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개방형 지열시스템의 효율적 설계를 위한 영향인자에 대한 연구
박병학,전원탁,이보현,이강근,Park, Byeong-Hak,Joun, Won-Tak,Lee, Bo-Hyun,Lee, Kang-Kun 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.4
Open-loop groundwater heat pump (GWHP) system generally has benefits such as a higher coefficient of performance (COP), lower initial cost, and flexible system size. The hydrogeological conditions in Korea have the potential to facilitate the use of the GWHP system because a large number of monitoring wells show stable groundwater temperatures, shallow water levels, and high well yields. However, few studies have been performed in Korea regarding the GWHP system and the most studies among them dealt with Standing Column Well (SCW). Because the properties of the aquifer have an influence on designing open-loop systems, it is necessary to perform studies on various hydrogeological settings. In this study, the hydrogeological and thermal properties were estimated through various tests in the riverside alluvial layer where a GWHP system was installed. Under different groundwater flow velocities and pumping and injection rates, a sensitivity analysis was performed to evaluate the effect of such properties on the design of open-loop systems. The results showed that hydraulic conductivity and thermal dispersivity of the aquifer are the most sensitive parameters in terms of performance and environmental aspects, and sensitivities of the properties depend on conditions.
박병학,이희승,문일 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1
열통합된 연속식 증류탑에 대해 각 장치에서의 물질수지와 에너지 수지는 물론 비선형 Hydraulic 방정식과 열역학적 관계식을 고려해 상세 동적 모델링을 수행하였으며 연속/이산 변수가 혼합된 모델의 동적모시를 통해 계의 동특성을 연구하였다. 대상 공정은 벤젠과 톨루엔의 2성분계를 선택하였는데 모델링을 통해 1,062개의 미분대수 방정식으로 수식화하였다. 동적모사의 결과 증류탑을 구성하고 있는 각 장치에서의 온도, 압력, 조성 및 액상과 기상의 몰당 유속에 대한 동적거동의 수치적 해를 얻을 수 있었다. 본 연구의 특징은 에너지 절감을 위해 개조 설계된, 즉 열통합을 고려한 연속식 증류탑의 동적모사를 통해 기존의 연속식 증류탐과의 성능비교를 했다는 점이다. 공정의 개시운전에서 정상상태에 이르기까지. 그리고 제품의 생산이 시작되는 시점에서 또 다른 정상상태에 이르는 일련의 과정을 동적모사하여 열통합 증류공정이 기존의 증류공정보다 에너지 절감의 측면에서 효율이 높다는 것을 증명하였다. 이전의 연구에서는 정상상태 모사를 통한 검증은 있었으나 비정산 상태를 고려한 동적모사를 통한 검증은 이루어지지 않았다. 또한 증류탑 이외에도 재비기, 환류드럼, 펌프, 밸브, 디지털 제어기 등의 주변장치에 대한 동적모델링을 수행함으로써 전체 공정의 운전절차를 동적모사에 반영할 수 있도록 하였다. A rigorous dynamic modeling and dynamic simulation are performed to find the dynamic behaviour of a distillation column model including continuous/discrete variables, considering material balances, heat balances, nonlinear hydraulic equations and themodynamic correlations in all equipments. Target process of this study is a distillation column aimed at separating benzene and toluene. Through dynamic modeling, 1,062 differential algebraic equations are acquired. Numerical solutions of dynamic behaviour such as pressure, temperature, fraction and molar flow rate in liquid and vapor phase. The feature in this study is to compare the energy consumption of a conventional distillation column with that of a heat integrated distillation column using dynamic simulation method. This study verifies energy efficiency through dynamic simulation in series of start-up of processes. There are some verifications of a heat integrated distilation column in view of steady state simulation but no verification in view of dynamic simulation. Also, this study considers operating procedures of the process in dynamic simulation through modeling of all equipments such as reboilers, refluxdrums. pumps, valves, digital PI controllers etc.
박병학 여수대학교 1997 論文集 Vol.11 No.2
Applicability of the RNG κ-εmodel to the analysis of unsteady axisymmetric turbulent flow of a reciprocating engine including intake system is studied numerically. The predicted results using the RNG κ-εmodel are compared to these from the modified κ-εmodel and experimental data. Using the RNG κ-εmodel, the predicted axial and radial velocity at the valve exit and in-cylinder region show good agreements with the experimental data. The application of the RNG κ-εmodel seems to have some potential for the simulations of the unsteady turbulent flow within a port/valve-cylinder assembly over the modified κ-εmodel.
신제품개발을 위한 프론트로딩 요소 우선순위 도출 :자동차부품 설계단계 중심으로
박병학,옥영석,천동필,박세훈 한국산업경영시스템학회 2019 한국산업경영시스템학회지 Vol.42 No.4
The purpose of this study is to provide the priority of the front-loading factors in the design stage of the automotive parts development process in order to efficiently and effectively respond to the demands of the car maker (customer). Front-loading is defined as a strategy in order to improve development performance by shifting the identification and solving of design problems to earlier phases of a product development process. Two approaches of the front-loading are project-to-project knowledge transfer and rapid problem solving. For the study, a survey was conducted on the R&D department in the automobile parts company and analyzed by AHP (Analytic Hierarchy Process) method. The result of the survey shows the cost savings is the highest weight in terms of front-loading effect and in terms of front-loading factors, it gives priorities as “the problems of past project” first, “Design Review” second, “CAE (Computer Aided Engineering)” third, “FMEA (Failure Mode and Effects Analysis)” fourth, “benchmarking” and SR (Sourcing of Requirements). The results of the study will be helpful to provide practical value for improving product design of component development.
양식산 넙치와 자연산 넙치의 관능적 특성 및 저장중 신선도 변화 연구
박병학,박소희,조재선 한국조리과학회 2003 한국식품조리과학회지 Vol.19 No.1
This study was conducted to investigate the physicochemical and organoleptic characteristics and freshness of wild and cultivated Paralichthys olivaceus during storage. By the results of morphological observation, wild Paralichthys olivaceus had white abdomen, light black skin and transparent muscle, but cultivated Paralichthys olivaceus had black spotted abdomen, dark black skin and dark pink muscle. Moisture contents of wild and cultivated Paralichthys olivaceus were similar, but the lipid content was higher in cultivated Paralichthys olivaceus than that of wild Paralichthys olivaceus. Sensory scores of appearance, Taste, texture and overall acceptability were higher in wild paralichthys olivaceus than that of cultivated Paralichthys olivaceus. The reason was that lipid content was higher in cultivated Paralichthys olivaceus. The freshness of cultivated paralichthys olivaceus seemed to last shorter than that of wild one due to rapid increase of the volatile basic nitrogen content, pH and total microbial count during storage.