In this master's thesis, the interaction between the suction lines of two internal gear hydraulic pumps with different displacements in an open circuit hydraulic system was investigated. Under certain operating conditions, such a design can lead to an uneven flow distribution between the suction lines and thus to different flow conditions at the inlet of each pump. In extreme cases, this can lead to the occurrence of cavitation, which has a negative effect on performance. In this work, we have analysed the various influencing conditions that can lead to interactions between the two suction lines numerically and experimentally. We have shown that as the distance between the suction lines decreases, the interaction between the pumps increases, resulting in a higher pressure drop at the inlet of the pump. We found that the diameter of the suction lines and the frequency of the pumps' drive shaft can have an exponential influence on the pressure drop at the inlet of the pumps. We have shown that the use of baffles has a positive effect on liquid stilling and air entrainment, but a negative effect if the design impedes flow through the tank. We have also shown that as the volume of hydraulic fluid decreases and the height of the tank relative to the pump decreases, the amount of air in the oil increases, which also leads to higher pressure losses and a deterioration of the inlet conditions in the pump.
|
