农业工程学报2017，Vol.33Issue(23)：93-100,后插1,9.DOI:10.11975/j.issn.1002-6819.2017.23.012
比例施肥泵驱动活塞受力分析及内部流动模拟与试验
Force analysis of drive piston and simulation and experiment of internal flow for proportional fertilizer pump
摘要
Abstract
Taking proportional pump as the main research object, the force of the drive piston in the process of reciprocating motion was analyzed. On the basis of the Fluent simulation software, a three-dimensional dynamic simulation model of proportional pump was established through writing dynamic mesh programs according to UDF (user defined function) and choosing the reasonable turbulent model. The computational simulation model was also validated by using the experimental data. On this basis, the internal flow field of the proportional pump was simulated. The results showed that the numerical simulation model had good accuracy. The relationships between the flow rates and the differential pressures obtained by simulation were basically consistent with that by testing, and the error between simulated value and experimental value was within 4.20％. The simulated values of piston movement frequency were larger than the experimental values in the full differential pressure range. However, the variation trend of the simulated movement frequency with the differential pressure was the same as the experimental trend. The relative error between the simulated value and the experimental value was 9.5％ under the differential pressure of 0.03 MPa. When the differential pressure increased to 0.15 MPa, the relative error between the simulated value and the experimental value increased to 11.2％. The relative errors between the simulated values and the experimental values for the piston movement frequency were controlled within 12％. The simulated velocities of the piston were slightly higher than the experimental values. However, the variation trends were consistent, and the movement velocity reached the steady state after a short time for both simulating and testing. The movement law for upward movement was similar to downward movement, and the drive piston was accelerated and then kept uniform motion. The force in different surfaces for the drive piston increased linearly with the increase of differential pressure. The flow velocities in the inlet valve and outlet valve were very large, which was conducive to mix the fertilizer and water. The upward movement time of the drive piston during a period was 0.33 s and the downward movement time was 0.275 s under the differential pressure of 0.09 MPa, which indicated that the upward movement time was longer than the downward movement time. The flow velocity in most of the flow field was low and the kinetic energy was basically converted to pressure to drive the piston in the reciprocating motion process of the drive piston. Under the differential pressure of 0.09 MPa, the maximum flow velocity increased from 7.5 m/s at 0.02 s in the downward stage to 9 m/s at the end of downward movement. Similarly, the maximum flow velocity increased from 6.5 m/s at 0.02 s in the upward stage to 8.5 m/s at the end of the upward movement. In downward movement stage, the force on the first surface and the third surface fluctuated greatly at the initial stage and then reached a relatively steady state after a certain amount of time under the differential pressure of 0.09 MPa. The force on the second surface decreased from 699.3 to 335.9 N in 0.055 s and then remained stable. In upward movement stage, the force on the first and third surfaces was basically stable at a certain level, and the force on the second surface increased from 0 to 359.7 N in 0.034 s and then kept stable under the differential pressure of 0.09 MPa. The force on the first surface and the third surface was driving force, and the force on the second surface was resistance. The results can provide valuable information for the design method of the proportional pump as well as the reasonable adjustment of the differential pressure during the operational process.关键词
泵/肥料/流场/压差/流量/动网格Key words
pump/fertilizer/fluid fields/differential pressure/flow rate/dynamic mesh分类
农业科技引用本文复制引用
汤攀,李红,骆志文,孙彩珍..比例施肥泵驱动活塞受力分析及内部流动模拟与试验[J].农业工程学报,2017,33(23):93-100,后插1,9.基金项目
国家自然科学基金(51679109 （）
51609104) （）
公益性行业(农业)科研专项(201503130) （农业）
江苏省 2015 年度普通高校研究生科研创新计划(KYLX15_1062) （KYLX15_1062）
