• Title/Summary/Keyword: head shapes

Search Result 165, Processing Time 0.021 seconds

Effect of Guide Nozzle Shape on the Performance Improvement of a Very Low Head Cross Flow Turbine

  • Chen, Zhenmu;Singh, Patrick Mark;Choi, Young-Do
    • The KSFM Journal of Fluid Machinery
    • /
    • v.17 no.5
    • /
    • pp.19-26
    • /
    • 2014
  • The cross flow turbine attracts more and more attention for its relatively wide operating range and simple structure. In this study, a novel type of micro cross flow turbine is developed for application to a step in an irrigational channel. The head of the turbine is only H=4.3m and the turbine inlet channel is open ducted type, which has barely been studied. The efficiency of the turbine with inlet open duct channel is relatively low. Therefore, a guide nozzle on the turbine inlet is attached to improve the performance of the turbine. The guide nozzle shapes are investigated to find the best shape for the turbine. The guide nozzle plays an important role on directing flow at the runner entry, and it also decreases the negative torque loss by reducing the pressure difference in Region 1. There is 12.5% of efficiency improvement by attaching a well shaped guide nozzle on the turbine inlet.

Experiments and Numerical Validation for FPSO Bow Water Shipping (FPSO 선수부 갑판침수 현상에 대한 실험 및 수치적 검증)

  • Lim, Ho-Jeong;Lee, Hyun-Ho;Park, Sun-Ho;Rhee, Shin-Hyung
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.49 no.1
    • /
    • pp.6-13
    • /
    • 2012
  • As ocean resources in shallow water areas are being exhausted, deep sea development is becoming common these days. Therefore floating type offshore structures are more competitive than fixed type structures, and FPSO is the most popular one these days. FPSO's are generally operated in a specific region and positioned to meet mostly head or bow waves in order to reduce roll motions. However this makes these vessels more vulnerable to green water around the bow region, and therefore the bow shape must be properly designed to mitigate green water damage. In the present study, experimental results for three different FPSO bow shapes in regular head waves were analyzed and compared to each other. Also CFD computations were carried out as a sample validation case for the database built for CFD code validation.

Extracting 3D Geometry Parameters of Hip Joint for Designing a Custom-Made Hip Implant (맞춤형 인공관절 설계를 위한 인체 고관절의 3차원 형상 정보 추출)

  • Seo, Jeong-Woo;Jun, Yong-Tae
    • Korean Journal of Computational Design and Engineering
    • /
    • v.13 no.3
    • /
    • pp.200-208
    • /
    • 2008
  • Total Hip Replacement(THR) is a surgical procedure that replaces a diseased hip joint with a prosthesis. A plastic or metal cup forms the socket, and the head of the femur is replaced by a metal ball on a stem placed inside the femur. Due to the various types and shapes of human hip joint of every individual, a selected commercial implant sometimes may not be the best-fit to a patient, or it cannot be applied because of its discrepancy. Hence extracting geometry parameters of hip joint is one of the most crucial processes in designing custom-made implants. This paper describes the framework of a methodology to extract the geometric parameters of the hip joint. The parameters include anatomical axis, femoral head, head offset length, femoral neck, neck shaft angle, anteversion, acetabulum, and canal flare index. The proposed system automatically recommends the size and shape of a custom-made hip implant with respect to the patient's individual anatomy from 3D models of hip structures. The proposed procedure creating these custom-made implants with some typical examples is precisely presented and discussed in this paper.

Computational Performance Prediction of Main Coolant Pump for the Integral Reactor SMART (일체형원자로 SMART 냉각재 순환펌프의 전산성능예측)

  • Kim M. H;Lee J. S;Park J. S;Kim J. I;Kim K. K
    • Journal of computational fluids engineering
    • /
    • v.8 no.3
    • /
    • pp.32-40
    • /
    • 2003
  • CFD analyses of the three-dimensional turbulent flow in the impeller and diffuser of an axial flow pump including suction and discharge parts are presented and compared with experimental data. The purpose of the current study is to validate the CFD method for the performance analysis of the main coolant pump for SMART and to investigate the effect of suction and discharge shapes on the pump performance. To generate a performance curve, not only the design point but also the off-design points were computed. The results were compared with available experimental data in terms of head generated. At the design point, the analysis accurately predicts the experimental head value. In the range of the higher flow rates, the results are also in very good agreement with the experimental data, in magnitude but also in terms of slope of variation. For lower flow rates, the results shows that the analysis considering the suction and discharge well describe the typical S-shape performance curve of the axial pump.

An Experimental Study on the Characteristics of the In-cylinder Eccentricity Swirl Flow with Intake Port Shapes in a 4 Valve Diesel Engine (4밸브 디젤기관의 흡기포트 형상에 따른 실린더 내 편심 선회유동 특성에 관한 실험적 연구)

  • 이지근;김덕진;강신재;노병준
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.6 no.1
    • /
    • pp.59-72
    • /
    • 1998
  • This experimental study was carried out to investigate the characteristics of the in-cylinder eccentricity swirl flow generated by a 4 valve cylinder head with a tangential and a helical intake port. the measurements of the in-cylinder velocity field have been made by a two-channel LDA system. The mean flow coefficient(Cf(meam)), swirl ratio(Rs) and mass flowrate with valve eccentricity ratios and an intake port partition between the two intake ports were measured in the steady flow test fig using the ISM(impulse swirl meter). The experimental results indicated that the mass flowrate through the tangential intake port was 19% and 7.7% more than that of the helical intake port in case of with and without intake port partition respectively. There was a tendency to be a single rotation flow in swirl flow fields formed by a 4 valve cylinder head because of the interaction between the two intake ports. As the intake port partition was not set between flow coefficient(Cf(mean)) was 7.35%.

Experimental Investigation of the Bow Configuration Influence on the Green Water on FPSO (FPSO 갑판 침입수 현상에 대한 선수부 형상 영향의 실험적 고찰)

  • Lee, Hyun-Ho;Lim, Ho-Jeong;Rhee, Shin-Hyung
    • Journal of Ocean Engineering and Technology
    • /
    • v.23 no.5
    • /
    • pp.9-14
    • /
    • 2009
  • The green water on deck has many harmful effects on the vessel in rough seas such as damages to hull structures, damages to cargos, increase of the downtime, decrease of the stability, and so on. Floating Production Storage and Offloading vessels (FPSOs) are operated in a specific location and are normally positioned to meet mostly head or bow waves in order to reduce the roll motions. But this makes FPSOs more vulnerable to green water around the bow region therefore the bow shape should be properly designed to mitigate the green water damage. In this paper, experimental results in regular head waves for three kinds of bow shapes are compared and some design considerations are proposed, with the building a database for computational fluid dynamics (CFD) validation in mind.

Facial Type Analysis of Adult Women for Correct Make-up (수정메이크업을 위한 성인 여성의 얼굴 유형 분석)

  • Yi, Kyong-Hwa;Kim, Jeong-Hee
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.31 no.11
    • /
    • pp.1487-1499
    • /
    • 2007
  • In this study, photographs of 600 Korean females aged from 20 to 50years old were indirectly measured in Venus face 2D program. The measurements were analyzed by statistical methods. The purpose of this study was to differentiate the facial types of adult women for the beauty industry. As a result of factor analysis, 6 factors were selected the key factors of facial shape: head height(factor 1), head width(factor 2), side face width(factor 3), head width and circumference(factor 4), face length(factor 5), and side face width(factor 6). We categorized facial type into 5 groups with the previous 6 factor. 5 types were most common facial shapes: Oblong face(type 1), Square face(type 2), Oval face(type 3), Round face(type 4), Triangle face(type 5). The results of facial type analysis were showed that Round face(26.6%), Triangle face(25.3%), Oval face(22.3%), Square face(20.0%), Oblong face(5.7%).

A Study on Design Preference about Traditional Feminine Head Ornament for Development of Fashion Cultural Products (패션문화상품 개발을 위한 전통 여성 수식의 디자인 선호도 연구)

  • Kwon, Jin;Kim, Sun-Young
    • Journal of the Korean Society of Costume
    • /
    • v.62 no.4
    • /
    • pp.69-80
    • /
    • 2012
  • This research aims at the contribution to globalize and modernize the traditional Korean image by comprehending the taste of design that domestic college students have for traditional feminine head ornaments and subsequently elaborate the development of cultural products that are related to these decorative objects. In regards to this research method, the examination on the traditional feminine ornaments was followed through a review of literature and precedent studies and a survey was conducted on the preference about them. After the adoption of final valid responses, an analytical method, PASW 18.0, was used for frequency analysis, technical analysis, reliability, and regression analysis. The results were as follows. First, in the category of tendency analysis for the application of traditional feminine headpiece in fashion cultural products, it was revealed that a taste for the design that meet the satisfaction for both trend and practicability was prominently prevalent. Also, the design that express the individual characteristic was taken as a preferred option. Second, in the preference for the design of traditional feminine headpieces in fashion cultural products, the result indicated that the modern type was preferred in the form of re-creation as long as those products deform the tradition. As for the selective taste for patterns, their preference came in the order of plant, animal, and geometry-abstract types. Especially, for the case of plant and animal patterns, the reinterpreted design of modernized shapes were opted rather than a simply recopied format of the conventional type of the feminist head ornament. Third, for the category of item selection to apply the feminine head ornament in order to design the fashion cultural products, it turned out that people preferred the application to accessory rather than clothing. Lastly, it was found that rarity, harmony with other fashion goods, pattern, and design should be considered when the traditional motif was used for cultural products.

Major Morphological Characteristics of Safflower(Carthamus tinctorius L.) Accessions (홍화 수집종의 주요 형태적 특성)

  • 김재철
    • Korean Journal of Plant Resources
    • /
    • v.13 no.3
    • /
    • pp.213-218
    • /
    • 2000
  • Morphological characteristics of 16 collected safflower (Carthamus tinctorius L.)accessions were studied at Gyongbuk A.T.A. Uisong Medicinal Plant Experiment Station in 1998. As for plant height, 5 lines were tall(more than 131cm), which were mainly foreign safflower. Middle and small were 5 and 6 accessions, respectively. Number of branch per plant was 11∼13 in 2 accessions of domestic safflowers while foreign safflowers have more than 50 branches per plant. Leaf shapes were oblong(3 lines), lanceolate(10 lines) and broadly linear(3 lines). There were three types of leaf margin shape which were repand(7 lines), serrate(4 lines) and parted serrate(5 lines). Flower color was white(1 line), yellow(13 lines) and red orange(2 lines). As for flower head shape, 14 lines were conical and 2 lines were flattened. There were thorns on bract of flower head in 11 lines but in 5 lines there were not. Domestic safflower lines had seeds of conical shape. Contrastively, seed shapes of foreign saffower lines were oval.

  • PDF

An experimental study for estimation of head loss coefficients at surcharged four-way combining manholes (과부하 4방향 합류맨홀에서의 손실계수 산정을 위한 실험 연구)

  • Ryu, Taek Hee;Kim, Jung Soo;Yoon, Sei Eui
    • Journal of Korea Water Resources Association
    • /
    • v.49 no.12
    • /
    • pp.1015-1025
    • /
    • 2016
  • In general, manholes installed as urban drainage facilities are a variety forms such as straight path manholes, 90 degree bend manhole, three-way combining manhole, and four-way combining manhole. In particular, the surcharged flow at a four-way manholes installed in the downstream of urban sewer system is the main cause of the urban inundation caused by the energy loss. Therefore, it is necessary to analyze the flow characteristics and estimate the head loss coefficients at surcharged four-way combining manholes. The hydraulic experimental apparatus which can change the manhole shapes (square, circle) and flow ratios were installed to estimate the head loss coefficients. In the experiments, two inflows ($Q_m$, $Q_{lat}$) were varied from 0 to $4.8{\ell}/sec$ and 24 combinations were tested in total. The flow ratios $Q_{lat}/Q_{out}$ were varied from 0 to 1 for a total flow $Q_{out}$ ($Q_{out}=Q_m+2Q_{lat}$) of 2, 3, 4, and $4.8{\ell}/sec$, respectively. The variation of head losses were strongly influenced by the lateral inflow because the head loss coefficient increases as the flow ratios $Q_{lat}/Q_{out}$ increases. It was estimated head loss coefficients of the circular manhole is slightly lower than those of the square manhole. However, there was no significant difference of head loss as discharges change. The range of head loss coefficients at four-way combining manhole according to the change of the lateral inflow ratio was estimated to be 0.4 to 0.8. Also, the relation equations between the head loss coefficients (K) and the lateral inflow ratios ($Q_{lat}/Q_{out}$) were suggested in this paper.