• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.163-169
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• 2013

In order to make the vertical-axis cross flow wind turbine commercially feasible, a guide vane is adopted and the effect of the guide vane shape is examined in order to improve the wind turbine performance. CFD analysis on the performance and internal flow of the turbine is carried out for the wind turbine model. The result shows that when the guide nozzle is installed, almost over two times of power coefficient are achieved in comparison with the case of no guide nozzle installation. The guide nozzle acts as a role of suppressing the flow resistance at the blade passage, which is found when the guide nozzle is installed. Moreover, in this study, two kinds of the guide vane with a straight type and a curved type are adopted and compared. The curved guide vane nozzle produces higher power coefficient in comparison with that of straight guide vane nozzle.

• International Journal of Fluid Machinery and Systems
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• v.1 no.1
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• pp.155-168
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• 2008

This paper investigates a variable geometry (VG) mixed flow turbine with a novel, purposely designed pivoting nozzle vane ring. The nozzle vane ring was matched to the 3-dimensional aspect of the mixed flow rotor leading edge with lean stacking. It was found that for a nozzle vane ring in a volute, the vane surface pressure is highly affected by the flow in the volute rather than the adjacent vane surface interactions, especially at closer nozzle positions. The performance of the VG mixed flow turbine has been evaluated experimentally in steady and unsteady flow conditions. The VG mixed flow turbine shows higher peak efficiency and swallowing capacity at various vane angle settings compared to an equivalent nozzleless turbine. Comparison with an equivalent straight vane arrangement shows a higher swallowing capacity but similar efficiencies. The VG turbine unsteady performance was found to deviate substantially from the quasi-steady assumption compared to a nozzleless turbine. This is more evident in the higher vane angle settings (smaller nozzle passage), where there are high possibility of choking during a pulse cycle. The presented steady and unsteady results are expected to be beneficial in the design of variable geometry turbochargers, especially the ones with a mixed flow turbine.

• International Journal of Fluid Machinery and Systems
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• v.1 no.1
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• pp.47-56
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• 2008

The flow behind the variable area nozzle which corresponds to the flow at the leading edge of the impeller was measured with a 3-hole yaw probe and calculated with CFD. Two nozzle throat-areas were investigated. One is the smallest and the other is the largest opening for the variable nozzle. Test results agreed with the calculated results qualitatively. The leakage flow through the tip clearance of the nozzle vane significantly affected the flow field downstream of the nozzle vane with the smallest opening. However, the effect on leakage flow on the flow field downstream of the nozzle vane with the largest opening was very weak and the effect of wake is dominant.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.88-96
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• 2008

Effects of the duct inlet guide vane on the flowrate distribution characteristics of the defroster nozzle exit in a defrost duct system were investigated experimentally to design the optimum heating, ventilation and air conditioning (HVAC) system applied in an automotive compartment. A 3-dimensional hot-wire anemometer system was used to measure the velocity field in the vicinity of the defroster nozzle jet flow and the velocity distributions near the windshield interior surface. At first, two cases of with- and without-duct inlet guide vanes were considered as the test condition, and then three cases of the duct inlet guide vane were tested to determine the optimum guide vane shape and their positions. The arrangement of the duct inlet guide vanes has an effect on the improved flowrate distribution at the defroster nozzle exit and near the windshield interior surface. However, the application of the lots of guide vane to control the flow direction leads to increase the flow resistance, resulting in the decreased flowrate issuing from the defroster nozzle. The shape of the duct inlet guide vane affects not only the flowrate distribution between the driver side and the assistant driver side but also the reduction of the flow resistance in the defrost duct system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.23-23
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• 1998

Jet Vane Type 추력방향제어 시스템의 구조적 안정성을 검토하기 위해 시스템의 해석을 Vane, Ablation & Bracket Interface, Nozzle flange & Housing Interface 및 Fastener의 세 부분으로 나누어 수행하였다. 해석을 위한 외력조건은 유동해석을 통해 얻어진 온도 및 압력분포에 근거하였으며, Vane의 응력해석을 위해서는 상용 Software인 Patran 및 Nastran이 사용되었다. 이번 연구는 Test Model 단계로서 충분한 강도의 고정 Housing이 사용되어, 이에 대한 해석은 수행되지 않았지만 추후 Flight Model 단계에서는 함께 고려되어질 것이며, 각 경우의 Margin of Safety값들을 도출하여 구조적 안정성을 검토하였다.

• International Journal of Fluid Machinery and Systems
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• v.9 no.2
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• pp.137-142
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• 2016

Variable Geometry System (VGS) is widely applied to the nozzle vane for the radial inflow turbine constituting automotive turbochargers for the purpose of optimizing the power output at each operating condition. In order to improve the performance of radial turbines with VGS, it is necessary to clarify the influences of the setting angle of nozzle vane on the internal flow of radial turbine. However, the experimental measurements are considered to be difficult for the flow in radial turbines because of the small size and the high rotational speed. In the present study, the numerical calculations were carried out for the flow in the radial turbine at three operating conditions by applying the corresponding nozzle vane exit angles, which were set up in the experimental study, as the inlet boundary condition. The numerical results revealed the characteristic flow behaviors at each operating condition.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.21-21
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• 1998

추력방향 제어시스템 설계에 있어서 가장 기본적으로 요구되는 Requirement는 Rocket Motor의 추력, 요구되는 최대 Side Force, Rocket Motor의 외경, System의 총 구동시간, 구동후의 분리여부 등이다. 이러한 Requirement를 만족하기 위해서는 Nozzle 출구의 분출가스 물성치로부터 초음속 유동해석을 통하여 Vane 주위의 속도, 온도, 압력 분포를 구하고, Vane의 받음각 변화에 대한 Aerodynamic Force와 Moment를 계산하고, Side Force를 만족하는 최대 받음각의 결정, Torque를 만족하는 감속기와 Motor의 선정 및 Housing 기본 형상을 설계하였다. 금번 개발에서는 지상 시험용으로서 안전 계수를 Flight Model보다 약간 높게 설계하였으며, 작동 완료 후 System이 Nozzle로부터 떨어져나가는 분리시스템은 포함하지 않았다.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.757-764
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• 2011

In this study, we analysed the influence of the performance and inflow flow of a radial inflow turbine with the variation of vane nozzle exit angles for a 100kW class turbine applicable in the waste heat recovery system. For this, three-dimensional CFD analysis was performed using commercial code called ANSYS Fluent 12.1. As the vane nozzle exit angle was more increased the reattachment region near blades of the vane nozzle got smaller, and also the Mach number at vane nozzle exit was observed to be 1 due to the effect of the cross section reduction. Through this study, we expect that the analysed results will be used as the design material for the composition of the turbine optimal design parameters corresponding to the target output power.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.2
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• pp.34-41
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• 2012

Thrust vector control system is a control device which is mounted on the exit of the nozzle to generate pitch, yaw and roll directional force by deflecting flow direction of the supersonic jet from the nozzle. Thermal and aerodynamic loads are acting on the surface of jet vane when it is exposed to the jet flow. Axial thrust loss and side thrust loss are affected by shock patterns and interactions between jet-vanes which varies with jet-vane geometry and turning angle. In this research, the performance estimation using the numerical simulation analysis of the nozzle is given and the investigation of the flow visualization and aerodynamic performance with the enforced power to the vane is taken.

• Journal of ILASS-Korea
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• v.10 no.4
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• pp.1-7
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• 2005

The purpose of this study is to investigate the effect of swirler vane angle and the aspect ratio of swirl chamber of nozzle on the characteristics of single spray. The characteristics of sprat's have been investigated by measuring the spray angle, droplet size and velocity Visualization of spray was conducted to obtain the spray angle and breakup process. The spray characteristics such as droplet size and velocity were measured by Phase Doppler Anemometry(PDA). It was found that the spray angle was increased with increasing the swirler angle. For both sprays, the axial velocity and SMD were decreased with increasing the swirler vane angle. It was also shown that the axial velocity and SMD were decreased with increasing the aspect ratio of swirl chamber The effect of vane angle un the spray characteristics was greater than the aspect ratio of swirl chamber for single spray.