Processing math: 100%
  • Title/Summary/Keyword: CFX

Search Result 512, Processing Time 0.036 seconds

A Study on the Flow Characteristics according to the Change of Structure in Filtration Using the Numerical Model (수치모형을 이용한 여과기 내 구조 변경에 따른 유동특성 연구)

  • Kim, Taewon;Song, Sooho;Choi, Changhyung;Park, Youngjin;Kim, Jiho
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2017.05a
    • /
    • pp.285-285
    • /
    • 2017
  • 최근 전 세계적으로 심각해지는 물 부족 현상과 수질오염으로 대량의 원수를 빠른 시간 내에 여과하기 위한 여과장치의 개발 및 효율성 향상을 위한 연구의 필요성이 증가되고 있다. 특히 여과필터의 내부구조에 의해 유동이 편중되는 현상이 발생하면 여과효율 및 여과필터 유지관리에 문제가 발생되기 때문에 최적의 여과필터를 설계하는 것이 중요하다. 이에 본 연구에서는 수리모형실험으로 검토하기에 어려움이 있는 여과기 내부구조에 대한 유동특성을 수치해석을 이용하여 검토하였다. 수치해석은 유한요소법 기반의 수치모형으로 여과기 내부를 상세하게 모의할 수 없기 때문에 유한체적법 기반인 ANSYS CFX 모형을 이용하였다. 여과기 내 여과필터는 두께 2.0 mm, 공극율 25%로 가정하고 다공성 기법(porous media)을 적용하였다. 검토를 위한 경계조건은 유입부에 목표 취수량, 유출부에 대기압 조건을 적용하였으며, 여과기에 비해 매우 작게 구성된 여과필터 내부의 유동특성을 검토하기 위해 여과기는 최소 3.0 mm, 여과필터는 1.0 mm의 격자를 적용하였다. 현재 실제 여과시설에 적용되고 있는 여과기 제품 형상을 기준으로 여과기 내부 흐름공간의 크기 및 각도 조정에 따른 유동특성을 검토하여 여과효율을 비교하였으며 통과유량, 유속, 유속벡터 등을 검토하여 균등한 유량과 유속이 발생되는 최적의 여과장치 구조를 도출하였다. 본 연구에서 여과기 내부 구조 변경에 따른 유동특성 검토를 통해 도출된 최적의 여과기 내부크기 및 각도에 대한 설계인자는 여과기 내 여과필터의 효율을 증가시킬 뿐만 아니라 내구성 증진에 도움이 될 것으로 예상된다.

  • PDF

Numerical Analysis on the Effects of Supply Channel and Jet Hole Arrangement on Heat Flow Characteristics of Impingement Jet (충돌제트에서의 유량공급 채널 및 제트 홀 배열에 따른 열유동 특성 수치해석)

  • Hwang, Byeong Jo;Chung, Heeyoon;Joo, Won Gu;Cho, Hyung Hee
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.20 no.4
    • /
    • pp.77-86
    • /
    • 2016
  • A numerical analysis is performed to investigate the effect of a supply channel and jet hole arrangement on the heat flow characteristics of impingement jet. The jet holes in a supply channel are composed of a single or staggered array from the center of a leading edge channel. The software ICEMCFD is used to generate the structured grids for calculation domain and a CFD code CFX 15.0 to perform the simulation. The present solutions are validated by comparison with the experimental and numerical ones of others. A comparison of mass flow rates of impingement jets and Nusselt numbers on the impingement surface for the single or staggered arrays is made.

CFD ANALYSIS OF HEAVY LIQUID METAL FLOW IN THE CORE OF THE HELIOS LOOP

  • Batta, A.;Cho, Jae-Hyun;Class, A.G.;Hwang, Il-Soon
    • Nuclear Engineering and Technology
    • /
    • v.42 no.6
    • /
    • pp.656-661
    • /
    • 2010
  • Lead-alloys are very attractive nuclear coolants due to their thermo-hydraulic, chemical, and neutronic properties. By utilizing the HELIOS (Heavy Eutectic liquid metal Loop for Integral test of Operability and Safety of PEACER2) facility, a thermal hydraulic benchmarking study has been conducted for the prediction of pressure loss in lead-alloy cooled advanced nuclear energy systems (LACANES). The loop has several complex components that cannot be readily characterized with available pressure loss correlations. Among these components is the core, composed of a vessel, a barrel, heaters separated by complex spacers, and the plenum. Due to the complex shape of the core, its pressure loss is comparable to that of the rest of the loop. Detailed CFD simulations employing different CFD codes are used to determine the pressure loss, and it is found that the spacers contribute to nearly 90 percent of the total pressure loss. In the system codes, spacers are usually accounted for; however, due to the lack of correlations for the exact spacer geometry, the accuracy of models relies strongly on assumptions used for modeling spacers. CFD can be used to determine an appropriate correlation. However, application of CFD also requires careful choice of turbulence models and numerical meshes, which are selected based on extensive experience with liquid metal flow simulations for the KALLA lab. In this paper consistent results of CFX and Star-CD are obtained and compared to measured data. Measured data of the pressure loss of the core are obtained with a differential pressure transducer located between the core inlet and outlet at a flow rate of 13.57kg/s.

Convergence Study on Flow Characteristic due to the Configuration of Water Tank (물탱크의 형상에 따른 유동 특성에 관한 융합 연구)

  • Oh, Bum-Suk;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
    • /
    • v.10 no.6
    • /
    • pp.185-190
    • /
    • 2019
  • In this study, the flow characteristics happening inside water tank due to the configuration of various water tank were analyzed by using a computation fluid dynamics program, ANSYS CFX. This study also examined which model was most efficient at the flow by changing the flow conditions of the inlet and outlet due to the configuration of various tank. Same material was applied to models A, B and C. As the result of flow analysis, it was shown that model B had the best flow and model C had the highest pressure applied to the flow. So, though the water tank has the same material according to the configuration of product, the velocity and pressure of flow become different. Therefore, it is thought to develop the tank good for the fluid flow due to the product configuration through this flow analysis result. On the basis of this study result, the esthetic sense can be shown as the analysis data of flow due to the configuration of fluid tank are grafted onto the real life.

Optimal Design of Impeller according to Blade Shape Variation Using CFD Simulation (CFD를 이용한 블레이드 형상 변화에 따른 블로워 임펠러 최적설계)

  • Yu, Da-Mi;Kim, Semo;Jang, Hye-Lim;Han, Dae-Hyun;Kang, Lae-Hyong
    • Journal of Aerospace System Engineering
    • /
    • v.13 no.1
    • /
    • pp.29-37
    • /
    • 2019
  • The objective of this study was to investigate the influence of the blade shape on the impeller performance, for design optimizing of the high airflow impeller. First, the quantity, angle, and length of blades, which are considered to have a large influence on the impeller performance, were selected as design variables. Then, 27 cases of impeller shapes were selected according to the design of experiment (DOE). To predict the conduct of the blower based on the selected impeller shape, flow analysis was performed using the immersed solid method of ANSYS CFX. In the CFD results, the highest airflow was expected in the impeller having a combination of 50 EA, 6 and 5 mm. Finally, a blower with the original impeller shape and the optimized impeller shape was fabricated using a 3D printer, and the analysis tendency and experimental tendency were verified through experiments.

Numerical Analysis on the Cavitation Performance of a Seawater Cooling Pump (해수냉각 펌프의 캐비테이션 성능에 대한 수치해석)

  • Tran, Bao Ngoc;Kim, Jun-ho
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.25 no.1
    • /
    • pp.130-137
    • /
    • 2019
  • In this study, a centrifugal seawater cooling pump was analyzed to investigate its cavitation behavior over different operating flow rates. 3D two-phase simulations were carried out with ANSYS-CFX commercial code. The kε turbulence and Rayleigh-Plesset cavitation models were employed in the simulations. A head drop characteristics curves for three discharge rates was built based on numerical predictions. At higher flow rates, the impeller was more vulnerable to bubble cavitation. The 3 % head drop points of the pump working at 0.7Q, Q, and 1.3Q (Q: design flow rate) corresponded with NPSHa 1.21 m, 1.83 m, and 3.45 m, respectively. The volume of vapor bubbles was estimated and cavitation locations were anticipated to visualize the development of the cavity within the impeller. Moreover, the distribution of pressure coefficient and a blade loading chart are specifically presented, bringing out the harmful impacts of cavitation on the pump operation.

Numerical Study on Heat Transfer and Flow Characteristics of Pin Fin with Swept Airfoil Shape Vortex Generator (후퇴익형 형상의 와류발생기가 있는 핀휜 유동의 전열 및 유동 특성 분석에 관한 수치적 연구)

  • Lee, Changhyeong;Oh, Yeongtaek;Bae, Jihwan;Lee, Deukho;Kim, Kuisoon
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.23 no.4
    • /
    • pp.28-34
    • /
    • 2019
  • In this study, pin-fin arrays, which are widely used for cooling turbine blades, were studied. The vortex generator in pin-fin arrays is located in front of the circular tube. The cross-section of the vortex generator is NACA-9410. The purpose of this study is to analyze heat transfer performance and flow characteristics of pin-fin arrays. The position of vortex generator is changed with the vertical flow direction on the bottom wall. Pin-fin arrays were calculated with 6000, 10000 and 15000 Reynolds number. The commercial program ANSYS v18.0 CFX and the turbulence model kω SST were used. As a result, the heat transfer performance increased up to 5.8% and pressure loss increased less than 1%.

Effect of Absorbent Thickness on the Noise Level Reduction of Fire-Extinguishing Nozzle (흡음재 두께가 소화노즐 소음도 저감에 미치는 영향)

  • Kim, Hak-Sun;Hwang, In-Ju;Kim, Youn-Jea
    • Fire Science and Engineering
    • /
    • v.33 no.1
    • /
    • pp.99-104
    • /
    • 2019
  • In a gas system fire extinguishing system, extinguishing agents are usually stored with approximately 280 bar at 21C and are released at approximately 8 MPa through the decompression valve and orifice to quickly suppress the fire. When extinguishing agents are discharged, they cause a loud noise (approximately 140 dB), which can damage electronics, such as hard disk drives (HDDs). Therefore, the noise is becoming a serious issue in the gas extinguishing system. The method of the noise reduction by adding an absorbent is most general and in this study, the thickness of the absorbent was as a selected design variable. The noise level at the observation point and the flow characteristics inside the nozzle were numerically calculated and analyzed using the commercial code ANSYS CFX ver. 18.1.

Experimental, Theoretical and Numerical Studies for Concentrations and Velocities of Gas Jets (가스 제트 누출의 농도 및 속도에 대한 실험, 이론 및 수치해석 연구)

  • Bang, Boo-Hyoung;Kim, Hong-Min;Kim, Sung-Hoon;Lee, Keun-Won
    • Journal of the Korean Institute of Gas
    • /
    • v.26 no.1
    • /
    • pp.20-26
    • /
    • 2022
  • The results of experimental, theoretical, and numerical analysis were compared regarding the concentrations and velocities of flammable gas jets generated by pressurized leakage of methane gas. The concentration was measured through experiments for the jet dispersion process, and the velocities was calculated by applying the self-similarity theory. And the velocities and concentrations were calculated using CFD tools - FLACS and CFX- compared with the results. The difference between self-similarity model and CFD is due to the buoyancy term, which increases as the distance from a leak source increases. The results are compared with dimensionless parameters using the leak source radius and velocity components along the leak axis.

Numerical prediction of the proximity effects on wind loads of low-rise buildings with cylindrical roofs

  • Deepak Sharma;Shilpa Pal;Ritu Raj
    • Wind and Structures
    • /
    • v.36 no.4
    • /
    • pp.277-292
    • /
    • 2023
  • Low-rise structures are generally immersed within the roughness layer of the atmospheric boundary layer flows and represent the largest class of the structures for which wind loads for design are being obtained from the wind standards codes of distinct nations. For low-rise buildings, wind loads are one of the decisive loads when designing a roof. For the case of cylindrical roof structures, the information related to wind pressure coefficient is limited to a single span only. In contrast, for multi-span roofs, the information is not available. In this research, the numerical simulation has been done using ANSYS CFX to determine wind pressure distribution on the roof of low-rise cylindrical structures arranged in rectangular plan with variable spacing in accordance with building width (B=0.2 m) i.e., zero, 0.5B, B, 1.5B and 2B subjected to different wind incidence angles varying from 0° to 90° having the interval of 15°. The wind pressure (P) and pressure coefficients (Cpe) are varying with respect to wind incidence angle and variable spacing. The results of present numerical investigation or wind induced pressure are presented in the form of pressure contours generated by Ansys CFD Post for isolated as well as variable spacing model of cylindrical roofs. It was noted that the effect of wind shielding was reducing on the roofs by increasing spacing between the buildings. The variation pf Coefficient of wind pressure (Cpe) for all the roofs have been presented individually in the form of graphs with respect to angle of attacks of wind (AoA) and variable spacing. The critical outcomes of the present study will be so much beneficial to structural design engineers during the analysis and designing of low-rise buildings with cylindrical roofs in an isolated as well as group formation.