the blade pitch be reduced to70mm or80mm.