Abstract:The influence of contaminated particles on hydraulic external gear pump from the perspective of leaks caused by contaminant wear was discussed. First, the contaminant sensitivity theory (Omega theory) and the contaminant sensitivity test method of pumps were introduced. Then based on the external gear pump leakage model to optimize the test data and applying the analytical model of pump contaminant sensitivity, the value of external gear pump contaminant sensitivity was calculated, as well as the pump contaminant life was forecasted. The results show that this method can accurately evaluate pumps' resistance on contaminant wear and predict pumps' contaminant wear-life, which can offer theoretical guidance on pump selecting and reliability analysis.