Optimized Design Of Vehicle Cooling Water Pump And Research On Characteristic Of Cavitations Vibration

Water Pump is one of the important component of all the components inside the vehicle engine cooling system and it plays an important role in terms of power performance, economical efficiency and reliability of engine. It is important in the cooling of engine as well as for the engine running. Hence under meeting with the requirements like noise vibration, cavitations performance and environmental protection, the reliability requirement of it is getting stricter. In this article, we take Vehicle Cooling Pump as the subject of the research, we adopted the method of combining numerical value and test, we optimized the design of two segments of blade profile of vane of variable camber, we aimed at changing the position of variable camber, inlet angle as well as blade wrap angle, and then check to see the effects it caused to the internal flow field and external characteristic. Based on this, we made comparison and analysis on the effects caused to outer characteristic of Vehicle Water Pump and internal flow field by6vanes and8vanes. Besides, we have made numerical value modeling and test analysis on the cavitations performance of modeling pump and we made the study on the cavitations performance of two segments of variable camber vane profile under different clearance. We also made tests and comparison analysis on pressure pulsation and vibration under normal condition and cavitations condition. Below are the main research topics and the relative conclusions:(1)We made the research on the optimized design of Vehicle Cooling Water Pump Impeller. We adopted the orthogonal array of three factors and three levels, choosing different impeller parameter (including blade wrap angle, vane camber changing position and inlet angle), we designed6different impellers, we carried out the CFD numerical value calculation, analyzed the simulated result and fixed the final design scheme, we got the parameter of45°for blade wrap angle, vane camber changing position for1/2, inlet angle of8°. We made comparison between the optimized impeller and original impeller regarding their outer characteristic and internal flow field by way of numerical value modeling and we found that the performance of the optimized impeller was far better than the original impeller and this proved the feasibility of orthogonal array method.(2)We made the research on the performance of Vehicle Cooling Water Pump of different blade tip clearance. We made calculation on modeling pump of different blade tip clearance by way of numerical value modeling; we set different blade tip clearance (0.25mm,05.mm,1mm,2mm). We compared the outer characteristic of different clearance, combining internal flow field, analyzing influence mechanism the clearance is to the outer characteristic. We found that blade tip clearance is having great influence on the centrifugal pump lifting efficiency and this change is more obvious when blade tip clearance reached to a certain level. The cavitations of the two segments of variable camber and semi-open type of centrifugal pump is similar with the common semi-open type of centrifugal pump and as the blade tip clearance of blade tip is increasing, cavitations of modeling pump is getting weaker.(3)We made research on the performance of Vehicle Cooling Water Pump under different number of blades. Through the optimized design, we increased the number of blade, we adopted the numerical value analysis and we predicted the influence of cavitations by lifting and efficiency. We found that compared with6blades of modeling pump, turbulent fluctuation of internal flow field of the8blades of modeling pump was smaller, under different kinds of working condition, the maximum value of turbulent fluctuation was happened on the side of blade tip clearance on the crossing of impeller and volute. As for the different size of clearance, the turbulent energy distribution was consistent.(4) We made unsteady simulation research on the full flow passage of Vehicle Cooling Water Pump. From the study and analysis on the internal pressure field of modeling pump under non cavitations condition, we found that separation tongue was the main pulsation source of pressure pulsation caused by the interference between rotating impeller and still volute, and as the flow volume increased, pressure pulsation amplitude decreased gradually, this proved that the optimized working condition was usually happened under the condition of big flow volume.(5) We made pressure pulsation and vibration test on Vehicle Cooling Water Pump. By comparing the numerical value modeling result, we found that blade frequency was the main frequency content of vehicle water pump pressure pulsation. However as the cavitations generates, pulsation value inside volute increased compared with situation under the normal working condition; and low frequency composition pulsation generates; at the same time disperse pulsation intensity increased, broadband pulsation intensity also increases, this proved that intensity of pressure fluctuation was increased as the cavitations intensity increases. Comparing the vibration spectrogram map of under cavitations condition and under normal condition, the vibration broadband amplitude was not changed much, this proved that the main driving frequency in the vibration spectrogram map of vehicle water pump was shaft frequency, vane frequency and frequency multiplication. Fluid vibration generated by cavitations had little effect on the whole water pump.