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
제19권 제5호 (2017년 10월) 28건
1.
2017.10
구독 인증기관 무료, 개인회원 유료
In this study, we analyzed the radiant heat performance of ballast fin when the aspect ratio of the fin of ballast was changed. The minimum size of the mesh was 0.02 mm, and the grid number was about more than 11 thousand. In order to analyze the radiant heat performance of ballast fin, the aspect ratio of fin was 1.00(2 mm:2 mm), 1.80(1.5 mm:2.7 mm), and 0.56(2.7 mm:1.5 mm) respectively; that the heat transfer area was constantly 0.4 mm 2 . The numerical condition was that heat flux was constantly 1×10 5 W/m 2 , and measuring times were 0.1 second, 0.2 second, 0.5 second, 2 seconds, 5 seconds and 10 seconds respectively. The temperature values of fin at the 1.00 and 1.80 of aspect ratios were extremely large when heat flux time was 10 seconds. As a result, the maximum value of radiant heat performance of ballast fin appeared to the aspect ratio of 1.80.
4,000원
2.
2017.10
구독 인증기관 무료, 개인회원 유료
In this paper, the influence of the injector failure of the GDI engine on the air-fuel ratio inside the combustion chamber can be analyzed through time and shape analysis of the damping process of the ignition coil secondary waveform at 800rpm, 1500rpm, 2000rpm, 3000rpm. In particular, there is a correlation that affects air pollution associated with global warming, such as HC and NOx. To prevent this, periodic injector inspections can improve the fuel efficiency of the vehicle and reduce exhaust pollutants.
4,000원
3.
2017.10
구독 인증기관 무료, 개인회원 유료
The combustion instability in a dual swirl combustor was investigated experimentally. The effects of thermal power and combustor length on combustion instability were evaluated. Pressure and heat release fluctuation were measured simultaneously. In a conventional combustor, the frequency was decreased with increasing combustor length and decreasing thermal power. However, it showed different results with a dual swirl combustor. In regime 1 where thermal power was relatively high, the results showed same tendency with a conventional combustor. In regime 2 where thermal power was relatively low, the frequency was almost constant with increasing combustor length. It was found that a beating phenomenon occurred with increased combustor length in regime 2 by measuring sound pressure fluctuation. By confirming that beating phenomenon occurs only in regime 2, it is considered that beating phenomenon is the dominant factor of combustion instability in regime 2. This beating phenomenon inside combustion chamber greatly affected to combustion instability. The reason of the beating phenomenon seemed to be the difference oscillating period between main flame and pilot flame.
4,000원
4.
2017.10
구독 인증기관 무료, 개인회원 유료
This study was discussed with the friction effects due to surface roughness of the interface between the base material and a reinforcement at the downward inclined interfacial crack under shear loading. The fracture parameter are analyzed by finite element method of the ANSYS. As the friction coefficient of the surface is assumed zero and 0.3, the fracture is analyzed. This study was analyzed with inclination angles about 0 degrees, 45 degrees and 90 degrees. As the results, at the inclination angle of 0, the energy release rate is reduced by about 3%. About 16%, and 2% are decreased at 45 degree and 90 degree respectively. If the inclination angle is 45 degrees, the friction effect by the sliding resistance between the interface was found to be most effective.
4,000원
5.
2017.10
구독 인증기관 무료, 개인회원 유료
In the present study, single-phase heat transfer characteristics for downstream flow in the support grid of 6×6 rod bundle were investigated. It has been known that a turbulence generation due to a support grid with split mixing vanes enhances heat transfer in rod bundle but its heat transfer enhancement actually affects to relatively shorter distance. On the other hand, it has been also turned out that a support grid with large scale vortex flow (LSVF) mixing vanes results in heat transfer enhancement to a longer distance. Based on the results of literatre survey, single-phase water heat transfer experiments were performed for Reynolds numbers at around 30,000, and the heat transfer enhancement effect with both i) the split mixing vanes and ii) the LSVF mixing vanes was compared in this study. The key results showed that the effect of heat transfer enhancement in rod bundle region by the split mixing vanes was maintained up to the length of 15Dh behind the spacer grid. For the Reynolds numbers at around 30,000, it was also observed that the effect using the LSVF mixing vanes was stronger at about 3% when compared to the case using the split mixing vanes only for the distance ranging from 1 to 15Dh behind the spacer grid.
4,000원
6.
2017.10
구독 인증기관 무료, 개인회원 유료
It is necessary to develop a device for the design of wet scrubber with a more efficient deodorization performance in order to enhance the odor reducing effect of the wet scrubber. Therefore in this study, the superiority of the new wet scrubber with the centrifugal separation function different from the conventional wet scrubber was analyzed by the computational fluid dynamics. From CFD analysis, the pressure and velocity distribution, the peak vorticity, the retention time and the flow uniformity were calculated and compared with the performance characteristics of the centrifugal separator. As the results of CFD analysis, the peak vorticity and retention time of the gas flow were increased about 22% and the flow uniformity was improved about 7.2% by the centrifugal separator. Therefore the centrifugal separator in the wet scrubber will improve the deodorizing effect and the cleaning condition of the gas.
4,000원
7.
2017.10
구독 인증기관 무료, 개인회원 유료
The volume of fluid method is used to investigate the behavior of a liquid water slug in a PEMFC trapezoidal gas channel(GC) with a open angle of 60 degrees. To evaluate the effect of the contact angle of the top and side walls, the gas diffusion layer water coverage ratio(GWCR) and water volume fraction(WVF) in a inspection control volume are analyzed. As the contact angle increases, GWCR increases and WVF decreases. The cases with the GC contact angle of 60 and 80 degrees show the more favorable water removal characteristics compared to the other cases in a GC flooding condition.
4,000원
8.
2017.10
구독 인증기관 무료, 개인회원 유료
The object of research is based on 1.5 MW wind turbine blade. This paper has carried out the aerodynamic shape optimization design of wind turbine blade. Based on the aerodynamic basic theory of wind turbine blade design and combined with particle swarm optimization algorithm(PSO), the design optimization model of the aerodynamic shape of blade is established. Through this study, the optimization results of the angle inducing ′ and tangential inducing were obtained. The calculation programs are written and calculated chord length and torsion angle of the blade used by ′ and . The calculation result for the optimized wind turbine was 1.38 MW when the wind speed was 16 m/s. The 8 % error could be considered as an engineering acceptable error and the calculated values can be proved the correctness of the design value.
4,000원
9.
2017.10
구독 인증기관 무료, 개인회원 유료
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.
4,000원
10.
2017.10
구독 인증기관 무료, 개인회원 유료
Shape optimization is needed to enhance the performance or efficiency of many industrial products, for instance, such as small-scale electric parts, automotive design and so on. In, especially, small-scale apparatus with heat transfer, it is not easy to decide optimal shape of apparatus. Therefore, the shape of power auxiliary apparatus in automotive engine was investigated using numerical analysis which includes k- model and unsteady state. The relations between temperature and heat transfer were simulated in case of 3 Type and 3 Point for power auxiliary apparatus. As the results, the heat transfer was decreased due to flow recirculation in case of Type-1. Further high temperature did not always mean high heat transfer when the shape interacted with surrounding fluid.
4,000원
11.
2017.10
구독 인증기관 무료, 개인회원 유료
Impact damage tolerance is an important design requirement for composite structures. In this study, the effect of post impact damage and hole size of the composite sandwich skin / sandwich with core specimen on compressive strength of the laminate was analyzed. Three specimen tests were performed in this research. Two tests were carried out on pure bending test specimens subjected to impact damage to the skin and specimen with a hole in one of its skin as a damage. Through this test, we compared the reduction of compressive strength due to the size of skin damage and the size of the hole. Also, core-free specimen with an open hole under uniaxial loading were tested to produce reference data for comparison with the series tested earlier. As results of the tests, the sandwich beams with damage size and open hole are almost identical, and we concluded that the prediction of compressive strength reduction after impact of the sandwich skin structure can be predicted using an analytical model assuming skin open hole as impact inputs.
4,000원
12.
2017.10
구독 인증기관 무료, 개인회원 유료
As the size of the wind turbine tower becomes larger and larger, research on assembled wind turbine tower that is advantageous for transportation and installation is continuing. Large wind turbine tower require door openings for maintenance. The opening of the tower has an irregular cross section, and an excessive stress is generated due to the door opening. The result is structural damage to the tower and many accidents. In this research, stress analysis was performed on a model with internal stiffener to prevent excessive stress. The stress was investigated around the openings where the tower was resonant and excessive stressed, and the shape of the openings was optimized. Through optimization, we confirmed that the maximum stress was reduced by about 6% with respect to the initial value.
4,000원
13.
2017.10
구독 인증기관 무료, 개인회원 유료
The damping effects on stabilities of a simply supported pipe conveying fluid is investigated using the complexification-averaging method. The flow is assumed to vary harmonically about a mean speed. Unstable conditions of a piping system included with the viscous and material damping are analytically obtained for primary, secondary and combination parametric resonances. The primary and secondary resonances occur when the frequency of flow fluctuation is close to one and two times the natural frequency. And when this frequency is close to the sum of any two natural frequencies, combination resonances occur. The effects of damping parameters on the regions of three parametric resonances are discussed.
4,000원
14.
2017.10
구독 인증기관 무료, 개인회원 유료
The planetary gearing system is compact and lightweight. The performance of planetary gearing system which uses floating intermediate rings have been found to be very good for practical systems. To apply this system for the reduction of rotation of an engine, in designing stage, the quantitative estimate of the load sharing factors is required for understanding the performance. The method widely used for this purpose is to make use of elastic deformation of components of the structure or to utilize hydrodynamic oil film. This paper shows the way how to analyze the static load sharing factors by using the coefficient ''. This method can be applied for non-linear systems such as oil film bearing. The influences of various factors on '' of oil film spring are also shown. Furthermore, It is established in this study that the use of floating intermediate ring in designing the planetary gearing system has a very high reliability.
4,000원
15.
2017.10
구독 인증기관 무료, 개인회원 유료
This paper uses finite element analysis to analyze the equivalent stress and fatigue duration distributed in the timing belt pulley of the rotating part. The pulley structure used for analysis was categorized into one body type and separate axis type and their characteristics were analyzed when materials S45C and SCM440-870C were applied. A static structural analysis and durability analysis show that when external forces are applied to the pulley, the separate axis structure is structurally safer and more favorable in terms of fatigue, compared to the one body. In addition, the separate axis structure using SCM440-870C material was found to have the best safety factor at 10.4 and infinite fatigue life. These findings are expected to be useful when manufacturing timing belt pulleys.
4,000원
16.
2017.10
구독 인증기관 무료, 개인회원 유료
Recently, weight lightening is a key issue for various mechanical components to improve the fuel efficiency. For this reason, many researchers have been studying focused on the development of surface hardening treatment and metallic materials with high strength and wear resistance. In this study, we examine the formation of carbide at the surface of the gear machined by SCM420H steel after super-carburizing in order to improve the wear resistance of gear. The experimental results show that super-carburizing heat treatment gives rise to carbide dispersion across wider range of depth and higher carbon concentration than general carburizing heat treatment. Carbide having spheroidal or spherical shape had a size under 2 micro-meter produced in austenite grain boundaries or within austenite grains during super-carburizing. The super-carburized specimen maintained the hardness, HV700 above, at the 0.6mm depth and had a 10.4% lower coefficient of friction which was 0.766. This results from the dispersed carbide which lowered the coefficient of friction and ended up affecting wear resistance. Consequently, we conclude that super-carburizing heat treatment has more influence on the improvement of hardness, wear resistance compared to general carburizing heat treatment.
4,000원
17.
2017.10
구독 인증기관 무료, 개인회원 유료
This Paper deals with the measurement and analysis of the brake squeal noise, the wheel’s and block brake’s vibration. The squeal noise, a kind of self-excited vibration, is generated by the friction between the rim of the revolving wheel and the block brake. The goal of this paper is to investigate experimental the relation between brake squeal noise and vibration mode of railway wheel with block brake to the track of friction surface on tread of railway wheel and the tread rake angle of railway wheel. Experimental results with Mode Analysis and Run Mode Analysis show that vibration mode of railway wheel with block brake is related with brake squeal noise.
4,000원
18.
2017.10
구독 인증기관 무료, 개인회원 유료
Numerical analysis has been performed to investigate the stress distribution characteristics of auxiliary axle system in a compact special vehicle. Structural and running stability of compact special vehicle is largely affected by auxiliary axle system installation. Structural characteristics of stress and deformation distributions with safe factor in the auxiliary axle system are analyzed. It can be seen that maximum stress happens near the local axle position, and deformation is also predicted. Simulation results are also compared with experimental test data. These results from this study could be applicable for optimal design of diverse axle systems in the compact special vehicle.
4,000원
19.
2017.10
구독 인증기관 무료, 개인회원 유료
The object of this paper is to examine the noise generating mechanism at ship construction and repair precess. To accomplish the object; A noise generating mechanism of high noise machine, which is mounted in the ship construction and repair process, was investigated. The measurement method of the noise for the machine by ship construction were investigated. The noise at the 250 points of the manufacturing process machine in the 40 processes of the 3 factories, 3 business fields was measured. The database of the noise was built from the measurement data. The major sound sources and frequency range for the manufacturing process of metal material product machine was investigated.
4,000원
20.
2017.10
구독 인증기관 무료, 개인회원 유료
Although most of the automobile bodies are made of steel, the application of aluminum alloy sheet with high strength is under consideration for the development of environmentally friendly lightweight body for fuel economy improvement and carbon dioxide emission reduction. In the case of some inner plates, application of magnesium alloy sheet is examined. TRB plate has been studied mainly for weight reduction and rigidity reinforcement of steel plate parts. Recently, research on aluminum TRB rolled plate for light and environment friendly automobile application has been started, It is expected that the development of eco - friendly TRB rolling material made of light alloy will increase as the importance of light weight body for future energy efficiency increases. Therefore, in this study, we tried to obtain the technology to improve the quality of the product by pre - verifying the cooling performance of the hot forming process through the heat flow analysis and evaluating the cooling performance through the temperature distribution analysis. As a result, it was found that the temperature distribution through the flow velocity problem and the flow of the cooling channel can influence the quality of the final product through different heat distribution and cooling time depending on the shape of the mold and the product.
4,000원
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