Abrasive Water Suspension Jets Research Articles

PROCESS OPTIMIZATION BY APPLYING THE RESPONSE SURFACE METHODOLOGY (RSM) TO THE ABRASIVE SUSPENSION WATER JET CUTTING OF PHENOLIC COMPOSITES

The paper introduces the study on the cutting of the industrial composite phenolic resin, based on the thermoset materials reinforced with cotton cloth by the Abrasive Water Suspension Jet (AWSJ). The size reduction of abrasive grains during the formation of the jet and the erosion phenomenon are shown. The results of the machining process's critical factors as nozzle length, nozzle diameter, and abrasive mass flow rate on the maximal cutting depth, are indicated. To build a model of the process, the method of the response surface (RSM) was applied. The second-degree multinomial equation is selected for creating the cutting model. The research indicates the optimal control factors of the process, to achieve the best cutting depth performance.

A Proposed Modification to the JAYA Optimization Algorithm - Application to an Abrasive Water Suspension Jet Machining Process

Optimization plays a vital role in the application of the Industry 4.0 features in the manufacturing sector. Several optimization techniques are in use to date and immensely benefit the user. JAYA is a metaheuristic optimization method that doesn’t require any algorithm-specific parameters. This algorithm has the disadvantage of sometimes getting locked at local optima. This article offers a Modified-JAYA (ModJAYA) algorithm that incorporates the concept of ‘diversity’ into the JAYA algorithm to address the above-mentioned problem. It also hastens the entry of elite solution candidates from diverse solution space. The proposed algorithm ModJAYA is tested on two standard benchmark functions. It is then applied to an Abrasive Water Suspension Jet (AWSJ) machining process to optimize the process parameters. The effectiveness of the ModJAYA algorithm is compared with that of the JAYA algorithm and verified with that of the PSO algorithm. The ModJAYA algorithm outperformed JAYA and PSO algorithms by taking the least mean number of generations for convergence.

Post-Test Analyses of the CMMR-4 Test

Abstract Understanding the final distribution of core materials and their characteristics is important for decommissioning the Fukushima Daiichi Nuclear Power Station (1F). Such characteristics depend on the accident progression in each unit. However, boiling water reactor (BWR) accident progression involves great uncertainty. This uncertainty, which was clarified by MAAP-MELCOR crosswalk, cannot be resolved with existing knowledge and was thus addressed in this work through core material melting and relocation (CMMR) tests. For the test bundle, ZrO2 pellets were installed instead of UO2 pellets. A plasma heating system was used for the tests. In the CMMR-4 test, useful information was obtained on the core state just before slumping. The presence of macroscopic gas permeability of the core approaching ceramic fuel melting was confirmed, and the fuel columns remained standing, suggesting that the collapse of fuel columns, which is likely in the reactor condition, would not allow effective relocation of the hottest fuel away from the bottom of the core. This information will help us comprehend core degradation in boiling water reactors, similar to those in 1F. In addition, useful information on abrasive water suspension jet (AWSJ) cutting for debris-containing boride was obtained in the process of dismantling the test bundle. When the mixing debris that contains oxide, metal, and boride material is cut, AWSJ may be repelled by the boride in the debris, which may cut unexpected parts, thus generating a large amount of waste in cutting the boride part in the targeted debris. This information will help the decommissioning of 1F.

Effect of the Process Parameters on Machining of GFRP Composites for Different Conditions of Abrasive Water Suspension Jet Machining

The selection of parameters for abrasive water suspension jet (AWSJ) machining of GFRP composites is a major aspect to be considered for optimizing the process. Generally, machining of plastics, polymer matrix composites are accomplished by the AWSJ machining carried out in the presence of atmospheric air; however, the existence of air around the AWSJ may lead to expansion of jet which results in increase in the kerf width and surface roughness; thus to overcome this drawback, an effort has been made in the current work to compare the effect of different process parameters on kerf width and surface roughness while using AWSJ techniques for machining glass fibre-reinforced plastic composite submerged in water. The exploratory outcomes have herewith validated the fact that the surface roughness and kerf width diminishes in under water machining when contrasted with that of free air machining; this is majorly attributed to the fact that the jet diameter reduces in under water AWSJ machining, thereby reducing the kerf width and surface roughness for optimized values of the parameters of speed, feed and standoff distance. Further, the experimental trials have clearly shown that the AWSJ machining used with an optimized set of parameters yields better machining capabilities as compared to abrasive water jet machining.

Stabilization of Abrasive Concentration in Abrasive Water Suspension Jets using Bypass System

Stabilization of Abrasive Concentration in Abrasive Water Suspension Jets using Bypass System

Stabilization of Abrasive Concentration in Abrasive Water Suspension Jets Using Valve Operation

Stabilization of Abrasive Concentration in Abrasive Water Suspension Jets Using Valve Operation

Stabilization of Abrasive Concentration in Abrasive Water Suspension Jets using Valve System

Stabilization of Abrasive Concentration in Abrasive Water Suspension Jets using Valve System

バルブ制御によるアブレシブ・サスペンションジェット内の研磨材濃度の安定化

バルブ制御によるアブレシブ・サスペンションジェット内の研磨材濃度の安定化

A Review of Research on Water Jet with Slurry Injection

Abrasive water jet has been used for more than thirty years. It quickly became one of the core non-conventional technologies for cutting operations of various materials, ranging from soft and easy to cut materials, through ductile metal materials to brittle, hard to cut ceramics and metals. Abrasive water suspension jet (AWSJ) did not gain much popularity in machining industry in the beginning as opposed to abrasive water injection jet, but has found niche applications where its advantages were put to use. In this study a review of recent development in the eld of AWSJ is presented. Micro-machining, as a potential application for AWSJ, is discussed at the beginning, followed by several advances in the AWSJ technology. At the end, typical applications for AWSJ as decommissioning and dismantling of structures or rock drilling are presented.

1417 アブレシブ・サスペンションジェットにおける研磨材濃度の安定化(流体工学IX)

1417 アブレシブ・サスペンションジェットにおける研磨材濃度の安定化(流体工学IX)

バイパス方式によるアブレシブ・サスペンションジェット内の 研磨材濃度の安定化

バイパス方式によるアブレシブ・サスペンションジェット内の 研磨材濃度の安定化

Numerical Analysis of Flow through Abrasive Water Suspension Jet: The Effect of Garnet, Aluminum Oxide and Silicon Carbide Abrasive on Skin Friction Coefficient Due To Wall Shear and Jet Exit Kinetic Energy

It is well known that the abrasive particles in the abrasive water suspension has significant effect on the erosion characteristics of the inside surface of the nozzle. Abrasive particles moving with the flow cause severe skin friction effect, there by altering the nozzle diameter due to wear which in turn reflects on the life of the nozzle for effective machining. Various commercial abrasives are available for abrasive water jet machining. The erosion characteristic of each abrasive is different. In consideration of this aspect, in the present work, the effect of abrasive materials namely garnet, aluminum oxide and silicon carbide on skin friction coefficient due to wall shear stress and jet kinetic energy has been analyzed. It is found that the abrasive material of lower density produces a relatively higher skin friction effect and higher jet exit kinetic energy.

CFD Simulation of Flow in an Abrasive Water Suspension Jet: The Effect of Inlet Operating Pressure and Volume Fraction on Skin Friction and Exit Kinetic Energy

Abrasive particles in the suspension mixture in an abrasive water suspension jet (AWSJ) machining causes acute skin friction effect thereby effectively changing the jet diameter due to wear, which in turn influences jet exit kinetic energy. This results in lowering the life of the jet for effective machining. In consideration of this aspect, the present work examines the effect of inlet pressure on skin friction coefficient and jet exit kinetic energy. It is inferred from the analysis that an increase in inlet pressure causes a significant increase in skin friction coefficient and also results in proportional increase in the exit kinetic energy of the jet. Further, it is revealed from the analysis that an increase volume fraction of abrasive (abrasive concentration) in water results in significant decrease in the skin friction coefficient and jet exit kinetic energy.

Abrasive Water Suspension Jet Technology Fundamentals, Application and Developments

The introduction of abrasive material into water jet technology in the 80s extended the range of materials, which could be cut to practically all technical materials, which has been one of the largest step of development in this technological branch. Since then, two different types of abrasive water jets developed. Due to their different jet generation these differ in their properties, which define their application fields. Whereas abrasive water injection jets are mainly applied for industrial machining, the core application fields of abrasive water suspension jets are in the decommissioning and dismantling of offshore structures and nuclear power plants as well as in demilitarisation. In this paper the generation mechanisms of abrasive suspension jets are explained, and the influence of the main parameters on the cutting efficiency presented. The properties of this type of jet are marked of those of abrasive water injection jets leading to their specific application fields. Additionally new developments in this technological branch are presented in this paper.

Effect of helium atmospheres on abrasive suspension water jets

The coherence of cutting pure water jets can be enhanced by shooting them into low-density atmospheres. To answer the question about the possibility to also improve the coherence of abrasive water suspension jets (AWSJ), experiments were performed surrounding AWSJs with a parallel stream of helium. Although in some cases a change on the structure of the jets was recognized, the studied jets shot into helium atmospheres did not show appreciable improvements on their cutting and kerfing performance.

A Sheathed Nozzle for Abrasive Water Suspension Jets in Submerged Environments

The drilling capability of abrasive water suspension jets (AWSJs) under submerged condition decreases steeply with the increase of the standoff distance, and effective working distance for drilling and cutting is restricted in small standoff distance region. When the standoff distance is small, the nozzle may be damaged by the reflected jet. In narrow environments the nozzle can not be set closer to the work sometimes. Accordingly we have to find methods to extend the effective working distance for submerged AWSJs. In this paper, a sheathed AWSJ nozzle is proposed as a means extending the effective working distance for submerged AWSJs. Experiments are conducted to clarify the drilling capability of the sheathed AWSJ nozzle with specimens of stainless steel. Observation of the jet is also carried out with and without abrasive. A sheathed nozzle is useful for extending the effective working distance between the nozzle and works without drastic reduction in drilling capability.

EFFECTIVENESS OF SHEATHED ABRASIVE WATER SUSPENSION JET NOZZLE FOR SUBMERGED APPLICATION(Water Jet)

The drilling capability of abrasive water suspension jets (AWSJs) under a submerged condition decreases steeply with the increase of the standoff distance, and the effective working distance for drilling and cutting is restricted in a small standoff distance region. When the standoff distance is small, the nozzle may be damaged by the reflected jet. In narrow environments, the nozzle sometimes cannot be set closer to the workpiece. Accordingly, we need methods that extend the effective working distance for submerged AWSJs. In this paper, a sheathed nozzle for AWSJs is proposed as a means of extending the effective working distance in submerged environments. Experiments are conducted to clarify the drilling capability of the jet delivered by this sheathed AWSJ nozzle using specimens of stainless steel at an injection pressure of 12MPa. A favorable nozzle shape for the sheathed AWSJ nozzle is discussed from the points of view of drilling capability and lifetime of the sheath.

LASER OBSERVATION ON THE INNER FLOW STRUCTURE OF WATER JETS(Water Jet)

To make clear the structure of the straight-water jets (STWJ, or plain-water jets), the axial and radial distributions of the STWJ were measured by using a laser-doppler-velocimeter (LDV). Abrasive-water suspension jets (AWSJ) velocity was also examined experimentally and compared with the STWJ velocity. Experimental data showed that the average AWSJ velocity exceeded the average STWJ velocity in the range of the diffused flow region far from the nozzle.

Prevention of Nozzle Wear in Abrasive Water Suspension Jets (AWSJ) Using Porous Lubricated Nozzles

This paper introduces a novel method for preventing nozzle wear in abrasive water jets. It consists of using a porous nozzle, surrounded by a reservoir containing high-viscosity lubricant, which is exposed to the same driving pressure as the flow in the nozzle. The pressure difference across the porous medium, generated due to the high-speed flow in the nozzle, continuously forces lubricant through it. The resulting thin oil film forming on the walls of the nozzle protects the walls from the impact and shear caused by the abrasive particles. The porous nozzles were manufactured using Electric Discharge Machining and examined with Scanning Electron Microscopy. Two test facilities were used for evaluating the porous lubricated nozzles. The first was a two-dimensional facility, supporting a 145 μm wide nozzle with windows on both sides, which enabled visualization of the oil film and measurements of the liquid and abrasive-particle velocities using Particle Image Velocimetry. The measured slip velocities were also compared to computed values from a simple numerical model involving one-way coupling. The second facility used a 200 μm axisymmetric nozzle to determine the extent of nozzle wear under different conditions. We found that the presence of an oil film substantially reduced the extent of nozzle wear, from 111 percent of the diameter, when the nozzle was not lubricated, to 4 percent, when the oil viscosity was 1800 mm2/s and its flow rate was 2.4 percent of the water flow (over the same period). The wear increased as the lubricant flow rate and viscosity decreased. The presence of the oil film also improved the coherence of the jet.

1202 鞘付きノズルによって形成される AWSJ の水中せん孔特性

An abrasive water suspension jet (AWSJ) has a greater capacity for drilling and cutting than the abrasive water injection jet (AWIJ). The drilling capability of the AWSJ under submerged condition decreases steeply with the increase of the standoff distance. In order to expand the effective standoff distance of the AWSJ under submerged condition, a sheath AWSJ nozzle is proposed and the drilling capability of the sheath AWSJ nozzle is clarified through drilling tests with specimens of stainless steal.