Numerical Computation The Interior Flow Field Of The New Type Axial-balancing Device Gap Based On CFD

The axial thrust magnitude must be one of the important factors which impact the operational stability and life in the application process of the pump. Information from the large amount of documentation, it is easy to see that the existing balance devices are subject to a certain degree restrictions in the balance capacity and the application scope. And the study of axial thrust formula has always been weak in the design of pump. A new type axial-balance device is proposed by tracking the difficult and hot question in the water pumps industry. The principle of the new balance device balancing centrifugal pump axial thrust is studied in theory. The interior flow field of axial gap is compute by application FLUENT software, and a theoretical basis is offered to the axial thrust calculation by exploring the pressure distribution law.The main achievements are listed as fellows.The great significance of studying centrifugal pumps' axial thrust is stated, and traditional balance methods are analyzed. A new type axial-balance device is proposed by tracking the latest progress of studying balance device.Firstly, the operation of the new type axial-balance device is illustrated. Laminar flow is supposed when the interior flow of the new type axial-balance device gap is analyzed. And the mathematic model of interior flowing are established respectively in radial and axial gap, then the theoretical pressure distribution law in the balance device interior gap and the function of leakage is gained by solving the incompressible flow N-S equation group and the continuity of flow equation and the equation of water pump, the work will be helpful to understand the calculation of axial thrust.Secondly, building the computing model of the new type axial-balance device axial-gap by applying GAMBIT software, then the interior flow field is calculated by applying FLUENT software. The impact of the various grid numbers on the result is analyzed by comparing their respective press distribution figure and radial velocity vector figure in the section. By analyzing the pressure and velocity figure of the flows within axial gap, it is found that the outer fluid of the axial gap flows uneasily to the interior and the leakage of the balance device decreases because the bigger whirlpool occurs in the radial range of the 85mm to 102mm. By analyzing the data of the pressure distribution along the radial direction and using the data fit method, gains the curve equations, then draws the graph of the pressure distribution.Thirdly, it can be seen that the two pressure distribution curves of the different calculation methods are very approximate and flat by comparing them. Linear distributionmay be fit to application in engineering calculations.Finally, aim at the project example, the theoretical pressure distribution curve and the ideality curve are applied to calculate the surplus axial thrust, and respectively 122.5N and 157.8N, and the balance capacity must reach around 99%. Comparing with the method of the drilling balance holes, it is clear that new type axial balance devices must be balanced better and accord with the engineering applications.