• Title/Summary/Keyword: inlet geometry

Search Result 202, Processing Time 0.02 seconds

Numerical Study on Geometries and Operating Parameters of a Steam Reformer for Hydrogen Production (수소 생산을 위한 수증기 개질기의 형상 변화와 작동 조건에 대한 수치해석 연구)

  • Byun, Kang-Soo;Lee, Jae-Seong;Kim, Ho-Young
    • Journal of the Korean Society of Combustion
    • /
    • v.16 no.3
    • /
    • pp.1-11
    • /
    • 2011
  • The main objective of this paper is to investigate characteristic of steam reformer at various geometries and operating conditions. In this paper, the steam reforming is studied by a numerical method and three dimensional simulations were used for effective analytical study. User - Defined Function (UDF) was used to simultaneously calculate reforming and combustion reaction. And the numerical model is validated with experimental results at the same operating conditions. In order to understand the relationship between operating conditions such as gas hourly space velocity(GHSV), mass flow rate of combustor inlet, various numerical investigations are carries out for various geometries. Numerical results show that cylindrical geometry is more effective than rectangular geometry for heat transfer to reactors and reforming efficiency. As mass flow rate of combustor inlet increase, reaction occurs more faster and temperature increase with each geometry. On the other hand, reaction and hydrogen conversion decrease as mass flow rate of reactor decreases.

Experimental Study on Effects of Inlet Boundary Layer Thickness and Boundary Layer Fence in a Turbine Cascade (터빈 캐스케이드 입구경계층 두께와 경계층 펜스 효과에 대한 실험적 연구)

  • Jun, Y.M.;Chung, J.T.
    • Proceedings of the KSME Conference
    • /
    • 2000.04b
    • /
    • pp.853-858
    • /
    • 2000
  • The working fluid from the combustor to the turbine stage of a gas turbine makes various boundary layer thickness. Since the inlet boundary layer thickness is one of the important factors that affect the turbine efficiency. It is necessary to investigate secondary flow and loss with various boundary layer thickness conditions. In the present study, the effect of various inlet boundary layer thickness on secondary flow and loss and the proper height of the boundary layer fences for various boundary layer thickness were investigated. Measurements of secondary flow velocity and total pressure loss within and downstream of the passage were taken under 5 boundary layer thickness conditions, 16, 36, 52, 69, 110mm. It was found that total pressure loss and secondary flow areas were increased with increase of thickness but they were maintained almost at the same position. At the fellowing research about the boundary layer fences, 1/6, 1/3, 1/2 of each inlet boundary layer thickness and 12mm were used as the fence heights. As a result, it was observed that the proper height of the fences was generally constant since the passage vortex remained almost at the same position. Therefore once the geometry of a cascade is decided, the location of the Passage vortex and the proper fence height are appeared to be determined at the same time. When the inlet boundary layer thickness is relatively small, the loss caused by the proper fence becomes bigger than endwall loss so that it dominates secondary loss. In these cases the proper fence hight is decided not by the cascade geometry but by the inlet boundary layer thickness as previous investigations.

  • PDF

A Parametric Study on Inlet Duct Treatment for Improving the Operational Stability of a Centrifugal Compressor (운전안정성 향상을 위한 원심 압축기의 유입부 형상변화에 관한 연구)

  • Seo, Tae-Wan;Heo, Man-Woong;Kim, Kwang-Yong
    • The KSFM Journal of Fluid Machinery
    • /
    • v.19 no.5
    • /
    • pp.12-19
    • /
    • 2016
  • In present study, a parametric study of a centrifugal compressor with inlet treatment has been performed numerically using three-dimensional Reynolds-averaged Navier-Stokes equations. The shear stress transport turbulence model was used for analysis of turbulence. The finite volume method and unstructured grid system were used for the numerical solution. Tested parameters were related to the geometry of the inlet duct. It was found that the application of circumferentially distributed holes in the inlet duct improves operational stability of the compressor compared to that with conventional inlet duct.

Transmission Loss Analysis of Simple Expansion Chambers with Multiple Inlets and Outlets (다입력/다출력관을 갖는 확장관의 투과손실 해석)

  • 박기춘;김양한
    • Journal of KSNVE
    • /
    • v.8 no.5
    • /
    • pp.807-813
    • /
    • 1998
  • Transmission loss of the simple expansion chamber with multiple inlet and outlet ports is obtained. Transfer matrices which represent the relation between the power variables(pressure and velocity) of inlets and outlets depend on the input relatons as well as the acoustic system parameters(i.e. geometry of the chamber, wall admittance, etc.). The analysis has been performed analytically, including the effects of higher order modes for the 2-inlet/1-outlet, 1-inlet/2-outlet and 2-inlet/2-outlet systems. This study yeilds that phase difference between the inlet ports can significantly increase the transmission loss in low frequency range.

  • PDF

An Optimization Method Based on Hybrid Genetic Algorithm for Scramjet Forebody/Inlet Design

  • Zhou, Jianxing;Piao, Ying;Cao, Zhisong;Qi, Xingming;Zhu, Jianhong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2008.03a
    • /
    • pp.469-475
    • /
    • 2008
  • The design of a scramjet inlet is a process to search global optimization results among those factors influencing the geometry of scramjet in their ranges for some requirements. An optimization algorithm of hybrid genetic algorithm based on genetic algorithm and simplex algorithm was established for this purpose. With the sample provided by a uniform method, the compressive angles which also are wedge angles of the inlet were chosen as the inlet design variables, and the drag coefficient, total pressure recovery coefficient, pressure rising ratio and the combination of these three variables are designed specifically as different optimization objects. The contrasts of these four optimization results show that the hybrid genetic algorithm developed in this paper can capably implement the optimization process effectively for the inlet design and demonstrate some good adaptability.

  • PDF

AN OPTIMUM DESIGN STUDY OF INTERLACING NOZZLE BY ANALYZING FLUID FLOW INSIDE INTERLACING NOZZLES

  • Juraeva Makhsuda;Ryu Kyung Jin;Kim Sang Dug;Song Dong Joo
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2005.10a
    • /
    • pp.93-97
    • /
    • 2005
  • Air interlacing serves to protect the yarn against damage, strengthens inter-filament compactness or cohesion, and ensures fabric consistency. The air interlacing nozzle is used to introduce intermittent nips to a filament yarn so as to improve its performance in textile processing. This study investigates the effect of interlacing nozzle geometry on the interlacing process. The geometries of interlacing nozzles with multiple air inlets located across the width of a yarn channels are investigated. The basic interlacing nozzle is the yarn channel, with a perpendicular single air inlet in the middle. The yarn channel shapes are cross sections with semicircular or rectangular shapes. This paper presents three doubled sub air inlets with main air inlet and one of them is slightly inclined doubled sub air inlets with main air inlet. The compressed air coming out from the inlet hits the opposing wall of the yarn channel, divides into two branches, flows trough the top side of yarn channel, joins with the compressed air coming out from the sub air inlet and then creates two free jets at both ends of the yarn channel. The compressed air moves in the shape of two opposing directional vortices. The CFD-FASTRAN was used to perform steady simulations of impinging jet flow inside of the interlace nozzles. The vortical structure and the flow pattern such as pressure contour, particle traces, velocity vector plots inside of interlace nozzle geometry are discussed in this paper.

  • PDF

Numerical Simulation of Duct Flow about Shape and Arrangement of Inlet Guide Vane to Increase the Temperature Uniformity (전치 가이드 베인 배치 및 형상에 따른 보일러 입구 온도분포의 수치해석 연구)

  • Lee, Su-Yun;Shin, Seung-Won
    • Proceedings of the SAREK Conference
    • /
    • 2008.06a
    • /
    • pp.1172-1177
    • /
    • 2008
  • Diverging channel from gas burner exit to the inlet section of Heat Recovery Steam Generator (HRSG) has been re-designed for 1 MW steam supply and power generation system. Three different test geometries have been chosen for the numerical simulation. The existing design for 300 kW HRSG system (CASE B) has been improved by geometry and position changes of inlet guide vanes along with gas velocity entrance angle at the diverging channel inlet (CASE C). Both cases has been compared with the case where hot combustion gas is directly injected without any guide vanes (CASE A). Improved design shows overall uniform velocity and temperature distribution compared to existing design.

  • PDF

Numerical Study on the Effect of Reactor Internal Structure Geometry Treatment Method on the Prediction Accuracy for Scale-down APR+ Flow Distribution (원자로 내부 구조물 형상 처리 방법이 축소 APR+ 유동분포 예측 정확도에 미치는 영향에 관한 수치적 연구)

  • Lee, Gong Hee;Bang, Young Seok;Woo, Sweng Woong;Cheong, Ae Ju
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.38 no.3
    • /
    • pp.271-277
    • /
    • 2014
  • Internal structures, especially those located in the upstream of a reactor core, may have a significant influence on the core inlet flow rate distribution depending on both their shapes and the relative distance between the internal structures and the core inlet. In this study, to examine the effect of the reactor internal structure geometry treatment method on the prediction accuracy for the scale-down APR+ flow distribution, simulations with real geometry modeling were conducted using ANSYS CFX R.14, a commercial computational fluid dynamics software, and the predicted results were compared with those of the porous medium assumption. It was concluded that the core inlet flow distribution could be predicted more accurately by considering the real geometry of the internal structures located in the upstream of the core inlet. Therefore, if sufficient computational resources are available, an exact representation of these internal structures, for example, lower support structure bottom plate and ICI nozzle support plate, is needed for the accurate simulation of the reactor internal flow.

IDENTIFICATION OF TWO-DIMENSIONAL VOID PROFILE IN A LARGE SLAB GEOMETRY USING AN IMPEDANCE MEASUREMENT METHOD

  • Euh, D.J.;Kim, S.;Kim, B.D.;Park, W.M.;Kim, K.D.;Bae, J.H.;Lee, J.Y.;Yun, B.J.
    • Nuclear Engineering and Technology
    • /
    • v.45 no.5
    • /
    • pp.613-624
    • /
    • 2013
  • Multi-dimensional two-phase phenomena occur in many industrial applications, particularly in a nuclear reactor during steady operation or a transient period. Appropriate modeling of complicated behavior induced by a multi-dimensional flow is important for the reactor safety analysis results. SPACE, a safety analysis code for thermal hydraulic systems which is currently being developed, was designed to have the capacity of multi-dimensional two-phase thermo-dynamic phenomena induced in the various phases of a nuclear system. To validate the performance of SPACE, a two-dimensional two-phase flow test was performed with slab geometry of the test section having a scale of $1.43m{\times}1.43m{\times}0.11m$. The test section has three inlet and three outlet nozzles on the bottom and top gap walls, respectively, and two outlet nozzles installed directly on the surface of the slab. Various kinds of two-dimensional air/water flows were simulated by selecting combinations of the inlet and outlet nozzles. In this study, two-dimensional two-phase void fraction profiles were quantified by measuring the local gap impedance at 225 points. The flow conditions cover various flow regimes by controlling the flow rate at the inlet boundary. For each selected inlet and outlet nozzle combination, the water flow rate ranged from 2 to 20 kg/s, and the air flow rate ranged from 2.0 to 20 g/s, which corresponds to 0.4 to 4 m/s and 0.2 to 2.3 m/s of the superficial liquid and gas velocities based on the inlet port area, respectively.

Development of Standard Series for Turbo Blowers (터보 블로워 표준화 제품 개발 사례)

  • Song, Kween;Kim, Kwang-Ho;Kim, Shin Hyoung;Kim, Hwe-Ryong
    • 유체기계공업학회:학술대회논문집
    • /
    • 2000.12a
    • /
    • pp.99-103
    • /
    • 2000
  • This paper describes the development of standard series for turbo blowers. In mass production system, it is very required to standardize blowers to improve the productivity of ordering, estimating, manufacturing. To standardize blowers, we performed researches on the effects of $b_1$(impeller inlet width), $b_2$(impeller outlet width), ${\beta}_1$(blade inlet angle), ${\beta}_2$(blade outlet angle), Z(number of blades) of impellers and geometry of casing experimentally. Through this study, we chose the several best model of turbo blowers with high efficiency and low noise, which represent each specific speed series 63, 80, 100, 125, 160, 200, 250, 315. After the development of such standardized blowers, the test results are used to prepare the fan geometry and performance database for a selection software.

  • PDF