| Lubricating oil pump is an important component of the aero engine lubricating system, which is mainly used for the transmission and recovery the lubricating oil of the engine bearing and the transmission gear. Because of the characteristics of the pan- oil pump with compact structure, small volume, light weight, good filling performance, small pressure fluctuation, etc.. Many domestic and foreign scholars have studied on its forming way, working characteristic and volume efficiency. At present, our country and some developed countries in Europe and the United States have begun to use in the aviation engine widely.To improve the rotary speed of the pan- oil pump can reduce the geometric size of the rotor, so that the volume of oil pump is reduced, and the increase of rotor speed can be enhanced due to the throttling effect, which is conducive to the improvement of the volume efficiency. As a result of the aircraft engine lubricating oil pump is generally driven by the engine spindle or accessory gearbox. Raise the rotary speed, can effectively reduce the structure weight, so as to achieve the effect of reducing the weight of the engine.However, in the process of the selection of the parameters of the rotor of the air pump rotor, mapping and testing are the main methods in the field of aviation in our country. In the practical application found pan-cycloid lubricating oil pump under the condition of high rotary speed, prone to cause oil filling badness and cavitations problems due to the unreasonable oil inlet and outlet cavity structure design, which seriously affect the pan-cycloid pump volumetric efficiency, flow pulsation rate performance, and the high speed development.In this paper, the main factors affecting the performance of the pan-cycloid pump are analyzed based on the forming principle and working principle. And on the basis of the predecessors, according to the design steps and acceptance requirements of aviation lubricating oil pump, the design method of the rotor with the minimum volume as the design object, and the flow rate and the sliding coefficient as the performance constraint, considering the rotating speed and rotor width is presented, for the first time. The problem that the previous design method is difficult to meet the requirements of high rotating speed is improved.In order to promote the development of the high speed of the pan-cycloid lubricating oil pump, the CFD method is used to study the fluid structure coupling. By studying the sensitivity of the structure of the inlet and outlet cavity to the pump volume efficiency, the structure of the diagonal oil groove is found better than those of the other two kinds of oil tanks, in the aspect of volume efficiency. Aimed at the high rotating speed of pump operating characteristics, further optimization found, when inlet and outlet cavity center line formed about 25 DEG included angle, inner rotor speed 15000 r / min, the ground volumetric efficiency decrease slightly, high altitude volumetric efficiency come to the highest. When the oil groove depth is near 4.9mm, the oil groove depth is the most suitable.Based on the guarantee of the volume efficiency, the single stage pump can get better results by communicating with the inlet and outlet of the oil tank at the same time. Further analysis found, when the rotor speed is 15000r/min, at the ground state, smaller communication area and larger oil groove spacing have little impact on the volumetric efficiency and flow pulsation, while the large communication area and the small oil groove spacing seriously affect the performance of pump. At high altitude, the highest actual volume efficiency comes when the communication area is between 7.03 ~ 8.85 mm2 and the oil groove spacing is between 1.9 ~ 2.5mm. Compared to the case without communication, it increases by about 10%. The minimum value of the flow pulsation occurs in the area of communication: between 5.19 ~ 8.85 mm2, the oil groove spacing: 2.5 ~ 3.1mm. Compared to the case without communication, it decreases by about 13%. The measurement of dislocation can make the two stage pump reduce the flow pulsation by about 40%. Provide reference for the design of aviation oil pump. |
