The Magneto-Rheological fluid is the suspended material having the ferromagnetic particles with micrometer size that can change properties by applying magnetic fields. In this paper, the shape design of the T-Flange Magneto-Rheological brake is conducted theoretically. The equations for transmitted torque are derived according to T-Flange configurations of the Magneto-Rheological brake. This feature has more output torque than conventional types. The validity of theoretical results is verified by conducting an analysis of an electromagnet using the finite element method. Then the effectiveness of braking torque is verified to reinforce by comparing the output torque of the conventional Magneto-Rheological brakes.
This paper presents the approach of design parameters optimization based on Taguchi method for the uniformity of outlet pressure in a plasma discharge chamber. The key issue of a plasma discharge chamber is to have the uniformity of outlet pressure which can make a high performance of surface treatment. To extend the length of a outlet from 60mm to 250mm with the uniformity, This study optimally designed the middle holes, outlet width and height, and diameter of the second chamber by using SolidWorks and flow simulation tool. Simulation results demonstrate the validity of the proposed approach.
The heat transfer characteristics of a louver fin for a radiator are numerically analyzed to investigate the performance of radiator for automotive. The commercial code FLUENT is utilized to simulate a louver fin to analyze both the flow fields of air and the solid region of lover fin. The numerical analysis is performed with the variation of air mass flow rate. The results show that as mass flow rate increases, louver fin efficiency is nearly constant. The correlation of the average Nu is derived. The results of numerical study is useful in louvered fin design.
Because of environmental pollution and lack of resources, necessity of energy efficiency improvement and reduction of exhaust gas emission and CO2 have grown in importance. Therefore a lot of studies are conducted for HEV(hybrid electric vehicle) and PHEV(plug-in hybrid electric vehicle). In addition, automobile companies are researching and manufacturing HEV and PHEV. Due to cost and time problem, simulation is preferred than experimental test to find better component size for efficiency improvement. In this research, backward simulation program is developed base on Dynamic Programming. Using this simulation program, fuel economy sensitivities for each parameter are analyzed and compared. Fuel economy is measured for a combined cycle that is calculated from FTP-75 and HWFET cycle. The target parameters are front/rear power train efficiency, drag coefficient, vehicle mass, rolling resistance coefficient, tire radius, center of gravity. The most sensitive parameter is front power train efficiency and second is drag coefficient. Rear power train efficiency, vehicle mass, rolling resistance coefficient are third, forth and fifth. By comparing sensitivities, we can choose a better way to improve fuel economy of HEV.
An experimental study was conducted to investigate the atomization characteristics of spray from the effervescent atomizer, which has separated two aerator tubes. The atomization characteristics were examined through the influence of ALR and the changes of atomizer geometry such as nozzle orifice diameter, diffusion angle, mixing chamber volume. PDPA(Phase Doppler Particle Analyzer) was used to evaluate the atomization characteristics. During the experiments, the mass flow rate of liquid was kept constant at 2.8g/s and the mass flow rate of atomizing air was changed from 0.2 to 0.6g/s. Experimental results showed that SMD was not a linear function of ALR. While SMD is very sensitive to the changes of ALR, the changes of atomizer geometry had little effect on droplet mean diameter. As the effervescent atomizer with separated two aerator tubes is insensitive to the changes of atomizer geometry, it is expected that the effervescent atomizer with separated two aerator tubes is capable of requirements of many applications, without the drawbacks of atomization characteristics.
A numerical investigation was performed based on the Reynolds-Averaged Navier-Stokes(RANS) equations for the two-dimensional unsteady incompressible flow around a vertical axis turbine(VAT) with NACA0012 and NACA0018 wing sections. FLUENT was used as a numerical tool to predict the flow filed around the VATs and the performance of the VATs. CFD analysis using FLUENT was carried out at several angles of attack for NACA0012 and NACA0018 wing sections and the results were compared with the corresponding experimental data for validation and calibration of the numerical analysis results. The VATs with 3, 4 wings were adopted to determine the characteristics of the change in the number of wings. The results of the numerical analysis were compared each other to determine the characteristics of the VATs according to the thickness variation of the wing section.
Buzz, squeak, rattle noise that are referred as BSR have become important part in vehicle's quality because vehicle NVH(noise vibration harshness) reduction technology of main parts like engine and drive-line has made great progress except BSR noise. BSR test is progressed by composing many road excitation power spectrum density(PSD) profiles into a composite PSD profile. Shakers which are input by composite PSD profile make time histories(time-acceleration data) by aggregate of a large number of harmonics related with composite PSD profile in general. But when only composite PSD profile is input to shaker, the time histories from shakers exhibits Gaussian distribution characteristics and can't reflect all road excitation PSD profiles. In this study, we search other studies that try to solve the problems occurring when a shaker is input only PSD profile and analyze time histories resulted from BSR test to check ways of shaker's operation.
The flow acting on a confined jet flow can be represented as a conventional turbulence flow with its complex phase and characteristics. This is still effectively applied in a variety of industries, for example in ejectors. In this study coaxial confined model made of transparent acrylic pipe and driving water nozzle in order to figure out of recirculation flow near the wall of pipe and prove how flow in the pipe can be developed. It was revealed that length of the recirculation flow adjacent to wall of pipe was characterized to be larger when Reynolds Number is getting bigger.
In this study, we have modeled the rear side of the HVAC diffuser with square prism and tried to investigate the influence of a wake flow by PIV and a numerical analysis using computational fluid dynamics based on steady-state Navier-Stokes equation and standard k-ε model. A commercial CFD program, FLUENT, is used on the analysis. The wake is generated by a square prism, which is installed at the divergent flow. The results show that a fluid are distributed up and down directions of prism, and the recirculation regions are decreased.
In this paper, as the transport cask was moved in the reactor, the structural integrity on the cask had to be evaluated in the normal transport condition. The drop height of the cask was determined by the weight of the cask in the normal transport condition by regulations about assessment test. It was determined that the drop height of the cask was 1.2 m by regulations. The velocity of the drop impact was calculated to perform the drop impact analysis by the principle of the conservation of energy. Using results of the simulation about the drop impact analysis, the structural integrity assessment on the transport cask was performed by ASME Boiler and Pressure Vessel Code.
This study aims at analyzing the property of the structural body bonded with alumimum foam by the utilization of the aluminum foam of closed type used generally with impact absorbent. The structural bodies bonded with the aluminum foam of DCB and TDCB are designed in this study, and then the fatigue analysis and experiment are carried out. At fatigue analysis, the maximum load happens at all of each specimen models when the fatigue life of 0 to 50 cycle is proceeded. And from the point of time that the maximum load happens, the load at the bonded surface is seen to be decreased in cases of analysis and experiment. As the specimen thickness is increased, the maximum load happened at specimen is increased. It is confirmed that the result of fatigue analysis becomes similar to that of fatigue experiment for verification. It is thought that the study data on various specimen thicknesses can be secured simply without the extra fatigue experimental procedure. By using this study result, the mechanical properties of the structural bodies bonded with the alumimum foams of DCB and TDCB with mode Ⅲ type can be thought to be analyzed effectively.
This is to develop a micro water turbine which makes some power from just a fluid velocity in the water pipe. While power is produced from impulsive force which generated by a high head in the case of existing water turbine, this is to produce a power from rotating force of helical turbine which rotated by fluid velocity in the water pipe. Some results of analysis fluid pattern at turbine blade for design shows that bubble is generated from turbulence surrounding blade and pulsatory motion generated as fluid being blocked and opened by blade due to turbine structure. This two phenomena cause to lower power production efficiency and shorten turbine durability. So this is studied to minimize bubble generation and pulsation for optimizing design of turbine blade. Therefore it is determined that the number of blade is three, geometric form of blade is NACA 4420 and angle of blade is 30 degree. An experiment equipment of water turbine is manufactured on the base of these factors(NACA 4420, angle 30。). It is obtained that power production of turbine increases in proportion to velocity which is changed from 1.7 m/sec to 3.5 m/sec. When fluid velocity is 1.7m/sec the power production of turbine is 355W. Power production increase continuously as increasing the fluid velocity and power is 2kW on 3m/sec of fluid velocity.
The most time consuming operation during the tryout of new parts is the compensation of geometric deviations induced by springback. The variation of springback due to the noise factors such as material properties and forming conditions increase the difficulties of the compensation operation. If the forming process includes a drawing operation followed by a restriking operation, a robust design for springback compensation is needed for both operations. In this study, a new 2-stage procedure for robust springback compensation using Taguchi's orthogonal array experiments combined with the Pick-the-Winner rule and the design space reduction method is proposed. The effectiveness of the proposed method is shown with an example of the sidewall curl springback compensation in U-channel forming.
The simulation analysis about the mechanical behavior by thickness on the compression procedure of the bonded aluminum foam is carried out in this paper. The maximum equivalent stress is increased very rapidly at three models. This stress approaches the yielding point when the compressive displacement is proceeded as much as 6mm. After yielding point, this stress approaches the maximum point. A value of this stress is about 1.0MPa. The reaction force approaches the maximum point when the compressive displacement is proceeded as much as 6mm. These reaction forces are shown to be 3000N, 5000N, 7100N respectively at the specimen thicknesses of 15, 25 and 25 mm. The maximum deformation energy is abruptly increased from the displacement of 6 mm and the compressive energy in case of the specimen thickness of 15 mm is shown to highest among three specimens when the displacement is proceeded as much as 13 mm. The experiment with the case of specimen thickness of 25mm is carried out in order to verify these analysis results. The mechanical properties of the bonded structures composed of aluminum foams can be thought to be analyzed effectively.
The bending exercises of radial tire is one of the most important structural properties of the sidewall relating to ride and road noise of automobiles. The frequency band analysis is more useful for analyzing tire road noise due to property change of tread and sidewall. In this paper, the vertical stiffness and lateral stiffness of tire which have a various tread and sidewall is measured and the road noise is measured about same road condition. Furthermore, we investigated the effect on the structure of the tire tread and sidewall for the sound pressure level.
In this study, the effect of slit length on the reduction of waste material was studied numerically. At the same time, the tightening axial force between steering shaft and asymmetry pinch yoke was also studied and compared. To achieve this study, the numerical simulation was performed by AFDEX commercial code. The slit length(Ls) of pinch yoke was increased from 25mm to 34mm by the steps with an interval of 3mm. AISI 1025 was applied for the source material of asymmetry pinch yoke. Amount of deformation was applied as much as 0.1mm for tightening the pinch bolt yoke and the steering gear shaft. It was revealed that the stress of steering shaft ear in XX-direction and YY-direction showed the highest value in 34mm and 31mm of slit length cases, respectively. The stress of ZZ-direction has the same value in all cases. The tightening stress between the asymmetry pinch yoke and the shaft of steering gear had the highest value in XY-direction. In additions, when slit length was increased by the steps with an interval of 3mm, the material was more wasted approximately as much as 0.844g. In conclusions, 31mm of lit length was the optimal length in aspect of the tightening stress and the waste material.
The electromagnetic interference(EMI) shielding sheet of grid pattern for the wireless charger has been designed by using grid pattern metal sheet, PET & DST stacking and laminating technology. For this purpose, the twisting protection and the bubbling prevention device, the automatic position adjustment controller, the visual sensors and the motor actuator for controller, the EMI shielding sheet cutting device and the main control system have been developed for manufacturing the apparatus. As the study result, the development on manufacturing the equipment and shielding sheet of the EMI shielding sheet of grid pattern for the wireless charger having the lamination productivity of 27.4m/min exceeded the target of 8m/min in this study. In addition, the magnetic induction and the applicable shielding sheet were prepared in the magnetic resonance system, all of the two wireless charging system. The power with a band of average 6.87MHz of shielding sheet was greater than the target of 30dB to 32.57dB. The available frequency with a band of average 7.95MHz the target was exceeded by a 7.00MHz.
This study describes the effects of treated water (TW) on PH changing, growth of watermelon seedlings, canola oil and diesel absorption, the antibacterial ability of the filter that composited from polyurethane(PU) and silver powder(Ag) producing by Electrospinning. In this study, we used the battery energy acquired from solar cell, the water has been processed when it pass through the electromagnetic field. The results of this research indicated that the PH value of TW changed slightly compared with untreated water (UW), but the TW could absorb smell of PH reagent. In addition, the TW could also promote the growth of watermelon seedling, and the growth of watermelon seedling stem length was about twice compared with UW. On the effects of canola oil and diesel absorption, the TW also showed a good oil absorptive capacity, especially for the diesel absorption, it could absorb 28% diesel. For the PU+PU+Ag/CNT filter, it showed about 100% of the antibacterial rate on strain 1 (Staphylococcus aureus ATCC 6538P) and 2 (Escherichia coli ATCC 8739).
This study aimed to develop the movable bed cultivating system for strawberry cultivation that enables to increase crop yield and save labor through high-density cultivation. In comparison with a conventional raised-bed system, the best feature of the system is a culture bed moving freely, left, right, up and down. This system consists of four devices; longitudinally- and laterally-moving device, nutrient solution supply device, and a control device. A comparative study showed that there was no significant difference on strawberry growth between a conventional raised bed and the movable bed cultivation systems. In addition, the change of growing environment to high-density cultivation did not influence strawberry growth, which proved the applicability of the movable bed cultivation system. Additional finding of this study showed that about 1.7 times more plants can be planted in movable beds. High-density cultivating using movable beds enables to plant more strawberry within the same cultivated area, which eventually contribute to reduce energy consumption per strawberry.
Wire rods having various sectional shape are generally used directly in various applications. In the shape rolling, a couple of grooved rollers are used and the groove match the sectional shape of the wire rod. In this 2 roll system, a couple of rollers must be changed whenever the sectional shape of the wire rod is changed, and the frequent changes of roller cause rise of manufacturing cost. We developed a 4 roll wire rolling mill that reduce the disadvantage of 2 roll rolling, at the same time improving quality of the wire rods and reducing production costs. The present work is focused on the development of a high precision 4 roll wire rolling mill for the wire rods that have various rectangle sectional shape.