It is known that the cooling performance can be improved about 5~12% and the COP (Coefficient of Performance) can be improved about 10~15% when the IHX (Internal Heat Exchanger) was applied in a vehicle. Thus, the aim of this study was to observe the influence of the fins shape on the turbulence flow and turbulence kinetic energy gradient in IHX. All the applied parameters of the fin such as rotation angle, spacing ratio, height ratio and mass flow rate are changed. The governing equations for the flow motion simulation were applied to continuity equation and Navier-Stokes equation, and the turbulence model was applied by the Shear Stress Transport(SST) model, which has the advantage of turbulence simulation. As the rotation angles of the front and back fins were increased, the difference in the maximum turbulent kinetic energy gradient between fins was reduced. As the inlet flow mass increased, the turbulent kinetic energy difference between front and back fins were increased. The turbulence area tended to increase with increasing fin height ratio.
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.
This paper aims to reveal the effects of the K- turbulence model on the performance analysis of battery cooling system for electric vehicle. The maximum temperature, the difference of temperature, and temperature distributions on the battery module were compared with and without K- turbulence model under the different flow rate. It can be expected that the maximum temperature of K- turbulence model is corrected by using the average error rate without the result of K- turbulence model.
The study is the development of stone processing machines for larger blocks of stone for more than 2 meters. The wire saw were replaced by the cutting of existing prototypes and employed as a new form of cutting tools equipped with industrial diamonds. In addition, a turn table was developed to enable the milling of large blocks of stone allowing them to spin. On the other hand, large processing machinery has been imported and used mostly by Chinese machinery and has caused many inconveniences in managing and using equipment. Therefore, it is difficult for domestic production products to remain unstable, thus maintaining the nation`s crumbling granite industry. As a result, it is uncomfortable to find domestic products, but it is difficult to maintain the domestic stone industry. Therefore, we look forward to the revitalization of the domestic stone industry through this development.
돌그릇 제품은 특성상 강도가 있으면서도 무겁고 취약하여 가공이 매우 어렵고, 작업환경의 열악, 작업 공간과 작업능률의 비효율성 등의 단점이 있다. 본 연구개발을 통해 각기 다른 2대의 가공기계에서 2공정에 의해 2명이 작업하던 돌솥 본체가공을 1인에 의해 1대의 기계에서 2공정의 작업을 거쳐 가공을 완료 할 수 있도록 하였으며, 작업공간의 효율적 배치와 작업자의 환경 및 안전을 고려한 자동 돌솥 본체 가공 전용 기계를 개발하였다.
This paper aims to reveal the effects of the K-ε turbulence model on the performance analysis of battery cooling system for electric vehicle. The maximum temperature, the difference of temperature, and temperature distributions on the battery module were compared with and without K- ε turbulence model under the different flow rate. It was found that there was no need to apply K-ε turbulence model when the flow rate is over 500m3/h because the difference of maximum temperature is under the 6℃.
본 연구개발은 2m 이상 대형 석재에 대한 가공기계 개발에 관한 것으로서, 종전에 강철재 원형톱을 회전시켜 석재를 절단하던 방식을 개선하여 와이어에 공업용 다이아몬드를 장착한 와이어 쏘우를 절단도 구로 채용하였다. 또한 부수장치로 거대 석재를 전후좌우 및 회전이 가능하여 다각도 가공이 가능하도록 턴테이블식 공작물 베드를 설계 및 개발하였다. 한편 대형 석재 가공기계는 대부분 중국산 기계가 수입되어 사용되어지고 있으며, 이로 인한 장비 관리 및 사용에 있어서 여러 가지 불편한 점들이 산재해 있으나 국내 생산 제품이 전무하여 불편함을 감수하면서 어렵게 국내 석재산업을 유지하여 오고 있는 실정이다. 따라서 본 개발을 통해서 국내 석재산업의 활성화를 기대해 본다.
It analyzes the new structure and mechanism of organ type accel pedal to have a double curve to obtain a low effort force has been devised an electronic accel pedal consisting of two springs. To confirm the characteristics of effort force on variation of spring constants for two springs, dynamic analyzes were performed by using the ADAMS software program. According to the result of the simulation analysis, new mechanism of organ type accel pedal has an inflection point of the curve of pedal effort force on variation of spring constants, k, in various range of pedal angle.