Numerical Investigations of Transient Flow Characteristic in Axial Flow Pump and Pressure Fluctuation Analysis Based on the CFD Technique

The technique of Computational fluid dynamics was applied to investigate flow field analysis including static pressure, axial, radial and tangintial velocities vectors as well as fluctuations of pressure analyses in axial pump. Pressure fluctuations are the core causes increase noise level and vibration. For studying pressure mechanism fluctuation in pump changed monitoring rotating points are stalled at an impeller blade. Standard k-epsilon turbulence model and sliding mesh technique are adopted by using CFD. The numerical investagation found that pressure in an axial flow pump rises near inlet impeller region to outer part. Higher value of pressure was take place at impeller outlet region. Also, the computational analysis noted that the when a pump functions in larger mass flow, the area of high-pressure in impeller outlet decreases. Moreover, under low flow rate (5 l/min) in middle surface the high-speed area appears near or closed blade and blade tip region for all velocities under investigations. Furthermore. fluctuations of pressure for different point under different flows has four valleys and peaks the similar number of axial impeller passages blades. The results foun that there are two imprtant regions the first one ispositive and second one is negative pressures, this happends owing to this negative pressure area has lower pressure value. Therefore, due to the decline in the water pressure in this area may cause cavitation.