• Title/Summary/Keyword: 전압력손실계수

Search Result 14, Processing Time 0.027 seconds

Enhancement of the Performance a Centrifugal Compressor in an Automobile Turbocharger by Modifying the Circumferential Inlet Height of Volute (원주방향 볼류트 입구 높이를 수정한 자동차용 터보차저 원심압축기의 성능 향상)

  • Zhou, Tianjun;Lee, Geun Sik
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.38 no.2
    • /
    • pp.115-120
    • /
    • 2014
  • To enhance the performance of an automobile turbocharger compressor, the circumferential inlet heights of the volute were modified and the flow field for the combined region of the diffuser and volute was numerically investigated using commercial software. Basically, a well-designed volute should have a high pressure recovery coefficient and a low loss coefficient for the total pressure. In this study, two circular volutes with the same cross sectional shape and tongue angle, but circumferentially different volute inlet heights, were selected. One volute had the middle inlet in the cross-section at the circumferential angle of $90^{\circ}$ but gradually lower inlet heights for the angles between $90^{\circ}$ to $360^{\circ}$ with respect to the cross sectional center of the volute, while maintaining the same height between the tangential line connecting the lowest positions of the cross section and the line connecting the volute inlets in the circumferential direction (case 1 volute). The other volute has an inlet height that is 2 mm lower than in case 1 volute such that the tongue section has a tangential inlet (case 2 volute). The results showed that the case 2 volute had a higher total pressure ratio because of its higher pressure recovery coefficient and higher isentropic efficiency, resulting from the lower loss coefficient along the circumferential position than the case 1 volute.

Optimal Design for a Conic Winglet of a Dual Type Combined Fan (이중구조팬의 Conic Winglet 최적설계)

  • Kim, Jin-Wook;Kim, Woo-Teak;Ryu, Min-Hyoung;Cho, Lee-Sang;Cho, Jin-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.44 no.6
    • /
    • pp.468-476
    • /
    • 2016
  • In this study, the conic winglet which is made by rotating wing tip airfoil by each 3 axis is applied to the dual type combined fan to reduce the wing tip leakage loss. Computational Fluid Dynamics is used to calculate the loss and optimum technique is used to get minimum loss. Optimization results shows that total pressure loss coefficient was reduced by 3.4 %, and optimization model was a bended shape at the end of wing forward to pressure side.

Study on the Effect of Total Pressure Loss by Bell Mouth Inlet Screen (벨 마우스 흡입구 보호망에 의한 전압력 손실영향 연구)

  • Lee, Changwook;Choi, Seong Man
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.25 no.6
    • /
    • pp.29-35
    • /
    • 2021
  • Bell mouth inlet is applied in various industries due to the advantage of little pressure loss and accurate flow measurement. In this study, the configuration of the bell mouth intake is designed in a long radius shape, and a suitable grid size was selected to minimize the pressure drop and to prevent the engine damage by foreign objects at outdoor operating conditions. It was able to present a modified pressure drop coefficient equation from two data obtained from the computational simulation and experimental results for the total pressure loss by inlet screen installation.

Three-dimensional Flow and Aerodynamic Loss Downstream of First-Stage Turbine Vane Cascade (터빈 제1단 정익 익렬 하류에서의 3차원 유동 및 압력손실)

  • Jeong, Jae Sung;Bong, Seon Woo;Lee, Sang Woo
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.41 no.8
    • /
    • pp.521-529
    • /
    • 2017
  • Three-dimensional flow characteristics within a high-acceleration first-stage turbine vane passage has been investigated in a newly-built vane cascade for propulsion. The result shows that there is a strong favorable pressure gradient on the vane pressure surface. On its suction surface, however, there exists not only a much stronger favorable pressure gradient than that on the pressure surface upstream of the mid-chord but also a subsequent adverse pressure gradient downstream of it. By employing two different oil-film methods with upstream coating and full-coverage coating, a four-vortex model horseshoe vortex system can be identified ahead of each leading edge in the cascade, and the separation line of inlet boundary layer flow as well as the separation line of re-attached flow is provided as well. In addition, basic flow data such as secondary flow, aerodynamic loss, and flow turning angle downstream of the cascade are obtained.

Effects of Pressure-Side Winglet at an Elevation of Tip Surface on the Tip-Leakage Flow and Aerodynamic Loss Downstream of a Turbine Blade Equipped with Pressure-Side Squealer Tip (압력면익단소익이 터빈 동익 압력면스퀼러팁 하류의 팁누설유동 및 압력손실에 미치는 영향)

  • Cheon, Joo Hong;Lee, Sang Woo
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.40 no.10
    • /
    • pp.645-651
    • /
    • 2016
  • Effects of pressure-side winglet width on the tip leakage flow and aerodynamic loss downstream of a turbine blade with a pressure-side squealer rim have been investigated for the tip gap-to-span ratio of h/s = 1.36%. The pressure-side squealer has a fixed height-to-span ratio of $h_p/s=3.75%$ and the pressure-side winglet, which is installed at an elevation of tip surface, has width-to-pitch ratios of w/p = 2.64%, 5.28%, 7.92% and 10.55%. The results show that with increasing w/p, aerodynamic loss in the passage vortex region decreases, whereas that in the leakage flow region increases. As a result, the mass-averaged loss coefficient all over the measurement plane tends to decrease minutely with the increment of w/p. It is concluded that the pressure-side winglet for the pressure-side squealer tip can hardly contribute to the tip-leakge loss reduction.

Controlling the Horseshoe Vortex by the Leading-Edge Fence at a Generic Wing-Body Junction (일반적인 날개 형상에서의 앞전 판에 의한 말굽와류 제어)

  • Cho, Jong-Jae;Kim, Kui-Soon
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.37 no.4
    • /
    • pp.336-343
    • /
    • 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.

Improvement of the Flow Around Airfoil/Flat-Plate Junctures by Optimization of the Leading-Edge Shape (날개-평판 접합부에서의 날개 앞전 형상 최적화를 통한 유동특성 향상)

  • Cho, Jong-Jae;Kim, Kui-Soon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2009.11a
    • /
    • pp.257-265
    • /
    • 2009
  • The present study deals with the leading edge shape on a wing-body junction to decrease a horseshoe vortex, one of the main factors to generate the secondary flow losses. The shape of leading-edge is optimized with design variables form the leading-edge shape. Approximate optimization design method is used for the optimization. The study is investigated using $FLUENT^{TM}$ and $iSIGHT^{TM}$. As the result, total pressure coefficient of the optimized design case was decreased about 9.79% compare to the baseline case.

  • PDF

Improvement of the Flow Characteristics by Optimizing the Leading-Edge Shape Around Airfoil/Flat-Plate Junction (날개-평판 접합부에서의 날개 앞전 형상 최적화를 통한 유동특성 향상)

  • Cho, Jong-Jae;Kim, Kui-Soon
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.13 no.6
    • /
    • pp.24-33
    • /
    • 2009
  • The present study deals with the optimization of the leading edge shape around a wing-body junction to minimize the strength of the horseshoe vortex, which is one of the main factor generating the secondary flow losses. For this purpose, approximate optimization method is used for the optimization. The study is performed by using $FLUENT^{TM}$ and $iSIGHT^{TM}$. The total pressure coefficient for the optimized model was decreased about 9.79% compared with the baseline model.

Improvement of the flow around airfoil/flat-plate junctures by optimization of the leading-edge fence (날개-평판 접합부에서의 날개 앞전 판 최적화를 통한 유동특성 향상)

  • Cho, Jong-Jae;Kim, Kui-Soon
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.37 no.9
    • /
    • pp.829-836
    • /
    • 2009
  • 3-Dimensional flow which is represented by horseshoe vortex is generated as a type of secondary flow about the main flow. As well, it causes the flow loss. The present study deals with the leading edge fence shape on a wing-body junction to decrease a horseshoe vortex, one of the main factors to generate the secondary flow losses. The shape of leading-edge fence was optimized with the design variables of the installed height, length, width, and thickness of the fence as the design variables. Approximate optimization design method is used as the optimization. The study was investigated using $FLUENT^{TM}$ and $iSIGHT^{TM}$. Total pressure coefficient of the optimized design case was decreased about 7.5 % compare to the baseline case.

Developing the flow quality in an wing-body junction flow by the optimizing method (최적화 기법을 이용한 일반적인 날개 형상에서의 유동특성 향상)

  • Cho, Jong-Jae;Kim, Kui-Soon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2009.05a
    • /
    • pp.303-307
    • /
    • 2009
  • Secondary flow losses can be as high as $30{\sim}50%$ 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 optimizes the shape of leading-edge fence with the shape factors, such as the installed height, length, width, and thickness of the fence as the design variables. The study was investigated using $FLUENT^{TM}$ and $iSIGHT^{TM}$. Total pressure loss coefficient was improved about 7.5 % than the baseline case.

  • PDF