백연 저감을 위한 열교환 시스템의 배기 열전달 특성에 관한 연구

왕쩐후안,전종균,권영철 한국기계기술학회 2018 한국기계기술학회지 Vol.20 No.6

In this study, effects of reducing white smoke at a heat exchange system for white smoke reduction were studied in the winter season. For this purpose, the heat transfer processes on the exhaust air were investigated by Solidworks. Five wave heat exchangers of air-to-air and air-to-water type were applied for the exhaust air heat recovery. The analytical condition of the exhaust air was fixed and the computational analysis was performed according to the change of SA(supply air) inlet velocities. In order to evaluate the performance of the heat exchange system for white smoke reduction, W(water)/SA recovered capacities and the temperature/absolute humidity reduction rate were calculated. As SA inlet velocity increased, the exit temperature andabsolute humidity of the mixing zone were reduced by up to about 40℃ and 0.12kg/kg respectively. Also, W/SA recovered capacities increased linearly up to about 35%.

EES를 이용한 백연저감 열교환 시스템의 성능해석 연구

왕쩐후안,권영철 한국기계기술학회 2019 한국기계기술학회지 Vol.21 No.6

In this study, a white smoke reduction simple prediction model of white smoke reduction heat exchange system was developed by using EES. In order to verify the reliability of the EES model, it was compared with the computational results. The developed EES predictive model was used to calculate the temperature and absolute humidity of the mixed SA and EA according to the change of cooling water capacity, flow rate ratio of SA/EA, and SA inlet temperature. The difference between final temperature and absolute humidity at the outlet of the mixer calculated by computational analysis and EES was within 1.4% and 3.6%. As the cooling water capacity and the inlet flow rate ratio increased, and as the inlet air temperature decreased, the temperature and absolute humidity of the mixer decreased. The most influential factor in the white smoke reduction effect among the design variables of the white smoke reduction heat exchange system was the flow rate ratio of SA/EA.

인가하중에 따른 테이블의 피로 및 진동해석

왕쩐후안,변선준,권영철 한국기계기술학회 2018 한국기계기술학회지 Vol.20 No.5

In this study, the fatigue and vibration analysis were performed by using Solidworks program to investigate the damage percentage, life cycle and vibration mode depending on the types and positions of load applied to the table (Cases 1, 2, 3, 4). The farther the point of action of the load was, the more the fatigue damage and stability of the table were greatly reduced. The life cycles of Case 1 and 4 were over 100,000 cycles and the fatigue damage was less than 70%. From the vibration analysis, five modes and natural frequencies of Case 1 were confirmed. As the natural frequency increases, the shape of the corresponding mode is predicted not to be deformed.

파형 열교환기의 열전달 및 유동특성에 관한 전산해석 연구

왕쩐후안,변선준,차재민,권영철 한국기계기술학회 2017 한국기계기술학회지 Vol.19 No.4

In this study, the heat flow characteristics of wave heat exchanger was investigated by being applied to the white smoke reduction system. Through numerical analysis, the heat transfer and flow characteristics of the wave heat exchanger with the change of inlet condition of air-side and water-side were analyzed. To investigate the temperature, the absolute humidity, heat transfer rate, pressure drop and turbulence characteristics of the wave heat exchanger, the simulation analysis was conducted by using the commercial computational fluid dynamics software (Solidworks Flow Simulation) under uniform flow conditions. As the inflow rate of air decreased and the inflow temperature of water increased, the heat transfer coefficient of the wave heat exchanger decreased. When the experimental conditions of water-side were the same, the air outlet temperature and absolute humidity of the wave heat exchanger increased with increasing inflow rate of air. To reduce the white smoke, the air outlet temperature and absolute humidity of the wave heat exchanger must be reduced. Therefore, the lower the air velocity and the water inflow temperature into the wave heat exchanger, the more effective it is.

흡착압력에 따른 수직 평판유리 변형특성에 대한 구조해석

왕쩐후안,권영철 한국기계기술학회 2020 한국기계기술학회지 Vol.22 No.1

In this study, the flat glass and adsorption pad were modeled using SolidWorks Simulation, to understand the deformation characteristics of the vertical flat glass by the adsorption pressure during vertical transport of LCD. The horizontal and vertical displacements and equivalent stresses of the flat glass were investigated by the structural analysis. From the displacement and stress visualization according to the adsorption pressure, the higher the adsorption pressure, the larger the glass surface protruded. The horizontal deformation of flat glass increased with increasing thickness and the vertical deformation increased with decreasing thickness. In addition, the maximum equivalent stress applied to the flat glass increased significantly as the adsorption pressure increased and the thickness decreased. As a result of the structural analysis, the thinner the thickness of the plate glass, the greater the effect on the adsorption pressure. Especially, the effect of the adsorption pressure was clearly observed at the thickness of 0.5mm.

자동차 센터필러의 측면충돌에 관한 시뮬레이션 해석

왕쩐후안,권영철 한국기계기술학회 2018 한국기계기술학회지 Vol.20 No.4

Prior to the design and production stages of the center pillar, the structural analysis must be carried out at the concept stage. Commercial softwares for the structural analysis provide benefits such as performance prediction and deformation. In this study, the structural analysis using SolidWorks was performed to investigate the stress and displacement characteristics of the center pillar for two types of collision positions and velocities. As the impact velocity increased, the maximum equivalent stress and displacement of the center pillar were larger. In the case of passenger cars, the equivalent stress and displacement according to the velocity change increased by about 133% and 116% at 16.5m/s, based on 5.5m/s. Also, the equivalent stress and displacement in the SUV car increased by about 119% and 378%, respectively.

동절기 백연저감 열교환 시스템의 열전달 성능에 대한 실험적 연구

왕쩐후안,권영철 한국기계기술학회 2018 한국기계기술학회지 Vol.20 No.3

In the present study, the white reduction system was designed and manufactured to evaluate the performance of a heat exchange system using a wave heat exchanger. The reducing effect of white smoke and the amount of heat recovered from cooling water were investigated experimentally using the cooling and dehumidifying method. The white smoke reduction system consists of two parts; the generating part and the reducing part of white smoke. Experimental conditions on EA(exhaust air) and SW(supply water) were fixed. And the outlet temperature and absolute humidity of EA were measured according to inlet velocity of SA(supply air). The outlet temperatures and absolute humidities of EA gradually decreased as inlet velocities of SA increased. From the experimental results, we can see that the absolute humidity reduction rate of EA was max. 84%, and the heat recovery rate of SW was max. 42%.

파형 열교환기 피치에 따른 공기측 열전달 성능에 대한 실험적 연구

왕쩐후안,변재기,권영철 한국기계기술학회 2017 한국기계기술학회지 Vol.19 No.6

In this study, the performance of a small - sized wave heat exchanger to be applied to the white smoke reduction system was experimentally confirmed. The heat transfer rate, drain and pressure drop were measured according to the air flow rate, water flow rate and relative humidity change of the wave heat exchanger for two kinds of pitch numbers. A constant temperature and humidity calorimeter and a constant temperature water bath were used to measure the performance of the wave heat exchanger. The heat transfer rate and drain increased gradually with changes of water flow rate. Case 2 showed more than 50% higher heat transfer rate and drain than Case 1. The increase of air heat transfer rate and drain according to air flow rate was greatly increased when the number of pitches was the same or increased, unlike the result of water flow rate change. In the temperature visualization using a thermal imaging camera, it can be seen that as the water flow rate and the number of pitches increase, the heat transfer becomes more effective in Case 2.

백연저감 시스템용 Pilot 파형 열교환기 열전달 특성에 대한 실험적 연구

왕쩐후안,변선준,권영철 한국기계기술학회 2017 한국기계기술학회지 Vol.19 No.5

In this study, the heat transfer characteristics of pilot wave heat exchanger for white smoke reduction system was investigated. The performance of the wave and honeycomb heat exchanger combined with the first stage, second stage and third stage was tested using a calorimeter. Air and water inlet/outlet temperature and flow rate, pressure drop and dehumidification amount were measured to compare the heat transfer performance according to the type and the combination of heat exchanger. The heat transfer rate and dehumidification amount of the wave heat exchanger were higher than that of the honeycomb heat exchanger, and the pressure drop was low. As the stage increased, the heat transfer rate and the increase of the dehumidification amount were more pronounced, and the pressure drop linearly increased. The wave heat exchanger had a lower flow resistance than the honeycomb heat exchanger with the honeycomb structure and had a higher heat transfer effect due to the convection, so the water outlet temperature was higher in the wave heat exchanger.

높이조절 테이블의 하중에 따른 구조해석

왕쩐후안,권영철 한국기계기술학회 2018 한국기계기술학회지 Vol.20 No.3

In this study, the structural analysis was performed by using Solidworks program to investigate the stress and displacement characteristics of upper desk and table arm depending on the types and positions of load applied to the height-adjustable table(Cases 1, 2, 3, 4). The simulation was used to model the table and create the mesh for computational analysis. The height-adjustable table consists of three parts, upper desk, table arm and support body. Case 3 with the side concentrated load showed the maximum stress and maximum displacement at table arm and upper desk. From the stress and displacement characteristics of the upper desk and table arm, the stresses at the bending part of table arm and the deflection at the front part of upper desk were the greatest.