The CFD Analysis of Pressure Pulsation in the Aircraft Engine and Control Systems Lubrication Pump

Fluid pressure pulsation in a fluid system is an inherent consideration in applications such as aircraft engine and control systems where mechanical component fatigue life and flow performance are critical. Positive displacement pumps transmitting fluid through hydraulic lines under high pressure impart periodic flow pulses to the fluid which can induce undesirable pressure ripple. Some failures of advanced aircraft prototype hardware were traced to a break in the hydraulic component of the control system due to severe localized responses to periodic pressure pulsations produced by a pump flow-induced ripple at the system resonant frequency. This response is associated with a strong structural fluid resonance that is not sufficiently damped by fluid leakage internal to the aircraft hydraulic system. In the case of pumps or hydraulic motors the main source of pulsation energy is in the flow-induced pressure wave associated with the system plumbing pressure pulsations. The pressure wave may propagate in both the pumping wall and fluid as a result of fluid/structure coupling. For a high level of pressure pulsation, the resulting pumping wall motion can then cause mechanical fatigue and unwanted radiated noise and cavitation. This report describes the application of CFD analysis in an aircraft engine control system's vane pumps with a non-intrusive fluid wave in the system. The ultimate goal is to understand the root cause of the pressure pulses and to define improvements or corrective action.