• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.1
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• pp.1-13
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• 2000

A numerical study for performance analysis of a crossflow-type forced draft cooling tower has been performed based on the finite volume method with non-orthogonal body fitted, and non-staggered grid system. For solving the coupling problem between water and air, air enthalpy, moisture fraction, water enthalpy, and water mass balance equations are solved with Navier-Stoke's equations simultaneously. For the effect of turbulence, the standard k-$\varepsilon$ turbulent model is implied in this analysis. The predicted result of the present analysis is compared with the experimental data and the commercial software result to validate the present study. The predicted results show good agreement with the experimental data and the commercial software result. To investigate the influence of the cooling tower design parameters such as approach, range and wet bulb temperature, parametric studies are also performed.

• Corrosion Science and Technology
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• v.20 no.2
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• pp.77-84
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• 2021

This study aims to optimize the DL-EPR test solution for duplex stainless steel S31083 using the Taguchi design. The test solution parameters applied to the Taguchi design are H₂SO₄, NaCl, KSCN concentration, and temperature. In the experimental design, an orthogonal array of 4 levels 4 factor L₁₆(4⁴) was used. Output values for the orthogonal array were used for resolution (degree of sensitization) and selective etch (I_a) values. The optimal test solution conditions were selected by comparing the normalized S/N ratio for the two reaction properties. As a result, the H₂SO₄ and NaCl were identified as the main factors influencing the sensitivity measurement, but the delta statistics showed that the KSCN concentration and temperature had relatively low influence. The optimal condition was identified as 1.5 M H₂SO₄+0.03 M KSCN+1.5M NaCl at 30 ℃. The degree of sensitization presented a tendency to depend on the heat treatment temperature and time in the optimal test solution. This investigation confirmed the possibility of optimizing the experiment solution for the DL-EPR test of stainless steel using the Taguchi technique.

• Proceedings of the Safety Management and Science Conference
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• 2000.05a
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• pp.265-273
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• 2000

A study to analyze and solve problems of polyacetal resin cutting experiment has presented in this paper. We have taken Taguchi's parameter design approach, specifically orthogonal array, and determined the optimal levels of the selected variables through analysis of the experimental results using S/H ratio.

• Journal of the Korea Safety Management & Science
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• v.5 no.1
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• pp.103-113
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• 2003

A study to analyze and solve problems of a stone surface process experiment has presented in this paper. We have taken Taguchi's parameter design approach, specifically orthogonal array, and determined the optimal levels of the selected variables through analysis of the experimental results using S/N ratio.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4149-4155
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• 2013

High speed machining for higher cutting speed and feedrate lead to a increase of surface quality and material removal rate. This paper presents a study of the influence of cutting conditions on the vibration characteristics obtained by machining with face milling cutter for high speed machining. In this paper, Taguchi experimental design method which is based on orthogonal array table was applied to study vibration characteristics with high speed face milling cutter. The experimental conditions used orthogonal array of $L_{27}(3^{13})$. In this work, design and analysis of experiments is conducted to study the effects of these parameters on the vibration by using the S/N ratio, analysis of variance. Four cutting parameters namely, feed rate, champer length, cutting speed, and depth of cut were optimized with consideration of vibration characteristics.

• Journal of Korean Institute of Industrial Engineers
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• v.7 no.2
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• pp.55-59
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• 1981

An Application of Experimental Designs to Improve the quality of Industrial product : optimization Methodology of statistical model. The primary object of this paper is to aid scientists and Engineers, in applying response surface procedures to obtain operating conditions for many technical fields, particularly for industrial manufacturing processes. The problem considered in this paper is to select technically and scientifically some important factors affecting the quality of products through the experimental design and analysis of response surface. Even though the mathematical model is unknown these statistical analysis can be applicable to control the quality of industrial products and to determine optimum operating conditions for many technical fields, particularly, for industrial manufacturing processes. This paper proposes a method to obtain the optimum operating condition, and how to find the condition by using table of orthogonal array experiments, and optimization methodology of statistical model.

• Journal of Korean Society for Quality Management
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• v.7 no.2
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• pp.22-28
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• 1979

The problem considered in this paper is to select the vital factor effect to the product quality through the experimental design and analysis of response surface, so as to control the quality improvement of industrial product. In this time, even through the mathematical model is unknown it could be applicable to control the quality of industrial products and to determine optimum operating condition for many technical fields, particulary, for industrial manufacturing process. When a set of data is available from an experimental design, it is often of interest 1:0 fit polynominal repression model in independent variables (eg, time, temperature, pressure, etc) the optimize the response variable (eg. yield, strength etc). This paper proposes a method known to obtain the optimum operating condition, and how to find the condition by using table of orthogonal array experiments, and optimization methodology of statistical model. A criterion can be applied determining to optimum operating conditions in manufacturing industry and improving the fit of response surface which may be used for prediction of responses and quality control of industrial products.

• Design & Manufacturing
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• v.18 no.2
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• pp.41-50
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• 2024

In this study, experimental design methods were used to derive optimal process conditions for improving the thickness uniformity of a 0.40 mm, 3.5 inch light guide panel. Process mapping and expert group analysis were used to identify factors that influence the thickness of injection molded products. The key factors identified were mold temperature, mold temperature, injection speed, packing pressure, packing time, clamp force, and flash time. Considering the resin manufacturer's recommended process conditions and the process conditions for similar light guide plates, a three-level range was selected for the identified influencing factors. L27 orthogonal array process conditions were generated using the Taguchi method. Injection molding was performed using these L27 orthogonal array to mold the 3.5 inch light guide plates. Thickness measurements were then taken, and the results were analyzed using the signal-to-noise ratio to maximize the CpK value, leading to the determination of the optimal process conditions. The thickness uniformity of the product was analyzed by applying the derived optimum process conditions. The results showed a 97.5% improvement in the Cpk value of 3.22 compared to the process conditions used for similar light guide plates.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.6
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• pp.484-490
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• 2012

Experiments of circulating water channel and two dimensional numerical simulations were performed to investigate the fluctuating characteristics of pressure in moonpool. Based on the quasi-two dimensional characteristics of pressure fluctuations disclosed by the spatial cross-correlations, the numerical results showed qualitatively good agreement with experimental data. Proper orthogonal decomposition was employed to the spatial distributions of pressure fluctuations in order to find the first and second modes of fluctuations. The first mode of pressure fluctuations showed that the fluctuating characteristics of pressure were related to the behaviors of vortical structures. The velocity fluctuations were conditionally averaged to make clear that the coherent structures were responsible for the pressure fluctuations in moonpool.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.211-213
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• 2005

In this paper, the frequency compensator for digital protective relay is introduced. Due to sudden appearance of generation-load or fault in power system, the frequency can deviate from its nominal value. The Orthogonal filter adopted to digital protective relay is exposed to the problem. Therefore, the frequency variation makes a difficult to protective function and power measurement in digital protective relay. The essential property of the proposed algorithm presented is its outstanding immunity to both signal orthogonal component magnitudes and DFT filter gain variations which ensures below 0.05Hz accuracy of estimation. Additionally, the proposed method has excellent characteristics with low signal sampling rate. Based on the frequency estimation, author design under frequency protection relay for generator and verifies its performance with several experimental tests.