scholarly journals Particle Distribution and Motion in Six-Stage Centrifugal Pump by Means of Slurry Experiment and CFD-DEM Simulation

2021 ◽  
Vol 9 (7) ◽  
pp. 716
Author(s):  
Liwen Deng ◽  
Qiong Hu ◽  
Jun Chen ◽  
Yajuan Kang ◽  
Shaojun Liu

Six-stage centrifugal pumps are used in deep-sea mining lifting systems and are required to convey slurry containing coarse particles. A six-stage centrifugal pump suitable for operation in a natural mining system was manufactured. High-flow and full-scaled slurry conveying experiments at a 5% and 9% volume concentration of particles was carried out at a large modified test site with artificial nodules. CFD-DEM simulations were carried out to obtain slurry transport characteristic curves, particle transport and distribution characteristics, where the simulation method was validated by the experiment data. A clarified two-stage pump can be used instead of a multi-stage pump for simplified simulation calculations with acceptable accuracy. Local agglomeration of particles caused by backflow was found at the outlet of the diffuser, and such agglomeration decreased with increasing flow rates. It was found that particles are transported non-uniformly, particles transport in diffusers in strands. Particles are transported in a pulse-like mode within the pump, with the latter stage showing similar particle characteristics to those transported in the previous pump stage.

2011 ◽  
Vol 130-134 ◽  
pp. 711-714
Author(s):  
Ling Zhou ◽  
Wei Dong Shi ◽  
Wei Gang Lu ◽  
Hui Li

Axial force is one of the main factors which affect the pump safety and reliability during the operation of pumps, especially in multi-stage centrifugal pumps. 150QJ20 type deep-well centrifugal pump (DCP) is selected as an example to research the pump performance and axial force with the numerical simulation and experiment method. The numerical simulation results were compared with experimental measurements, and such result was analyzed. The results show that the change trend of the pump performance and axial force acquired by numerical and experiment is similar. At rated operating point, the error of axial force between the numerical simulation and experimental measurements is less than 3%. This confirmed the feasibility of predict the pump performance by numerical simulation method.


Author(s):  
Andreas Weiten ◽  
Dieter-H. Hellmann

For radial multistage centrifugal pumps a combination of a radial exiting impeller, a vaned diffuser and a row of return guide vanes is used for each stage of the pump. Hence the inner diameter of the stage casing is much larger than the diameter of the impeller. In case when the space for installing the pump is limited, for example in case of submersible pumps, a high number of pump stages is necessary to produce a sufficient hydraulic head. Pump stages with an impeller diameter equal to the inner diameter of the casing can reduce the number of the stages, but up to now the efficiency of such pumps is lower than the one of a conventional pump. Improving the design of these pumps in order to increase efficiency, stationary diffusers were developed at the Institute for Turbomachinery and Fluid mechanics at TU Kaiserslautern. While the pump liquid cannot exit the impeller in radial direction, the hub diameter is reduced by the width of the impeller at the outer diameter. Hence the pump liquid now exits the impeller in axial direction. This design affects both the hydraulic and the rotor dynamic performance of the pump. Furthermore the axial thrust has dropped, because the flow and the allocation of static pressure in the impeller side spaces has changes compared to radial pump stages. In this paper results of measurements of vibration and axial thrust at radial centrifugal pump with four stages are compared with these of a four stage pump with small stage diameter. Furthermore the hydraulic datas of both designs a presented.


2014 ◽  
Vol 44 (1) ◽  
pp. 105-110
Author(s):  
L. ZHOU ◽  
W. D. SHI ◽  
L. BAI ◽  
W. G. LU ◽  
W. LI

 In the operation process of centrifugal pumps, especially in multi-stage pumps, axial force is one of the main factors which affect the pump safety and reliability. This paper presents the axial force study in a deep-well centrifugal pump (DCP) with theoretical calculation, numerical simulation and experimental measure. Three different calculation formulas were respectively introduced and used in the model pump. The calculated results were compared and analyzed with the numerical simulation values and experimental results, and the detailed numerical simulation methods and experimental configuration were explained. Finally, the more accurate formula for calculating the axial force in oblique flow centrifugal impeller was selected out. At the rated flow point, the deviation of the axial force obtained by numerical simulation and the experimental value is approximately 3.8%, and the calculated result of selected formula only less than the experimental results of 2.6%. The results provide a theoretical basis for the axial force calculation in the centrifugal impeller design process.


2014 ◽  
Vol 651-653 ◽  
pp. 780-783
Author(s):  
Gao Feng Liang ◽  
Qiang Gao

Currently the application of traditional centrifugal pump design theory to develop the multi-stage centrifugal pumps is very mature, but the factor of affecting hydraulic performance of centrifugal self-priming pump is still unclear. In this paper, using CFD method to simulate the hydraulic performance of the multistage self-priming pump in different operating conditions, and get the performance prediction curve. The simulation results were compared with experimental data, the result shows that simulation method can accurately predict the performance and internal flow characteristics of multi-stage self-priming pump. The impact on the hydraulic performance by water-keeper chamber and the gas-liquid separation chamber is very limited. The self-priming components can provide a better hydraulic performance. This will be as a reference for the design of self-priming pump.


Author(s):  
F.-K. Benra ◽  
H. J. Dohmen

The knowledge of the flow behavior in pump stages which consist of an impeller, a bladed diffuser and a bladed return channel is of great importance for the design of multistage centrifugal pumps. Especially the Interaction of the impeller flow with the stationary diffuser blades and the behavior of the return channel blades affect the efficiency of a pump stage in a considerable way. In this contribution the transient flow in an industrial centrifugal pump stage, which has an impeller with seven blades, a radial diffuser with ten blades and a return channel with also ten separate blades, has been simulated numerical by using the commercial software code CFX-5.7. Because of the unfavorable ratio of blade numbers a complete meshing of all flow channels was necessary. In consequence the cumulative amount of grid nodes reached a number of nearly 6 million nodes. As a result of the numerical investigation of the time dependent flow accomplished for this contribution, the influence of the rotating impeller on the flow in the stationary parts of the pump is presented in detail. All flow parameters are shown as a function of time and are discussed with respect to the position of the impeller relative to the stator blades.


Author(s):  
Stefan Berten ◽  
Philippe Dupont ◽  
Laurent Fabre ◽  
Maher Kayal ◽  
Francois Avellan ◽  
...  

In centrifugal pumps, the interaction between the rotating impeller and the stationary diffuser generates specific pressure fluctuation patterns. When the pump is operated at off design conditions, these pressure fluctuations increase. The resulting rise of mechanical vibration levels may negatively affect the operational performance and the life span of mechanical components. This paper presents detailed pressure fluctuation measurements performed in a high speed centrifugal pump stage at full scale at various operating conditions. The impeller and stationary part (diffuser, exit chamber) of the pump stage have been equipped with piezoresistive miniature pressure sensors. The measured data in the impeller have been acquired using a newly developed onboard data acquisition system, designed for rotational speeds up to 6000 rpm. The measurements have been performed synchronously in the rotating and stationary domains. The analysis of pressure fluctuations at the impeller blade trailing edge, which had significantly larger amplitudes as the pressure fluctuations in the stationary domain, allowed the detection and exploration of stalled channels in the vaned diffuser. This stall may be stationary or rotating with different rotational speeds and number of stalled channels, depending on the relative flow rate and the rotational speed of the pump. The stall yields pressure fluctuations at frequencies which are multiples of the rotational speed of the impeller and generates additional sources of mechanical excitation.


2018 ◽  
Vol 1 (2) ◽  
pp. 24-39
Author(s):  
A. Farid ◽  
A. Abou El-Azm Aly ◽  
H. Abdallah

Cavitation in pumps is the most severe condition that centrifugal pumps can work in and is leading to a loss in their performance.  Herein, the effect of semi-open centrifugal pump side clearance on the inception of pump cavitation has been investigated.  The input pump pressure has been changed from 80 to 16 kPa and the pump side clearance has been changed from 1 mm to 3 mm at a rotation speed of 1500 rpm. It has been shown that as the total input pressure decreased; the static pressure inside the impeller is reduced while the total pressure in streamwise direction has been reduced, also the pump head is constant with the reduction of the total input pressure until the cavitation is reached. Head is reduced due to cavitation inception; the head is reduced in the case of a closed impeller with a percent of 1.5% while it is reduced with a percent of 0.5% for pump side clearance of 1mm, both are at a pressure of 20 kPa.   Results also showed that the cavitation inception in the pump had been affected and delayed with the increase of the pump side clearance; the cavitation has been noticed to occur at approximate pressures of 20 kPa for side clearance of 1mm, 18 kPa for side clearances of 2mm and 16 kPa for 3mm.


Author(s):  
Weihui Xu ◽  
Xiaoke He ◽  
Xiao Hou ◽  
Zhihao Huang ◽  
Weishu Wang

AbstractCavitation is a phenomenon that occurs easily during rotation of fluid machinery and can decrease the performance of a pump, thereby resulting in damage to flow passage components. To study the influence of wall roughness on the cavitation performance of a centrifugal pump, a three-dimensional model of internal flow field of a centrifugal pump was constructed and a numerical simulation of cavitation in the flow field was conducted with ANSYS CFX software based on the Reynolds normalization group k-epsilon turbulence model and Zwart cavitation model. The cavitation can be further divided into four stages: cavitation inception, cavitation development, critical cavitation, and fracture cavitation. Influencing laws of wall roughness of the blade surface on the cavitation performance of a centrifugal pump were analyzed. Research results demonstrate that in the design process of centrifugal pumps, decreasing the wall roughness appropriately during the cavitation development and critical cavitation is important to effectively improve the cavitation performance of pumps. Moreover, a number of nucleation sites on the blade surface increase with the increase in wall roughness, thereby expanding the low-pressure area of the blade. Research conclusions can provide theoretical references to improve cavitation performance and optimize the structural design of the pump.


Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 60
Author(s):  
Khaled Alawadhi ◽  
Bashar Alzuwayer ◽  
Tareq Ali Mohammad ◽  
Mohammad H. Buhemdi

Since centrifugal pumps consume a mammoth amount of energy in various industrial applications, their design and optimization are highly relevant to saving maximum energy and increasing the system’s efficiency. In the current investigation, a centrifugal pump has been designed and optimized. The study has been carried out for the specific application of transportation of slurry at a flow rate of 120 m3/hr to a head of 20 m. For the optimization process, a multi-objective genetic algorithm (MOGA) and response surface methodology (RSM) have been employed. The process is based on the mean line design of the pump. It utilizes six geometric parameters as design variables, i.e., number of vanes, inlet beta shroud, exit beta shroud, hub inlet blade draft, Rake angle, and the impeller’s rotational speed. The objective functions employed are pump power, hydraulic efficiency, volumetric efficiency, and pump efficiency. In this reference, five different software packages, i.e., ANSYS Vista, ANSYS DesignModeler, response surface optimization software, and ANSYS CFX, were coupled to achieve the optimized design of the pump geometry. Characteristic maps were generated using simulations conducted for 45 points. Additionally, erosion rate was predicted using 3-D numerical simulations under various conditions. Finally, the transient behavior of the pump, being the highlight of the study, was evaluated. Results suggest that the maximum fluctuation in the local pressure and stresses on the cases correspond to a phase angle of 0°–30° of the casing that in turn corresponds to the maximum erosion rates in the region.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 886
Author(s):  
Cui Dai ◽  
Chao Guo ◽  
Yiping Chen ◽  
Liang Dong ◽  
Houlin Liu

The strong noise generated during the operation of the centrifugal pump harms the pump group and people. In order to decrease the noise of the centrifugal pump, a specific speed of 117.3 of the centrifugal pump is chosen as a research object. The bionic modification of centrifugal pump blades is carried out to explore the influence of different bionic structures on the noise reduction performance of centrifugal pumps. The internal flow field and internal sound field of bionic blades are studied by numerical calculation and test methods. The test is carried out on a closed pump test platform which includes external characteristics and a flow noise test system. The effects of two different bionic structures on the external characteristics, acoustic amplitude–frequency characteristics and flow field structure of a centrifugal pump, are analyzed. The results show that the pit structure has little influence on the external characteristic parameters, while the sawtooth structure has a relatively great influence. The noise reduction effect of the pit structure is aimed at the wide-band noise, while the sawtooth structure is aimed at the discrete noise of the blade-passing frequency (BPF) and its frequency doubling. The noise reduction ability of the sawtooth structure is not suitable for high-frequency bands.


Sign in / Sign up

Export Citation Format

Share Document