scholarly journals CFD Simulations to Study Parameters Affecting Gas Explosion Venting in Compressor Compartments

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Kang Cen ◽  
Bin Song ◽  
Yan Huang ◽  
Qingsheng Wang
Keyword(s):  
Unit Area ◽  
Orthogonal Experiment ◽  
Area Ratio ◽  
Blockage Ratio ◽  
Cfd Simulations ◽  
Relational Analysis ◽  
Safety Design ◽  
Grey Relational Grade ◽  
Grey Relational ◽  
The Impact

In this work, a series of vented explosions in a typical compressor compartment are simulated using FLACS code to analyze the explosion venting characteristics. The effects of relevant parameters on the pressure peaks (i.e., overpressure and negative pressure) are also numerically investigated, including vent area ratio of the compressor compartment, vent activation pressure, mass per unit area of vent panels, and volume blockage ratio of obstacles. In addition, the orthogonal experiment design and improved grey relational analysis are implemented to evaluate the impact degree of these relevant parameters. The results show that the pressure peaks decrease with the increase of vent area ratio. There is an approximately linearly increasing relationship between the pressure peaks and the vent activation pressure. The pressure peaks increase with the mass per unit area of vent panels. The pressure peaks increase with the volume blockage ratio of obstacles. Based on the grey relational grade values, the effects of these relevant parameters on the overpressure peak are ranked as follows: volume blockage ratio of obstacles > vent activation pressure > vent area ratio > mass per unit area of vent panels. These achievements provide effective guidance for the venting safety design of gas compressor compartments.

The impact of subway operation on urban traffic: A GRA-BNs based study

2021 ◽  
pp. 1-16
Author(s):  
Lixin Yan ◽  
Tao Zeng ◽  
Yubing Xiong ◽  
Zhenyun Li ◽  
Qingmei Liu
Keyword(s):  
Bayesian Networks ◽  
Operating Characteristic ◽  
Urban Traffic ◽  
Relational Analysis ◽  
Traffic Security ◽  
Structural Network ◽  
Random Decision Forest ◽  
Roc Area ◽  
Grey Relational ◽  
The Impact

With the development of urbanization, urban traffic has exposed many problems. To study the subway’s influence on urban traffic, this paper collects data on traffic indicators in Nanchang from 2008 to 2018. The research is carried out from three aspects: traffic accessibility, green traffic, and traffic security. First, Grey Relational Analysis is used to select 18 traffic indicators correlated with the subway from 22 traffic indicators. Second, the data is discretized and learned based on Bayesian Networks to construct the structural network of the subway’s influence. Third, to verify the reliability of using GRA and the effectiveness of Bayesian Networks (GRA-BNs), Bayesian Networks with full indicators analysis and other four algorithms (Naive Bayes, Random Decision Forest, Logistic and regression) are employed for comparison. Moreover, the receiver operating characteristic (ROC) area, true positive (TP) rate, false positive (FP) rate, precision, recall, F-measure, and accuracy are utilized for comparing each situation. The result shows that GRA-BNs is the most effective model to study the impact of the subway’s operation on urban traffic. Then, the dependence relations between the subway and each index are analyzed by the conditional probability tables (CPTs). Finally, according to the analysis, some suggestions are put forward.

scholarly journals Multi Performance Optimizationof Shoulder Milling Process Parameters of AA6063 T6 Aluminium Alloy by Taguchi Based GRA

2019 ◽  
Vol 8 (10S) ◽  
pp. 420-425
Keyword(s):  
Process Parameters ◽  
Grey Relational Analysis ◽  
Removal Rate ◽  
Analysis Data ◽  
Milling Process ◽  
Depth Of Cut ◽  
Analysis Method ◽  
Relational Analysis ◽  
Grey Relational Grade ◽  
Grey Relational

In this paper, a grey relational analysis method based on Taguchi is proposed to improve the multi-performance characteristics of VMC shoulder milling process parameters in the processing of AA6063 T6. Taking into account four process parameters such as coolant, depth of cut,speed and feed, there are three level of each process parameter in addition to two levels of coolant. 18 experiments were used by L18 orthogonal array using the taguchi method. Multi-performance features like surface roughness and material removal rate are used. Grey Relational Analysis method is used to obtain the Grey Relational Grade, and the multiperformance characteristics of the process are pointed out. Then, the Taguchi response table method and ANOVA are used to analysis data. In order to ensure the validity of the test results, a confirmation test was conducted. The study also shows that this method can effectively improve the multi-function characteristics of shoulder milling process.In his work microstructure and mechanical properties of AA6063 T6before and after shoulder milling have been investigated.

Development of Microwave Hybrid Heating Welded Joints of Inconel-600 Superalloys using Grey Relational Analysis

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ravish Arora ◽  
Jatinder Kapoor ◽  
Rakesh Chandimal Sharma
Keyword(s):  
Grey Relational Analysis ◽  
High Strength ◽  
High Wear Resistance ◽  
Powder Particle Size ◽  
Hybrid Heating ◽  
Inconel 600 ◽  
Relational Analysis ◽  
Microwave Hybrid Heating ◽  
Grey Relational ◽  
The Impact

Inconel-600 superalloys have a number of applications in space and aerospace sector due to its unique characteristics of high strength at elevated temperature, low weight, corrosion resistance and high wear resistance. However, due to these characteristics, Inconel-600 superalloy poses challenges in joining. Therefore, an attempt has been made to resolve these issues using microwave hybrid heating (MHH). The characteristics of the constituents of MHH process have large impact on the welded joint’s strength. This paper examines the impact of control parameters on the ultimate tensile strength (UTS) and percentage elongation (EL) of Inconel-600 plates, which are welded via MHH. Design of experiments was carried out in accordance with Taguchi L16 orthogonal array (OA), taking in consideration of filler powder particle size (FPS), susceptor and separator. Multi-performance features were optimized via the effective utilization of Taguchi-based grey relational analysis (GRA) approach. ANOVA results show that the predominating factor to govern the joint strength is FPS followed by the susceptor and separator. The validation experiments are performed on the predicted optimized setting of process parameters. First level of FPS (30μm), second level of susceptor (Graphite) and second level of separator (SiC) were found as the optimized parametric settings.

Impact of Tile Design on Thermal Performance of Open and Enclosed Aisles

2017 ◽  
Author(s):  
Sadegh Khalili ◽  
Mohammad I. Tradat ◽  
Kourosh Nemati ◽  
Mark Seymour ◽  
Bahgat Sammakia
Keyword(s):  
Data Centers ◽  
Area Ratio ◽  
Inlet Temperature ◽  
Open Area ◽  
Cfd Simulations ◽  
Physical Separation ◽  
Hot Air ◽  
Airflow Distribution ◽  
The Impact ◽  
Lower Noise

In raised floor data centers, tiles with high open area ratio or complex understructure are used to fulfill the demand of today’s high-density computing. Using more open tiles reduces pressure drop across the raised floor with the potential advantages of increased airflow and lower noise. However, it introduces the disadvantage of increased non-uniformity of airflow distribution. In addition, there are various tile designs available on the market with different opening shapes or understructures. Furthermore, a physical separation of cold and hot aisles (containment) has been introduced to minimize the mixing of cold and hot air. In this study, three types of floor tiles with different open area, opening geometry, and understructure are considered. Experimentally validated detail models of tiles were implemented in CFD simulations to address the impact of tile design on the cooling of IT equipment in both open and enclosed aisle configurations. Also, impacts of under-cabinet leakage on the IT equipment inlet temperature in the provisioned and under-provisioned scenarios are studied. Finally, a predictive equation for the critical under-provisioning point that can lead to a no-flow condition in IT equipment with weaker airflow systems is presented.

Design optimization of micromixer with circular mixing chambers (M-CMC) using Taguchi-based grey relational analysis

2020 ◽  
Vol 18 (9) ◽  
Author(s):  
Ranjitsinha R. Gidde
Keyword(s):  
Grey Relational Analysis ◽  
Design Parameters ◽  
Relational Analysis ◽  
Mixing Dynamics ◽  
Depth Study ◽  
Grey Relational Grade ◽  
Grey Relational ◽  
Mixing Chambers ◽  
Optimal Set ◽  
Level Analysis

AbstractThe aim of the present study is to optimize the micromixer with circular mixing chambers (M-CMC) using Taguchi-based grey relational analysis approach. Simulations are performed to investigate the effect of design parameters viz. chamber diameter, transverse offset and width of constriction channel on performance characteristics for parameter sets corresponding to Orthogonal Array (OA) L9. Further, grey relational grade is used to identify the optimal set of design parameters. In depth study of flow and mixing dynamics are carried out to visualize the mixing mechanism for optimal and other two cases of proposed micromixer design configuration for Re in the range from 0.1 to 50. In order to assess the response of each design variable at each level, analysis of variance (ANOVA) is also performed to analyse influence of design parameters on mixing index and pressure drop.

Multiple Response Optimization with Grey Relational Analysis of Friction Stir Welding Parameters in Joining Dissimilar Aluminium Alloys by Taguchi Method

2014 ◽  
Vol 592-594 ◽  
pp. 555-559 ◽  
Author(s):  
S. Ravikumar ◽  
V. Seshagiri Rao ◽  
V. Pranesh
Keyword(s):  
Grey Relational Analysis ◽  
Aluminium Alloys ◽  
Welding Process ◽  
Welding Parameters ◽  
Friction Stir ◽  
Relational Analysis ◽  
Novel Approach ◽  
Grey Relational Grade ◽  
Response Optimization ◽  
Grey Relational

This paper presents a novel approach for the optimization of welding parameters on dissimilar friction stir welded joints between AA6061T-651 and AA7075T-651 aluminium alloys with multiple responses based on orthogonal array by grey relational analysis. Experiments are conducted by varying the welding parameters related to three pin profiles. In this study, welding parameters namely rotational speed, welding speed and pin profiles are optimized with the considerations of multi responses such as ultimate tensile strength and hardness. A grey relational grade is obtained from the grey analysis. Based on the grey relational grade, optimum levels of parameters have been identified and significant contribution of parameters is determined by ANOVA (Analysis of Variance). Confirmation test is conducted to validate the test result. Experimental results have shown that the responses in welding process can be improved effectively through this novel approach.

The Grey Relational Analysis between Industrial Structure and Water Resource Consumption in Jing-Jin-Ji Region of China

2013 ◽  
Vol 726-731 ◽  
pp. 3521-3525 ◽  
Author(s):  
Zhi Wei Xu
Keyword(s):  
Water Resource ◽  
Grey Relational Analysis ◽  
Water Resource Management ◽  
Industrial Structure ◽  
Resource Consumption ◽  
Relational Analysis ◽  
Basic Work ◽  
Grey Relational Grade ◽  
Secondary Industry ◽  
Grey Relational

Jing-Jin-Ji region of China is facing a contradiction between economic development and water resource shortage. The basic work to strengthen water resource management is finding out what the relation between industrial structure and water resource consumption is. The article measures the correlation by the grey relational analysis. The result is that Hebei province has a lowest grey relational grade in primary industry. Tianjin and Beijing has a relatively weak correlation in secondary industry and tertiary industry separately. The conclusion provides a direction for water resource optimization and cooperation within the region.

scholarly journals Optimization of Nozzle Inclination and Process Parameters in Air-Shielding Electrochemical Micromachining

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 846 ◽  
Author(s):  
Minghuan Wang ◽  
Yongchao Shang ◽  
Kailei He ◽  
Xuefeng Xu ◽  
Guoda Chen
Keyword(s):  
Process Parameters ◽  
Optimal Parameter ◽  
Test Method ◽  
Electrochemical Micromachining ◽  
Machining Performance ◽  
Relational Analysis ◽  
High Efficient ◽  
Grey Relational Grade ◽  
Orthogonal Test Method ◽  
Grey Relational

Microstructures on metal surfaces with diameters of tens to hundreds of micrometers and depths of several micrometers to tens of micrometers can improve the performance of engineering parts. Air-shielding electrochemical micromachining (AS-EMM) is a promising method for fabricating these microstructures, owing to its advantage of high efficient and better localization. However, the machining performance is often influenced by the machining or nonmachining parameters in AS-EMM. In order to get a better machining result in AS-EMM, the optimization of AS-EMM, including nozzle inclination and process parameters, was studied in this paper. Firstly, nozzle inclination was optimized by the different selected air incidence angles (θ) in simulation, and θ = π/4 was advised. Then, the grey relational analysis based on the orthogonal test method was used to analyze the grey relational grade for parameters and obtain the optimal parameter combination, i.e., at electrolyte velocity 5.5 m/s, gas velocity 160 m/s, and voltage 8 V. Finally, the optimization result was verified experimentally.

Measuring Governance

2017 ◽  
pp. 104-128
Author(s):  
Vesna Jankovic-Milic ◽  
Marija Džunić
Keyword(s):  
World Bank ◽  
Grey Relational Analysis ◽  
Analysis Procedure ◽  
Eu Countries ◽  
Relational Analysis ◽  
Governance Indicators ◽  
Grey Relational Grade ◽  
Governance Quality ◽  
World Governance Indicators ◽  
Grey Relational

The governance concept has become very popular in recent decades and in this regard has increased interest in measuring its quality. The most widely used measures of governance are World Governance Indicators, which represent composite perceptions-based indicators, published by World Bank Institute. There are six composite indicators and the data for constructing those indicators are obtained from 32 individual data sources. The objective of this chapter is to highlight the applicability of Grey Relational Analysis in the ranking of EU countries according to the governance quality. The Grey Relational Analysis entails calculation of Grey relational grade for governance quality. The final stage of the Grey Relational Analysis procedure involves ranking of EU countries according to Grey relational grade and their comparison with ranks obtained from World Bank Institute. The full contribution of Grey Relational Analysis arises on this stage, where ranks of countries have been changed.

Research on the Application of Weighted Grey Relational Analysis on the Failure Diagnosis of Complicated Electronic Equipment

2013 ◽  
Vol 333-335 ◽  
pp. 1543-1547
Author(s):  
Hong Yan Zhao ◽  
Jun Zhang ◽  
Guo Ping Hu ◽  
Jian Qiang Zhang
Keyword(s):  
Failure Mode ◽  
Grey Relational Analysis ◽  
Failure Diagnosis ◽  
Reference Sequence ◽  
Relational Analysis ◽  
Grey Relational Grade ◽  
Diagnosis Method ◽  
Diagnosis Accuracy ◽  
The Individual ◽  
Grey Relational

Based on weighted grey relational analysis, a new failure diagnosis method for complicated electronic equipments is proposed. First, according to the typical failure samples and weight values to construct grey reference sequence. Secondly, calculating the individual relational coefficient and grade to form grey relational grade sequence. Finally, according to the maximal grey relational grade to choose the corresponding failure mode as the finally diagnosis result. The results of analyses show that the proposed method has higher diagnosis accuracy and reliability than the traditional grey relational method.

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