The purpose of this study was to investigate the flow characteristics and cooling performance for the heavy turbine blade with different shapes. Research was focused on the numerical study on forced convective heat transfer coefficients for three different blades with base, tip, and hole. Thus, selected local locations for various temperature distributions were shown in the flow domain. Final temperature on the local surface of blades was compared with three different blades. According to the results of velocity and temperature distributions in the fluid domain, the blade with holes had the best convective cooling performance with higher 13-16% average heat transfer coefficient than the other two blades. Apparent vortex at the tip of tip and hole blade caused the stable temperature drop. According to the calculations of local convective heat transfer coefficient between blade surface and atmosphere in the blade, approximately 18% of heat transfer coefficient at hole was higher than the base blade and 7% at hole blade was higher than the base blade. Lowest cooling performance existed at the center position of all three blades.

This study is to investigate convection cooling performance of the Secondary Battery of Electric Vehicle without heat sink. Research is focused on the comparative study on cooling between forced convection and natural convection cooling. Selected local locations for various temperature distributions had shown in the flow domain. Final temperature on the cell surface has been compared by forced convection with natural convection. According to the results of velocity and temperature distributions in the fluid domain, Buoyancy appear by density difference in the natural convection. Apparent vortex was detected in the fluid domain for forced convection. According to calculations of convective heat transfer coefficient between cell and atmosphere in the battery pack, average value of more 70-78% heat transfer coefficient increased by forced convection than natural convection. Average temperature value of the cell surface decreased up to 46.50% by forced convection. Due to vortex by air, cooling performance of forced convection is excellent. In addition, cooling on edge of the battery is better than heat source location.