摘要
为了提高IS50-32-160低比转数离心泵在设计工况下的扬程和效率,采用数值模拟、试验设计、近似模型和遗传算法相结合的优化方法,选取了泵叶轮的叶片出口宽度、叶片出口安放角和叶片包角3个参数作为设计变量,采用最优拉丁超立方试验设计方法进行20组方案设计,应用ANSYS CFX 14.5软件对各方案进行定常数值计算,得到设计工况下的效率和扬程,并将效率和扬程作为设计目标,根据Kriging近似模型建立了设计目标与设计变量之间的近似函数,采用遗传算法对近似函数进行求解,得到最优的叶轮参数组合。研究结果表明:原始方案的外特性数值模拟结果与试验结果吻合程度较好,设计工况下预测扬程偏差为3.3%;优化后的泵水力效率提高了4.18%,而且近似模型在预测性能的准确性高;通过对比原始方案和优化方案的内流场特性,优化方案内部流动得到改善,优化的叶轮的漩涡区域比原始方案的较小;优化使得效率在主频和次频下的脉动幅值分别下降了1.52和0.84,叶轮内的较大压力脉动强度区域减小,隔舌附近监测点在主频下的压力脉动系数幅值下降了0.02。非定常压力脉动强度降低,从而泵的运行稳定性提高。提出的优化设计方法对低比转数离心泵高效以及无过载特性的优化具有一定的参考意义。
In order to improve the efficiency and head of a centrifugal pump with low-specifc-speed under design flow rate, an optimization approach of performance of the low-specific-speed centrifugal pump of IS50-32-160 was proposed by combining numerical simulation, design of experiment, approximation model and genetic algorithm. Three geometrical parameters containing blade outlet width, blade outlet angle, and blade warp angle were chosen as the design variables, and then 20 impellers were designed by Optimal Latin Hypercube Sampling method （OLHS）. Commercial software ANSYS CFX 14.5 was used to conduct the steady numerical simulation to calculate the head and efficiency under design condition, which were chosen as the optimal objectives. Approximation model was built by using the Kriging model between the objectives and design variables, and had good prediction accuracy with R-square values of 0.9513 for efficiency and 0.9294 for head. Finally, the best combination of impeller parameters was obtained by solving the approximation model with genetic algorithm. To demonstrate the improvement of performance, the velocity distribution obtained by steady simulation and the pressure fluctuation intensity distributions calculated by unsteady simulation were compared. The results showed that the performance curves obtained by experiment and numerical simulation had a good agreement and the head deviation under design flow rate was 3.3%. The optimization improved the hydraulic efficiency by 3.2%, while, the head did not improve, but it still met the requirement of design. Compared with the parameters of original impeller, the blade outlet width of optimized impeller was smaller, the blade wrap angle was larger and the blade outlet angle did not change. The optimized impeller was redesigned with the optimal parameters, and the performance was calculated. It can be found that the predicted head and efficiency deviations were 3.3% and 0.056%, respectively. The internal velocity flow characteristics in the optimal impeller were
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2015年第5期46-52,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金青年基金(51409123)
江苏省自然科学基金青年基金(BK20140554)
中国博士后科学基金面上项目一等资助(2014M560402)
江苏高校优势学科建设工程资助项目(PAPD)
关键词
泵
模型
算法
多目标优化
试验设计
数值模拟
pumps
models
algorithms
multi-objective optimization
design of experiment
numerical simulation
