Study On Space Guide Vane Internal Flow And Structure Dynamic Characteristics Of Long Axis Pump

The long shaft pump is used in the limited space of the radial size, and the space guide vane is used to replace the radial spiral case. Although the radial dimension of the pump is reduced by the space guide vane, but it makes the radial direction fluid into the axial flow. So,fluid flow in the flow channel is more complicated. At present, there are few studies on the flow characteristics of the space guide vane of long axis pump. Especially, the design of long axis pump by means of digital software, and through computational fluid dynamics method to study the characteristics of the internal flow field in the space guide vane of long axis pump.The research results have important significance for the rapid design of long axis pump and the optimization design of space guide vane.On the basis of theoretical analysis, this paper makes a fast and efficient design of long axis pump through CFturbo digital software, and numerical simulation is carried out to study the flow field characteristics and performance. Combined with CFturbo software to change the parameters of space guide vane, the flow field characteristics and the influence on the performance of long axis pump are studied by numerical simulation. At the same time, the structure field of long axis pump is calculated. The main contents and conclusions of this paper are:1. Application of digital software CFturbo on the hydraulic design of long axis pump blade and guide vane, determine its main parameters, and use UG software for three-dimensional modeling of long axis pump. The numerical simulation was carried out by ANSYS-CFX software to verify the feasibility and efficiency of the digital software design.2. Through numerical simulation, the flow field characteristics of the different annular space distance, the guide vane inlet angle and the vane number were studied, and the influence of these parameters on the performance of the long axis pump was analyzed.The distance of Impeller outlet edge and guide vane inlet edge in the 0.3b2~0.6b2 is more appropriate. When the value is too small, then the guide vane inlet shock is obvious, and the shaft power is high under the high flow rate. When the value is too large, then the overall performance of the pump is decreased.Guide vane inlet angle at 15 degrees ~30 degrees is more appropriate. When the smaller value is taken, the efficiency point will appear in small flow conditions, and the efficiency point will appear in large condition when the large value is taken. When the inlet angle is positive, the flow field distribution of the long shaft pump in the large flow condition is good,and vortices are generated at low pressure side.The guide vane controls fluid. Blades are too few to control the fluid, resulting in a decline in the overall performance of the pump. Too much of the blade will cause the increaseof the flow rate of the fluid, resulting in a decline in the ability of the guide vane to convert the kinetic energy into the pressure energy.3. Based on Fluid-Structure Interaction the stress distribution and structural deformation of three structures under different working conditions were calculated and analyzed. The results show that the fluid load plays a major role in the force and deformation of the impeller,because of the use of space guide vanes, so the distribution of stress and deformation is more average. The impeller deformation increases with the increase of the radius, and the deformation at the outlet of the impeller is the largest. The stress on the inlet side of the space guide vane is more concentrated, and the deformation is uniform under different conditions.Axial stress distribution is uniform, there is no stress concentration phenomenon. Under the design condition, the strength meet the requirements.4. Study on dynamic characteristics of long axis pump rotating structure by modal analysis. The analysis shows that the centrifugal force and water pressure have little influence on the vibration frequency and mode shape of the rotating structure of the long shaft pump,and the natural frequency of the rotational structure has less probability of occurrence of resonance with shaft frequency or blade frequency.