• Journal of the Korea Convergence Society
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• v.11 no.3
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• pp.195-200
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• 2020

In this study, the flow analyses were performed on the fluid clutch turbine blade shapes of models 1, 2 and 3, with eight turbine blades tilted at 45 °, 40 °, and 35 ° angles on the propulsion shaft, respectively. The larger the angle of inclination on the propulsion shaft, the higher the flow pressure among the flow models after the back of the turbine blades. On the other hand, the smaller the angle of inclination on the propulsion shaft of the turbine wing, the lower the flow rate. It can be seen that the smaller inclination angle of the turbine blade surface on the propulsion shaft, i.e., the wing shape close to perpendicular to the flow of fluid, is more suitable for efficiently connecting and disconnecting the fluid clutch. By applying the flow analysis by type of turbine blade of fluid clutch,the study result at this paper is considered to be favorable as the convergent research material which can apply the aesthetic design.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.4
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• pp.273-279
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• 2011

Turbulent flow analysis around a wind turbine blade was performed to evaluate the power performance of offshore wind turbine. Fluent package was utilized to solve the Reynolds-averaged Navier-Stokes equations in non-inertial rotating coordinates. The realizable k-$\varepsilon$ model was used for turbulence closure and the grid system combining structured and unstructured grids was generated. In the first, lift and drag forces of 2-D foil section were calculated and compared with existing experimental data for the validation. Then torque and thrust of the wind turbine blade having NACA 4-series sections were calculated with fixed pitch angle and rpm. Tip speed ratio was varied by changing wind speed. In the next, three kinds of end plate were attached at the tip of blade in order to increase the power of the wind turbine. Among them the end plate attached at the suction side of the blade was found to be most effective. Furthermore, performance analysis with tilt angle and rake was also performed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.10-10
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• 1998

본 연구에서는 제트 추진 기관의 터빈 익렬에서의 유동과 대기 중에 부유되어 있는 입자 또는 연소 생성물들이 제트엔진 내부로 유입될 경우 이에 따른 압축기 및 터빈 날개의 마모 및 충돌 부위를 예측하기 위하여 수치해석을 수행하였다. 일반적으로 각종 항공기의 추진 기관용 가스 터빈 엔진은 대기중에 부유되어 있는 각종 입자들의 영향을 받게 된다. 특히, 확산 지역을 통과하는 항공기나 먼지 입자 부유물이 많은 공업지대 또는 사막지역을 비행하는 항공기의 경우는 모래 알갱이, 먼지 및 연소 입자의 직접적인 영향을 받아 각 요소들에 심각한 부식 및 마모가 발생됨으로써 성능 저하 및 냉각 통로의 막힘, 압축기와 터빈 날개의 손상 등이 예측되어진다. 특히 항공기용 추진 기관은 엔진 입구에 유입 공기를 정화하기 위한 여과장치의 설치가 불가능하며, 자동차용 가스터빈 엔진의 경우는 여과 장치를 부착하여도 미세한 입자들이 여과 장치에 여과되지 않고 엔진 내부로 침투하게 되므로 치명적인 손상이 예상된다. 이러한 손상들은 초기에는 미세하게 발생하지만, 손상 정도가 점점 누적됨에 따라서 항공기의 안전 운전에 심각한 위험 요소로서 작용할 수 있으며, 경제적으로도 기관의 유지 보수비용의 증가를 가져올 수 있다. 따라서 압축기에 화산재 또는 대기중에 부유되어 있는 금속 입자나 먼지입자 등이 유입되었을 경우, 압축기 날개의 손상 부위와 정도를 예측하는 것이 필요하다. 따라서 본 연구에서는 Lagangian방법을 적용하여 압축기 날개위의 부유 입자 충돌 부위를 예측하고, 설계 시 이를 보완할 수 있는 기준을 제시하였다. 아울러 설계 입구각과 크게 벗어난 유동의 유입시에 발생되는 박리 현상과 이에 따른 입자의 유동 및 날개의 입자 접착 부위를 예측하였다. 본 연구에서는 여러 크기의 입자(다양한 Stokes 수)들을 주어진 속도에서 유선을 따라 압축기 입구에서 압축기 유로로 여러 위치에서 부유 시켜서 그 입자들의 궤적 및 충돌, 점착 위지를 고찰하고, 정량적인 충돌량을 해석하기 위하여 입자 충돌 계수를 정의하여 압축기 날개 표면의 충돌특성을 알아보았다. 이러한 예측을 통하여 압축기 날개 표면의 충돌 부위를 예측하고, 날개의 표면을 코팅하는 등 보호 개선책을 제시할 수 있고, 연소의 반응물 입자가 터빈 날개에 충돌하여 발생되는 날개 표면의 파손, 냉각 홀의 막임, 연소 입자의 점착 부위 등을 예측하여 보완책을 준비할 수 있도록 하였다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.1
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• pp.20-26
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• 2014

It is essential to consider the effect of blade deformation in order to design a better tidal stream turbine being operated in off-design condition. Flow load causes deformation on the blade, and the deformation affects the turbine performance. In the present study, CFD analysis procedures were developed to predict open water performance of horizontal axis tidal stream turbine (HATST). The developed procedures were verified by comparing the results with existing experimental results. Fluid-structure interaction (FSI) analysis method, based on the verified CFD procedure, have been carried out to estimate the turbine performance for a turbine with flexible composite blades, and then the results were compared with those for rigid blades.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.2
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• pp.61-70
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• 2013

Hydrodynamic aspects on three-dimensional effects were investigated in this study for simple and convenient conversion of tidal stream energy using a Vertical-Axis Turbine (VAT). Numerical approach was made to reveal the differences of flow physics between 2-D estimation and rigorous 3-D simulation. It was shown that the 3-D effects were dominant mainly due to the variation of tip vortices around the tip region of rotor blade, causing the loss of lift for steadily translating hydrofoil and the reduction of torque for rotating turbine blade. The 3-D effect was found to be rather prominent for the typical VATs considered in this paper. Simple and yet efficient 2-D approach with the correction of its three-dimensionality was also proposed for practical design and analysis of VAT.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.845-852
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• 2007

An OWC-type Wave Energy Conversion passes through 3 steps energy conversion process. This paper deal with the impulse turbine with staggered blade to improved performance by numerical analysis using commercial CFD code, FLUENT Maximum value of axial airflow velocity during exhalation is higher than that during inhalation This paper deal with special-type of Impulse Turbine so-called "Staggered Blade" for more efficiency to making air flow direct to on pressure side. Also, this paper has proposed special-type turbine with self-pitched blade more efficient.

• Plant Journal
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• v.18 no.4
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• pp.48-57
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• 2023

In this study, I discussed a way of the improved operation criteria to detect combustion instability in advance F-Class Gas Turbine, which adopts lean pre-mixed combustion system. The data of 16 blades path temperature thermocouple installed radially at the gas Turbine exit were collected to analyze the variation of individual blade path temperature. The cumulative variation in individual blade path temperature for one week under normal combustion conditions was confirmed to be up to 26℃. On the other hand, in the event of combustion instability, the symptoms of increased temperature variations in the individual thermocouple were mostly seen from a few days ago. Based on the results of this study, it is deemed appropriate to inspect and maintain in Ulsan Thermal Power Gas Turbine when the individual blade path temperature exceeds 50℃ of the cumulative variation for 10 days.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.05a
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• pp.55-63
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• 1994

국내에서 실제 운전되고 있는 천연가스 복합발전플랜트의 성능 예측에 대한 공정전산 해석을 수행하였다. 가스터빈 사이클은 압축기, 연소기, 터빈 및 터빈 날개의 냉각을 위한 냉각계통으로 구성하였으며, 중기터빈 사이클은 폐열회수보일러, 고압/중압/저압터빈, 펌프 및 부속공정으로 구성하였다. 해석결과는 실제 플랜트의 운전자료와 정성적 및 정량적으로 잘 일치하였으며, 폐열회수보일러의 적절한 설계에 의하여 전체 플랜트의 출력향상을 도모할 수 있음을 제시하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.4
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• pp.336-343
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• 2009

Secondary flow losses can be as high as 30~50% of the total aerodynamic losses generated in the cascade of a turbine. Therefore, these are important part for improving a turbine efficiency. As well, many studies have been performed to decrease the secondary flow losses. The present study deals with the leading edge fences on a wing-body to decrease a horseshoe vortex, one of the factors to generate the secondary flow losses, and investigates the characteristics of the generated horseshoe vortex as the shape factors, such as the installed height, and length of the fence. The study was investigated using $FLUENT^{TM}$. Total pressure loss coefficient was improved about 4.0 % at the best case than the baseline.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.9-14
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• 2009

A numerical investigation was performed based on the Reynolds-Averaged Navier-Stokes(RANS) equations for the two-dimensional unsteady flow around a vertical axis turbine(VAT) with three or four blades. VAT is one of the promising devices for tidal current energy conversion. The geometry of the turbine blade was $NACA65_3$-018 airfoil, for which CFD analysis using Fluent was carried out at several angles of attack and the results were compared with the corresponding experimental data for validation and calibration. Then CFD simulations were carried out for the whole vertical axis turbine with a two-dimensional setup. The CFD simulation demonstrated the usefulness of the method to study the typical unsteady flows around VATs and the results showed that the optimum turbine efficiency could be achieved for carefully selected combinations of the number of blade and Tip-Speed Ratio(TSR).