Study On The Rotor System’s Stability Of 430DY450-HY Centrifugal Pump

Many factors affect the stability of the multistage split casing centrifugal pump. One of the reasons causing the vibration of the multistage split casing centrifugal pump is the relative position of impeller, keyway and volute tongue which may have influences on the force, couple on the shaft and the pressure fluctuation. In this paper, the research object is a four-stage volute oil pipeline pump. The pump has a model of 430DY450-HY and it is manufactured by a domestic corporation. According to the randomness for designing the relative position of impeller, keyway and volute tongue, we design 4 programmers by different relative positions of impeller, keyway and volute tongue in order to study the influence on the stability of the multistage split casing centrifugal pump of the relative position.1. Firstly, we did some steady numerical simulations for the original scheme under different working conditions, calculated the external characteristic curves and compared it with the experimental values. The results showed that the external characteristic curve obtained by the simulation matched well with the experimental results and it was proved that the numerical simulation method used in this paper was feasible.2. We also did some steady numerical simulations for the other 3 programmers under different working conditions. Using the data obtained by numerical simulation, the radial force on the impellers was calculated, and we found that the size and direction of the radial force on each impeller was basically the same. But when the radial force which was subjected to the impeller at all levels was simplified on the shaft, we found that the stress was relatively minimal in the third programmer which changed the circumferential position of impellers with 25.7 degree.3. This article did the unsteady numerical simulation under different conditions(0.8Q,1.0Q, 1.2Q) of the four programmers, According to the data obtained by numerical simulation, the radial force of the four impellers during a cycle under different working conditions was calculated. We did the transient dynamic analysis of shaft system after load the radial forces during a cycle onto the shaft. The results showed that vibration displacement, vibration speed and vibration intensity on the third programmer’s shaft were reduced compared with first programmer’s shaft. Comparing with the first programmer, the vibration intensity on the third programmer’s shaft under different working conditions(0.8Q, 1.0Q, 1.2Q) reduced 52.74%, 31.10%, 41.81% separately. It shows that a suitable relative position of impeller, keyway and volute tongue could improve the stability of the multistage split casing centrifugal pump.