• Journal of Biosystems Engineering
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• 제29권5호
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• pp.433-440
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• 2004

Worldwide consumption of vegetable soybean has been increasing recently, but in the process of vegetable soybean production, threshing and separation work accounts fur about $80\%$ of overall labor. Therefore, developing of the vegetable soybean thresher is necessary to reduce the cost of labor. The main objective of this study is to acquire the basic in-formations for design of the vegetable soybean thresher which is suitable for domestic circumstances. We made the experimental system to investigate the threshing and separating performance at the several speeds of threshing cylinder and separating blower according to the kinds of threshing tooth. The result are as follows; Threshing performance of vegetable soybean thresher was shown as the best in case the threshing tooth made of rubber which has the 80 of Shore hardness was used at the circumference speed of cylinder of 5.8$\~$8.1m/s. Also separating cleaning performance of vegetable soybean thresher was shown as the best at more than 1,300 rpm of blower speed and $60\~80\%$ of opening ratio of suction port.

• KIEAE Journal
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• 제13권3호
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• pp.79-89
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• 2013

The purpose of this study is to evaluate the airtightness performance of New Han-ok and to supply fundamental data for standards establishment. Air leakage testings were accomplished by means of blower door test in 26 bedrooms of 16 Han-oks located in Jeonnam happy villages. Followings are results. 1) Air change per hour at 50 Pa(ACH50) is located on 8.42~78.38. 2) No correlation between ACH50 and volumes, floor area, above grade surface area. 3) The more wood structural elements are exposed, attached spaces, wooden sliding and casement windows, the less airtightness performance. 4) An Airtightness with ACH50/20(NL, Normalized leakage) is located on 0.42~3.92 and building leakage class following F(4%), G(11%, sufficiently leaky, No need mechanical ventilation), H(4%, Need of cost-effective tightening), I(31%), J(50%) by a single-story house the normalized leakage of ASHRAE.

• 항공우주시스템공학회지
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• 제13권1호
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• pp.29-37
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• 2019

본 논문에서는 높은 풍량을 갖는 임펠러 형상 최적 설계를 위하여, 블레이드 형상이 임펠러의 성능에 미치는 영향을 파악하였다. 먼저 임펠러 성능에 큰 영향을 미칠 것이라 판단되는 블레이드 개수, 각도, 길이를 설계변수로 선정하고, 실험계획법에 의거하여 정한 설계 수준에 따라 각기 다른 27가지 임펠러 형상을 설계하였다. 그리고 블레이드 형상 변화에 따른 임펠러 성능변화를 예측하기 위해 ANSYS CFX로 유동해석을 진행하였다. CFD 결과, 블레이드 개수 50개, 각도 $6^{\circ}$, 길이 5 mm 조합의 임펠러 형상에서 가장 높은 풍량이 발생되었다. 마지막으로 해석 결과를 바탕으로 3D프린터를 이용하여 기존 임펠러 형상과 시험군 임펠러 형상을 제작하였고, 블로워의 토출구에서의 유량을 측정하여 CFD 결과와 비교하는 검증 실험을 진행하였다.

• International Journal of Fluid Machinery and Systems
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• 제5권3호
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• pp.117-125
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• 2012

In the present experimental study, the authors try to clarify the characteristics of the flow around and inside a cross-flow impeller in a typical geometry, over a wide parameter range of an aspect ratio $L/D_2$. In order to eliminate the complicated casing factors, the impeller rotates in open space without any casings. As a result, by using hot wire anemometer measurements and by conventional flow visualisations with a particle image velocimetry technique, the authors show that both the outflow rate and the maximum vorticity attain the maximum for $L/D_2$ = 0.6. In order to investigate the aspect-ratio effect, we further reveal minute fluctuating pressures on an impeller end wall for a singular $L/D_2$ = 0.6. Especially in these pressure measurements, the eccentric vortex is prevented to revolute by the insertion of a tongue, in order to consider the spatial structure of flow more precisely.

• 토지주택연구
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• 제11권3호
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• pp.69-74
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• 2020

Since the design Standard for Energy Conservation in Building was implemented in 2008 for the first time, building elements such as window and door should satisfy the minimum criteria to apply for a building. Though its regulation does not cover the whole building yet, recent demand to reduce energy consumption in building sector grows rapidly year by year and also draws a lot of interest to ensure the whole building level. For example, a Zero energy building, one of low-energy buildings, requires a customized solution to resolve the air leakage issue to meet the standards in achieving the high level of air tightness. In this study, six non-residential buildings were tested by fan pressurization method to observe the air tightness of whole building to suggest the construction guideline for air tightness of low-energy building. Five out of six tested buildings showed 0.27 to 1.16 h^-1 of number of air changes except one community center. These buildings were carefully constructed not only for building planning but also for parts where there was a concern of air leakage, thereby securing high levels of air-tightness. The construction skills were developed as a checklist to manage and supervise the construction site. It is our suggestion to use this checklist at construction sites for ZEB with the high level of air-tightness.

• 해양환경안전학회지
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• 제29권6호
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• pp.697-703
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• 2023

최근 대기오염으로 인한 환경오염을 줄이고자 국제 산업계의 노력의 일환으로 국제해사기구(IMO)의 규제 발효등으로 이어지고 있다. IMO는 EEXI,EEDI,CII 등 선박에서 나오는 대기오염을 줄이기 위해 각종 규제를 발효시키고 선박에서 소모되는 전력을 줄여 에너지를 절약하는 방안을 추진하고 있다. 선박에서 사용되는 전력의 대부분은 전동기가 차지한다. 선박에 설치된 전동기 중 큰 부하를 차지하는 기관실 송풍기는 수요와 관계없이 정속운전으로 운전하기 때문에 주파수제어를 통한 에너지절감을 기대할 수 있다. 본 연구에서는 발전기의 과급기에 연소공기를 공급하는 발전기 송풍기의 전동기 주파수를 제어하여 에너지 절감에 대한 실효성을 입증하였다. 송풍기 주파수 입력에 따른 과급기출구 온도의 출력 데이터를 기반으로 시스템을 모델링하고, 과급기 출구온도를 목표값으로 하여 주파수를 제어하는 PI 제어계를 형성하여 과급기 설계기준 출구온도를 유지하면서 송풍기의 주파수 제어를 통해 연간 15,552kW 전력소모량을 절감하였다. 송풍기 팬 주파수 제어를 통한 에너지절감액의 유효성은 하계(4월~9월) 및 동계(3월~10월) 기간동안 검증하였으며 이를 토대로 실습선의 연간 6,091천원의 유류비 절약과 이산화탄소 8.5Ton, SOx 2.4kg, NOx 7.8kg의 대기오염물질 저감을 달성하였다.

• 한국산학기술학회논문지
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• 제19권2호
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• pp.117-124
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• 2018

본 논문은 KM-SAM 다기능레이더용 축류형 송풍기에 대한 국산화 개발 내용을 서술하고 있다. KM-SAM 다기능레이더는 중/저고도 위협표적을 탐지 및 추적하는 핵심 장비로 지속적인 외부 환경의 영향을 받는다. 이러한 장비의 원활한 운용을 위해서는 내부 온도 및 습기를 조절하는 송풍기가 필수적이며, 현재까지 다기능레이더용 송풍기는 전량 해외업체 수입에 의존하고 있다. 이러한 문제점 해결을 위해 국산화 개발 연구가 제안되었으며, 국산화 개발은 원제작사와 체계장비 규격 등 관련 기술자료 검토를 통한 요구도 분석, 시제품 설계, 성능시험 및 환경시험을 통한 설계요구조건 검증 등을 포함한다. 송풍기는 가이드 베인이 있는 축류형 팬으로 구성되고 모터는 최대 970 CFM의 풍량과 4.8 IWG 풍압을 발생하도록 제작되었다. 또한 신뢰성 있는 데이터 획득을 위해 AC 전원 공급기, 팬 성능시험기 및 데이터 수집 장비를 구축하여 시험평가를 수행하였으며, 시제품 모두 수입품 대비 동등수준 이상의 설계 요구도 검증이 이루어졌다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.924-926
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• 2001

This paper presents the characteristics of current harmonics and torque ripple of Brushless DC motor, which is developed the fan blower of vehicles, according to permanent magnet shape input voltage wave form. To investigate the torque ripple and the phase current harmonics, these characteristics is analysed and compared the experimental results. In the process of analysis, FEM is introduced and computed a transient state torque of BLDC with a sinusoidal and a PWM wave voltage.

• 한국생산제조학회지
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• 제22권2호
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• pp.304-309
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• 2013

In chemical, medical or biology laboratories Fume Hoods are basic facilities which can protect researchers from dangerous gas as blowing the contaminated air outside. After the air inside the laboratory room is sucked into the hume hood, then, it is blew out by a fan rotated by an AC induction motor. In addition, a damper controls the inside opening of a duct, which the air flows through. The face velocity, air velocity through the front door, have to be kept constant as the set value even though the opening of the door is varied. However, conventional fume hood used to be operated by operator's manual switches. So that, in this paper an automatic control system is developed which controls the face velocity by adjusting the rotating speed of the blow motor and the opening of the damper. Experiments show that this developed system can be used at such laboratories.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.316-319
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• 2002

Injection mold is a manufacturing process used to produce parts of complicated shape at a low cost. Many factors affect the quality of injection molded part during injection molding process. A study on the optimization of injection mold is progressed by using a simulation software like Moldflow. Filling, packing and cooling phases of injection molding processes are analyzed according to the mold design considering the shrinkage of molded part, the degree of filling rate and the wearing of a mold. Taguchi method is applied to analyze the significance of processing parameters and the dynamic characteristics according to the variation of processing parameters. From the results, the mold temperature and packing pressure influenced strongly the shrinkage of injection molded part.