Optimization Design and Inner Flow Analysis on a Medium-High Specific Speed Centrifugal Pump

2013 ◽  
Author(s):  
Fan Zhang ◽  
Shouqi Yuan ◽  
Qiang Fu ◽  
Bo Hu ◽  
Yi Tao ◽  
...  
Keyword(s):  
Optimization Design ◽  
Design Method ◽  
Flow Analysis ◽  
Design Flow ◽  
Test Results ◽  
Centrifugal Pumps ◽  
Parameters Selection ◽  
Wrap Angle ◽  
Specific Speed ◽  
Low Efficiency

Aiming at the problems of low efficiency, easily overload and having humps of the TS100–200 centrifugal pumps, four impellers are designed with different blade curves to improve the performances of the pumps. Non-overload design method is adopted for parameters selection of impellers. The 3-D models and the 1.61 million structure grids were generated by Pro/E and ICEM respectively. After the boundary conditions of velocity inlet, outflow in the outlet and no-slip wall were specified, and the flow model was complemented with the standard k-ε model by using the commercial software CFX 12.1. The distributions of pressure, turbulence kinetic energy and streamlines in four impellers are obtained during simulation, as well as their hydraulic performances. The wrap angle φ is a critical parameter to the blade shape. Impeller-2 with appropriate wrap angle φ shows good hydraulic characteristics and excellent inner flow patterns, and it is produced for experiments by prototyping rapidly. The test results are in accordance with the simulating results. The head of impeller-2 is 5% higher than the design parameter at most and the efficiencies are nearly 6% higher than the efficiencies of the prototype pump at the design flow rate QR. The test results also show a good non-overload performances. The results prove that it is an effective and reliable method to the optimal design of centrifugal pumps with medium-high specific speed.

Performance Investigations of Large Capacity Centrifugal Compressors

1978 ◽  
Author(s):  
H. Mishina ◽  
I. Gyobu
Keyword(s):  
Pressure Ratio ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Design Procedure ◽  
Test Results ◽  
Three Dimensional Flow ◽  
Loss Analysis ◽  
Area Distribution ◽  
Specific Speed ◽  
Sectional Shape

An experimental investigation concerning the optimum relative velocity distribution within impellers, the optimum diffusion ratio of vaned diffusers and the optimum circumferential area distribution, sectional shape of scrolls was carried out using high specific speed shrouded impellers with backward leaning blades. A performance design procedure based on loss analysis and quasi-three-dimensional flow analysis was also developed and modified by introducing experimental results. The design procedure was applied to a 7900-kw four-stage air compressor to demonstrate the usefulness. Field test results of the complete machine showed that the maximum isothermal efficiency was 75 percent with the pressure ratio of 5.96 and the flow rate of 29.3 m3/s.

Case Study of Improved High Specific Speed Radial Impeller

2003 ◽  
Author(s):  
Takuji Tsugawa
Keyword(s):  
Design Method ◽  
Velocity Ratio ◽  
Flow Analysis ◽  
Design Parameters ◽  
Mixed Flow ◽  
Shape Factors ◽  
Flow Angle ◽  
Diffusion Factor ◽  
Cavitation Performance ◽  
Specific Speed

It is usually thought that the axial impeller is used for high specific speed impeller and the radial impeller is used for low specific speed impeller. In the previous paper, the optimum meridian profile of axial impeller and radial impeller were obtained for various specific speed by means of the optimization of four shape factors using diffusion factor. The four shape factors were inlet relative flow angle β1, turning angle Δβ, axial velocity ratio (meridian velocity ratio) kc = Cm2/Cm1 and impeller diameter ratio kd = D1c/D2c in mid span stream surface. In case of axial impeller, the optimum meridian profiles agreed with meridian profiles of conventional impellers. To develop the radial high specific speed impeller, the optimum four shape factors of radial high specific speed impellers were calculated by diffusion factor. And the optimum meridian profiles of radial high specific speed impellers were proposed. In case of the radial impeller, the hub diameter is equal to the tip diameter in impeller outlet (the outlet hub-tip ratio is 1.0). And in axial impeller, the outlet blade height depends on the outlet hub-tip ratio. On the other hand, in mixed flow impeller, the outlet hub-tip ratio is various and the outlet blade height is independent of the outlet hub-tip ratio. To obtain the optimum meridian profile of mixed flow impeller, the hub-tip ratio of impeller outlet ν2 is adopted new additional independent shape factor for optimization in this paper. The mixed flow angle on tip meridian stream line (= 0 degree in axial impeller, = 90 degrees in radial impeller) isn’t able to be decided by this optimization using diffusion factor. But, the mixed flow angle will be decided by the number of blade and solidity. And, it will be decided by meridian velocity distribution from hub to tip for each specific speed of impeller. So, in this paper the five shape factors are used for optimization by diffusion factor. (β1, Δβ, kc, kd, ν2) The optimum meridian profiles of mixed flow impellers for various specific speed are obtained. The relative efficiency or the cavitation performance of mixed flow impeller is better than that of radial or axial impeller. In this optimum method, the relative efficiency and the cavitation performance are calculated for all specified combinations of five shape factors. The number of five shape factors are expressed by Nβ1, NΔβ, Nkc, Nkd and Nν2. The number of calculations is expressed by Nβ1 × NΔβ × Nkc × Nkd × Nν2. The calculation time of five shape factors method is Nν2 times the calculation time of four shape factors method. Then, the best 1000 combinations of five shape factors are plotted on β1 - Δβ, kc - kd and kd - ν2 plane. The aspect of the best 1000 optimum conditions are found by these three figures. In initial step of impeller design, the result of the efficiency and cavitation performance of impeller calculated in optimum principal design parameters is important. The principal design parameters are hub-tip ratio, inlet-outlet diameter ratio, axial velocity ratio, solidity, inlet flow angle, turning angle and blade number. The author proposed the optimum meridian profile design method by diffusion factor for various condition of design parameters. There is a good correlation between the optimum hub-tip ratio and the specific speed considering cavitation performance. The optimum solidity is obtained for the specific speed considering efficiency and cavitation performance. It was found that the optimum meridian profile of high specific speed impeller with appropriate efficiency and cavitation performance had large inclination on hub and tip stream lines. The calculated data base is five dimensional using five shape factors β1, Δβ, kc, kd and ν2. Using the five shape factors in case of the best efficiency, the optimum meridian profile of improved radial flow impeller is able to be calculated. At first step of the case study, the best 1000 optimum meridian profiles and the best design parameter are selected using five dimensional optimum method. Next, the blade section shape of impeller is decided by the blade or cascade design method. Using impeller flow analysis, the cavitation performance decided by 3% head reduction is calculated. Finally, the relations between the many type of meridian profile and its impeller performance by flow analysis are obtained. These relations are very useful for new type of high specific speed impeller design. Consequently, radial impellers and axial impellers are improved by the consideration of the additional shape factor, that is, outlet hub-tip ratio ν2. This calculation shows that the improved radial high specific speed impeller considering outlet hub-tip ratio is used for high suction specific speed and high efficiency.

Dimension Optimization Design of the Stewart Platform in FAST

2011 ◽  
Vol 308-310 ◽  
pp. 2110-2113 ◽  
Author(s):  
Rui Yao ◽  
Wen Bai Zhu ◽  
Qing Ge Yang
Keyword(s):  
Radio Telescope ◽  
Optimization Design ◽  
Design Method ◽  
Stewart Platform ◽  
Design Flow ◽  
Guizhou Province ◽  
Objective Functions ◽  
The World ◽  
Adjustable Mechanism ◽  
Feed Support System

China is now building the largest single dish radio telescope in the world in Guizhou province, which is called Five-hundred meter Aperture Spherical radio Telescope (FAST). A Stewart platform is introduced in FAST as an accuracy adjustable mechanism for feed receivers. The main purpose of this paper is to discuss dimension optimization design method of the Stewart platform based on three optimization objective functions. The optimization objective functions can reflect the operability and accuracy of the Stewart platform, and optimization design flow is presented according to the important degree of the three optimization objectives. Finally, a set of optimized parameters is obtained, and the study in this paper provides a basis for the coming optimization the feed support system for FAST in the next step.

Design and Multiparameter Optimization of Jet-Pumps in a Pipeline Loops Using CFD Tools

2018 ◽  
Author(s):  
Jens Toteff ◽  
Miguel Asuaje Tovar
Keyword(s):  
Design Method ◽  
Oil Field ◽  
Dynamics Simulation ◽  
Preliminary Design ◽  
Centrifugal Pumps ◽  
Simulation And Optimization ◽  
Flow Capacity ◽  
Operational Variables ◽  
Jet Pumps ◽  
Low Efficiency

Despite their low efficiency compared with centrifugal pumps, jet-pumps are highly reliable robust equipment with modest maintenance which is ideal for many applications, mostly in the oil & gas industry. For example, jet-pumps could result attractive compared to other multiphase pump systems in terms of reactivating transport lines of heavy crude oil. Nevertheless, their design method and performance analysis are rarely known in the literature and keep a high experimental component like most of the pumping equipment. Starting with a pump designed by a traditional method, this paper aims to evaluate the effect of multiple geometrical and operational variables that influence the jet-pump performance combining CFD (Computational Fluid Dynamics) simulation and optimization algorithms using commercials software (ANSYS CFX® and PIPEIT® tool). Automatically, the geometric parameters are modified according to the rules of the optimization routines seeking to maximize the flow capacity, respecting restrictions such as energy consumption. A case study is presented for the preliminary design of a pump to boost flow capacity in a trunk line of a heavy oil field. As preliminary design all simulations were carried out using single phase water flow. With this method, it was possible to quickly evaluate around 400 geometries of jet-pumps. The geometry of the optimum final pump is consistent with other pumps reported by other works. This pump enhances the fluid capacity of the line in 17% over the traditional design for the same parameters of power or consumed energy.

Numerical Analysis of Design and Off-Design Performance of High Specific Speed Mixed Flow Pumps

2011 ◽  
Author(s):  
Yumiko Sekino ◽  
Yoichi Tanabe
Keyword(s):  
Steady Flow ◽  
Periodic Boundary ◽  
Flow Analysis ◽  
Flow Patterns ◽  
Design Flow ◽  
Cfd Analysis ◽  
Mixed Flow ◽  
Blade Passage ◽  
Specific Speed ◽  
Flow Pump

In most cases of high specific speed mixed flow pump applications, it is necessary to control off-design performance such as shutoff power/head and unstable characteristic as well as design point performance. The authors have been working on multi-objective optimization strategy of mixed flow pump design considering off-deign performance by means of Computational Fluid Dynamics (CFD). In the design optimization process, it was found that the steady CFD analysis using one pitch blade passage adopting periodic boundary condition could be used for relative comparison of the important performance characteristics such as the level of efficiency, the shutoff performance and the stall characteristics of different designs. However, the steady CFD analysis with one pitch blade passage showed that absolute values of head and shaft power were estimated lower than those of the experimental results especially in the partial capacity range. In order to improve the accuracy of CFD results it should be necessary to use full pitch model. In this paper, the evaluation results of three CFD approaches on the capability of the performance prediction of the mixed flow pumps will be shown. The approaches evaluated are steady flow analysis with one pitch blade passage using periodic boundary conditions, full pitch steady flow analysis and unsteady flow analysis. It was found from the evaluation results that the full pitch steady flow analysis showed the same tendency as one pitch analysis and the unsteady CFD provided higher accuracy of the shutoff head. However, the steady analysis should still be useful to reduce the high computational cost and the amount of time. Meanwhile the unsteady analysis clarifies the details of the off-design flow patterns. The effects of the turbulence models and the details of the off-design flow patterns were also discussed in this paper.

Applied Micro Genetic Algorithm to Optimize Design Low Specific Speed Pump Impeller

2013 ◽  
Vol 816-817 ◽  
pp. 1010-1014
Author(s):  
Deng Song Li ◽  
Wen Wu Song ◽  
Fu Jie ◽  
Tian Long Wu
Keyword(s):  
Genetic Algorithm ◽  
Optimization Design ◽  
High Efficiency ◽  
Design Method ◽  
Pump Impeller ◽  
Shaft Power ◽  
Low Specific Speed ◽  
Micro Genetic Algorithm ◽  
Specific Speed ◽  
Design Deficiencies

The combination of enlarged flow design and micro-genetic algorithm constitute a new optimization design method, which be applied to optimization design of low specific speed pump impeller. It improves enlarged flow design deficiencies, and making overall performance of the pump better. The experimental results of a low specific speed centrifugal pump impeller designed by proposed method show that pump high efficiency range is extended, the hump phenomenon is eliminated, and shaft power overload phenomenon has been resolved.

Impeller Geometry Suitable for Mini Turbo-Pump

2001 ◽  
Vol 123 (3) ◽  
pp. 500-506 ◽  
Author(s):  
Shuhong Liu ◽  
Michihiro Nishi ◽  
Kouichi Yoshida
Keyword(s):  
Performance Test ◽  
Design Method ◽  
Flow Analysis ◽  
Tip Clearance ◽  
Blade Tip ◽  
Axial Clearance ◽  
Low Performance ◽  
Low Efficiency ◽  
Impeller Geometry ◽  
Turbo Pump

The objective of the present study is to investigate the suitable impeller geometry for a mini turbo-pump, which is defined as the size having impeller diameter between around 5 mm and 50 mm. This is treated because those pumps having the above size are regarded as low efficiency machines if efficiency is less than 40 percent or 50 percent. Considering that not only low Reynolds number and tip clearance but the design method are the major causes for low performance, we carried out the performance test experimentally using two semi-open centrifugal impellers: one is named as Impeller B of 36 mm diameter and the other is Impeller C of 34 mm diameter. And the former is designed by a conventional method and the latter is based on the proposed method. In the performance tests, rotational speed was varied between 3000 rpm and 10,000 rpm and the axial clearance at the blade tip of impeller exit was between 0.2 mm and 0.8 mm. It is clearly seen from the results that Impeller C gives the better hydraulic performance. It is also clarified that the effect of tip clearance on Impeller C performance is much smaller than that of the Impeller B. Further, we conducted numerical calculation of impeller performance, where the commercial CFD code named TASCflow was used with k-ω turbulence model. From the results, the turbulent flow analysis is reasonably usable to study the flow in the above mini impellers.

Unsteady flow characteristics and cavitation prediction in the double-suction centrifugal pump using a novel approach

2019 ◽  
Vol 234 (3) ◽  
pp. 283-299 ◽  
Author(s):  
Ji Pei ◽  
Majeed Koranteng Osman ◽  
Wenjie Wang ◽  
Jianping Yuan ◽  
Tingyun Yin ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Optimization Design ◽  
Flow Analysis ◽  
Prediction Method ◽  
Internal Flow ◽  
Computational Time ◽  
The Novel ◽  
Centrifugal Pumps ◽  
Pump Design ◽  
Novel Approach

The recent advances in centrifugal pump design do not only require a better suction performance but also there have been attempts to reduce design time at a lower cost. The traditional trial-and-error optimization design method, however, depends on the designer's experience, which requires longer cycles. This is because the computational process of calculating the net positive suction head required (NPSHr) involves several calculation steps and this consumes a lot of computational time. An investigation was therefore carried out to test a novel NPSHr prediction method in a double-suction centrifugal pump using unsteady numerical simulations. In the new approach, a new boundary pair was introduced and an algorithm was used to estimate a good value for a static pressure value that correlates to a 3% drop in pump head to determine the critical cavitation point. Experiments were conducted to validate the hydraulic performance and the cavitation model. The NPSHr and the characteristic “sudden” head-drop were very well predicted by the novel approach in only three simulation steps. The internal flow analysis showed that for 0.6 Q d, the flow around the volute tongue was uneven at NPSH = 10.06 m, inducing flow separation and recirculation at the tongue region. Attached cavities were also observed around the suction ring in the spiral suction domain. The pressure fluctuations were analyzed also and the dominant frequency at the pump outlet and tongue region was the blade passing frequency. Consequently, the novel approach proved very robust and efficient in NPSHr prediction and would be a good alternative to shorten simulation time during cavitation optimization design process in centrifugal pumps.

Numerical Analysis of Unsteady Flow in Centrifugal Pumps With Impellers Based on Different Hydraulic Design Principles

2010 ◽  
Author(s):  
Jianping Yuan ◽  
Hongqin He ◽  
Zhixia He ◽  
Shouqi Yuan
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Design Method ◽  
Outlet Section ◽  
Centrifugal Pumps ◽  
Lower Efficiency ◽  
Fluctuation Phenomenon ◽  
Low Specific Speed ◽  
Specific Speed

The centrifugal pump is one of the most widely used pumps. Lower efficiency, worse cavitation performance and stronger unsteady flow are three main problems for the low-specific-speed centrifugal pumps. Due to unsteady flow within pumps, pressure is fluctuant, which further induces vibration and noise. For a centrifugal pump with different impellers, its characteristics of unsteady flow are also different. In this paper, five different impellers were designed adopting low-specific-speed design method, splitter-blades design method and velocity-coefficient method with a set of performance parameters (Q = 25m3/h, H = 10m, n = 1450r/min). 3D unsteady turbulent flow field within the centrifugal pump was simulated. The periodic fluctuation phenomenon and the unsteady flow characteristics were investigated. The static pressure fluctuation in the volute and at the volute outlet and the instantaneous head changes were showed for the pumps with five different impellers operated at design and off-design conditions. The pressure fluctuation is the strongest near the tongue and is slighter at the volute outlet section. The transient head fluctuation increases with the flow rate. The transient head fluctuation of the pump with the low-specific-speed designed impeller is the biggest, while that of the pump with the normal-designed impeller is the smallest. Among the three splitter-blade impellers, the transient head fluctuation of the impeller with splitter blades leaned to the corresponding suction side of the long blades is the smallest. Eventually, the different design schemes were evaluated using the unsteady flow analysis. These conclusions from this paper can supply some references for the design of low-specific-speed centrifugal pumps considering its pressure fluctuation and flow-induced vibration and noise.

Applicability of Wall-Function Approach in Simulations of Turbomachines

2015 ◽  
Author(s):  
Kay Juckelandt ◽  
Frank-Hendrik Wurm
Keyword(s):  
Boundary Layer ◽  
Numerical Simulations ◽  
Function Method ◽  
Design Flow ◽  
Centrifugal Pumps ◽  
Wall Function ◽  
Modeling Error ◽  
Local Modeling ◽  
Low Specific Speed ◽  
Specific Speed

Numerical simulations of centrifugal pumps with low specific speed show significant differences in calculated efficiency from experiments. This causes designers to refrain from CFD methods and stick to prototyping. Investigations regarding the applicability of numerical simulations on these pumps are carried out. Unsteady simulations of a low specific speed pump are performed. The focus of this paper is boundary layer treatment, as losses due to boundary layer flow are dominant in low specific speed pumps. The wall-function as well as the low-Reynolds-number method is applied for boundary layer treatment. A method to calculate the local modeling error of the wall-function method is introduced. Experiments on a test pump are conducted to validate the simulations. Performance curves, locally highly resolved pressure distributions and velocity profiles are obtained. Simulations with resolved boundary layers match experimental data very good. It is shown that simulated efficiency is sensitive to the boundary layer treatment. The wall-function simulations deviate significantly at off-design flow rate, particularly at overload. The analysis reveals that modeling errors of the wall-function method mainly contribute to incorrect loss prediction. A local modeling error distribution is calculated and a meshing guideline for low specific speed pumps is derived.

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