Modeling of Surface Waviness in Abrasive Waterjet Offset-Mode Turning

2014 ◽  
Vol 621 ◽  
pp. 202-207
Author(s):  
Iman Zohourkari ◽  
Mehdi Zohoor ◽  
Massimiliano Annoni

In this paper, surface waviness produced by turning aluminum parts with abrasive waterjet has been studied regarding changes in some process parameters. Effect of five major parameters such as water pressure, cutting head traverse speed, abrasive mass flow rate, workpiece rotational speed and depth of cut have been investigated using analysis of variances. Second order regression model presented forwaviness.The validity of the model wasconfirmed bycomparing with experimental data. It found thatabrasive mass flow rate, cutting head traverse speed and DOC are the most influencing parameters while water pressure and workpiece rotational speed show lesser effectiveness.

2014 ◽  
Vol 599-601 ◽  
pp. 555-559
Author(s):  
Iman Zohourkari ◽  
Mehdi Zohoor ◽  
Massimiliano Annoni

In this paper, surface waviness quality in abrasive waterjet offset-mode turning has been studied regarding variations of some process parameters. Influence of five main operational parameters such as water pressure, cutting head traverse speed, abrasive mass flow rate, workpiece rotational speed and depth of cut on surface waviness of turned parts have been investigated using statistical approach. Second order regression model presented for surface waviness. The model accuracy was verified by comparing with experimental data. It found that abrasive mass flow rate, cutting head traverse speed and DOC are the most influential parameters while water pressure and workpiece rotational speed show lesser effectiveness.


2014 ◽  
Vol 6 ◽  
pp. 624203 ◽  
Author(s):  
Iman Zohourkari ◽  
Mehdi Zohoor ◽  
Massimiliano Annoni

The effects of the main operational machining parameters on the material removal rate (MRR) in abrasive waterjet turning (AWJT) are presented in this paper using a statistical approach. The five most common machining parameters such as water pressure, abrasive mass flow rate, cutting head traverse speed, workpiece rotational speed, and depth of cut have been put into a five-level central composite rotatable experimental design (CCRD). The main effects of parameters and the interaction among them were analyzed by means of the analysis of variance (ANOVA) and the response surfaces for MRR were obtained fitting a second-order polynomial function. It has been found that depth of cut and cutting head traverse speed are the most influential parameters, whereas the rotational speed is insignificant. In addition, the investigations show that interactions between traverse speed and pressure, abrasive mass flow rate and depth of cut, and pressure and depth of cut are significant on MRR. This result advances the AWJT state of the art. A complete model discussion has been reported drawing interesting considerations on the AWJT process characterising phenomena, where parameters interactions play a fundamental role.


2019 ◽  
Vol 895 ◽  
pp. 301-306
Author(s):  
Keshav Kashyap ◽  
S. Srinivas

This study evaluates the effect of process parameters on depth of penetration and surface roughness in abrasive waterjet (AWJ) cutting of copper. Full factorial experiments are carried out on trapezoidal blocks for each of the three abrasive particle sizes used. Experimental parameters - abrasive mass flow rate, water jet pressure and traverse speed are varied at three levels. Main effects and contributions of process parameters to depth of penetration and surface roughness is calculated. From the data, it is observed that, high abrasive mass flow rate, high water jet pressure and low traverse speed resulted in higher depth of penetration and a high abrasive mass flow rate, high water jet pressure and low traverse speed resulted in lesser Ra value. Using experimental data a statistical model for predicting depth of penetration & surface roughness is developed. Error between experimental and statistical values are compared to validate the statistical model. The maximum DOP of 49.32mm was observed at AMFR=405.4 g/min, P=300 MPa, TS=60 mm/min, MS=60 Mesh and minimum DOP of 4.27mm was observed at AMFR=200 g/min, P=100 MPa, TS=90 mm/min, MS=80 Mesh.


2013 ◽  
Vol 797 ◽  
pp. 27-32
Author(s):  
Zhong Bo Yue ◽  
Chuan Zhen Huang ◽  
Hong Tao Zhu ◽  
Jun Wang ◽  
Peng Yao ◽  
...  

A study on the radial-mode abrasive waterjet turning (AWJT) process is presented and discussed. An experimental investigation is carried out to explore the influence of process parameters on the depth of turning and material removal rate (MRR) when turning 96% alumina ceramics. The experiment is designed by the multifactor orthogonal experiment methods. The effect of feed speed, water pressure, abrasive mass flow rate, nozzle tilted angle and surface speed are investigated by the range analysis and variance analysis. The results show that the feed speed is the most significant variables affecting the depth of turning. Based on the test conditions, it is found that the most efficient conditions to maximize depth of turning are at a jet angle of 105 degree, a water pressure of 310MPa, an abrasive mass flow rate of 11.5 g/s, a surface speed of 5.5m/s and a feed speed of 0.05mm/s. At last, the effect mechanism of process variables on the depth of turning is analyzed qualitatively.


Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1362
Author(s):  
Jennifer Milaor Llanto ◽  
Ana Vafadar ◽  
Muhammad Aamir ◽  
Majid Tolouei-Rad

Abrasive waterjet machining is applied in various industries for contour cutting of heat-sensitive and difficult-to-cut materials like austenitic stainless steel 304L, with the goal of ensuring high surface integrity and efficiency. In alignment with this manufacturing aspiration, experimental analysis and optimization were carried out on abrasive waterjet machining of austenitic stainless steel 304L with the objectives of minimizing surface roughness and maximizing material removal rate. In this machining process, process parameters are critical factors influencing contour cutting performance. Accordingly, Taguchi’s S/N ratio method has been used in this study for the optimization of process parameters. Further in this work, the impacts of input parameters are investigated, including waterjet pressure, abrasive mass flow rate, traverse speed and material thickness on material removal rate and surface roughness. The study reveals that an increasing level of waterjet pressure and abrasive mass flow rate achieved better surface integrity and higher material removal values. The average S/N ratio results indicate an optimum value of waterjet pressure at 300 MPa and abrasive mass flow rate of 500 g/min achieved minimum surface roughness and maximum material removal rate. It was also found that an optimized value of a traverse speed at 90 mm/min generates the lowest surface roughness and 150 mm/min produces the highest rate of material removed. Moreover, analysis of variance in the study showed that material thickness was the most influencing parameter on surface roughness and material removal rate, with a percentage contribution ranging 90.72–97.74% and 65.55–78.17%, respectively.


Author(s):  
Mohammad J. Izadi ◽  
Alireza Falahat

In this investigation an attempt is made to find the best hub to tip ratio, the maximum number of blades, and the best angle of attack of an axial fan with flat blades at a fixed rotational speed for a maximum mass flow rate in a steady and turbulent conditions. In this study the blade angles are varied from 30 to 70 degrees, the hub to tip ratio is varied from 0.2 to 0.4 and the number of blades are varied from 2 to 6 at a fixed hub rotational speed. The results show that, the maximum flow rate is achieved at a blade angle of attack of about 45 degrees for when the number of blades is set equal to 4 at most rotational velocities. The numerical results show that as the hub to tip ratio is decreased, the mass flow rate is increased. For a hub to tip ratio of 0.2, and an angle of attack around 45 degrees with 4 blades, a maximum mass flow rate is achieved.


2021 ◽  
Author(s):  
Raghuvaran D. ◽  
Satvik Shenoy ◽  
Srinivas G

Abstract Axial flow fans (AFF) are extensively used in various industrial sectors, usually with flows of low resistance and high mass flow rates. The blades, the hub and the shroud are the three major parts of an AFF. Various kinds of optimisation can be implemented to improve the performance of an AFF. The most common type is found to be geometric optimisation including variation in number of blades, modification in hub and shroud radius, change in angle of attack and blade twist, etc. After validation of simulation model and carrying out a grid independence test, parametric analysis was done on an 11-bladed AFF with a shroud of uniform radius using ANSYS Fluent. The rotational speed of the fan and the velocity at fan inlet were the primary variables of the study. The variation in outlet mass flow rate and total pressure was studied for both compressible and incompressible ambient flows. Relation of mass flow rate and total pressure with inlet velocity is observed to be linear and exponential respectively. On the other hand, mass flow rate and total pressure have nearly linear relationship with rotational speed. A comparison of several different axial flow tracks with the baseline case fills one of the research gaps.


Author(s):  
Dominik Schlüter ◽  
Robert P. Grewe ◽  
Fabian Wartzek ◽  
Alexander Liefke ◽  
Jan Werner ◽  
...  

Abstract Rotating stall is a non-axisymmetric disturbance in axial compressors arising at operating conditions beyond the stability limit of a stage. Although well-known, its driving mechanisms determining the number of stall cells and their rotational speed are still marginally understood. Numerical studies applying full-wheel 3D unsteady RANS calculations require weeks per operating point. This paper quantifies the capability of a more feasible quasi-2D approach to reproduce 3D rotating stall and related sensitivities. The first part of the paper deals with the validation of a numerical baseline the simplified model is compared to in detail. Therefore, 3D computations of a state-of-the-art transonic compressor are conducted. At steady conditions the single-passage RANS CFD matches the experimental results within an error of 1% in total pressure ratio and mass flow rate. At stalled conditions, the full-wheel URANS computation shows the same spiketype disturbance as the experiment. However, the CFD underpredicts the stalling point by approximately 7% in mass flow rate. In deep stall, the computational model correctly forecasts a single-cell rotating stall. The stall cell differs by approximately 21% in rotational speed and 18% in circumferential size from the experimental findings. As the 3D model reflects the compressor behaviour sufficiently accurate, it is considered valid for physical investigations. In the second part of the paper, the validated baseline is reduced in radial direction to a quasi-2D domain only resembling the compressor tip area. Four model variations regarding span-wise location and extent are numerically investigated. As the most promising model matches the 3D flow conditions in the rotor tip region, it correctly yields a single-cell rotating stall. The cell differs by only 7% in circumferential size from the 3D results. Due to the impeded radial migration in the quasi-2D slice, however, the cell exhibits an increased axial extent. It is assumed, that the axial expansion into the adjacent rows causes the difference in cell speed by approximately 24%. Further validation of the reduced model against experimental findings reveals, that it correctly reflects the sensitivity of circumferential cell size to flow coefficient and individual cell speed to compressor shaft speed. As the approach reduced the wall clock time by 92%, it can be used to increase the physical understanding of rotating stall at much lower costs.


Author(s):  
Pau Cutrina Vilalta ◽  
Hui Wan ◽  
Soumya S. Patnaik

Abstract In this paper, we use various regression models and Artificial Neural Network (ANN) to predict the centrifugal compressor performance map. Particularly, we study the accuracy and efficiency of Gaussian Process Regression (GPR) and Artificial Neural Networks in modelling the pressure ratio, given the mass flow rate and rotational speed of a centrifugal compressor. Preliminary results show that both GPR and ANN can predict the compressor performance map well, for both interpolation and extrapolation. We also study the data augmentation and data minimzation effects using the GPR. Due to the inherent pressure ratio data distribution in mass-flow-rate and rotational-speed space, data augmentation in the rotational speed is more effective to improve the ANN performance than the mass flow rate data augmentation.


Author(s):  
Sibel Tas ◽  
Sertac Cadirci ◽  
Hasan Gunes ◽  
Kemal Sarioglu ◽  
Husnu Kerpicci

The aim of this experimental study is to investigate the mass flow rate of the lubricating oil in a hermetic reciprocating compressor. Essential parameters affecting the performance of the lubrication are the rotational speed of the crankshaft, the viscosity of the oil, the operating temperature and the submersion depth of the crankshaft. An experimental setup was built as to measure the oil mass flow rate with respect to the oil temperature variation during different operating conditions. The influence of the governing parameters such as the rotational speed, temperature (viscosity) and the submersion depth on the mass flow rate from crankshaft outlet are studied in detail. In addition, the oil flow visualization from the upper hole of the crankshaft is performed using a high-speed camera in order to observe the effectiveness of the lubrication of the various parts of the compressor. This study reveals that with increasing rotational speed, the submersion depth of the crankshaft and with decreasing viscosity of the lubricant, the mass flow rate from the crankshaft increases.


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