An experimental study for the comparison of performances of external gear pumps with symmetric and asymmetric gears

In this thesis, an experimental study is presented for the comparison of performances of gear pumps designed by using symmetric and asymmetric spur gear pairs. Parameters for performance measurement include volumetric flowrate, flowrate fluctuation coefficient, noise level, vibration level and power consumption rate. The symmetric and asymmetric gear tooth are modelled by using an automated software in which coordinates of all points on the tooth profile are determined. These models are converted to solid models and simulated by using SolidWorks® software. Both symmetric and asymmetric gears have been manufactured by using Electro Discharge Machining (EDM) method. Experiments are carried out by using two sets of symmetric gear pair and four sets of asymmetric gear pair. The experiments have been performed at three different rotational speed of the pump. Volumetric flowrate, noise, vibration and power consumption of the motor are measured and flowrate fluctuation is calculated for all cases. Experimental results showed that; gear pump which has asymmetric gear pair has less noise, less vibration and less power consumption with respect to symmetrical gears. Volumetric flowrate did not differ much for both cases. However, flowrate fluctuation is reduced considerably by using asymmetric gear profile.