你的位置:水利论文 >> 论文 >> 江苏省 >> 江苏大学 >> 详细内容 在线投稿

带分流叶片离心泵全流场数值预报和设计方法研究 【作者】张金凤 【导师】袁寿其

热度126票 浏览89次 【共0条评论】【我要评论 时间:2007年7月01日 21:31
水利论文BW4cIi[

带分流叶片离心泵全流场数值预报和设计方法研究水利论文M1@-Q$o&R DXq@

水利论文A0\3L;rk;y)s;wI

【作者】张金凤导师袁寿其水利论文-h"JU s"jek x
【作者基本信息】江苏大学,流体机械及工程,2007年,博士

9P)AZS B(ns0

ptNq }uD n0
"` h*\5ECo0【中文摘要】 低比速离心泵广泛应用于国民经济各个领域,为了进一步提高其水力性能,改善内部流动状态,人们在叶轮相邻两长叶片之间添置分流叶片。课题组前期研究表明,添置分流叶片后离心泵的性能确有提高。本文在高等学校博士点基金项目的资助下,采用数值计算和实验验证相结合的方法,对带分流叶片的低比速离心泵进行研究,旨在找出分流叶片对全流场内部流动以及对低比速离心泵性能的影响规律,完善带分流叶片离心泵的设计方法。主要研究工作和创造性成果有:(1)简要回顾了离心泵内部流动测试与数值模拟的研究进展;讨论了分流叶片对低比速离心泵内部流动改善和效率提高的机理,并对其研究现状进行了分析;对离心泵的理论特性、内部流动机理和粘性损失作了较全面的概括。(2)总结了本课题组前期在分流叶片方面的研究工作:正交试验得出的分流叶片的几何参数对性能的影响情况,及CFD数值计算与PIV测试的对比结果等。在此基础上,针对分流叶片的进口直径和周向偏置度进行多方案设计和叶轮内的流场计算,深入探索了分流叶片改善叶轮内部流动的机理。首次引入湍动能及叶片载荷的概念,深入分析了添置分流叶片后对叶轮做功,及对叶轮内“射流-尾流”结构的改善原理;通过对单个流...更多道内多截面的速度分布分析,了解分流叶片偏置对两个分流道内流量分布及速度分布的影响趋势。(3)引入叶片数作为设计变量,进行多方案改进设计,首次对包括叶轮前后腔体的离心泵全流场进行数值模拟。针对其中一个设计方案,采用不同的湍流模型网格数以及迭代残差,对数值模拟的计算精度进行了验证,尽可能地把人为误差控制在最小范围内,确保后期计算结果的稳定性。预报了各设计方案离心泵的性能曲线,得出添加分流叶片后对泵性能的影响趋势:H-Q曲线更趋平坦,η-Q曲线向大流量方向偏移,且高效区变宽;P-Q曲线更加陡增。(4)通过对分流叶片及长叶片上的作用力矩分析,以及叶轮内流场的湍动能分布规律,首次提出了“分流叶片作用力矩为正”的原则,来确定分流叶片进口直径取值的上限;并结合以往设计经验,建立了适用于低比速离心泵的分流叶片进口直径的设计公式。(5)首次通过数值模拟方法,预测了不同工况下叶轮盖板内外侧表面的粘性损失及圆盘摩擦损失;并把圆盘摩擦损失值与经验公式计算结果对比,二者在设计点处有较好的一致性,但计算得到的不同工况下的圆盘摩擦损失分布规律是一种新的发现,各个方案都在1.0Qd附近有极小值,圆盘摩擦损失所占轴功率比例为15%左右,在0.4Qd附近有极大值,圆盘摩擦损失可占30%以上。(6)采用L9(34)正交试验设计方案,应用FDM熔丝沉积成形工艺加工叶轮,并进行外特性实验。通过正交试验,获得分流叶片几个设计参数对泵性能影响的主次顺序,并提出了分流叶片各设计参数的取值原则。为了与前期数值计算部分对应起来,验证数值预报离心泵性能规律的准确性,对第四章改进设计中的几个叶轮加工并进行试验对比。结果表明,二者性能曲线分布规律相似,但实验数据要比数值预报所得扬程和效率略低,扬程预测误差在5%左右,效率预测误差在10%以内,基本满足工程要求。(7)首次对带分流叶片离心泵的无过载特性进行探索。对某一带分流叶片叶轮方案,与同一型号性能较好的蜗壳进行配对,并进行全流场数值模拟和结果对比分析,发现喉部面积的改变可以改变高效点的位置,但性能曲线的形状基本没有改变。对于另外一个型号有高效率和无过载要求的带分流叶片的低比速离心泵,进行了蜗壳的多方案设计、数值模拟和实验研究,分析了蜗壳喉部面积设计对带分流叶片的离心泵无过载特性的影响关系,探索其对轴功率特性的改进,但发现单纯通过减小蜗壳喉部面积,很难实现功率特性的控制。(8)总结了低比速离心泵分流叶片几何参数的设计方法。对添置分流叶片的低比速离心泵叶轮的设计,在分析实验数据的基础上,修正了加大流量设计法的流量放大系数,并对主要几何参数的确定方法进行探讨;建议在进行分流叶片离心泵设计时,要兼顾无过载特性,尤其叶片出口安放角β2的取值在允许的范围内要取较小值;提出了蜗壳喉部面积是保证带分流叶片离心泵无过载特性的关键因素,面积比应在0.73~1.90范围内取值。  还原

0w*e,WLV[n0水利论文pt"L)r:I/x%@7J

【英文摘要】 The low-specific speed centrifugal pump has been used widely in most industrial fields, in order to improve its hydraulic performance and control the inner flow condition, splitter blades were added between two long blades. The former researches show that, the adding of splitter blades does improve the performance of centrifugal pumps. Based on the Foundation of National College Doctoral Program, numerical simulation and performance tests were adopted to study the centrifugal pumps with splitter blades, to explore the relation among the design of splitter blades, the pump inner flow condition and pump performance, and to improve the design method for the centrifugal pumps with splitter blades. The innovative achievements and important conclusions obtained are as followings:(1) The research states of inner flow tests and numerical simulations for centrifugal pumps were reviewed briefly, the principle of performance improvement and efficiency increase for adding splitter blades were disc...更多ussed, and the research state for splitter blades was analyzed also; meanwhile, the theoretical characteristics, inner flow laws and the viscous losses for centrifugal pumps were introduced comprehensively.(2) The former research achievements in our work group were summarized, which including the impacts of splitter blades to centrifugal pumps performance from the orthogonal tests, and the comparison results between CFD(Computational Fluid Dynamics) and PIV(Particle Image Velocimetry). On these bases, several schemes were designed with different splitter blades inlet diameters and the bias angle in peripheral direction, and the simulations of inner flow in impeller were done, to explore the principle of improving the flow conditions. And the variables of turbulence kinetic energy and blade loading were adopted here for the first time to analysis the relation between the adding of splitter blades and impeller work applied, and to find the principle of improving the "jet-wake" structure. And by the analysis the velocity of the multi-sections of one flow passage, the distribution of velocity and flow rate in two sub-passages were visualized.(3) Blade number was adopted in design, and several improved design schemes were given, and the whole flow field simulations, which including the internal space between the pump volute and impeller, were carried out for the first time. And one of the schemes was picked out to analysis the calculation accuracy, which based on different turbulent models, grid sizes, and iterative residuals, to minimize the human error and provide accurate and stable calculation results for all the schemes. The performance curves for all schemes were forecasted, and the effects of splitter blades were concluded, the curve of H -Q is more flat, the curve ofη-Q move to the larger flow rate, and the district with high efficient broadened, the curve of P-Q is steeper.(4) By comparing the total moments on the surface of impeller blades, and combine the distribution law of turbulence kinetic energy, the principle of "the applied moment on splitter blades should be positive" was presented for the first time, to define the upper limits of the splitter blades inlet diameter; and based on the empirical methods, the calculation formula for the splitter blades inlet diameter was established.(5) The viscous losses on the inner and outer surface of impeller shroud and hub and the disc friction loss, under different operation flow rates, were forecast through the simulation analysis; and by comparing the value on the design point with the results from empirical calculation, they are good consistent with each other; and it is found out that the distribution law of disc friction loss with the varying of flow rate, the loss on the 1.0Qd point take about 15% of the whole shaft power, while the loss on the 0.4Qd point take more than 30%.(6) The L9 (34) orthogonal experiments was adopted, and the tested impellers were manufactured with the craft of FDM(Fused Deposition Modeling). By the orthogonal experiments, the primary and secondary sequence of the design parameters of splitter blades were obtained, and the design principles of them were also presented. In order to verify the former simulation results, several impellers in Chapter 4 were manufactured and performance tests were done; the comparison show that, the distribution law of the performance curves are coordinate well, but the data from simulated head is higher by about 5%, and the simulated efficincy higher by about 10%, which satisfy the engineering requirements.(7) The non-overload characteristics of the centrifugal pumps with splitter blades were analyzed for the first time. For the same impeller designed in the former chapter, a volute, which is the same type and has better shaft power performance, replace the original one, and the whole flow field simulation was done. The study result shows that, the modification of throat area can only change the position of the highest efficiency, while the curve shape is not varied. For another centrifugal pump with splitter blades and has the requirements of high-efficiency and non-overload, three volute schemes with different throat area were designed and numerical simulation and performance tests were done, the impact of the volute throat area on the non-overload requirement of centrifugal pumps with splitter blades, and the improvement of shaft power characteristics were analyzed, and a conclusion was drawn that it is difficult to control the shaft power characteristics through the single change of the volute throat area.(8) The design methods for the geometry parameters of the splitter blades in the low-specific centrifugal pumps were summarized. And for the impeller adding splitter blades, the coefficient of flow rate in the flow-enlarged method was revised based on the tests results analysis and several geometry parameters of impeller was discussed. And a recommendation was given, when design a centrifugal pump with splitter blades, the non-overload characteristic should be considered, especially the blade outlet angleβ2 should select a smaller one in the recommended value span, and the volute throat area is another key factor, which should be in the span of 0.73~1.90.  还原水利论文;{.T4nWo

U!zpMug&f0【中文关键词】 低比速离心泵; 分流叶片; 正交试验; 数值模拟; 喉部面积
I])w!N,?XZ0【英文关键词】 Low-specific centrifugal pump; Splitter blades; Orthogonal experiment; Numerical simulation; Throat area of volute水利论文x8VW.~H]`(f
水利论文 Gg%Y4S H4_ x

mS9J5h%e9B5|0 

5jQb IcH\H:n1G0
TAG: 流场 数值 叶片 袁寿其 张金凤
顶:16 踩:14
【已经有96人表态】
21票
极差
16票
很差
8票
较差
11票
稍差
10票
稍好
10票
较好
7票
很好
13票
极好
下一篇:荷电喷雾燃烧的基础研究——燃油静电喷雾及荷电两相湍流射流的研究 【作者】王军锋 …
上一篇:非线性波系统的精确解与解析近似解 【作者】卢殿臣 【导师】田立新
查看全部回复【已有0位网友发表了看法】

广告投放

广告投放