Which are the most important pressure effects in dynamic analysis of gear pumps?

In previous works, the authors have presented a numerical model of the dynamic behaviour of an external gear pump for automotive applications. The model takes the most important phenomena involved in the operation of this kind of machine into account. The simulation results have shown that the variable meshing stiffness has a notable contribution on the dynamic behaviour of the pump but this is not as important as the pressure phenomena. As a consequence, the original model was modified with the aim of improving the calculation of pressure forces and torques in order to achieve a result that was closer to measured values. The new pressure formulation includes several phenomena not considered in the previous one, such as the pressure variations at input and output ports, as well as an accurate description of the trapped volume and its connections with high and low pressure chambers. In particular in this paper the relative effect of each considered pressure phenomenon will be discussed ...