Lubrication and leakage characteristic research of aviation plunger pump considering plunger deflection

Aiming at the crucial issues of serious friction, wear and large leakage in the key friction pair on the aviation plunger pump, the influence factors of pressure and shear flow are introduced to correct the Reynolds governing equation of the clearance flow, the oil film thickness equation considering the deflection of the plunger was established, and the lubrication and leakage characteristics of the plunger/cylinder pair are analyzed using finite element method, and the following conclusions are obtained: the inclination angle of the plunger has a significant influence on the lubrication characteristics of the plunger pair, the maximum oil film pressure of the tilted plunger is significantly greater than that of the non-tilted plunger, a transition from elastohydrodynamic lubrication to mixed lubrication occurs in the plunger/cylinder pair at an inclination angle of 0.00015°. When the inclination angle is 0.00025°, the maximum oil film pressure is about 14 times than that without inclination, and the minimum oil film thickness when the plunger is deflected is significantly smaller than that without inclination. As the pressure difference gradually increases, the leakage ratio of a single plunger/cylinder pair mostly shows an approximate linear increase trend. When the contact length is 17 mm, the leakage amount is the largest and the slope of the varied curve is the steepest, when the unilateral clearance increases above 3 µm, the leakage ratio increases significantly. The research can provide references for the plunger/cylinder pair precise theoretical design and the instability of the core rotating components of aviation plunger pumps.