scholarly journals Anti-Cavitation Design of the Symmetric Leading-Edge Shape of Mixed-Flow Pump Impeller Blades

Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 46 ◽  
Author(s):  
Di Zhu ◽  
Ran Tao ◽  
Ruofu Xiao

Mixed-flow pumps compromise large flow rate and high head in fluid transferring. Long-axis mixed-flow pumps with radial–axial “spacing” guide vanes are usually installed deeply under water and suffer strong cavitation due to strong environmental pressure drops. In this case, a strategy combining the Diffusion-Angle Integral Design method, the Genetic Algorithm, and the Computational Fluid Dynamics method was used for optimizing the mixed-flow pump impeller. The Diffusion-Angle Integral Design method was used to parameterize the leading-edge geometry. The Genetic Algorithm was used to search for the optimal sample. The Computational Fluid Dynamics method was used for predicting the cavitation performance and head–efficiency performance of all the samples. The optimization designs quickly converged and got an optimal sample. This had an increased value for the minimum pressure coefficient, especially under off-design conditions. The sudden pressure drop around the leading-edge was weakened. The cavitation performance within the 0.5–1.2 Qd flow rate range, especially within the 0.62–0.78 Qd and 1.08–1.20 Qd ranges, was improved. The head and hydraulic efficiency was numerically checked without obvious change. This provided a good reference for optimizing the cavitation or other performances of bladed pumps.

2001 ◽  
Vol 7 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Steven M. Miner

This paper presents the results of a study using a coarse grid to analyze the flow in the impeller of a mixed flow pump. A commercial computational fluid dynamics code (FLOTRAN) is used to solve the 3-D Reynolds Averaged Navier Stokes equations in a rotating cylindrical coordinate system. The standardk-εturbulence model is used. The mesh for this study uses 26,000 nodes and the model is run on a SPARCstation 20. This is in contrast to typical analyses using in excess of 100,000 nodes that are run on a super computer platform. The smaller mesh size has advantages in the design environment. Stage design parameters are, rotational speed 1185 rpm, flow coefficientφ=0.116, head coefficientψ=0.094, and specific speed 2.01 (5475 US). Results for the model include circumferentially averaged results at the leading and trailing edges of the impeller, and analysis of the flow field within the impeller passage. Circumferentially averaged results include axial and tangential velocities, static pressure, and total pressure. Within the impeller passage the static pressure and velocity results are presented on surfaces from the leading edge to the trailing edge, the hub to the shroud, and the pressure surface to the suction surface. Results of this study are consistent with the expected flow characteristics of mixed flow impellers, indicating that small CFD models can be used to evaluate impeller performance in the design environment.


1960 ◽  
Vol 82 (4) ◽  
pp. 929-940 ◽  
Author(s):  
G. M. Wood ◽  
J. S. Murphy ◽  
J. Farquhar

A mixed flow impeller design was tested with six, five, and four vanes in a closed water loop to study the effects of cavitation on hydraulic performance and the results were compared with the work of other investigators. Two idealized flow models for incipient cavitation were derived to illustrate limits of cavitation design. It was found that both vane blockage and solidity effects are important when designing for optimum cavitation performance. Data showing incidence and speed effects plus the tip static pressure profiles in cavitating and noncavitating flow are also presented.


2021 ◽  
Vol 11 (2) ◽  
pp. 507
Author(s):  
Mengcheng Wang ◽  
Yanjun Li ◽  
Jianping Yuan ◽  
Fareed Konadu Osman

The spanwise distribution of impeller exit circulation (SDIEC) has an important influence on the performance of the impeller. To quantitatively study the influence of SDIEC on optimization results, a comprehensive optimization system composed of the computational fluid dynamics, inverse design method, design of experiment, surrogate model, and optimization algorithm was used to optimize a mixed flow pump impeller in two different cases. In the first case, the influence of SDIEC was ignored, while in the second case, the influence of SDIEC was considered. The result shows that the optimization upper limit can be further improved when the influence of SDIEC is considered in the optimization process. The pump efficiency of the preferred optimized impeller F1 obtained in the first case at 1.2Qdes, 1.0Qdes, and 0.8Qdes are increased by 6.48%, 2.41%, and 0.06%, respectively, over the baseline model. Moreover, the pump efficiency of the preferred optimized impeller S2 obtained in the second case further increased by 0.76%, 1.24%, and 1.21%, respectively, over impeller F1. Furthermore, the influence of SDIEC on the performance of the mixed flow pump is clarified by a comparative analysis of the internal flow field.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 260
Author(s):  
Mengcheng Wang ◽  
Yanjun Li ◽  
Jianping Yuan ◽  
Fareed Konadu Osman

When considering the interaction between the impeller and diffuser, it is necessary to provide logical and systematic guidance for their matching optimization. In this study, the goal was to develop a comprehensive matching optimization strategy to optimize the impeller and diffuser of a mixed flow pump. Some useful tools and methods, such as the inverse design method, computational fluid dynamics (CFD), design of experiment, surrogate model, and optimization algorithm, were used. The matching optimization process was divided into two steps. In the first step, only the impeller was optimized. Thereafter, CFD analysis was performed on the optimized impeller to get the circulation and flow field distribution at the outlet of the impeller. In the second step of optimization, the flow field and circulation distribution at the inlet of the diffuser were set to be the same as the optimized impeller outlet. The results show that the matching optimization strategy proposed in this study is effective and can overcome the shortcomings of single-component optimization, thereby further improving the overall optimization effect. Compared with the baseline model, the pump efficiency of the optimized model at 1.2Qdes, 1.0Qdes, and 0.8Qdes is increased by 6.47%, 3.68%, and 0.82%, respectively.


Author(s):  
M. Zangeneh ◽  
A. Goto ◽  
T. Takemura

This paper describes the design of the blade geometry of a medium specific speed mixed flow pump impeller by using a 3D inverse design method in which the blade circulation (or rVθ) is specified. The design objective being the reduction of impeller exit flow non-uniformity by reducing the secondary flows on the blade suction surface. The paper describes in detail the aerodynamic critria used for the suppression of secondary flows with reference to the loading distribution and blade stacking condition used in the design. The flow through the designed impeller is computed by Dawes viscous code, which indicates that the secondary flows are well suppressed on the suction surface. Comparison between the predicted exit flow field of the inverse designed impeller and a corresponding conventional impeller indicates that the suppression of secondary flows has resulted in substantial improvement in the exit flow field. Experimental comparison of the flow fields inside and at exit from the conventional and the inverse designed impeller is made in part 2 of the paper.


Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 905 ◽  
Author(s):  
Mengcheng Wang ◽  
Yanjun Li ◽  
Jianpin Yuan ◽  
Fan Meng ◽  
Desmond Appiah ◽  
...  

The spanwise distribution of impeller exit circulation (SDIEC) has a significant effect on the impeller performance, therefore, there is a need for its consideration in the optimization design of mixed-flow pumps. In this study, a combination optimization system, including a 3D inverse design method (IDM), computational fluid dynamics (CFD), Latin hypercube sampling (LHS) method, response surface model (RSM), and non-dominated sorting genetic algorithm (NSGA-Ⅱ) was used to improve the performance of the mixed-flow pump after considering the effect of SDIEC on the performance of the impeller. The CFD results confirm the accuracy and credibility of the optimization results because of the good agreement the CFD results established with the experimental measurements. Compared with the original impeller, the pump efficiency of the preferred impeller at 0.8Qdes, 1.0Qdes, and 1.2Qdes improved by 0.63%, 3.39%, and 3.77% respectively. The low-pressure region on the blade surface reduced by 96.92% while the pump head difference was less than 1.84% at the design point. In addition, a comparison of the flow field of the preferred impeller and the original impeller revealed the effect of SDIEC on mixed-flow pump performance improvement and flow mechanism.


Author(s):  
Renfang Huang ◽  
Xianwu Luo ◽  
Zhihong Zhai ◽  
Jiajian Zhou

A mixed-flow waterjet pump with a vaneless diffuser is treated to improve its hydraulic efficiency as well as cavitation performance. In order to conduct the design optimization, the authors apply a multiobjective strategy combined with design of experiments (DOE), computational fluid dynamics (CFD), inverse design method, surface response method (RSM) and non-dominated sorting genetic algorithm-II (NSGA-II). The hydraulic efficiency and the total vapor volume are selected as the optimization targets, and nine parameters are used to describe the blade shape with the same meridional section. For numerical simulation, RANS method is applied with SST k-ω turbulence model and a mass transfer cavitation model based on the Rayleigh-Plesset equation. Optimal Latin hypercube design method is used in the design of experiments to uniformly sample in variation ranges and global optimization is then conducted by using non-dominated sorting genetic algorithm-II (NSGA-II) based on the input-target approximation functions built by the response surface model (RSM). The optimization results demonstrate that both hydraulic efficiency and cavitation performance are improved at the design point through this multiobjective strategy. Based on analysis of the internal flows, secondary flows would be important contributor to the hydraulic loss as well as the nonuniform flow at impeller exit, and can be suppressed by adjusting the blade load along the hub or shroud by using the inverse design method.


1996 ◽  
Vol 118 (3) ◽  
pp. 544-551 ◽  
Author(s):  
A. Goto ◽  
T. Takemura ◽  
M. Zangeneh

In Part 1 of this paper, a mixed-flow pump impeller was designed by a fully three-dimensional inverse design method, aimed at suppressing the secondary flows on the blade suction surface. In this part, the internal flow fields of the impeller are investigated experimentally, using flow visualization and phase-locked measurements of the impeller exit flow, in order to validate the effects of secondary flow suppression. The flow fields are compared with those of a conventional impeller, and it is confirmed that the secondary flows on the blade suction surface are well suppressed and the uniformity of the exit flow fields is improved substantially, in both circumferential and spanwise directions. The effects of tip clearance and the number of blades for the inverse designed impeller are also investigated experimentally and numerically.


Author(s):  
A. Goto ◽  
T. Takemura ◽  
M. Zangeneh

In Part I of this paper, a mixed-flow pump impeller was designed by a fully three-dimensional inverse design method, aimed at suppressing the secondary flows on the blade suction surface. In this part, the internal flow fields of the impeller are investigated experimentally, using flow visualization and phase-locked measurements of the impeller exit flow, in order to validate the effects of secondary flow suppression. The flow fields are compared with those of a conventional impeller, and it is confirmed that the secondary flows on the blade suction surface are well suppressed and the uniformity of the exit flow fields is improved substantially, in both circumferential and spanwise directions. The effects of tip clearance and the number of blades for the inverse designed impeller are also investigated experimentally and numerically.


Sign in / Sign up

Export Citation Format

Share Document