• 한국자동차공학회논문집
• /
• 제1권1호
• /
• pp.32-40
• /
• 1993

Flow fields in model engine cooling passages are studied numerically by using TURBO-3D program, a finite volume based 3-D turbulent flow program adopting a general body fitted coordinate system. The effects of exit position on mass flow rate at each gasket hole are examined for a model cooling passage in order to understand the flow distribution inside the water jacket. The results of the present study can be applied to the design of high performance, high reliability engine.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 추계학술대회 논문집
• /
• pp.496-500
• /
• 1996

An air flow measurement device is proposed. The thermal characteristic of a semiconductor element is adopted as a cooling parameter of thermal convection rate. The difference between forced convection and natural convection of two Zener diodes results enough difference in temperature. Experiment at various air flow conditions shows the measuring capability of the air flow in a duct. This measuring device has some merits, such as a reliability n hard field condition, simple circuit for signal processing, small volume of the element, less air flow resistance, independance of various ai temperature. The experimental result shows that it is an exact and usefull air flow measurement device.

• 한국시뮬레이션학회논문지
• /
• 제7권2호
• /
• pp.17-32
• /
• 1998

The flow fields in Gas Bubble Driven Circulation Systems were numerically analyzed. In various gas flow rate and bubble size, the flow characteristics were predicted. Eulerian-Eulerian approach was used for the formulation of both the continuous and dispersed phases. The modification of the general purpose computer program PHOENICS code was employed to predict the mean flow fields, turbulent characteristics, gas dispersion, volume fraction. The predicted shows very satisfactory agreement with experimental results for all regions of ladle. The results are of interest in the design and operation of wide variety of material processing.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.998-1003
• /
• 2003

Ultrasonic flow metering(UFM) technology is being received much attention from a variety of industrial fields to exactly measure the flow rate. The UFM has much advantage over other conventional flow meter systems, since it has no moving parts, and offers good accuracy and reliability without giving any disturbances to measure the flow rate, thereby not causing pressure losses in the flow fields. In the present study, 3-dimensional, unsteady, compressible Navier-Stokes equations are solved by a finite volume scheme, based upon the second order upwind scheme for spatial derivatives and the multi-stage Runge-Kutta integral method for time derivatives. In order to simulate multi-path ultrasonic flow meter, an excited pressure signal is applied to three different locations upstream, and the pressure signals are received at three different locations downstream. The mean flow velocities are calculated by the time difference between upstream and downstream propagating pressure signals. The obtained results show that the present CFD method simulates successfully ultrasonic meter gas flow and the mean velocity measured along the chord near the wall is considerably influenced by the boundary layers.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
• /
• pp.74-79
• /
• 2011

This study was accomplished to evaluate the performance of Multi Effect Distillation(MED) for solar thermal desalination system. It was designed Multi effect distillation with $3m^3/day$ capacity and Shell&Tube type heat exchanger. Also, The effective heat transfer of Shell&Tube heat exchanger was used Cu(90%)-Ni(10%) corrugated tube. The parameters relating to the performance of Multi Effect Distillation are known as hot water flow rate. The experimental conditions for each parameters were $18^{\circ}C$ for sea water inlet temperature, $6m^3/hour$ sea water inlet volume flow rate, $75^{\circ}C$ for hot water inlet temperature, 2.4, 3.6, and $4.8m^3/hour$ for hot water inlet volume flow rate, respectively. The results are as follows, Development for Multi effect distillation was required about 40kW heat and 35kW cooling source to produce $3m^3/day$ of fresh water. And, Performance ratio of Development Multi effect distillation was about 2.0191.

• 한국태양에너지학회 논문집
• /
• 제31권1호
• /
• pp.1-7
• /
• 2011

This study was accomplished to evaluate the performance of Multi Effect Distillation(MED) for solar thermal desalination system. It was designed Multi effect distillation with $3m^3$/day capacity and Shell&Tube type heat exchanger. Also, The effective heat transfer of Shell&Tube heat exchanger was used Cu(90%)-Ni(10%) corrugated tube. The parameters relating to the performance of Multi Effect Distillation are known as hot water flow rate. The experimental conditions for each parameters were $18^{\circ}C$ for sea water inlet temperature, $6m^3$/hour sea water inlet volume flow rate, $75^{\circ}C$ for hot water inlet temperature, 2.4, 3.6, and $4.8\;m^3$/hour for hot water inlet volume flow rate, respectively. The results are as follows, Development for Multi effect distillation was required about 40kW heat and 35kW cooling source to produce $3m^3$/day of fresh water. Based on the results of this study, It makes possible to secure economics of desalination system with solar energy which is basically needed development of high efficiency fresh water generator.

• Structural Engineering and Mechanics
• /
• 제62권2호
• /
• pp.163-170
• /
• 2017

This study presents a particle-wall filtration model for predicting the particle motion behavior in a typical rotational flow field-filtration in blower system of cooker hood. Based on computational fluid dynamics model, air flow and particles has been simulated by Lagrangian-particle/ Eulerian-gas approaches and get verified by experiment data from a manufacturer. Airflow volume, particle diameter and local structure, which are related to the particle filtration has been studied. Results indicates that: (1) there exists an optimal airflow volume of $1243m^3/h$ related to the most appropriate filtration rate; (2) Diameter of particle is the significant property related to the filtration rate. Big size particles can represent the filtration performance of blower; (3) More than 86% grease particles are caught by impeller blades firstly, and then splashed onto the corresponding location of worm box internal wall. These results would help to study the micro-particle motion behavior and evaluate the filtration rate and structure design of blower.

• 대한기계학회논문집A
• /
• 제20권3호
• /
• pp.933-944
• /
• 1996

In this paper, two new techniques, the pattern filling and the refined flow field regeneration, based on the finite element method and Eulerian mesh advancement approach have been developed to analyze incompressible viscous flow with free surfaces. The gorerning equation for flow analysis is Navier-Stokes equation including inertia and gravity effects. The penalty and Newton-Raphson methods are used effectively for finite element formulation. The flow front surface and the volume inflow rate are calculated using the pattern filling technique to select an adequate pattern among five filling patterns at each quadrilateral control volume. By the refined flow field regeneration technique, the new flow field which renders better prediction in flow surface shape is generated and the velocity field at the flow front part is calculated more exactly. Using the new thchniques to be developed, the dam-breaking problem has been analyzed to predict flow phenomenon of fluid and the predicted front positions versus time have been compared with the reported experimental result.

• KSBB Journal
• /
• 제4권2호
• /
• pp.177-184
• /
• 1989

항생물질 발효액의 균사체 분리에 있어서 Modified regenerated cellulose 막을 이용한 Cross-flow filtration으로 높은 Flux를 얻을 수 있었다. 막분리시 가급적 높은 유속, 높은 온도, 특정 균사체농도(약 20% PMV)에서 높은 Flux를 보여주었으며 Fouling 정도는 균사체 농도가 높을수록 또한 유속이 낮을수록 심각한 것으로 나타났다. 발효액을 농축 분리할 때의 Flux profile은 1단계 Sublayer형성에 의한 급속감소, 2단계 평형, 3단계 Fouling에 의한 급속감소의 세 구간으로 나눌 수 있었으며 Diafiltration의 적용으로 3단계의 Flux 감소 현상을 현저히 완화시킬 수 있었다. 한편 Diafiltration에 의한 항생물질 회수시 초기부터Diafiltration하는 것보다는 특정 PMV까지 농축시킨 후 Diafiltration하는 경우에 작업시간과 여액의 Volume을 최소화 할 수 있었으며 본 실험에서는 98%의 회수율을 얻기 위해서 Di-afiltration을 시작하는 Optimum PMV는 20%였다.

• 대한교통학회지
• /
• 제26권4호
• /
• pp.229-239
• /
• 2008

기존의 고속도로 돌발상황 검지 알고리즘들은 돌발상황 발생시 혼잡이 발생하는 교통류상황을 전제로 하여 개발된 것으로 교통량이 낮아 혼잡이 발생하지 않은 경우에는 모형의 성능이 유지된다고 보기 어렵다는 단점이 있다. 따라서 본 연구에서는 3가지 교통류 유형 특성을 우선적으로 분석하고 속도변수를 기준으로 수정교통량-점유율 관계도를 생성한다. 또한, 제안된 새로운 관계도를 이용하여 교통류 상태를 5개 영역으로 구분하고 돌발상황을 검지하는 알고리즘을 개발하고 실제 고속도로 검지기 자료를 가지고 평가하는 것을 목적으로 한다. 수정교통량-점유율 관계도를 이용한 영역구분은 기존 McMaster 알고리즘에서 보여주었던 부정확한 영역구분으로 인해 낮은 교통량 상태에서 돌발상황 검지가 어렵다는 단점을 개선할 수 있을 것이다. 본 연구에서는 개발된 알고리즘의 평가결과로서 검지율과 오보율 등의 성능지표 측면에서 기존 McMaster 알고리즘과 비교평가하여 제시하고자 한다.