Dıştan dişli pompanın nümerik ve teorik analizi

External gear pumps are one of the mostly used pump types in the fluid power applications due to simplicity, low cost and long operation period. However, there are some disadvantages such as internal leakages, noise and vibration with gear pumps. This study investigates comparison of theoretical calculations and 2D-3D numerical simulations with considering temperature effects on tip leakage. 2D numerical simulations have been done for pressure difference from 2 bars up to 10 bars for seven different rotational speeds. Additionally, the effect of wall temperature varied from 303 K up to 333 K has been investigated on the performance of gear pump. 3D numerical simulations could be performed only for 2 cases due to long computational time. Because of extra assumptions made in theoretical calculations for tip leakages, it is shown that there are some deviations between theoretical and numerical results. These deviations are due to pressure drop which occurs because of energy dissipation between two teeth tips which can be observed in numerical simulations and fully developed flow assumption made in theoretical analysis. Results of numerical study show that the fully developed assumption in the gap between gear tooth and wall is not appropriate. In addition, face leakage and gearing zone leakage has been investigated in 3D numerical simulations to compare with theoretical calculations. Furthermore, it has been shown that leakages increase linearly with temperature rise at the wall due to the drop in the viscosity of the liquid.