• 한국작물학회지
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• 제41권1호
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• pp.62-67
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• 1996

본 실험은 비중선으로 종자밀도를 5등급으로 세분한 뒤 각 등급별 유묘의 유관속 발달 및 생육 특성에 미치는 영향을 구명하기 위하여 인디카형인 IR58과 자포니카형인 운봉7호를 공시하여 수해한 결과는 다음과 같다. 1. 종자의 밀도가 1.00이하에서 1.20이상으로 높아질수록 유묘의 엽신과 엽초에 발달된 유관속수와 크기가 증가하는 경향이었다. IR58은 운봉7호보다 유관속수와 크기가 양호하게 발달하였다. 2. 유묘의 생육특성인 초장, 엽수, 근수 및 근장은 종자의 밀도가 1.20이상까지 높아질수록 증가하였다. 3. 엽신과 엽초에 발달된 유관속수는 건물중과 고도로 유의한 정의 상관관계를 나타냈으며, 제4, 5엽신의 대유관속수는 엽신폭과 유의한 정상관을 보였다. 4. 종자의 밀도가 높아질수록 유묘의 유관속 발육을 좋게 하며 양수분의 원활한 이동으로 인하여 생육이 양호하게 건묘육성에 바람직하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.627-630
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• 2002

In the present study a mesh generation program is developed for the flow analysis of industrial mixers. With this program one can select various design parameters such as impeller types, vessel type, number of baffles, number of blades, blade pitched angle, stages of impeller, rotational speed etc. Post processing capabilities are also imbedded in the program. Along with brief explanation of the program, examples of flow simulation for various type of mixers by using the program are also presented to show effectiveness of the program. It is expected that this program can be used to understand the effect of design parameters on the performance of particular type of the mixer, and hence to achieve the optimal design.

• 대한조선학회지
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• 제17권3호
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• pp.5-17
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• 1980

A basic procedure to design marine propellers by a curved lifting line theory was shown. By adapting discrete singularity method, it became possible to take into account of skew, rake and the contraction of slip stream in the early stage of preliminary design procedure. It is also shown that lifting line theory based on the discrete singularity method converges to a common solution obtained by induction factor method with a relatively small number of discrete elements. Lifting the blade geometry more accurately on the basis of hydrodynamic principles. A number of numerical results from lifting line calculation are presented for the purpose of comparison with the previous method, and with these results two sample designs are carried out, which are wake-adapted optimum and wake-adapted non-optimum propellers.

• 대한조선학회 특별논문집
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• 대한조선학회 2008년도 특별논문집
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• pp.62-67
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• 2008

The hovercraft is the amphibious hovercraft. Design and manufacturing companies of the aero propeller exist rarely in the world. Hence the propeller has beef designed and manufactured by manufacturing companies which make aero propeller mainly. In this paper, the hovercraft propeller of similar, which is building and designing by HHIC, is considered the type of aero propeller, rotational speed, diameter, number of blades, Open air propeller efficiency. As the result of check, hovercraft which is necessary huge static thrust is needed the ducted propeller in order to improve climbing capacity. However, the number of blades and turning direction almost do not affect.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.97-103
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• 2011

With the aim to increase blade loadings and stable operating range in highly loaded compressors, this article has been conducted to explore, through a numerical parametric study, the potential of passive control using slotted bladings in cascade configurations. The objective of this numerical investigation is to analyze the influence of location, width and slope of the slots and therefore identify the optimal configuration. The approach is based on two dimensional cascade geometry, low speed regime, steady state and turbulent RANS model. The results show the efficiency of this passive technique to delay separation and enhance aerodynamic performances of the compressor cascade. A maximum of 28.3% reduction in loss coefficient have been reached, the flow turning is increased with approximately $5^0$ and high loading over a wide range of angle of attack have been obtained for the optimized control parameter.

• 한국기계가공학회지
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• 제13권4호
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• pp.36-43
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• 2014

Recently, research has been conducted to develop the ORC (organic Rankine cycle), to recover waste heat from facilities such as industrial plants ultimately to create mechanical or electrical energy. The ORC system consists of a heat exchange, a condenser, a pump and a boiler. In this paper, 84 flow analyses were conducted with 21 cases and three variables, i.e., a number of large wings, a number of small wings, and RPMs. R245fa was used as a refrigerant. The flow cavitation phenomenon was investigated through a flow analysis, and a flow stream analysis was conducted.

• 전기학회논문지
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• 제67권1호
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• pp.22-28
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• 2018

In case of developing a combined system by a number of distributed resources with storage device, a number of application suggests a huge capacity can derive operational flexibility both power supply issues or when unexpected situation imposed. However, it is important to determine a resonable energy capacity because the device have many controversial cost issues in current power system industry. An ESS application which focusing essentially required points can induce appropriate storage capacity that required in economic operation. In this paper, a curtailment supporting algorithm based on storage device is introduced, and applied in the capacity calculation method. The main algorithm pursues handling minor exceeding quantities which can cause mechanical load at blade; This paper tries to include it for configuring hybrid algorithm with pitch control. Several fluctuating conditions are utilized in simulation to reflect critical situation. The analyzing process focuses on the control feasibility with applied capacity and control method.

• 대한기계학회논문집
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• 제18권6호
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• pp.1598-1603
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• 1994

A preliminary design procedure for a multi-stage axial compressor is developed, which is based on the stage-stacking method. It determines the flow coefficient which gives rise to the design conditions required such as pressure ratio, mass flow rate and rotational speed for a given specific mass flow rate at inlet to a compressor. With this flow coefficient, blade radii, every stage and compressor performance characterics such as stage pressure ratio, adiabatic efficiency etc. are calculated by stacking each stage performance characteristics. It is shown that there is an optimum number of stage which results in the maximum of compressor overall efficiency for a given specific mass flow rate at inlet to a compressor. A test design was tried for three different geometric design constraints, and comparison with a previous study shows that present procedure could be used reliably in determining the number of compressor stage in preliminary design stage.

• 한국유체기계학회 논문집
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• 제14권6호
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• pp.76-84
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• 2011

The effect of inlet velocity profile on the heat transfer coefficient in a rotating smooth channel was investigated experimentally. Three simulated inlet flow conditions of fully developed, uniform, and distorted inlet conditions were tested. The Reynolds number based on the channel hydraulic diameter was ranged from 10,000 to 30,000 and the transient liquid crystal technique was used to measure the distribution of the heat transfer coefficient in the rotating channel. Results showed that the overall heat transfer coefficient increased as the Reynolds number increased. Also, the distribution of the heat transfer coefficient was strongly affected by the inlet flow condition. Generally, the fully developed flow simulated condition showed the highest heat transfer coefficient.

• 한국항공운항학회지
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• 제14권1호
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• pp.9-14
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• 2006

Averaged heat transfer coefficients in the trailing edge model of a turbine blade with double impingements were measured using transient liquid crystals technique and conventional copper plate-thermocouple technique. The detailed distributions of heat transfer coefficients by transient liquid crystals technique were also presented. Results showed that increased heat transfer coefficient due to the inpingements and the averaged heat transfer coefficients increased as Reynolds number increased. Results by transient liquid crystals technique showed that the heat transfer coefficient strongly depended on the main stream temperature used in heat transfer coefficient calculation. The averaged heat transfer coefficients measured by different methods showed similar trend as Reynolds number changed, but the value varied up to 40% depending on the measurement technique.