Influence of the Stochastic Nature Parameters of Throttle Channels on Characteristic of Automatic Balancing Device of the Centrifugal Pump

Automatic balancing device is used to balance the axial force. Moreover, this device acts as an end-seal of centrifugal pump and about 5% of whole power can be lost on it. Operating characteristics of automatic balancing device are determined by cylindrical and face throttles geometrical characteristics that have stochastic nature. It caused by the real constructional form of inlet in annular and face throttles, possible deformations, initial manufacturing, and installation misalignment and deviations depend on different stochastic factors. Using the example of static characteristic calculating of an automatic balancing device for a centrifugal pump, it is shown that considering the stochastic nature of the geometric characteristics of the throttle channels, the losses in the face throttle, gives a random character to the variation of the balancing device parameter. Obtained results showed not only the qualitative but also quantitative influence of the random changes of the hydraulic resistances on the values of the balancing axial force and the face gap (about 10–13%). The deviation of the gap value from the calculated one leads in any case to negative consequences: a decreasing - to scuffing and a complete failure of the whole device, increasing - to reducing the volume efficiency of the pump. Presented calculating technique can be recommended as easy-to-use and simple way to consider local losses in automatic balancing device.