• 한국연소학회:학술대회논문집
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• 한국연소학회 1997년도 제15회 KOSCO SYMPOSIUM 논문집
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• pp.135-151
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• 1997

The preliminary design and performance test for determining dimensions of gas turbine combustor were investigated. The combustor design program was developed and applied to design our combustor. and detailed design for determining of swirler. dome and liner holes were performed experimentally. The swirler. which govern the combustion characteristics of combustor, was determined $40^{\circ}$ as swirl angle at first performance test. After second performance test the swirler was re-determined by 24 mm i.d.. 34 mm o.d., and swirl angle of $45^{\circ}$. The geometry of liner holes were determined by considering the flame stability and recirculation zone size. It was found that flame can be more easily stabilized by adjusting the swirier dimensions rather than liner holes. The geometry of swirler and liner holes were re-determined by final performance test with dilution holes. Also. the performance of combustor was evaluated by analysis of exhaust gases.

• Journal of Advanced Marine Engineering and Technology
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• 제22권4호
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• pp.515-521
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• 1998

In this study the mixing process of two-phase flow which makes two jets existing vlocity difference are analyzed. The primary jet is jetted on the condition of the state mixed pulverized solid pariticle with air and the velocity in the secondary jet is changed into three kinds velocities(0.60, 75m/s) The velocity vector field concentration field and turbulent properties of solid particles are measured by using 3-Dimensional Particles Dynamics Analyzer. As the velocity of secondary jet increases the solid particle recirculation zone becomes larger. Also solid particle concentration gets dense due to velocity decrement of particles.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.151-163
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• 2001

A two color PIV technique has been developed for visualization of complex and high speed flow in a ramjet combustor. Two color PIV has the advantages that velocity distributions in high speed flowfields can be measured simply by varying the time interval between two different laser beams and a directional ambiguity problem can be solved by color separation, and then a signal-to-noise ratio can be increased through nearly perfect cross-correlation. As a basic research of the ramjet engine, a 2-D shaped combustor with two symmetric air intakes has been manufactured and an experimental study has been conducted using a two color PIV technique. The flow characteristics such as recirculation zones, intake air mixing and turbulent kinetic energy have been investigated varying inlet angles and dome heights. It was found that the primary recirculation zone is affected mainly by the dome height, whereas the secondary recirculation zone is influenced by the air inlet angle.

• 한국수자원학회논문집
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• 제49권7호
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• pp.635-644
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• 2016

본 연구에서는 2차원 수치모형을 이용하여 개수로 분류부에서 분류수로 폭과 유량비 변화에 따른 흐름특성을 파악하였다. 2차류 영향을 고려한 분류부 수치모의시 흐름분포를 실험결과에 더 정확하고 안정하게 모의가능하다. 분류수로내 통수능을 감소시키는 흐름분리구역과 2차류의 상호 작용에 의한 흐름정체 효과는 분류유량비를 감소시킨다. 분류부 상류 유입유량과 유속이 감소할수록 수로폭 변화에 따른 분류유량비 변화가 더 크다. 동일 하류단 경계조건에서 분류수로 폭을 감소시킬 때, 본류 하류부 프루우드 수-분류유량비 관계식의 변화율은 -2.4843~-2.6675로 유사하게 나타난다. 동일 분류유량비 조건에서 분류수로 폭이 감소할수록 수축계수는 증가하고, 흐름분리구역의 폭은 감소한다. 분류수로 폭을 증가시킬 경우 분류부 상류 유입유량이 적을수록, 그리고 분류부 상류 유입량을 증가시킬 경우 분류수로 폭이 좁을수록 흐름분리구역 폭 감소율이 더 크다. 동일 상류 유입유량 조건에서 분류수로 폭이 감소할수록 분류유량비, 흐름분리구역의 길이와 폭은 감소한다.

• 대한의용생체공학회:의공학회지
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• 제33권4호
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• pp.177-183
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• 2012

The inspiratory flow rate of a human is changed with the amount of the workload. The flow characteristic is affected by the inspiratory flow rate. In the flow field of airway, the both of turbulence intensity and secondary flow affect the deposition pattern of particles which is important for the drug-aerosol targeting. Thus the analysis of the flow characteristic in a human airway is important. The purpose of this study is to investigate the effects of the inspiratory flow rate on the flow characteristics in a human airway. The tubular airway is consistent with the oral cavity, pharynx, larynx and trachea. The relatively inspiratory flow rate is used at each case of human states regarding the workload. By the effect of geometric airway changes, transition to turbulent airflow after the larynx can occur with relaminarization further downstream. The low Reynolds number k-${\omega}$ turbulence model is used for analysis with flow regime. As the inspiratory flow rate is larger, the turbulence kinetic energy and secondary flow intensity increase in airway. On the other hand, the area of recirculation zone is smaller.

• 대한기계학회논문집B
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• 제25권2호
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• pp.252-259
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• 2001

Computational study has been performed to observe the flow characteristics of combustion chamber for geometrical modification in municipal solid waste incinerator. A series of geometrical modification has been carried out as an attempt to reduce the size of recirculation zone, to obtain uniform flow field in the secondary combustion chamber and to improve the mixing of combustion gas. Two dimensional non-reacting turbulent flow has been studied as the first step to get such goals and the result of design optimization is presented. In addition, three dimensional non-reacting and reacting flow analyses were performed to verify the validity of two dimensional approach.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.299-302
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• 2009

The objective of the present study is to analyze the transient flow through theejector system with the help of a computational fluid dynamics (CFD) method. An attempt is made to investigate the interesting and conflicting phenomenon of the infinite entrainment into the primary stream without an infinite mass supply from the secondary chamber. The results obtained show that the one and only condition in which an infinite mass entrainment can be possible in such types of ejectors is the generation of a re-circulation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium of pressures at the onset of the recirculation zone. A steady flow in the ejector system is valid only after this point.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.574-579
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• 2000

In this study. an off-design performance prediction program for centrifugal pumps is developed. To estimate the losses in an impeller flow passage, two-zone model and two-element in series(TEIS) model are used. At impeller exit. the mixing process occurs with an increase in entropy. In two-zone model. there are both primary zone and secondary zone for an isentropic core flow and an average of all non-isentropic streamtubes respectively. The level of the core flow diffusion in an impeller was calculated by using TEIS model. While internal losses in an impeller an automatically estimated by using the above models, some empirical correlations far estimating external losses. far example, disk friction loss, recirculation loss and leakage loss are used. In order to analyze the vaneless diffuser flow. the momentum equations for the radial and tangential directions are used and solved together with continuity and energy equations.

• Journal of Advanced Marine Engineering and Technology
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• 제25권3호
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• pp.637-643
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• 2001

Two-phase flow in a combustion chamber is experimentally analyzed according to the five different conditions in the Reynolds numbers of $1.02{\times}10^4$. As the height difference between the primary and secondary jets increases, the secondary has a little less effect on the primary one in the case on the same height difference, the primary jet is affects as the velocity of th secondary on increase. The primary-jet flow field cause the particle concentration since is controlled by the velocity of secondary jet, the height difference, and the angle of primary jet in the test section.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.86-92
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• 2000

Two-phase flow in a combustion chamber is experimentally analyzed according to the five different conditions in the Reynolds number of $1.02{\times} 10^4$ As the height difference between the primary and secondary jets increases the secondary has a little effect on the primary. In the case of the same height difference the primary jet is affected as the velocity of secondary increases. The primary-jet flow field causes the particle concentration since the particle stagnation phenomena appear in the recirculation zone. The particle concentration is controlled by the velocity of secondary jet the height difference and the angle of primary jet in the test section.