Slurry Pump Impeller Research Articles

ОСОБЕННОСТИ ВОССТАНОВЛЕНИЯ РАБОЧЕГО КОЛЕСА ГРУНТОВОГО НАСОСА ГРУ-16

The paper presents the technology of reconditioning the GrU-16 slurry pump impeller. A brief description is given of the pump design, its working conditions and causes of wear; the features of submerged arc maintenance welding are considered.

Slurry erosion wear of high chromium cast iron samples from a slurry pump impeller. Effect of impact angle variation

In this work, the impact angle effect on the erosive wear resistance of high chromium cast iron (HCCI) samples from a slurry pump impeller was evaluated. For this purpose, equipment was designed and built to carry out wet erosion tests. Erosion tests were carried out at angles of 30°, 45°, 60° and 90° using an erosive slurry with a concentration of 20%, by weight, of silica sand. The results indicated that the erosive wear rate followed the classic behavior of variation with the impact angle for ductile materials. There was an increase in the erosion rate with increasing angle until reaching the peak wear at 45°, followed by a decrease in wear down to the minimum wear rate at 90°. Significant differences were observed in the mass loss of the HCCI samples: the samples eroded at 45° showed a mass loss 2.7 times greater than the eroded condition at 90°, indicating that, due to the condition of slurry contact with the surface of the samples, erosive and abrasive mechanisms acted synergistically favoring wear at 45°. On the other hand, samples eroded at 30° and 60° showed similar and intermediate mass losses. In general, for the samples eroded at a normal angle (90°) the mechanisms of wear due to plastic deformation of the matrix and carbide fracture were observed, while for smaller angles, the mechanisms of micro cutting and micro grooving were more evident.

Wear Evaluation Results from a Practical Trial of Laser-Coated Pump Parts in the Mineral Processing Industry

Slurry pumps in the mineral processing industry are parts that erode very quickly. Erosion is predominantly caused by abrasion from fine particles of the ores. Because of this, the erosion process takes place on impeller blades and cover plates that directly contact the slurry. This paper evaluates the wear of laser-coated pump parts in the mineral processing industry. Building upon previous research conducted by the authors, we aimed to determine the best laser coating powder system to extend the useful life of specific laser-coated pump parts. Four blades of a slurry pump impeller were each treated with a different laser powder coating, then assessed for wear after 19 days of operation. During this real-life trial, each powder system performed differently. The laser coatings were worn away in two general directions. The first direction was along with the blade pattern, and the second wear direction was from the center of the impeller to the direct blade surface. Partial surface cladding led the material to wear away faster than complete surface cladding due to perpendicular force. Based on these results, in order to use material hardness and wear resistance to higher efficiency, we need to cover all surfaces with different thicknesses depending on the wear rate of the part. This study also showed that Powder System 2 was the most suitable coating material for this type of slurry pump.

Wear mechanism investigation in a centrifugal slurry pump impeller by numerical simulation and experiments

Centrifugal slurry pumps are widely used in ore mining, metal smelting, petrochemical and other industries. They are mainly used to transport muddy fluids containing a large number of solid particles. The impellers in slurry pumps always experience serious wear with damages the equipment. This study analyzed the flow in a slurry pump to identify the key sources of the wear. A centrifugal slurry pump was analyzed using the particle Eulerian-Eulerian multiphase flow model to study the impeller wear. The results show that increasing the flow rate causes the high solid volume fraction area to gradually move along the suction surface from the inlet to the outlet. At over-load flow rate, the high volume fraction area moves to the junction of the blade and the rear shroud. For the same conditions, increasing the concentration reduces the pump lift and efficiency, gradually increases the solid slip velocity at the blade outlet, and creates higher solid volume fractions on the suction surface of the blade than that on the pressure surface. The wear location predicted by the simulations agreed well with experimental observations. This study provides guidance on how to optimize slurry pump impeller designs to reduce the wear.

Optimal hydraulic design to minimize erosive wear in a centrifugal slurry pump impeller

Centrifugal slurry pumps are commonly used to convey solid materials in many industries including the mining, power, and marine industries. The solid particles in the slurry frequently impact the pump inner wall resulting in significant wear of the flow passage. Frequent replacement of the pump components is not only expensive, but also wastes manpower and time. Therefore, many studies have sought to find optimal designs of slurry pumps that are efficient and have less wear. This study used Eulerian-Eulerian mixture model to simulate the solid–liquid two-phase flow of quartz sand and water in a slurry pump. The impeller was optimized statistically. Then, the original pump design and the optimized pump design were manufactured for a geometric similarity ratio of 1:0.408. The wear rates in the two slurry pumps were then measured by weight loss measurements. The tests show that the optimized pump has less wear, longer service life and meets the design goals which shows that this optimization method is effective.

A review on erosion wear of different types of slurry pump impeller materials

Slurry transportation system has two basic types; packed flow and slack flow. A typical slurry transportation system considering conditions like maximum design and minimum flow, may work well for a maximum flow, but may function incorrectly in case of minimum volume. Different pneumatic or mechanical ash conveyors are employed based on the ash handling systems.

PBO-2GP-3B: A batch parallel known/unknown constrained Bayesian optimization with feasibility classification and its applications in computational fluid dynamics

In this work, we present a constrained batch-parallel Bayesian optimization (BO) framework, termed pBO-2GP-3B, to accelerate the optimization process for high-dimensional and computationally expensive problems, with known and unknown constraints. Two Gaussian processes (GPs) are simultaneously constructed: one models the objective function, whereas the other models the unknown constraints. The known constraint is penalized directly into the acquisition function. For every iteration, three batches are built in sequential order: the first two are the acquisition hallucination and the exploration batches for the objective GP, respectively, and the third one is the exploration batch for the classification GP. The pBO-2GP-3B optimization framework is demonstrated with three synthetic examples (2D and 6D), as well as a 33D multi-phase solid–liquid computational fluid dynamics (CFD) model for the design optimization of a centrifugal slurry pump impeller.

WearGP: A computationally efficient machine learning framework for local erosive wear predictions via nodal Gaussian processes

Computational fluid dynamics (CFD)-based wear predictions are computationally expensive to evaluate, even with a high-performance computing infrastructure. Thus, it is difficult to provide accurate local wear predictions in a timely manner. Data-driven approaches provide a more computationally efficient way to approximate the CFD wear predictions without running the actual CFD wear models. In this paper, a machine learning (ML) approach, termed WearGP, is presented to approximate the 3D local wear predictions, using numerical wear predictions from steady-state CFD simulations as training and testing datasets. The proposed framework is built on Gaussian process (GP) and utilized to predict wear in a much shorter time. The WearGP framework can be segmented into three stages. At the first stage, the training dataset is built by using a number of CFD simulations in the order of O(102). At the second stage, the data cleansing and data mining processes are performed, where the nodal wear solutions are extracted from the solution database to build a training dataset. At the third stage, the wear predictions are made, using trained GP models. Two CFD case studies including 3D slurry pump impeller and casing are used to demonstrate the WearGP framework, in which 144 training and 40 testing data points are used to train and test the proposed method, respectively. The numerical accuracy, computational efficiency and effectiveness between the WearGP framework and CFD wear model for both slurry pump impellers and casings are compared. It is shown that the WearGP framework can achieve highly accurate results that are comparable with the CFD results, with a relatively small size training dataset, with a computational time reduction on the order of 105 to 106.

An Enhanced Factor Analysis of Performance Degradation Assessment on Slurry Pump Impellers

Slurry pumps, such as oil sand pumps, are widely used in industry to convert electrical energy to slurry potential and kinetic energy. Because of adverse working conditions, slurry pump impellers are prone to suffer wear, which may result in slurry pump breakdowns. To prevent any unexpected breakdowns, slurry pump impeller performance degradation assessment should be immediately conducted to monitor the current health condition and to ensure the safety and reliability of slurry pumps. In this paper, to provide an alternative to the impeller health indicator, an enhanced factor analysis based impeller indicator (EFABII) is proposed. Firstly, a low-pass filter is employed to improve the signal to noise ratios of slurry pump vibration signals. Secondly, redundant statistical features are extracted from the filtered vibration signals. To reduce the redundancy of the statistic features, the enhanced factor analysis is performed to generate new statistical features. Moreover, the statistic features can be automatically grouped and developed a new indicator called EFABII. Data collected from industrial oil sand pumps are used to validate the effectiveness of the proposed method. The results show that the proposed method is able to track the current health condition of slurry pump impellers.

Improvement in the Wear Resistance of Brass Impeller of Slurry Pump used in Variation of Operating Speeds

Erosion wear is recognized as an engineering problem for Centrifugal slurry pumps it plays an important role in design and operation of slurry transportation systems. In most slurry pump applications the monetary loss due to pump failure consists of loss of production rather than the cost of the pump, since the process must be shut down when the pump fails. If the erosion rate can be estimated, the pump’s impeller can be changed out in time, during scheduled maintenance, The present work reports experimental investigations on dependence of erosion wear of brass alloys in sand water slurry. Systematic study on the failing impeller of a slurry pump used in irrigation has been carried out by means of scanning electron microscopy in order to clarify the failure mechanisms. The results show .The weight loss of the impeller due to the material removal from the impeller as result of erosion wear. In this investigation, experiments were carried out to evaluate the wear resistance using wear test rig designed and manufactured for this purpose. Three specimens of different brass alloys were used, namely (CuZn2Ge-CuZn4Ge-CuZn6Ge) Discs manufactured from. The accumulated loss of weight was measured and the wear rates were determined for each Case material at constant normal test load of 20kg and time24hr. Number of revolutions of tests equals (10001500-2000) r.p.m. were selected for the three test materials respectively during wear tests .The accumulated loss of weight was measured as a function of the number of revolutions. Wear rate was calculated. The results show Wear rate for material B3 (CuZn6Ge) is less than that of the wear rate for B2 (CuZn4Ge), B1 (CuZn2Ge) under the same testing conditions at (1000-1450-2000) r. p. m.

Prognostics of slurry pumps based on a moving-average wear degradation index and a general sequential Monte Carlo method

Slurry pumps are commonly used in oil-sand mining for pumping mixtures of abrasive liquids and solids. These operations cause constant wear of slurry pump impellers, which results in the breakdown of the slurry pumps. This paper develops a prognostic method for estimating remaining useful life of slurry pump impellers. First, a moving-average wear degradation index is proposed to assess the performance degradation of the slurry pump impeller. Secondly, the state space model of the proposed health index is constructed. A general sequential Monte Carlo method is employed to derive the parameters of the state space model. The remaining useful life of the slurry pump impeller is estimated by extrapolating the established state space model to a specified alert threshold. Data collected from an industrial oil sand pump were used to validate the developed method. The results show that the accuracy of the developed method improves as more data become available.

Heat treatment effect on microstructure, hardness and wear resistance of Cr26 white cast iron

High chromium cast iron(HCCI) is taken as material of coal water slurry pump impeller, but it is susceptible to produce serious abrasive wear and erosion wear because of souring of hard coal particles. The research on optimization of heat treatments to improve abrasive wear properties of HCCI is insufficient, so effect of heat treatments on the microstructure, hardness, toughness, and wear resistance of Cr26 HCCI is investigated to determine the optimal heat treatment process for HCCI. A series of heat treatments are employed. The microstructures of HCCI specimens are examined by using optical microscopy and scanning electron microscopy. The hardness and impact fracture toughness of as-cast and heat treated specimens are measured. The wear tests are assessed by a Type M200 ring-on block wear tester. The results show the following: With increase of the quenching temperature from 950 °C to 1050 °C, the hardness of Cr26 HCCI increased to a certain value, kept for a time and then decreased. The optimal heat treatment process is 2 h quenching treatment at 1000 °C, followed by a subsequent 2 h tempering at 400 °C. The hardness of HCCI is related to the precipitation and redissolution of secondary carbides in the process of heat treatment. The subsequent tempering treatment would result in a slight decrease of hardness but increase of toughness. The wear resistance is much related to the “supporting” effect of the matrix and the “protective” effect of the hard carbide embedded in the matrix, and the wear resistance is further dependent on the hardness and the toughness of the matrix. This research can provide an important insight on developing an optimized heat treatment method to improve the wear resistance of HCCI.

The optimisation and analysis of a centrifugal slurry pump impeller with 2 blades

With FLUENT, which is Computational Fluid Dynamics (CFD) software, it becomes possible to define the performance of complicated flow in turbo machines like pumps and blowers. It is not only reduced costs but also saves time. This study is aimed to optimize a commercial slurry pump impeller. Therefore, four different types of impellers were designed with using various blade angles, blade length and splitter blade on the impeller, which is the most crucial component of the pump. As a result of analysis it was seen that every impeller affected on the pump performance at different flow rate.

Failure Analysis of Slurry Pump Impeller in Chehe Dressing Plant

Chemical composition and metallographic organization were analyzed for the failure characteristics and main reasons of the imported slurry pump impeller used by Chehe Dressing Plant China Tin Group. A series of larger long strip form carbides found on the metallographic organization, which improving cut apart trend on matrix seriously, was the main reason of the impeller failure. Proper amount of vanadium, titanium and rare earth complex modifier can refine carbides and improve their morphology. The best mortar proportion was identified in the laboratory analysis conditions through the wear experiments.

Vibration-based fault diagnosis of slurry pump impellers using neighbourhood rough set models

Rough set models have been widely used as a method for feature selection in fault diagnosis. A neighbourhood rough set model can deal with both nominal and numerical features, but selecting the neighbourhood size for its application may be a challenge. In this article, the authors illustrate that using a common neighbourhood size for all features may overestimate or underestimate a feature's dependency degree. The neighbourhood rough set model is then modified by setting different neighbourhood sizes for different features. The modified model is applied to the fault diagnosis of slurry pump impellers. Results show that the chosen feature subsets generated by the modified neighbourhood rough set model can be physically explained by the corresponding flow patterns and can achieve higher classification accuracy than the raw feature subsets and the feature subsets generated by the original neighbourhood rough set model.

Failure analysis of the impeller of slurry pump used in zinc hydrometallurgy process

The failure of the trial impeller of slurry pump used in zinc hydrometallurgy process occurred only after a service of about a month, the expected service life was more than 3 months. The failure impeller was subjected to serious corrosive wear. This paper deals with failure analysis of the impeller (mainly including composition analysis of the slurry, corrosive wear surface characteristics by visual inspection and optical microscopes as well as scanning electron microscope (SEM), composition analysis of the impeller material by spectrum analyser and SEM–EDX, microstructure analysis by optical microscopes) and an improved method. Failure analysis revealed that an improper austenite/ferrite ratio of duplex stainless steel (DSS) material resulting from a too high nitrogen content was primarily responsible for the rapid failure of the impeller. In addition, a melting test in a vacuum furnace verified again that nitrogen content had a significant effect on austenite/ferrite ratio of duplex stainless steel, a comparing corrosive wear test revealed further that DSS consisting of equal austenite/ferrite volume showed better corrosive wear resistance.

Empirical wear relationships for centrifugal slurry pumps: Part 1: side-liners

Wear rate data on slurry pump inlet side-liners are reported. Experimental work has been conducted on different slurry pump impeller and side-liner geometries to determine the effects of solid particle size, slurry concentration and pump speed on wear. Explanations are offered for the resultant wear patterns and empirical wear relationships are outlined for the key variables.