• Title/Summary/Keyword: Radial Turbine

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Development of Radial Turbine for Air Cycle Refriger (공기 사이클 냉동기에 적응되는 반경 터빈의 개발)

  • Kwon, Gi-Hun;Lee, Ki-Ho;Kim, Jong-Seon
    • 유체기계공업학회:학술대회논문집
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    • pp.281-286
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    • 2001
  • The radial turbine has been successfully applied to the systems which request relatively small output compared with the axial turbine, and has low manufacturing cost due to it's small size and simple structure. Recently, the researches on the development and the efficiency maximization of the radial turbine are in progress corresponding with the trend toward miniaturization in turbo machinery and the development of small dispersed power generation systems. The radial turbine is to be applied to our turbo refrigerator of which engine speed is 26,000 rpm and turbine efficiency is $88\%$. Also, as a heat exchanger is accepted instead of a combustor in our turbo refrigerator, the design of radial turbine has been performed to be appropriate to the circumstance of low temperature air, not high temperature combustor gas, into the turbine inlet . This radial turbine is being developed in consideration with not only the aero-dynamic performance but also the simplification of manufacturing and integration, and the durability at operating condition. This paper refer to the performance evaluation about the radial turbine design by comparison with consulting from Russia and the our evaluation about various design factors which are considered in aero-dynamic design process.

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Numerical Analysis of Flow in Radial Turbine (Effects of Nozzle Vane Angle on Internal Flow)

  • OTSUKA, Kenta;KOMATSU, Tomoya;TSUJITA, Hoshio;YAMAGUCHI, Satoshi;YAMAGATA, Akihiro
    • 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.

Study of the radial Turbine for Wave Energy Conversion (파력발전용 레이디얼터빈성능에 관한 연구)

  • Kim Tae-Ho;Kim Heuy-Dong;Setoguchi Toshiaki
    • Proceedings of the KSME Conference
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    • pp.549-552
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    • 2002
  • The objective of this study is to clarify the detailed performances of the impulse type radial turbine and to present an optimum configuration of the turbine. The impulse type radial turbine has been manufactured and investigated experimentally under steady and sinusoidally oscillating flow conditions by model testing. Then, the starting characteristics under sinusoidally flow conditions have been evaluated by a numerical simulation using a quasi-steady analysis. As a result, the running and starting characteristics of the impulse type radial turbine for wave energy conversion have been clarified. Furthermore, the recommended configuration is presented, especially for setting angles of inner and outer guide vanes.

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An Investigation of Flow Characteristics of Radial Gas Turbine for Turbocharger under Unsteady Flow (과급기용 Radial Turbine의 비정상 유동특성에 관한 연구)

  • Choi, J.S.;Koh, D.K.;Winterbone, D.E.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.2
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    • pp.42-48
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    • 1994
  • Turbocharging is one of the best methods to improve the performance of diesel engines, because of its merits,-power ratio, fuel consumption and exhaust emissions. Most of them in small and medium diesel engines have adopted the pulse turbocharging method with twin entry vaneless radial turbines to maximize the energy utility of exhaust gas. This method requires the high performance of turbine under unsteady flow, and also the matching between turbine and diesel engine is most important. However, it is difficult to match properly between them. Because the steady flow data are usually used for it. Accordingly, it is necessary to catch the characteristics of turbine performance correctly over the wide range of the operation conditions under unsteady flow. In this paper, the characteristics of turbine performance under unsteady flow are represented at varying conditions, such as inlet pressure amplitude, turbine speed and frequence.

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The development of a preliminary designing program for ORC radial inflow turbines and the design of the radial inflow turbine for the OTEC (ORC 반경류터빈의 예비설계프로그램 개발 및 OTEC용 반경류터빈의 설계)

  • Kim, Do-Yeop;Kang, Ho-Keun;Kim, You-Taek
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.3
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    • pp.276-284
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    • 2014
  • The purpose of this study is to establish the designing method of ORC(Organic Rankine Cycle) radial inflow turbines. RTDM(Radial Turbine Design Modeler) Ver.2.1 which is a preliminary design program of radial inflow turbines was developed to achieve this purpose. The 200kW-class radial inflow turbine for OTEC(Ocean Thermal Energy Conversion) was designed by using the RTDM Ver.2.1 and CFD(Computational Fluid Dynamics) simulation was performed to verify the accuracy of RTDM Ver.2.1. With the result of simulation, the accuracy of RTDM Ver.2.1 was almost 94.6% based on the designed total enthalpy drop of the radial inflow turbine. Strategy of adjusting the mass flow rate was adopted on this study to satisfy the requirements of its power and rotor outlet's conditions for the designed radial inflow turbine. The mass flow rate was consequently increased to 21.2 kg/s for the designed 200kW-class radial inflow turbine for OTEC, and then Total to total and Total to static efficiency are 89.8% and 85.36% respectively.

A Study of the Second Stage Effect on a Partially Admitted Small Turbine (부분분사에서 작동하는 소형터빈에서 두 번째 단의 효과에 관한 연구)

  • Cho, Chong-Hyun;Cho, Bong-Soo;Choi, Sang-Kyu;Cho, Soo-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.9
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    • pp.898-906
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    • 2008
  • A tested turbine consists of two stages, and an axial-type and a radial-type turbine are applied to the first and second stage, respectively. The mean diameter of the axial-type turbine rotor is 70 mm, and the outer diameter of the radial-type turbine is 68mm at the inlet. In this experiment, an axial-type turbine, two different radial-type turbines, and three different nozzle flow angles are applied to find the optimal design parameters. To compare the turbine performance, the net specific output torque is evaluated. The test results show that the nozzle flow angle on the first stage is a more important parameter than other design parameters for partially admitted small turbines to obtain high operating torque. For a 3.4% partial admission rate, the net specific output torque is increased by 13% with the addition of a radial-type rotor to the second stage when the turbine operates at $75^{\circ}$ nozzle flow angle.

An Experimental Study on Flow in the Nozzle of a Radial Turbine (구심터빈의 노즐 내부 유동에 대한 시험 연구)

  • Kang, Jeong-Seek;Lim, Byeung-Jun;Ahn, Iee-Ki
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.1
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    • pp.35-41
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    • 2010
  • Experimental study on the flow field inside the nozzle for radial turbine was performed. At design point, the pressure is high and the Mach number is low at the pressure side of the nozzle inlet semi-vaneless space as the flow turns through the nozzle vanes. As the flow accelerates through the nozzle passage to the throat the pressure level at the pressure and suction sides becomes similar. The flow continued accelerating from the throat to the inlet of turbine wheel and the pressure field became uniform in the circumferential direction in the vaneless space. In high expansion ratio condition, strong favorable pressure gradient band region occurred just after the throat in the semi-vaneless space in the circumferential direction and the pressure became uniform in the circumferential direction after this band. In low expansion ratio condition, core flow acceleration is dominant after the throat and this non-uniform pressure field reached to the inlet of turbine wheel.

Numerical prediction of pressure pulsation amplitude for different operating regimes of Francis turbine draft tubes

  • Lipej, Andrej;Jost, Dragica;Meznar, Peter;Djelic, Vesko
    • International Journal of Fluid Machinery and Systems
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    • v.2 no.4
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    • pp.375-382
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    • 2009
  • Hydraulic instability associated with pressure fluctuations is a serious problem in hydraulic machinery. Pressure fluctuations are usually a result of a strong vortex created in the centre of a flow at the outlet of a runner. At every radial turbine and also at every single regulating axial turbine, the draft tube vortex appears at part-load operating regimes. The consequences of the vortex developed in the draft tube are very unpleasant pressure pulsation, axial and radial forces and torque fluctuation as well as turbine structure vibration. The consequences of the vortex are transferred upstream and downstream with amplitude and frequency modulation in respect of the turbine operating regime, cavitation conditions and air admitted content. Numerical prediction of the vortex appearance in the design stage is a very important task. The amplitude of the pressure pulsation is different for each operating regime therefore the main goal of this research was to numerically predict pressure pulsation amplitude versus different guide vane openings and to compare the results with experimental ones. For the numerical flow analysis of a complete Francis turbine (FT), the computer code ANSYS-CFX11 has been used.

A Study of Aerodynamic Design of a Radial Turbine for BOP of MCFC Fuel Cell System (연료전지 BOP용 구심터빈 공력설계에 관한 연구)

  • Choi, Bum-Seog;Ahn, Kook-Young;Park, Moo-Ryong
    • 유체기계공업학회:학술대회논문집
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    • pp.531-534
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    • 2006
  • This study is concerned with radial turbine design and performance improvement of a turbo generator system, which is used for maximizing performance of a 250kW MCFC fuel cell system. A preliminary design of a radial turbine has been performed under the thermodynamic and fluid-dynamic conditions determined by a cycle analysis of the MCFC BOP system. Basic demensions are determined by a meanline analysis and calculation of radial variation at the exit of the turbine. The turbine impeller is designed and modified by iterative processes of three dimensional flow analysis.

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Characteristics of the Starting Flow of a Rushton Turbine Mixer (러쉬톤 교반기의 초기 비정상 유동 특성)

  • Park, Gyeong-Hyeon;Kim, Gyeong-Cheon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.11
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    • pp.1543-1551
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    • 2001
  • The characteristics of starting flow of a six-blade Rushton turbine mixer were investigated by using a cinematic Particle Image Velocimetry technique. The flows were quantified by measurements of velocity fields with a 4 ms time interval for a blade rotational speed of 100 r.p.m, so that the turbine Reynolds number(ND$^2$/ ν) was fixed to 6,960. The radial shedding of the trailing vortices starts from passing four blades after the beginning of rotation. It clearly shows that the vortex pairing phenomena caused by the interactions between trailing cortices firm consequtive blades. The average convection velocity of the radial flow is found to be 28 % of the tip velocity. The starting flow seems to arrive at a steady state after 8 revolutions in this study, which corresponds nearly one circulation through the bulk flow trajectory with the average radial convection velocity.