scholarly journals Simple Approach for Evaluation of Abrasive Mixing Efficiency for Abrasive Waterjet Rock Cutting

2021 ◽  
Vol 11 (4) ◽  
pp. 1543
Author(s):  
Yohan Cha ◽  
Tae-Min Oh ◽  
Hyun-Joong Hwang ◽  
Gye-Chun Cho
Keyword(s):  
Flow Rate ◽  
Particle Density ◽  
Empirical Relationship ◽  
Cost Effective ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet ◽  
Mixing Efficiency ◽  
Abrasive Waterjets ◽  
Design Selection

The abrasive mixing variables, such as the abrasive and water flow rates and the focus geometry parameters, determine the profitability of an abrasive waterjet system. In this study, the mixing efficiency characteristics in abrasive waterjet rock cutting were investigated. To demonstrate comprehensively the efficiency reduction due to collision during abrasive mixing, the chance of collision was expressed as the distance between the abrasive particles in the focus. The mixing efficiency was then assessed by utilizing the empirical relationship between the experimental results and the developed model. Based on the particle density and the velocity, the closer particles showed higher chances of collision, thus yielding a reduced cutting performance. Using the distance between particles model, the optimum abrasive flow rate and the cutting performance of abrasive waterjet systems can be estimated. This developed model can be used for the design selection of abrasive flow rate and systems for the cost-effective use of abrasive waterjets.

scholarly journals Effects of Focus Geometry on the Hard Rock-Cutting Performance of an Abrasive Waterjet

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Yohan Cha ◽  
Tae-Min Oh ◽  
Gye-Chun Cho
Keyword(s):  
Momentum Transfer ◽  
Hard Rock ◽  
Empirical Relationship ◽  
Abrasive Particle ◽  
Rock Cutting ◽  
Maximum Energy ◽  
Cutting Performance ◽  
Granitic Rocks ◽  
Abrasive Waterjet ◽  
Cutting Depth

Abrasive waterjets are being increasingly used in civil engineering for rock and concrete cutting, particularly for the demolition or repair of old structures. The energy of an abrasive waterjet is primarily provided by the accelerated abrasive. The momentum transfer during mixing and acceleration determines the abrasive velocity, which affects the cutting performance. Meanwhile, the geometry of the focus at which mixing occurs influences the momentum transfer efficiency. In this study, the effects of the focus geometry on the optimum abrasive flow rate (AFR) and momentum transfer characteristics in hard rock cutting were investigated. Experiments were conducted using granite specimens to test the AFR under different focus geometry conditions such as diameter and length. The results show that the focus geometry significantly affects the maximum cutting depth and optimum AFR. The maximum cutting energy was analyzed based on the cutting efficiency of a single abrasive particle. In addition, the momentum transfer parameter (MTP) was evaluated from the empirical relationship between the maximum energy and the cutting depth for granitic rocks. Accordingly, a model for estimating the MTP based on the AFR was developed. It is expected that the results of this study can be employed for the optimization of waterjet rock cutting.

Effect of Abrasive Feed Rate on Rock Cutting Performance of Abrasive Waterjet

2019 ◽  
Vol 52 (9) ◽  
pp. 3431-3442 ◽  
Author(s):  
Tae-Min Oh ◽  
Gun-Wook Joo ◽  
Gye-Chun Cho
Keyword(s):  
Feed Rate ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet

scholarly journals Effect of Garnet Characteristics on Abrasive Waterjet Cutting of Hard Granite Rock

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tae-Min Oh ◽  
Gun-Wook Joo ◽  
Yohan Cha ◽  
Gye-Chun Cho
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet ◽  
Test Results ◽  
Abrasive Particles ◽  
Waterjet Cutting ◽  
Abrasive Waterjet Cutting

Abrasive waterjet cutting technology has come back into use in the field of rock excavation (such as for tunneling) due to the need for precision construction with low vibration. Because the abrasive particles play an important role in efficient erosion during the cutting process, the abrasive characteristics strongly affect the rock cutting performance. In this study, rock cutting tests were performed with five different coarse (40 mesh) garnets to explore the effect of the abrasive feed rate, physical properties, and particle size distribution on rock cutting performance. In addition, garnet particle disintegration was investigated with garnet characteristics for the abrasive waterjet. The test results indicate that the particle size distribution, garnet purity, specific gravity, and hardness are the most important parameters for rock cutting performance. This study offers better understanding of coarse garnet performance and efficiency according to the garnet characteristics. This should provide assistance in selection of the garnet needed to achieve the desired performance for hard rock cutting.

Effect of Abrasive Waterjet Parameters on Volume Removal Trends in Turning

1995 ◽  
Vol 117 (4) ◽  
pp. 475-484 ◽  
Author(s):  
A. I. Ansari ◽  
M. Hashish
Keyword(s):  
Experimental Investigation ◽  
Particle Size ◽  
Flow Rate ◽  
Removal Rate ◽  
Abrasive Particle ◽  
Sweep Rate ◽  
Abrasive Waterjet ◽  
Orifice Diameter ◽  
Abrasive Waterjets ◽  
Rate Limit

An experimental investigation was conducted to investigate the influence of abrasive waterjet parameters on the volume removal rate in abrasive waterjet turning. Abrasive mass flow rate, abrasive particle size, waterjet pressure, and orifice diameter were the principal variables that were investigated. Limited tests were also conducted with abrasive mixtures. The results show that the volume removal trends in abrasive waterjet turning are similar to those in linear cutting with abrasive waterjets. Increasing waterjet pressure, orifice diameter, and abrasive flow rate generally resulted in an increase in volume removal rate. However, the volume removal rate levels off either due to volume sweep rate limit or due to the abrasive waterjet limit. The results also suggest a potential for optimizing the abrasive flow rate and abrasive composition. The volume removal rate showed only a weak dependence on the abrasive particle size.

scholarly journals Performance and Reuse of Steel Shot in Abrasive Waterjet Cutting of Granite

2021 ◽  
Author(s):  
Yohan Cha ◽  
Tae-Min Oh ◽  
Gun-Wook Joo ◽  
Gye-Chun Cho
Keyword(s):  
Particle Size ◽  
Industrial Waste ◽  
High Hardness ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet ◽  
Steel Shot ◽  
Abrasive Surface ◽  
The Cost ◽  
Recycled Steel

AbstractSteel shots are suitable for abrasive waterjet rock cutting and recycling because of the high hardness and magnetic properties of steel. This study evaluated the rock-cutting performance and recycling characteristics of steel shot waterjet. The rock-cutting responses of steel shot and garnet were compared at the same waterjet conditions. The used steel shot was collected and the particle-size changes were evaluated before reuse, and its cutting performance was re-evaluated. Overall, the steel shot waterjet yielded improvements in performance in the range of 30–50% compared with the garnet waterjet. Moreover, the recycled steel shot yielded a 50% reduction in cutting performance. Rust was observed on the surface of the used steel shot, the used steel shots were partially destroyed, and the debris on the abrasive surface needed to be removed by drying. The reusable steel shot left on the 80th sieve converged to 60% in each recycling run. The results of this study can be used to reduce the cost of abrasive waterjet and industrial waste.

scholarly journals A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

2021 ◽  
Vol 11 (8) ◽  
pp. 3404
Author(s):  
Majid Hejazian ◽  
Eugeniu Balaur ◽  
Brian Abbey
Keyword(s):  
Molecular Dynamics ◽  
Flow Rate ◽  
Numerical Study ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Liquid Jets ◽  
Mixing Efficiency ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Time Required

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

scholarly journals Modeling and optimization of radish root extract drying as peroxidase source using spouted bed dryer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shahrbanoo Hamedi ◽  
M. Mehdi Afsahi ◽  
Ali Riahi-Madvar ◽  
Ali Mohebbi
Keyword(s):  
Kinetic Parameters ◽  
Flow Rate ◽  
Air Flow ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interactive Effects ◽  
Root Extract ◽  
Air Flow Rate ◽  
Spouted Bed ◽  
Radish Root

AbstractThe main advantages of the dried enzymes are the lower cost of storage and longer time of preservation for industrial applications. In this study, the spouted bed dryer was utilized for drying the garden radish (Raphanus sativus L.) root extract as a cost-effective source of the peroxidase enzyme. The response surface methodology (RSM) was used to evaluate the individual and interactive effects of main parameters (the inlet air temperature (T) and the ratio of air flow rate to the minimum spouting air flow rate (Q)) on the residual enzyme activity (REA). The maximum REA of 38.7% was obtained at T = 50 °C and Q = 1.4. To investigate the drying effect on the catalytic activity, the optimum reaction conditions (pH and temperature), as well as kinetic parameters, were investigated for the fresh and dried enzyme extracts (FEE and DEE). The obtained results showed that the optimum pH of DEE was decreased by 12.3% compared to FEE, while the optimum temperature of DEE compared to FEE increased by a factor of 85.7%. Moreover, kinetic parameters, thermal-stability, and shelf life of the enzyme were considerably improved after drying by the spouted bed. Overall, the results confirmed that a spouted bed reactor can be used as a promising method for drying heat-sensitive materials such as peroxidase enzyme.

scholarly journals Numerical Simulation of Rock Plate Cutting with Three Sides Fixed and One Side Free

2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
Zhenguo Lu ◽  
Lirong Wan ◽  
Qingliang Zeng ◽  
Xin Zhang ◽  
Kuidong Gao
Keyword(s):  
Numerical Simulation ◽  
Cutting Force ◽  
Cutting Speed ◽  
Rock Cutting ◽  
Numerical Results ◽  
Peak Force ◽  
Cutting Performance ◽  
Conical Pick ◽  
Cutting Method ◽  
Cutting Angle

In order to overcome conical pick wear in the traditional rock cutting method, a new cutting method was proposed on account of increasing free surface of the rock. The mechanical model of rock plate bending under concentrated force was established, and the first fracture position was given. The comparison between experimental and numerical results indicated that the numerical method is effective. A computer code LS-DYNA (3D) was employed to study the cutting performance of a conical pick. To study the rock size influenced on the cutting performance, the numerical simulations with different thickness, width, and height of a rock plate was carried out. The numerical simulation with the different cutting parameters of cutting speed, cutting angle, and cutting position influenced on cutting performance was also carried out. The numerical results indicated that the peak force increased with the increasing thickness of rock plate. With the increasing width and height of the rock plate, the peak force decreased and then became stable. Besides, the peak force decreased with the increasing of cutting position lxp/lx. Moreover, the peak force increased and then decreased with the increasing of cutting angle. The cutting speed has nonsignificant influence on the peak force. The strong exponential relationship was obtained between the peak force and cutting position, thickness, height, and width of the rock plate at a confidence level of 0.95. A binomial relationship was observed between the peak force and cutting angel. The cutting force comparison between traditional rock cutting and rock plate cutting indicated that the new cutting method can effectively reduce peak cutting force.

scholarly journals Influence of Traverse Velocity and Pump Pressure on the Efficiency of Abrasive Waterjet for Rock Cutting

2017 ◽  
Vol 40 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Paola Bruno Arab ◽  
Tarcísio Barreto Celestino
Keyword(s):  
Rock Cutting ◽  
Abrasive Waterjet ◽  
Pump Pressure

Analysis and Optimization of a Passive Micromixer With Curved-Shaped Baffles for Efficient Mixing With Low Pressure Loss in Continuous Flow

2010 ◽  
Author(s):  
Cesar A. Cortes-Quiroz ◽  
Alireza Azarbadegan ◽  
Emadaldin Moeendarbary ◽  
Mehrdad Zangeneh
Keyword(s):  
Pressure Loss ◽  
Cost Effective ◽  
Optimization Method ◽  
Secondary Flows ◽  
Design Parameters ◽  
Mixing Efficiency ◽  
Outlet Section ◽  
Optimization Strategy ◽  
Mixing Index ◽  
Trade Offs

Numerical simulations and an optimization method are used to study the design of a planar T-micromixer with curved-shaped baffles in the mixing channel. The mixing efficiency and the pressure loss in the mixing channel have been evaluated for Reynolds number (Re) in the mixing channel in the range 1 to 250. A Mixing index (Mi) has been defined to quantify the mixing efficiency. Three geometric dimensions: radius of baffle, baffles pitch and height of the channel, are taken as design parameters, whereas the mixing index at the outlet section and the pressure loss in the mixing channel are the performance parameters used to optimize the micromixer geometry. To investigate the effect of design and operation parameters on the device performance, a systematic design and optimization methodology is applied, which combines Computational Fluid Dynamics (CFD) with an optimization strategy that integrates Design of Experiments (DOE), Surrogate modeling (SM) and Multi-Objective Genetic Algorithm (MOGA) techniques. The Pareto front of designs with the optimum trade-offs of mixing index and pressure loss is obtained for different values of Re. The micromixer can enhance mixing using the mechanisms of diffusion (lower Re) and convection (higher Re) to achieve values over 90%, in particular for Re in the order of 100 that has been found the cost-effective level for volume flow. This study applies a systematic procedure for evaluation and optimization of a planar T-mixer with baffles in the channel that promote transversal 3-D flow as well as recirculation secondary flows that enhance mixing.

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