태양열 계간 축열조 내부 열성층화에 대한 탱크 종횡비 영향 연구

김성근(Seong Keun Kim),정성용(Sung Yong Jung) 한국가시화정보학회 2020 한국가시화정보학회지 Vol.18 No.2

In this study, we numerically investigated the thermal stratification in solar seasonal thermal storage tanks. The vertical in/out flows were unsuitable for the thermal stratification in a large scale. The effect of an aspect ratio (AR) on the thermal stratification was investigated. When AR was less than 2, water adheres and flows along the upper wall due to buoyance and the surface effect. Thereafter, hot water flows down and a large scale vortex occurs in entire tank. For high AR, jet flows ejected from the inlet pipe impinges to the opposite wall and splits. The divided flows create two vortex flows in the upper and lower regions. These different flows strongly influence temperature and thermal stratification. The thermal stratification was evaluated in terms of the thermocline thickness and degree of stratification. Compared to ARs, the maximum degree of stratification was obtained with AR of 5 having the minimum thermocline thickness.

농업용 드론 분사 노즐 위치의 최적화

김성근(Seong-Keun Kim),류재웅(Jae-Ung Ryu),장종민(Jong-Min Jang),정성용(Sung Yong Jung) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

Drones, which are autonomous flying machines range from large unmanned aerial vehicles (UAVs) flying thousands of kilometers to small vehicles flying in confined spaces, are utilized in carrying out a variety of operations including military tasks, search-and-rescue missions, reconnaissance, and load transportation. Much of the research related to these UAVs has concentrated on the autonomous control of UAV’s position, altitude, and attitude. Recently, the endurance is another issue in commercial applications. In addition to the control and endurance, a spray system is also important for an agricultural use. Although the spraying system has been well developed for agriculture, the design for an installation of the spraying nozzle on drones depends on designer’s experiences. In this study, a simulated spraying system having two blades and two nozzles was constructed to provide useful data for the design. Uniform spraying is required in an agricultural application, and the distance between nozzles is a major parameter for the uniformity of spraying. The spraying performance was measured with various nozzle distances from 0.8 to 1.2 m and it was evaluated by calculating variation coefficient with a digital image processing. The effective spraying width was 1622 m at the nozzle distance of 0.8 m. This study would be useful for a design of agricultural drones.

초음파와 UV에 의한 페놀 분해 특성에 관한 연구

김성근(Seong Keun Kim),손현석(Hyun Seok Son),임종권(Jong Kwon Im),김지형(Jee Hyeong Khim),조경덕(Kyung Duk Zoh) 大韓環境工學會 2010 대한환경공학회지 Vol.32 No.7

본 연구에서는 난분해성 물질인 페놀을 초음파와 자외선 광선(UV-C)을 이용하여 분해를 알아본 연구이다. 초음파,자외선,그리고 초음파와 자외선의 결합반응에서 주파수,온도,용액의 pH, 아르곤가스 Purging, 그리고 자외선 세기의 효과를 조사하였다. 초음파 단독 반응의 경우 pH 4, 5℃,35 kHz에서 360분 동안 30% 의 페놀의 최적 분해효율을 보였다. 자외선 (UV-C) 단독 반응의 경우 19.3 mw/㎠의 자외선 세기와pH₄, 5℃에서 60분에 100%의 페놀 분해 효율을 보였다. 이에 반하여 초음파와 자외선의 결합반응에서는 동일 조건에서 45분 동안 페놀이 모두 제거되었다. 초음파와 자외선의 결합 반응에서 페놀은 자외선 강도가 7.6 mW/㎠일 때 360분 안에 19.3 mW/㎠일 때는 45분 안에 완전히 분해되었고, 각각의 분해 속도 상수는 17.3x10-3 min-l 와 138.lx10-3 min-1이었다. 페놀의 분해반응에서 OH 라디칼의 scavenger로 작용하는 메탄올을 첨가하는 실험을 한 결과 초음파와 자외선 광선의 조합반응에서 페놀 분해의 주요인자는 OH 라디칼이라는 것을 확인할 수 있었다. 페놀 분해의 반응효율 비교는 초음파+광반응 조합반응〉자외선 광선 단독 반응〉초음파 단독 반응과 같이 확인되었다. This study investigated the degradation of phenol using sonication and/or UV-C. The effects of frequency, temperature, pH in solution, argon purging, with UV intensity were estimated in sonication-only, UV-only, and the combined reaction of sonication with UV. The optimum condition for degrading phenol in the sonication-only reaction was 35 kHz, 5℃, and pH 4. As this condition approximately 30% degradation of phenol was achieved within 360 min. However, phenol in the UV-only at 19.3 mw/cm2 under the same condition was completely degraded within 60 min. In the combined system of sonication with UV, the degradation of phenol was well fitted to first-order rate model, and phenol was completely degraded within 360 min and 45 min at UV intensity of 7.6 mW/cm2(17.3×10-3 min-1) and 19.3 mW/cm2(138.1×10-3 min-1), respectively. Adding methanol, as a radical scavenger, in the phenol degradation in the sonication reaction indicates that OH radical is a major factor in the degradation of phenol. The order of degradation efficiencies of phenol was in the order of as follows; combined reaction of sonication with UV > UV-only > sonication-only.

PEM 수전해의 성능 향상을 위한 flow channel 설계

김성근(Seong Keun Kim),문종운(Jong Woon Moon),정성용(Sung Yong Jung) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11

PEMWE (proton exchange membrane water electrolyzer) uses a polymer electrolyte membrane as an electrolyte and requires high manufacturing costs because precious metals are used as catalysts. Accordingly, many studies are being conducted to increase the hydrogen production efficiency of PEMWE. A general PEMWE uses a titanium mesh as a PTL (porous transport layer) for a constant current supply. However, the mesh disturbs the water contaction to the electrolyte membrane because the produced gas during the chemical reaction is not smoothly discharged. Therefore, this study compared the performance with various flow channel designs to improve gas reduction and water supply. Three types of flow channels, including serial type, parallel type, and dual-channel type, were designed and compared their performances. Water was supplied at 15 mL/min, 90 °C, and performances were measured with current densities ranging from 0 A/cm² to 0.8 A/cm². At a current density of 0.8 A/cm², the basic type was 3.80 V, the serial type was 3.13 V, the parallel type was 3.39 V and the dual-channel type was 3.27 V. The serial type has the best performance because gas discharge is more active than other flow channels.

수산물 식재료를 활용한 섬 음식관광 활성화 방안

김성근 ( Kim Sung-keun ),김보성 ( Kim Bo-seong ) 한국도서(섬)학회 2021 韓國島嶼硏究 Vol.33 No.1

관광자원은 관광 주체인 관광객으로 하여금 관광 동기나 관광의욕을 일으키게 하는 관광대상이다. 이러한 관광자원의 문화원형 분류 중 음식(농수특산물 포함)은 최근 급증한 ‘맛집 탐방’,‘먹방’,‘쿡방’등의 방송예능프로그램과 SNS상의 1인 미디어로 인해 주목받고 있다. 이런 상황을 고려하여 본 연구는 수산물 식재료를 활용하여 섬 음식관광 활성화 방안을 제시하는 것을 목적으로 하였다. 즉, 섬 관광과 어촌 지역 경제 활성화 및 지역주민의 삶의 질 향상 등 다양한 목적을 달성하고자 해당 지역의 수산물 식재료를 활용한 섬 음식관광상품 개발을 제안한 것이다. 그 결과, 먹방과 쿡방을 활용하는 전략적 접근의 필요성, 섬 음식관광 활성화를 위한 외국인 관광객 유치 전략 추진, 해양관광객의 어촌관광 동기분석에 따른 섬 음식관광활성화 전략 추진, 섬 및 어촌 지역 특정 수산물에 의한 지역브랜드 전략의 필요성을 제안하였다. 섬 관광 활성화를 추진해야 하는 우리나라 어촌지역의 섬 음식관광은 아직까지 시작단계에 머무르고 있다. 이는 섬 음식관광에 대한 이해 부족뿐만 아니라 수산물 식재료를 활용한 음식관광자원 및 그 특성에 대해 명확한 규명이 선행되지 않았기 때문이다. 그냥 단순하게 지역별 특화되지 않은 일반적인 수산물을 식재료로 활용한 음식들이 소개되고 있다. 또한 어촌지역중심의 특징 없고 유사한 음식만이 방송과 언론, 및 SNS 등을 통해 도발적·과시적으로 소개되거나 일부 몇몇 연구자들에 의해 분석되고 있다. 최근 한류(특히 대장금)의 영향과 슬로푸드(Slow Food) 열풍으로 인하여 우리나라 전통문화인 제철음식과 로컬 푸드(Local Food)가 세계각국의 잠재관광객들에게 관심과 애정을 받고 있다. 그러나 이러한 좋은 여건을 적극적으로 고려한 우리나라의 우수한 수산물 식재료를 활용한 외래 관광객 유치를 극대화 할 수 있는 섬음식관광에 대한 전략 개발이 미약한 실정이다. 이에 본 연구는 신한류 콘텐츠인 수산물 식재료를 활용한 섬 관광산업 활성화 및 다변화된 섬 관광목적지 개발, 그리고 지역경제 활성화를 위한 수단으로서의 섬 음식관광 활성화 방안을 모색하고자 한 것이다. 이를 위해서 단행본, 선행연구, 정부 간행물, 신문기사 등 문헌연구 등을 통해 수산물 식재료 활용 섬 음식관광 활성화 방안을 도출하고 제안하였다. 그리고 수산물 식재료 활용 섬 음식관광 활성화를 위해 필요한 정책을 제언하였다. 이는 최근 정부의 섬관광 활성화와 어촌관광 활성화 정책에 힘입어 섬과 어촌이 새로운 관광지로 부상하고 있다는 점에서 본 연구의 의의를 찾을 수 있다. 특히, 섬 관광과 어촌관광은 고유의 해양자연자원을 활용해 관광·레저·스포츠 등의 여가활동을 즐기는 것 외에도 축제, 특산물, 음식 등의 지역문화를 담은 인문관광자원도 포함한다. 이로 인해 해양레저가 가능한 어항이나 수산자원과 해양자원이 풍부한 어촌공간에는 이미 많은 해양관광객이 찾아오고 있다. 하지만, 어촌주민의 입장에서 보면 해양관광자원을 발굴하고 섬 및 어촌 지역문화를 관광상품으로 만들어 시장에 내놓아야만 소득이 생긴다는 점에서 어렵다는 것이다. 특히, 음식관광상품을 개발하는 일은 더욱더 어렵다는 점에서 전략적인 접근이 필요한 시점이다. Tourism resources are tourism targets that motivate tourists. Among the cultural archetypes of tourism resources, food is attracting attention due to the recent rapid increase in broadcasting entertainment programs such as “famous restaurants”, “mokbang(Eating broadcasts)”, and “cookbang(cooking broadcasts)” and individuals on social media. Therefore, the purpose of this study was to suggest a plan to activate island food tourism by using seafood ingredients. In other words, it attempted to achieve various purposes such as island tourism, revitalizing the local economy in fishing villages, and improving the quality of life of local residents. Through this, it was proposed to develop island food tourism products using the seafood ingredients of the island regions. As a result, first, the necessity of a strategic approach using food and cooking rooms, second, the promotion of strategies for attracting foreign tourists to revitalize the island food tourism, third, the promotion of strategies for activating island food tourism according to the analysis of motives for fishing village tourism of marine tourists, and fourth, the necessity of a regional branding strategy based on specific fishery products on islands and in fishing villages was proposed. Island food tourism in fishing villages in Korea, which must promote island tourism, is still in its infancy. This is because not only the lack of understanding of island food tourism, but also the fact that the food tourism resources using seafood ingredients and their characteristics have not been clearly identified. Foods that simply use general aquatic products that are not specialized for each region are being introduced. In addition, this is because only similar foods, which are not characterized by fishing villages, are introduced provocatively and showily through broadcasting, media, and social media Korean food is gaining popularity due to the recent influence of the Korean Wave (especially Daejanggeum) and the slow food craze. The traditional cultures of seasonal food and local food are attracting attention and affection from potential tourists from around the world. However, there are areas that have not actively utilized these good conditions. The development of strategies for island food tourism that can maximize the attraction of foreign tourists using Korea's excellent seafood ingredients is inadequate. Accordingly, this study promoted the activation of the island tourism industry and the development of diversified island tourism destinations using seafood ingredients, which are part of the new Korean Wave content. In addition, it sought to revitalize island food tourism as a means to vitalize the local economy. To this end, literature studies such as books, previous studies, government publications, and newspaper articles were conducted. Through this, a plan to revitalize island food tourism using seafood food materials was derived and proposed. In addition, it suggested policies necessary to revitalize island food tourism using seafood ingredients. The significance of this study can be found in that islands and fishing villages are emerging as new tourist destinations thanks to the recent government's policy of promoting island tourism and fishing village tourism.

PTL 구조가 PEM 수전해 성능에 미치는 영향

김성근(Seong Keun Kim),정성용(Sung Yong Jung) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.5

Flow channel 설계를 통한 PEM 수전해의 성능 향상 연구

김성근(Seong Keun Kim),정성용(Sung Yong Jung) 대한설비공학회 2022 대한설비공학회 학술발표대회논문집 Vol.2022 No.11

디퓨저 타입 계간 축열조 내부 열성층화에 대한 입구 유속 및 탱크 종횡비 영향 연구

김성근(Seong Keun Kim),정성용(Sung Yong Jung) 한국가시화정보학회 2021 한국가시화정보학회지 Vol.19 No.3

In this study, the thermal stratification in solar seasonal thermal storage tanks was numerically simulated. The effects of the aspect ratio (AR) and inlet velocity on the thermal stratification in the diffuser type heat storage tank were investigated. The temperature distributions inside the tank were similar with velocity fields. Jet flows from opposite diffusers encountered each other at the tank center region. Thereafter, the downward flows occurred, and this flows strongly affected the thermal stratification. When AR was smaller than 2, these downward flows influenced a further distance and enhanced mixing inside the tank. Thermal stratification was evaluated by thermocline thickness and degree of stratification, and AR of 3 had the highest degree of stratification. The inlet velocity effect was expressed with the ratio (Re/Ri) of Reynolds and Richardson numbers. The second-order approximation was found for the relationship between the thermocline thickness and log Re/Ri.

PTL 구조가 PEM 수전해의 전기화학적 성능에 미치는 영향

김성근(Seong Keun Kim),정성용(Sung Yong Jung) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.6

하수처리 : 초음파와 UV를 이용한 페놀 분해 반응에 관한 연구

김성근 ( Seong Keun Kim ),임종권 ( Jong Kwon Im ),조경덕 ( Kyung Duk Zoh ) 한국물환경학회 ( 구 한국수질보전학회 ) 2009 공동 추계학술발표회 Vol.2009 No.-