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.

An elliptic blending Reynolds stress transport equation model for Newtonian fluids has been extended to predict polymer-induced drag reduction FENE-P fluids. The conformation tensor equation which is related to the polymer stress is adopted from the model form of Resende et al., and the models of redistribution and dissipation rate terms for the Reynolds stress transport equation are considered by the elliptic blending equation. Also, the new model terms for viscoelastic turbulent transport and viscoelastic dissipation in the Reynolds stress transport equation are introduced to consider the polymer additives effect. The prediction results are directly compared to the DNS data to assess the performance of the present model predictions.

In this paper, we study the effect of cooling dehumidification process and wave heat exchanger on the reduction of white smoke and the efficiency by combination of heat exchanger with numerical analysis method. For this purpose, four types of heat exchange systems combined with 5-stage wave heat exchangers were selected to analyze the heat transfer characteristics of the heat exchange system in the winter condition. As the high temperature exhaust air flowed from HX 1 to HX 5, the final outlet temperatures of the four heat exchange systems(Cases 1, 2, 3 and 4) gradually decreased. The heat transfer rate and dehumidification amount were the best in Case 1 and Case 3, respectively. It can be seen that the heat flow in the heat exchanger is different according to the combination of the four kinds of wave heat exchanger and the fluid flow.

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.

Recently, uncertainty of demand and supply for energy has expanded as energy market change rapidly. Rapid accumulation storing of cold heat is a method for decreasing the gap between demand and supply of time, quantity and quality of heat energy. It is stored rapidly when electric power is on. And cold heat energy in heat is phase change material (PCM) heat storage is used when electric power is off. Porous media for cold heat is PCM. The present study has been conducted for improving performance of cold heat storage in refrigerator using characteristics on laten heat and phase change of PCM. This study provide basic data to improve performance of cold heat using characteristic of PCM. Also, this study predicts and measures specific points in PCM heat storage during process of phase change.

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.

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.

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.

In the present study, the structural and fatigue analysis on the shape change of an automatic press are investigated for prediction of operation safety and reliability of the automatic press along the thickness(t) and length(L) of head, and corner shapes(case 1, 2, 3). The equivalent stress and deformation characteristics of the automatic press were studied by computerized analysis method for the bushing production of the seat frame. An external stress of 14.0 MPa was applied to predict the operation stability and the fatigue limit of the structure. As the thickness of the header increased and the length of the header decreased, the load stability applied by the piston improved and the maximum stress and deformation were reduced. In addition, due to the change in shape of the corners, the load applied at the cross-sectional area of the corners decreases, and then the maximum stress and deformation appearing in the header are reduced. That is, the change of corner shapes affects the equivalent stress and deformation. That is the change of corner shapes affects the equivalent stress and deformation. From the fatigue and vibration analysis, fatigue failure does not occur even when the number of alternating operation of the automatic press increases, and the natural frequency is predicted for dynamic characteristics.

The present experimental study investigates single-phase heat transfer coefficients downstream of support grid in 6×6 rod bundles. Support grid with Split mixing vanes enhance heat transfer in rod bundles by generating turbulence but this turbulence is confined to a short distance. Support grid with large scale vortex flow(LSVF) mixing vanes enhanced heat transfer to a longer distance. In this study, the experiments were performed at reynolds numbers of 50,000. The characteristics of the heat transfer enhancement of the Split mixing vane and those of the LSVF mixing vane were compared. The results showed that the characteristics of the heat transfer enhancement of rods by the Split mixing vane were limited to 10 Dh after the spacer grid, but those by the LSVF mixing vane were maintained until 15 Dh after the spacer grid. For the reynolds number of 50,000, the heat transfer enhancement effect was 3.0% greater when using the LSVF mixing vane than when using the Split mixing vane between the 1 ∼ 15 Dh interval after the spacer grid.