scholarly journals Prediction of Cavitation Evolution and Cavitation Erosion on Centrifugal Pump Blades by the DCM-RNG Method

Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Han Zhu ◽  
Ning Qiu ◽  
Chuan Wang ◽  
Qiaorui Si ◽  
Jie Wu ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Cavitation Erosion ◽  
Flow Characteristics ◽  
Prediction Method ◽  
Pressure Change ◽  
Correction Method ◽  
Centrifugal Pumps ◽  
Suction Surface ◽  
Term Operation ◽  
Pressure Surface

Cavitation can reduce the efficiency and service life of the centrifugal pumps, and a long-term operation under cavitation conditions will cause cavitation damage on the surface of material. The external characteristic test of the IS65-50-174 single-stage centrifugal pump was carried out. Moreover, the cavitation mechanism under specific conditions was analyzed by numerical simulation. Considering the macroscopic cavitation flow structure in the centrifugal pump, three different cavitation erosion prediction methods were used to predict the erodible areas. The results show that the calculation results obtained by the density correction method (DCM) can well match the flow characteristics of the centrifugal pump under the rated conditions. When the centrifugal pump head drops by 3%, cavitation mainly occurs on the suction surface, and the cavity on the pressure surface is mainly concentrated near the front cover. The cavitation prediction method based on the time derivation of pressure change is not suitable for centrifugal pumps, while the prediction result of the erosive power method is more reasonable than the others. At time 0.493114 s, the maximum erosive power appears on the blade near the volute tongue, and its value is 1.46 e − 04  W.

scholarly journals Slurry Flow and Erosion Prediction in a Centrifugal Pump after Long-Term Operation

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1523 ◽  
Author(s):  
Yexiang Xiao ◽  
Bao Guo ◽  
Soo-Hwang Ahn ◽  
Yongyao Luo ◽  
Zhengwei Wang ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Reference Frame ◽  
Flow Characteristics ◽  
Centrifugal Pumps ◽  
Slurry Erosion ◽  
Material Loss ◽  
Term Operation ◽  
Erosion Mechanism ◽  
Erosion Prediction

After long-term operation, the material loss due to slurry erosion often leads to significant changes in the impeller geometry. This change can, in turn, affect the flow characteristics and the erosion mechanism in a centrifugal pump. To investigate this matter, we consider two geometric models based on a prototype stainless steel impeller, which failed due to huge erosion problems from the pulp slurry. These two models are different in the degree of wear, with one model at the pre-erosion stage and the other with worn blades. For both models, the flow characteristics have been obtained in the Eulerian reference frame by means of the SST k-ω model. Then, in order to determine the erosion patterns, the particles have been tracked in the Lagrangian reference frame. In this way, the influence of the flow characteristics on the erosion patterns has been analyzed. Results show that the geometric variations greatly affect the flow characteristics, and consequently the erosion patterns. Particularly, it has been found that the clearance flow plays a significant role in defining erosion characteristics, such as erosion distribution, areas, and rates. Interestingly, the simulation results for current study show that the erosion rates after long-term operation greatly decrease near both the outlet edge and the blade bottom. It follows also that for accurate erosion predictions, these geometric variations have to be considered in the numerical model. This paper provides a better understanding of the complex erosion mechanism in centrifugal pumps, which can help to reduce the wear in future designs.

scholarly journals Effects of a Combination Impeller on the Flow Field and External Performance of an Aero-Fuel Centrifugal Pump

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 919
Author(s):  
Jia Li ◽  
Xin Wang ◽  
Yue Wang ◽  
Wancheng Wang ◽  
Baibing Chen ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Power Plants ◽  
Flow Characteristics ◽  
Significant Feature ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Flow Losses ◽  
Simulation And Experiment ◽  
Aero Engines

Aero-fuel centrifugal pumps are important power plants in aero-engines. Unlike most of the existing centrifugal pumps, a combination impeller is integrated with the pump to improve performance. First, the critical geometrical parameters of the combination impeller and volute are given. Then, the effects of the combination impeller on the flow characteristics of the impeller and volute are clarified by comparing simulation results with that of the conventional impeller, where the effectiveness of the selected numerical method is validated by an acceptable agreement between simulation and experiment. Finally, the experiment is set to test the external performance of the studied pump. A significant feature of this study is that the flow characteristics are significantly ameliorated by reducing the flow losses that emerged in the impeller inlet, impeller outlet, and volute tongue. Correspondingly, the head and efficiency of a combination impeller are higher with comparison to a conventional impeller. Consequently, it is a promising approach in ameliorating the flow field and improving external performance by applying a combination impeller to an aero-fuel centrifugal pump.

scholarly journals Investigation on centrifugal pump performance degradation under air-water inlet two-phase flow conditions

2018 ◽  
pp. 41-48 ◽  
Author(s):  
Qiaorui Si ◽  
Qianglei Cui ◽  
Keyu Zhang ◽  
Jianping Yuan ◽  
Gérard Bois
Keyword(s):  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Flow Characteristics ◽  
Performance Degradation ◽  
Inlet Pressure ◽  
Pulsation Frequency ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Flow Rates ◽  
Pump Performance

In order to study the flow characteristics of centrifugal pumps when transporting the gas-liquid mixture, water and air were chosen as the working medium. Both numerical simulation and experimental tests were conducted on a centrifugal pump under different conditions of inlet air volume fraction (IAVF). The calculation used URANS k-epsilon turbulence model combined with the Euler-Euler inhomogeneous two-phase model. The air distribution and velocity streamline inside the impeller were obtained to discuss the flow characteristics of the pump. The results show that air concentration is high at the inlet pressure side of the blade, where the vortex will exist, indicating that the gas concentration have a great relationship with the vortex aggregation in the impeller passages. In the experimental works, pump performances were measured at different IAVF and compared with numerical results. Contributions to the centrifugal pump performance degradations were analyzed under different air-water inlet flow condition such as IAVF, bubble size, inlet pressure. Results show that pump performance degradation is more pronounced for low flow rates compared to high flow rates. Finally, pressure pulsation and vibration experiments of the pump model under different IAVF were also conducted. Inlet and outlet transient pressure signals under four IAVF were investigated and pressure pulsation frequency of the monitors is near the blade passing frequency at different IAVF, and when IAVF increased, the lower frequency signal is more and more obvious. Vibration signals at five measuring points were also obtained under different IAVF for various flow rates.

scholarly journals Computation of Viscous Flow Inside a Double-Channel Centrifugal Pump

2014 ◽  
Vol 8 (1) ◽  
pp. 613-618
Author(s):  
Su-Lu Zheng ◽  
Xiang-Ping Wang ◽  
Rui-Hang Zheng ◽  
Ai-Ping Xia ◽  
Yi-Nian Wang ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Centrifugal Pump ◽  
Design Method ◽  
Pure Water ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Solid Particles ◽  
Water Medium ◽  
Centrifugal Pumps ◽  
Double Channel

The double-channel centrifugal pumps are widely used to transport the two-phase flow including big solid particles in industry and agriculture. However, the related design theory and the design method are immature by far. In practice, the revised design method based on the pure water medium is still the main method for the solid-liquid twophase double-channel pump. Therefore, it is very necessary to deeply study the flow characteristics on the condition of the pure water medium. In this paper, in order to study the flow characteristics inside a prototype double-channel centrifugal pump in the case that the delivered medium is the pure water, the SIMPLE algorithm, RNG κ-ε turbulence model, and frozen rotor method are employed to calculate the incompressible, viscous, three-dimensional internal flow. The calculation results display the variation characteristics of the internal flow field and the external performance. The results show that the predicted pump head drops with the increasing flow rate, which manifest that the pump model is of good operation stability at the whole range of working. At the design point, a strong and large vortex remain appears at the middle section of the double-channel impeller. The computational fluids dynamic technology is competent to assess the internal viscous flow inside a double-channel centrifugal pump.

scholarly journals Study on the Effects of the Wear-Rings Clearance on the Solid-Liquid Two-Phase Flow Characteristics of Centrifugal Pumps

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2003
Author(s):  
Chaoshou Yan ◽  
Jianfei Liu ◽  
Shuihua Zheng ◽  
Bin Huang ◽  
Jiacheng Dai
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Suction Surface ◽  
Two Phase ◽  
Wear Area ◽  
Fluid Medium ◽  
Solid Liquid

In order to study the wear law of the centrifugal pump flowing surface under different wear-rings clearance, the McLaury wear model was used to conduct the full-passage numerical simulation of solid-liquid two-phase flow in a single-stage single-suction centrifugal pump. The reliability of the numerical calculation method is verified by comparing the experimental data and numerical simulation results. The clearance is 0.1, 0.15, 0.2, 0.3 and 0.5 mm, respectively. The results show that the wear of the centrifugal pump blades is mainly concentrated in the end part and the inlet part of the blade, and the wear of the pressure surface at the end of the suction surface and the front of the blade is more serious. As the clearance increases, the maximum wear value in the impeller increases first and then decreases, reaching a maximum at 0.15 mm. With the increase of the clearance, the wear degree and the wear rate of the volute wall surface first increase and then decrease, and reach the maximum at 0.2 mm. With the increase of the clearance and the concentration of the fluid medium, the wear at the clearance of the centrifugal pump is more serious, and the severe wear area exhibits a point-like circumferential distribution.

Flow loss analysis of a two-stage axially split centrifugal pump with double inlet under different channel designs

2019 ◽  
Vol 233 (15) ◽  
pp. 5316-5328 ◽  
Author(s):  
Majeed Koranteng Osman ◽  
Wenjie Wang ◽  
Jianping Yuan ◽  
Jiantao Zhao ◽  
Yiyun Wang ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Characteristics ◽  
Water Diversion ◽  
Centrifugal Pumps ◽  
Loss Analysis ◽  
Flow Losses ◽  
Water Pumping ◽  
Pumping Stations ◽  
Pump Head ◽  
Flow Loss

The double-stage axially split centrifugal pump is widely used in water diversion and water pumping stations due to their ability to deliver at high heads and large flow rate for long running hours. Their flow characteristics can be greatly influenced by the geometry of the channels between the stages, which is a prominent place for irreversible loss to occur. Numerical investigations were extensively carried out and a comparison was drawn between two multistage axially split centrifugal pumps, with different channel designs between its stages. The reliability of the numerical model was confirmed after a good agreement existed between numerical results and the experiments. Subsequently, entropy generation terms were used to evaluate turbulence dissipation to characterize the flow losses. The modified channels had a great effect on reducing swirl near the impeller eye, thereby improving pump head by 12.5% and efficiency by 4.98% at the design condition. They however induced flow impact, causing an unusual separation, which generated high turbulence dissipation at the blade surfaces. The channels and second stage impeller were identified as major areas for selective optimization since their turbulence dissipation was dominant. Consequently, entropy production analysis with computational fluid dynamics could be relied upon to reveal the loss locations for selective optimization in centrifugal pumps.

Film Cooling on a Modern HP Turbine Blade: Part III — Axial Shaped Holes

2002 ◽  
Author(s):  
Jeffrey D. Ferguson ◽  
James H. Leylek ◽  
Frederick A. Buck
Keyword(s):  
Turbine Blade ◽  
Film Cooling ◽  
Density Ratio ◽  
Flow Characteristics ◽  
Quality Data ◽  
Suction Surface ◽  
Predictive Tool ◽  
Pressure Surface ◽  
Blowing Ratio ◽  
Hole Shaping

A well-tested computational methodology and high-quality data from a companion experimental study are used to analyze the physics of axial-injected, shaped-hole film cooling on the pressure and suction surfaces of a modern high-pressure turbine blade. Realistic engine conditions, including transonic flow, high turbulence levels, and a nominal density ratio of 1.52, are used to examine blowing ratios of 1.0, 1.5, and 2.0 on the suction surface (SS) and 1.5, 3.0, and 4.5 on the pressure surface (PS). SS results show excellent film-cooling performance with the hole shaping, but massive hot crossflow ingestion is found using similar hole shaping on the PS. Primary mechanisms governing the near and far-field cooling effectiveness and crossflow ingestion are identified, including: (1) the nature of the coolant entry into the film hole; (2) location of hole shaping relative to major coolant flow characteristics; and (3) susceptibility of low-momentum fluid to pressure gradients. Changes in blowing ratio, while not introducing new physical mechanisms, significantly alter the extent to which the mechanisms already present affect the flow. These effects are highly non-linear for both SS and PS geometries, highlighting the inadequacy of one-dimensional design practices and the potential usefulness of CFD as a predictive tool.

Flow Characteristics of a Centrifugal Pump

1994 ◽  
Vol 116 (2) ◽  
pp. 303-309 ◽  
Author(s):  
C. H. Liu ◽  
C. Vafidis ◽  
J. H. Whitelaw
Keyword(s):  
Refractive Index ◽  
Centrifugal Pump ◽  
Radial Flow ◽  
Flow Characteristics ◽  
Secondary Flows ◽  
Laser Doppler Velocimeter ◽  
Suction Surface ◽  
Tip Leakage ◽  
Tip Velocity ◽  
Working Liquid

Measurements of velocity have been obtained in a centrifugal pump in terms of angle-resolved values in the impeller passages, the volute, the inlet and exit ducts and are presented in absolute and relative frames. The pump comprised a radial flow impeller with four backswept blades and a single volute, and the working liquid had the same refractive index as the transparent casing to facilitate the use of a laser-Doppler velocimeter. The flows in the impeller passages were found to depart from the curvature of the blade surfaces at off-design conditions with separation from the suction surface and from the shroud. Secondary flows from the suction to pressure surfaces were dominated by the influences of the relative motion between the shroud and impeller surfaces and the tip leakage. Geometric differences of 0.5 mm and one degree in spacing of the four blades caused differences in passage velocity of up to 6 percent of the impeller tip velocity close to the design flowrate and up to 16 percent at the lowest discharge. The flowrate from each impeller passage varied with volute circumferential position by up to 25 percent at an off-design flowrate. Poor matching of the impeller and volute at off-design conditions caused swirl and separation in the inlet and exit pipes.

scholarly journals Numerical Investigation of Pressure Fluctuation Characteristics in a Centrifugal Pump with Variable Axial Clearance

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Lei Cao ◽  
Zhengwei Wang ◽  
Yexiang Xiao ◽  
Yongyao Luo
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Maximum Pressure ◽  
Centrifugal Pumps ◽  
Pressure Surface ◽  
Clearance Flow ◽  
Rotor Stator Interaction ◽  
Entire Flow ◽  
Axial Clearance

Clearance flows in the sidewall gaps of centrifugal pumps are unsteady as well as main flows in the volute casing and impeller, which may cause vibration and noise, and the corresponding pressure fluctuations are related to the axial clearance size. In this paper, unsteady numerical simulations were conducted to predict the unsteady flows within the entire flow passage of a centrifugal pump operating in the design condition. Pressure fluctuation characteristics in the volute casing, impeller, and sidewall gaps were investigated with three axial clearance sizes. Results show that an axial clearance variation affects the pressure fluctuation characteristics in each flow domain by different degree. The greatest pressure fluctuation occurs at the blade pressure surface and is almost not influenced by the axial clearance variation which has a certainly effect on the pressure fluctuation characteristics around the tongue. The maximum pressure fluctuation amplitude in the sidewall gaps is larger than that in the volute casing, and different spectrum characteristics show up in the three models due to the interaction between the clearance flow and the main flow as well as the rotor-stator interaction. Therefore, clearance flow should be taken into consideration in the hydraulic design of centrifugal pumps.

Performance Prediction and Design Method for Centrifugal Pump Based on Computational Fluid Dynamics

2010 ◽  
Vol 97-101 ◽  
pp. 3463-3466
Author(s):  
Chun Lei Shao ◽  
Bo Qin Gu ◽  
X.L. Huang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Centrifugal Pump ◽  
Performance Prediction ◽  
Design Method ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Prediction Method ◽  
Design Quality ◽  
Advantages And Disadvantages

Using Reynolds average N-S equations closed by standard k- turbulence model, the steady and unsteady turbulent flow in centrifugal pump was simulated by using MRF model and SM model respectively. A method for predicting the performances of centrifugal pump was built on the basis of computational fluid dynamics. By the presented performance prediction method, not only the flow characteristics of centrifugal pump can be obtained, but also can its performances be evaluated quantitatively and qualitatively. The advantages and disadvantages of some traditional design methods for centrifugal pump were analyzed. On the basis of performance prediction and flow analysis, a new design method was put forward in consideration of the steady and unsteady performances of centrifugal pump. The proposed method can be used to design the centrifugal pump with high running stability, efficiency and cavitation resistance, and it is available for shortening development period and improving design quality of pump.

Sign in / Sign up

Export Citation Format

Share Document