Design Optimization of a Mixed Flow Waterjet Pump for Performance Improvement Involving Cavitation

2015 ◽  
Author(s):  
Renfang Huang ◽  
Xianwu Luo ◽  
Zhihong Zhai ◽  
Jiajian Zhou
Keyword(s):  
Genetic Algorithm ◽  
Design Of Experiments ◽  
Design Method ◽  
Inverse Design ◽  
Hydraulic Efficiency ◽  
Mixed Flow ◽  
Nsga Ii ◽  
Cavitation Performance ◽  
Inverse Design Method ◽  
Waterjet Pump

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.

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
Keyword(s):  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Design Method ◽  
Leading Edge ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Cavitation Performance ◽  
Optimal Sample ◽  
Dynamics Method ◽  
Flow Pump

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.

An inverse design method of diffuser blades by genetic algorithms

1998 ◽  
Vol 212 (4) ◽  
pp. 261-267 ◽  
Author(s):  
H-Y Fan
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Velocity Distribution ◽  
Design Method ◽  
Back Propagation ◽  
Inverse Design ◽  
Surface Velocity ◽  
Target Velocity ◽  
Constant Height ◽  
Inverse Design Method

A genetic algorithm incorporating a neural network technique is proposed to search for a turbo-machinery diffuser blade profile that produces a given velocity distribution on its surface. Such a new inverse design method works through minimizing the error between the surface velocity distribution of candidate blades and the target velocity distribution. For ease of employing the genetic algorithm, the blade profiles to be searched are parameterized by Bezier curves. To fix the surface velocity distribution of a candidate blade, a special type of back propagation (BP) neural network is implemented. The proposed approach is illustrated by a diffuser having two-dimensional blades with constant height and thickness. The simulations show that the new method is not only feasible but also reliable and efficient.

A Compressible Three-Dimensional Inverse Design Method Based on the Streamline Curvature Approach and Clebsch Formulation for Radial and Mixed Flow Turbomachines

2012 ◽  
Author(s):  
Xiao Pei Tian ◽  
Peng Shan
Keyword(s):  
Flow Field ◽  
Inverse Method ◽  
Design Method ◽  
Inverse Design ◽  
Periodic Flow ◽  
Mixed Flow ◽  
3 Dimensional ◽  
Streamline Curvature ◽  
Through Flow ◽  
Inverse Design Method

The through-flow inverse design method based on the streamline curvature approach is nowadays a widely used quasi-3-dimensional blades design method for radial and mixed flow turbomachines. The main limitation of this method is using the flow field on the mean stream surface S2,m to approximate the actual 3-dimensional flow field. Without an effective description of the periodic flow, it is impossible for this method to realize exactly the prescribed circumferentially averaged swirl rVθ. Is there any way to develop this classical through-flow inverse method to a 3-dimensional one conveniently? The answer is yes. A new compressible 3-dimensional inverse design method for radial and mixed flow turbomachines is presented in this paper. This new 3-dimensional inverse method provides a convenient and effective way to obtain the periodic flow field for the streamline curvature through-flow inverse method. Meanwhile, compared with another type of similar 3-dimensional inverse method firstly described by Tan etc. based on Stokes stream functions and Monge potential functions from the Clebsch formulation to calculate the circumferentially averaged flow and the periodic flow respectively, this new method has its own advantages. In order to assess the usefulness of the new method, four centrifugal impellers are designed under the same design specifications by four different inverse methods respectively. They are two quasi-3-dimensional streamline curvature through-flow inverse methods without and with a slip factor model, a 3-dimensional approximated inverse approach based on stream functions and Monge potential functions and the 3-dimensional inverse method presented here. The performances of the four impellers yielding from a RANS commercial solver are compared. The capabilities of the four methods to realize the target circumferentially averaged swirl are also studied.

Turbomachinery Blade Design Using 3-D Inverse Design Method, CFD and Optimization Algorithm

2001 ◽  
Author(s):  
Kosuke Ashihara ◽  
Akira Goto
Keyword(s):  
Simulated Annealing ◽  
Optimization Algorithm ◽  
Design Method ◽  
Three Dimensional ◽  
Inverse Design ◽  
Mixed Flow ◽  
Specific Speed ◽  
Inverse Design Method ◽  
Suction Performance ◽  
Flow Pump

An optimization approach for improving turbomachinery performance was proposed based on a three-dimensional inverse design method, a Computational Fluid Dynamics (CDF) and optimization algorithm. By combining the three-dimensional inverse design method and CFD predictions, the blade loading parameters which is the major inputs for the three-dimensional inverse design method were treated as design variables and the impeller performance predicted by CFD was treated as an objective function of the optimization problem. Firstly, to clarify the effects of optimization algorithm, mixed-flow pump impellers (Ns400), with a specific speed of 400 (m3/min,m,min−1) or 0.155 (non-dimensional), were optimized to improve the impeller efficiency by using several optimization algorithm. From these results, it was confirmed that turbomachinery optimization using the three-dimensional inverse design method is a multi-peak problem and it is essential to use exploratory techniques such as Simulated Annealing. Then, a mixed-flow pump impeller (Ns1350), with a specific speed of 1350 (m3/min,m,min−1) or 0.523 (non-dimensional), was optimized to improve the impeller efficiency with constraints for suction performance by Simulated Annealing. Reasonably high efficiency and high suction performance were confirmed by comparing the CFD results with those for the previous design which employed manual optimization.

Influence of Spanwise Distribution of Impeller Exit Circulation on Optimization Results of Mixed Flow Pump

2021 ◽  
Vol 11 (2) ◽  
pp. 507
Author(s):  
Mengcheng Wang ◽  
Yanjun Li ◽  
Jianping Yuan ◽  
Fareed Konadu Osman
Keyword(s):  
Design Method ◽  
Internal Flow ◽  
Inverse Design ◽  
Pump Efficiency ◽  
Mixed Flow ◽  
Baseline Model ◽  
Pump Impeller ◽  
First Case ◽  
Inverse Design Method ◽  
Flow Pump

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.

scholarly journals Matching Optimization of a Mixed Flow Pump Impeller and Diffuser Based on the Inverse Design Method

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 260
Author(s):  
Mengcheng Wang ◽  
Yanjun Li ◽  
Jianping Yuan ◽  
Fareed Konadu Osman
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Inverse Design ◽  
Pump Efficiency ◽  
Optimization Strategy ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Circulation Distribution ◽  
Inverse Design Method ◽  
Flow Pump

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.

A Fully Compressible Three Dimensional Inverse Design Method Applicable to Radial and Mixed Flow Turbomachines

1990 ◽  
Author(s):  
M. Zangeneh ◽  
W. R. Hawthrone
Keyword(s):  
High Speed ◽  
Design Method ◽  
Three Dimensional ◽  
Tangential Direction ◽  
Inverse Design ◽  
Mixed Flow ◽  
Exact Approach ◽  
Time Marching ◽  
The Difference ◽  
Inverse Design Method

A fully three dimensional compressible inverse design method for the design of radial and mixed flow machines is described. In this method the distribution of the circumferentially averaged swirl velocity, or rV¯θ on the meridional geometry of the impeller is prescribed and the corresponding blade shape is computed iteratively. Two approaches are presented for solving the compressible flow problem. In the approximate approach, the pitchwise variation in density is neglected and as a result the algorithm is simple and efficient. In the exact approach, the velocities and density are computed throughout the three dimensional flow field by employing Fast Fourier Transform in the tangential direction. The results of the approximate and exact approach are compared for the case of a high speed (subsonic) radial-inflow turbine and it is shown that the difference between the blade shapes computed by the two methods is well within the manufacturing tolerances. The flow through the designed impeller is analysed by using three dimensional inviscid and viscous time marching programs and very good correlations between the specified and computed rV¯θ is obtained.

scholarly journals Suppression of Secondary Flows in a Mixed-Flow Pump Impeller by Application of 3D Inverse Design Method: Part 1 — Design and Numerical Validation

1994 ◽  
Author(s):  
M. Zangeneh ◽  
A. Goto ◽  
T. Takemura
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Secondary Flows ◽  
Inverse Design ◽  
Experimental Comparison ◽  
Suction Surface ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Inverse Design Method ◽  
Flow Pump

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.

Suppression of Secondary Flows in a Mixed-Flow Pump Impeller by Application of Three-Dimensional Inverse Design Method: Part 2—Experimental Validation

1996 ◽  
Vol 118 (3) ◽  
pp. 544-551 ◽  
Author(s):  
A. Goto ◽  
T. Takemura ◽  
M. Zangeneh
Keyword(s):  
Design Method ◽  
Three Dimensional ◽  
Flow Fields ◽  
Secondary Flows ◽  
Inverse Design ◽  
Suction Surface ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Inverse Design Method ◽  
Flow Pump

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.

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