• 유기물자원화
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• 제28권4호
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• pp.69-75
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• 2020

본 연구에서는 원형침전지의 고액분리 효율을 향상시키기 위해 응집제 없이 lab scale 침강장치에 교반속도(rpm)와 baffle 각도를 조절하여 생응집(bio-flocculation) 실험을 수행하였다. 피드 웰(feed wall)부분을 개량하여 baffle를 설치하고 각도(10°)를 고정한 후 각각의 교반속도(0.0rpm, 0.6rpm, 1.2rpm) 변화에 따른 실험 결과 교반속도 0.6ppm에서, 농축효율이 2.0%, 유출수(SS 농도) 제거효율은 7.8% 상승되는 것으로 분석되어 교반속도에 따른 슬러지의 생응집 효율 향상을 확인할 수 있었다. 또한, 침강장치 baffle의 각도를 변화시켜 슬러지 침강특성 영향을 분석한 결과 baffle 각도 20°에서 슬러지 계면층의 압축이 매우 높게 나타났다. 본 연구결과는 원형침전지의 침전 효율향상을 위한 기초 인자로 활용이 기대된다.

• Korean Chemical Engineering Research
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• 제62권2호
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• pp.191-199
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• 2024

A study was conducted on a tubular heat exchanger to improve its heat transfer rate by using a novel baffle plate design with discontinuous swirling patterns. The design consisted of perforated baffle plates with rectangular air deflectors positioned at varying angles. The tubes in the heat exchanger were arranged in a consistent alignment with the airflow direction and exposed to a uniform heat flux on their surfaces. Each baffle plate included sixteen deflectors inclined at the same angle and arranged in a clockwise pattern. This arrangement induced a swirling motion of the air inside a circular duct where the heated tubes were located, leading to increased turbulence and improved heat transfer on the tube surfaces. The spacing between the baffle plates was adjusted at different pitch ratios, and the Reynolds number was controlled within a range of 16,000 to 29,000. The effects of pitch ratios and inclination angles on the heat exchanger's performance were analyzed. The results indicated that using a baffle plate with rectangular deflectors inclined at 30° and a pitch ratio of 1.2 resulted in an average increase of 1.29 in the thermal enhancement factor.

• 동력기계공학회지
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• 제21권4호
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• pp.62-69
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• 2017

Because the moist foods like anchovy were appeared lower quality by hot air that occurred the lipid oxidation, the drying system by using the cold air has been used widely. This study has been carried out on the performance improvement according to arrangement angle of baffle and location of air duct in the cold air dryer. The main parameters in this study are the arrangement angles which are without, $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$, and the locations of air duct are without, front, center and back. For this study we have conducted the numerical analysis method using fluent in order to obtain the optimal condition of the drying performance. As the arrangement angle of baffle is increased, the relative humidity is proportionally decreased, the value at $40^{\circ}$ is 42.2% that indicate the reduction of about 4% than without it. After the air duct was installed, the decreased relative humidity is showed within 1%, therefore, the effect of air duct for improving the dry capacity is more large than the arrangement angle of baffle. Finally, we have obtained the optimal conditions that the arrangement angle is $40^{\circ}$ with the air duct for a cold air dryer.

• 동력기계공학회지
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• 제12권3호
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• pp.26-31
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• 2008

This experimental study investigates the local heat transfer enhancement characteristics and the associated frictional head loss in the rectangular channel with a single inclined baffle. Four different types of the baffle are used. The inclined baffles have the width of 19.8 cm, the square diamond of $2.55cm{\times}2.55cm$, and the inclination angle of 5o, and number of holes of up to 9. Reynolds number is varied between 23,000 and 57,000. Results show that the heat transfer and friction factor depend significantly on the number of baffle holes and Reynolds number. The friction factor decreases with increasing Reynolds number and the number of holes on the baffle. It is found that the heat transfer performance of baffle type II(3 hole baffle) has the best values.

• 천문학회지
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• 제33권3호
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• pp.165-172
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• 2000

A baffle system for an airglow photometer, which will be on board the Korea Sounding Rocket-III(KSR-III), has been designed to suppress strong solar scattered lights from the atmosphere below the earth limb. Basic principles for designing a baffle system, such as determination of baffle dimensions, arrangement of vanes inside a baffle tube, and coating of surfaces, have been reviewed from the literature. By considering the constraints of the payload size of the KSR-III and the incident angle of solar light scattered from the earth limb, we first determined dimensions of a two-stage baffle tube for the airglow photometer. We then calculated positions and heights of vanes to prohibit diffusely reflected lights inside the baffle tube from entering into the photometer. In order to evaluate performance of the designed baffle system, we have developed a ray tracing program using a Monte Carlo method. The program computed attenuation factors of the baffle system on the order of $10^{-6}$ for angles larger than $10^{\circ}$, which satisfies the requirements of the KSR-III airglow experiment. We have also measured the attenuation factors for an engineering model of the baffle system with a simple collimating beam apparatus, and confirmed the attenuation factors up to about $10^{-4}$. Limitation of the apparatus does not allow to make more accurate measurements of the attenuation factors.

• International Journal of Air-Conditioning and Refrigeration
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• 제16권2호
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• pp.70-76
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• 2008

The effects of the inclined perforated baffles on the distributions of the local heat transfer coefficients and friction factors for air flows in a rectangular channel were determined for Reynolds numbers from 23,000 to 57,000. Four different types of the baffle are used. The inclined baffles have the width of 19.8cm, the square diamond type hole having one side length of 2.55cm, and the inclination angle of $5^{\circ}$, whereas the corresponding channel width-to-height ratio was 4.95. Results show that the heat transfer and friction factor depend significantly on the number of baffle holes and Reynolds number. The friction factor decreases with increasing Reynolds number and the number of holes on the baffle, and the heat transfer performance of baffle type II (3 hole baffle) has the best value.

• Journal of Electrochemical Science and Technology
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• 제14권4호
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• pp.333-348
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• 2023

In this study, a 3D model of the proton exchange membrane fuel cell is established, and a new 3D baffle structure is designed, which is combined with the parallel flow field and then optimized by numerical simulation methods. The number of baffles and the cross-sectional trapezoidal base angle are taken as the main variables, and their impacts on the performance indexes of the cathode side are analyzed. The results show that the 3D baffle can facilitate the convection and diffusion mass transfer of reactants, improve the uniformity of oxygen distribution, enhance the drainage capacity, and make the cell performance superior; however, too small angle will lead to excessive local convective mass flux, resulting in the decrease of the overall uniformity of oxygen distribution and lowering the cell performance. Among them, the optimal number of baffles and angle are 9 and 58°, respectively, which improves the net output power density by 10.8% than conventional flow field.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.3014-3021
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• 2015

셀-튜브 열교환기는 다양한 크기와 유동형태로 쉽게 제작이 용이함으로 산업분야에 널리 이용된다. 본 연구에서는 열교환기의 열전달성능을 도모하고자 배플의 컷 방향, 배플의 경사각 및 배플의 회전각 등을 변경하여 ANSYS FLUENT v.14를 사용한 SST $k-{\omega}$ 난류모델을 적용하여 쉘 내부의 열전달률 및 압력강하 특성을 해석하였다. 그 해석결과로 배플의 컷 방향은 수평형 모델 A보다 수직형 모델 B 및 각도 $45^{\circ}$형 모델 C가 이 열전달성능이 향상되는 것으로 나타났다. 또한 배플의 경사각을 $10^{\circ}$로 적용한 경우와 배플의 회전각을 $0^{\circ}-90^{\circ}-180^{\circ}-270^{\circ}$로 배치한 모델 D의 경우가 열전달률 및 압력강하 특성이 우수한 결과를 나타냈다.

• 동력기계공학회지
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• 제15권6호
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• pp.22-26
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• 2011

A numerical simulation on the flow field was carried out on the cylindrical shell with baffles. The steady incompressible 3-D Navier-Stokes solution is obtained with the actual operational condition and geometry of the heat exchanger. The effect of the location of inlet and outlet on the cylindrical shell with baffle is investigated by varying flow rate. The angle between the location of In/Outlet and baffle cutting part is $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$, $150^{\circ}$ and $180^{\circ}$. The present results show that the pressure drop is dependent on Reynolds number in the inlet area and position of inlet and outlet; i.e., the pressure drop increases with increasing Reynolds number and the pressure drop decreases with increasing angle between baffle cutting part and position of inlet and outlet.

• Membrane and Water Treatment
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• 제8권5호
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• pp.423-435
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• 2017

Settling Basins are one of the most important and popular methods for removal of suspended sediments irrigation and drainage networks or power canals taking off from an alluvial river and wastewater treatment plant. Improving the performance and so increasing sediment removal efficiency of settling basins by an alternative method is necessary. In the present work, the effect of baffle and its angle of attack with the flow (${\theta}$) on the sediment removal efficiency is investigated by conducting a series of experiments on a straight canal with 8 m length, 0.3 m width and 0.5 m height and 3 m length of basin equipped with an adjustable glass baffle. A numerical analysis has been carried out using ANSYS Fluent 3D software (a general purpose computational fluid dynamics simulation tool) for three Froude numbers from the experiments. The numerical and experimental results were found to match reasonably well.