Axial Eddy Current Flowing Of Theoretical Analysis

To improve the performance of centrifugal pump, it is very important to have a profound understanding of the mechanism to its internal flow phenomena, flow structure and energy loss. Currently, Internal complexity of the flow of hydraulic machinery research has depth to the unsteady stage, to further explore the internal turbulence structure runner and its unsteady flow mechanism, as well as between the mainstream and the blade unsteady interaction, to study its various influencing factors and effective control measures, which developed the kind of the wheel which has resources economizing with high efficiency of the characteristics , and this has become further improving hydraulic performance. Usually the relative flow of the interior of centrifugal impeller is considered uniform flow superimposed axial vortex flow. Understanding the characteristics of these two flows is recognized impeller velocity distribution and the resulting decision of the basic characteristics. Axial vortex researches, in the past, the main methods of analysis are based on theoretical or experimental results with some, but it is still relatively early stage.Vortex axial flow is a special impeller the relative movement of rotation in order to find the leaf axial eddy tract under different conditions of impeller speed distribution and especially its exports are part of the relative velocity, the study will be use theory and simulation ways to determine the specific rotation, as well as to study the fluid with viscosity and viscous both cases the vortex axial flow velocity distribution.In order to discover the characteristics of axial vortex flow , this subject will simulate of three different geometric border axial vortex flow, and finally verify and correct or enrich existing theoretical analysis and experimental. So this topic has the nature of basic research. The results of this study will enrich people's understanding of the axial vortex flow, which will improve the pros and cons questions of the pump research to a new level. The topic, firstly, uses theoretical approaches and Stodola Method to determine the relative velocity distribution of axial vortex flow of the ideal fluid in three typical cases of the geometric boundary, and then utilize computational fluid dynamics (CFD) methods, simulation, calculation, analysis to the three cases, the internal flow . Simulating between the impeller blades to simulate for instance, according to k-εtheory, selecting one model of a typical centrifugal pump impeller, using UG software sets up its three-dimensional geometric model of the impeller. By the Gambit software and tetrahedral body-fitted coordinate grid system to generate a computational grid, using FLUENT software which simulates internal flow field of three-dimensional can be obtained some parameters distribution of the centrifugal pump impeller such as flow rate, velocity-moment, and pressure. Finally by analyzing the simulation results, the characteristics of flow channel of the rotating impeller, with the theory derived from the mathematical expression Consistent, will be found. And come to the following important conclusions and experiences:(1) In the blade of the middle, because of the two relative flowing in the back of the blade direction and in the working face in the opposite direction, resulting the relative velocity of the working face will be less than the relative speed of the back of the vane. According to the Bernoulli equation, the pressure in the working face will be greater than the pressure in the back of the blade, so leading to produce a pressure difference on both sides of the blade.(2) In the exit of impeller, the real relative velocity vector in the exit of vane can not be with the blade surface tangent in the exit, it is also impossible with the impeller outer circumference tangent. So the actual flow angle, angle between the true relative velocity vectors and the circumference of the direction, will be less than the leaves placed angle. This will have a very significant impact to the head generated by the impeller.