간행물
한국기계기술학회지 KCI 등재 Journal of the Korean Society of Mechanical Technology 韓國機械技術學會誌
- 발행기관 한국기계기술학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1229-604X (Print)2092-0385 (Online)
- 수록기간 1999 ~ 2024
- 주제분류 공학 > 기계공학 공학 분류의 다른 간행물
- 십진분류KDC 550DDC 620
권호리스트/논문검색
제23권 제6호 (2021년 12월) 40건
21.
2021.12
구독 인증기관 무료, 개인회원 유료
In this study, the analysis of the unsteady viscous flow field using the uRANS equation in a moving mesh was studied. The simulation domain is composed of an overset zone fixed to a propeller and rotating at a constant angular speed and a far zone which is located in the far distance and does not move. Each zone is composed of a polyhedral meshes for the accurate and robust gradient calculation in addition to the reduction of computation time. Simulation technique was applied to the aerodynamic analysis of the 5-inch propeller and compared with those of the MRF and the thrust test. The thrust predicted by the moving mesh showed good correlation with the MRF result within 0.5% difference, but the torque showed a tendency to under-prediction by about 10% compared to the MRF. In the future, we plan to further validate the numerical analysis technique using the moving mesh by applying it to the configurations in which precise test results exist.
4,000원
22.
2021.12
구독 인증기관 무료, 개인회원 유료
Numerical analysis has been carried out to investigate the characteristics of seawater flow fields and turbine output in a compact double current tidal power generation system for various level differences. There are growing concerns for the development of efficient tidal power generation which is stable and less affected by environmental circumstances as ocean energy. Especially the flow field characteristics in the compact tidal power generation system have a large influence on the system power generation performance. Flow velocity, pressure, and streamline distributions are compared including vertical type turbine out, and it can be predicted that seawater is accelerated by vortex flow in front of the turbine and there is severe turbine output variation due to the water level difference with pressure difference. These results can be applied as basic data for the effective development of compact tidal power generation system.
4,000원
23.
2021.12
구독 인증기관 무료, 개인회원 유료
This study presents a numerical modeling and a transient simulation of a desiccant coated heat exchanger (DCHE) that is employed for dehumidification in buildings. DCHE is fabricated by coating type RD silica gel on the fin surfaces of a fin tube heat exchanger. The latent cooling load, which is 25 to 45% of the total cooling load in most weather conditions is removed by adsorption of vapor using DCHE. The saturated adsorbent is then regenerated by using either low-temperature waste heat from industry and/or renewable energy such as solar energy and geothermal energy. A mathematical model is established and a transient simulation has been carried out so as to analyze its performance in terms of average humidity difference (AHD), moisture removal capacity (MRC), latent cooling capacity(QL), and COP. Comparison between the simulation results and the experimental data was carried out and showed good agreement and a similar trend with a maximum discrepancy of 5%. Key results revealed that MRC, AHD, QL, and COP are largely affected by both air dry-bulb temperate and air wet-bulb temperature while they are less affected by the frontal air velocity. Furthermore AHD, MRC and QL are largely improved by hot-water temperature while COP decreases as hot-water temperature increases due to high regeneration energy consumption.
4,000원
24.
2021.12
구독 인증기관 무료, 개인회원 유료
The role of QR Code robots in smart logistics is great. Cognitive robots, such as logistics robots, were mostly used to adjust routes and search for peripheral sensors, cameras, and recognition signs attached to walls. However, recently, the ease of making QR Codes and the convenience of producing and attaching a lot of information within QR Codes have been raised, and many of these reasons have made QR Codes recognizable as visions and others. In addition, there have been cases in developed countries and Korea that control several of these robots at the same time and operate logistics factories smartly. This representative case is the KIVA robot in Amazon. KIVA robots are only operated inside Amazon, but information about them is not exposed to the outside world, so a variety of similar robots are developed and operated in several places around the world. They are applied in various fields such as education, medical, silver, military, parking, construction, marine, and agriculture, creating a variety of application robots. In this work, we are developing a robot that can recognize its current position, move and control in the directed direction through two-dimensional QR Codes with the same horizontal and vertical sides, and the error is to create a QR Code robot with accuracy to reach within 3mm. This paper focuses a study on the driving directions of QR Code-aware movable robots during the development of QR Code-aware indoor mobility robots.
4,000원
25.
2021.12
구독 인증기관 무료, 개인회원 유료
In this paper, a heat exchange system using cooling dehumidification and mixing process was proposed as an experimental study for a white smoke reduction heat exchanger system under winter condition. The white smoke reduction heat exchange system is divided into an EA part, SA part, W part and mixing zone. For the operating conditions, three types (Cases 1, 2, and 3) were selected depending on whether EA fan, SA fan, and A-W heat exchanger were operated. In addition, in order to visualize the white smoke exhausted from the mixing zone, it was photographed using CCTV. In order to investigate the performance of the white smoke reduction heat exchange system, the temperature reduction rate and absolute humidity reduction rate of EA and the heat recovery rate of W were calculated. The temperature change of EA and SA according to operating conditions was most effective in Case 3, and the temperature and absolute humidity at the outlet of the mixing zone were greatly reduced. From the results of the white smoke visualization, it was confirmed that the white smoke generation mechanism was different depending on the operating conditions, and the amount of white smoke generation was greatly reduced.
4,000원
26.
2021.12
구독 인증기관 무료, 개인회원 유료
In this study, controlling pattern gap was induced by deformation of the stretchable substrate. The pre-fabricated pattern was made by depositing an Au(gold) on the Si substrate, and PDMS(Polydimethylsiloxane) was used for the stretchable substrate in consideration of surface energy, formability, and viscoelastic characteristics. For uniform deformation of PDMS, it is manufactured in the form of a tensile specimen using a molding method. An external force is applied to the deformable substrate in the uni-axial direction using a self-manufactured JIG, and the Au thin film pattern is transferred to the substrate under tensile state. After that, the external force is removed, and the PDMS specimen is recovered to its initial state. At this time, it can be seen that the pre-fabricated pattern gap is shortened from the initial size due to the viscoelastic properties of the PDMS. As a result, it was characterized to deformation rate of the pattern gap according to elongation rate of PDMS.
4,000원
27.
2021.12
구독 인증기관 무료, 개인회원 유료
Noise is a sound that humans do not want. In this study, Based on the Rotax 912 engine, which is most commonly used in Korea, we will look at noise and thrust changes by changing the propeller blade angle by 1 degree for the two-blade Sensenich Propeller and the three-blade Wrap drive Propeller. Through this, we want to check which part of the propeller angle produces the least noise and the least thrust loss for each propeller, and propose a propeller operation plan in a noisy area based on the value.
4,000원
28.
2021.12
구독 인증기관 무료, 개인회원 유료
Magnetic abrasive finishing process is one of the advanced finishing technique, which is commonly used to improve the surface accuracy and dimensional of many products in various application such as for medical implant, automotive, electrical, and IT, etc. In this study, the MAF process using rotating magnetic field with flexible processing force is used to smooth the surface of STS 316L stents wire under the optimal conditions such as rotating speed: 150, 350, 600rpm; diamond grain size: 1, 3, 6-μm, and processing time: 20, 40, 60, 80min. The results showed that under the processing conditions, quality enhancement in surface accuracy of STS 316L stent wire is achieved, in which the surface roughness is reduced from 0.22 to 0.06-μm.
4,000원
29.
2021.12
구독 인증기관 무료, 개인회원 유료
We need data such as the number of lanes for lane change on the road as well as environmental and object recognition of the road for the autonomous vehicle of the future. This study proposed an algorithm that recognizes the left and right lanes and the center lane while driving differently from the black box image taken from a car. In general, deep learning does not recognize lanes individually but recognizes all lanes as only one lane. Therefore, using YOLO's object recognition function, the left and right lanes and the center lane were detected as different lanes, and a heuristic method was applied to recognize multi-lanes as more correct lanes. As a result of the performance evaluation, we confirmed that the proposed method detects the lane more accurately than Fast R-CNN and only YOLOv2.
4,000원
30.
2021.12
구독 인증기관 무료, 개인회원 유료
This study aimed to develop an algae reduction device using bubbles to improve algal blooms occurring in lakes or reservoirs in summer, and to design a venturi, a major core device for bubble generation and supply. As a measure to improve the bubble generation effect of the venturi, the venturi was devised to change the air intake characteristics, and the flow characteristics were analyzed through CFD simulation to achieve the optimal design.
4,000원
31.
2021.12
구독 인증기관 무료, 개인회원 유료
The cutting quality of abrasive water jet cutting of aluminum alloy(Al-5083) for shipbuilding is affected by the surface roughness, cutting pressure, cutting speed, and the distance between nozzle and material. The cross-section of water jet cutting is formed a V-shape as the cutting speed increase. The upper width(kerf width) is wide and the lower surface is narrow. The width of cutting cross-sections are effected in the order of cutting speed, cutting pressure, and distance between nozzle and material. From the experimental results, to improve of cutting quality of abrasive water jet cutting of aluminum alloy(Al-5083) for shipbuilding, the optimal cutting conditions to improve the surface roughness and kef width are proposed and discussed.
4,000원
32.
2021.12
구독 인증기관 무료, 개인회원 유료
Gas springs applied to various industrial fields are generally composed of a cylinder, a piston rod, a cover, and a seal mount. Because of the thin wall of the cylinder, small gas springs are manufactured using a roller forming process that presses the cylinder wall into a groove of cover in the cylinder. In this study, finite element analysis and process design of roller forming are performed to systematically manufacture the small gas spring and develop a roller forming machine. In order to perform roller forming analysis, tensile tests of structural steel pipe are performed and mechanical properties are analyzed. Roller forming process parameters such as radius and depth of roller grooves are derived using the incompressible condition of plastic deformation theory and the results of finite element roller forming analysis. Using the derived roller shape, a roller forming machine is developed and prototypes of the small gas spring are manufactured. Finally, the dimensional accuracy of the manufactured gas spring prototypes is analyzed through three-dimensional shape measurement.
4,000원
33.
2021.12
구독 인증기관 무료, 개인회원 유료
The efficient nutrient solution cooling system consisting of buffer tank, three-way valve, and heat pump et al. was developed for hydroponics of leafy vegetables at high temperatures period. It was designed in such a way that the buffer tank was first cooled to enable precise temperature control of the nutrient solution with small capacity heat pump. Developed system was installed in the NFT hydroponics farm cultivating leafy vegetables and performance evaluation was carried out. For cultivation of Lalique lettuce(Lactuca sativa var.), the temperature of nutrient solution tank, buffer tank, and the root zone, the performance of cooling system, and the environment of greenhouse were analyzed. Also, by measuring the growth and yield of lettuce, the effect of cooling nutrient solution on the growth of lettuce NFT hydroponics was analyzed.
4,000원
34.
2021.12
구독 인증기관 무료, 개인회원 유료
This paper is to study the technology of inspection and history management systems for wind power that are continuously increasing around the world. In the past, inspections and analysis of major devices in renewable energy system have been operated in an analog way that identifies problems through photography and passive method. To improve this problem, we conduct a study on VR-based inspection history management system using 3D texturing technique of drone image. The paper describes the current status and prospects of wind power, research and development of wind power blade inspection and history management systems, experiments and reviews in the field, and expected effects and future utilization of this technology. It is expected that the latest technology for inspection and management of renewable system will be secured and introduced to the site through the development research of this system to reduce maintenance costs and power generation costs.
4,000원
35.
2021.12
구독 인증기관 무료, 개인회원 유료
With the advancement of industrialization, modern industry had sophisticated technology, and manufacturers also demanded high-precision measurement accuracy. Improving the quality level by increasing the reliability of measurement results as well as accurate measurement is a key issue to increase the competitiveness of today's manufacturing industry. In general, measurement results depend on tolerances in the industrial field, and it may be difficult to guarantee the reliability of the data in the case of an industry that deals with precision parts. Currently, measurement uncertainty is mainly applied to the calibration and test fields of instruments. This study is aim to apply measurement uncertainty as a way to improve the accurate analysis and reliability of measurement results in the industrial field. For this, precision parts connected by shaft and hole were selected among geometric elements, and roundness and cylindricity were measured using a roundness measuring instrument and CMM. And, taking into account the environment in which these measurements were made, factors affecting the measurement results were derived, and a mathematical model was established to calculate the measurement uncertainty. Applying uncertainty in the field in this way is expected to improve the level of quality and accurate analysis of measurement results.
4,000원
36.
2021.12
구독 인증기관 무료, 개인회원 유료
In this study, the following conclusions were obtained after friction stir welding of Al 6061-T651.
1) The organization of the welding unit is largely divided into four parts, the Stir zone, themal-mechanical affected zone, heat affected zone, it was confirmed that it is clearly separated into the material portion.
2) As a result of observing the hardness test results of the welding unit, the minimum hardness value was about 45Hv, which was significantly lower than the hardness of the base material about 72Hv.
3) The tensile strength of the welding part was about 2/3 compared to the tensile strength of the base material.
4,000원
37.
2021.12
구독 인증기관 무료, 개인회원 유료
In this study, an accelerated weathering test was performed to examine the variation of thermal insulation performance according to the service life. A widely used class 1 thermal screen (matt georgette + polyethylene (PE) foam + chemical cotton + felt + matt georgette) was selected as the target thermal screen. The ultraviolet irradiation that reached the target thermal screen specimen (60 x 60cm) was 5mW/cm2. Thus, the ultraviolet irradiance was set to 5mW/cm2, and the exposure periods of accelerated weathering conditions on the specimens were set to 0, 282, 847, and 1412h. The radiation exposure periods of the weathering conditions for 0, 282, 847, and 1412h indicate the amount of ultraviolet accumulation for 0, 1, 3, and 5years, respectively. In the accelerated weathering test, the target specimens that completed each exposure phase were subjected to the hotbox test to analyze their thermal insulation performances. Consequently, the thermal insulation performance of the multi-layer thermal screen was estimated to degrade rapidly after approximately two years. In the accelerated weathering condition, a quadratic function model was used to calculate the expected service life, since it adequately described the variation in thermal insulation of the thermal screen according to time. The results showed that when the thermal insulation performance degraded by 5, 10, 20, and 30%, the expected service lives were 2.5, 3.3, 4.5, and 5.5years, respectively.
4,000원
38.
2021.12
구독 인증기관 무료, 개인회원 유료
Recently, as interest in external environments such as fine dust has increased, the interior environment is also becoming important. The specifications for range hoods in the kitchen have been changed to improve ventilation of indoor air. Accordingly, the performance improvement through the structural design of the range hood was studied. Experiments were conducted on flow rates, pressure, temperature, and noise by A, B, and C-Type for performance analysis according to internal structure. For C-Type, the wind volume () was 223.69, 2nd stage 257.46, showing results of not less than 240 and not more than 280 within the ±1 m/s flow rate error range. Noise (dB) was an average value of 54.83 in the first stage and 60.65 in the second stage, showing results not more than 60 dB within the ±1 dB margin of error. This is the result of meeting KS C 9304:2020 Ventilation System Specification.
17,400원
39.
2021.12
구독 인증기관 무료, 개인회원 유료
The purpose of this study is to compare and analyze the conventional constant-speed compressor driven by an induction motor and the BLDC-applied capacity variable compressor in order to improve the energy efficiency of the refrigeration system. Through this study, it was found that, when a reciprocating hermetic compressor is operated, more power is consumed than a BLDC compressor due to the consumption of current through the instantaneous starting capacitor when operating at a constant voltage than a BLDC compressor.
4,000원
40.
2021.12
구독 인증기관 무료, 개인회원 유료
When compact HVAC is applied to a building, various variables exist in performing the functions of air conditioning, ventilation, and hot water supply of the building, and various experimental and empirical evaluations according to the energy performance evaluation method of the building occur. We are going to present research data for preparing domestic evaluation standards for energy evaluation methods for compact HVAC and zero-energy buildings to be applied in the future.
4,000원
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