Hyo Min Jeong

Water Cooling Characteristics in an Enclosed Vacuum Tank by Water Driven Ejector

The general cooling tower is a device for cooling water in industrial condensers or heat exchangers. The present cooling towers have defects with noises, complicated structures and environmental problems. This paper focuses on a new water cooling system using the latent heat of evaporation in an enclosed vacuum tank and a water driven ejector system. Several experiments were carried out to improve high vacuum pressure and water cooling characteristics. The ejector performance was tested with various water temperatures. Based on the vacuum pressure of the water driven ejector, the water cooling characteristics were investigated for the condensed and vaporized air and the effect of increased evaporating surface area in an enclosed tank.

Fluid Flow Characteristics in the Aquaculture Tank for a Breeding Fish

The aquaculture tank is used for breeding fish in sea water which was pumped up to land. The flow characteristics in the aquaculture were investigated with varying the tank geometry and flow rate. The numerical analysis has been employed for calculating the velocity and temperature distributions in a water tank of rectangular type. The finite volume method and SIMPLE algorithm with 3-dimensional standard k-ε turbulence model were used for the numerical analysis. For comparison with experimental results, the PIV system was applied to visualize the flow patterns quantitatively. The numerical results showed good agreements with the experimental results. The mean velocity and temperature versus aquarium depth were represented for various circulating flow rates. Especially, the aquaculture environment is recommended that the aquarium depth has to be d=0.5 m, and this case is the condition of higher velocity and temperature in winter season.

ASME Code Evaluation on Stress Analysis of Snubber

Small snubber of hydrogen compressor do duty as buffer pulsation of compressed hydrogen. Snubber is a kind of internal pressure vessel and design optimum of snubber very important problem. In this paper, we will estimation results of elastic finite element structural analysis using the commercial program such as ANSYS for comparison to the limits in ASME Code Sec. Ⅷ that are related to membrane and bending stresses. In case of membrane stress in a circular cylindrical due to internal pressure or to distributed live loads. Bending stress in the central portion of flat head due to pressure. In addition, We will propose optimum design value of snubber for hydrogen compressor.