In this study, the effect of flow rate ratio (R) and total flow rate (Q) on the surface temperature of thermal barrier coatings (TBC) was investigated using a newly developed small-scale methane-oxygen burner rig. Subsequently, the failure mode of electron beam physical vapor deposition (EB-PVD) TBC was examined, and the relationship between surface temperature and coating life was established. The surface temperature of the TBC was found to be strongly dependent on both the flow rate ratio and the total flow rate. Specifically, surface temperature exhibited a proportional relationship with total flow rate, while it showed an inverse relationship with flow rate ratio. The failure mode of the EB-PVD TBC involved a gradual increase in delamination from the rim to the center of the coin-shaped specimen, and this failure mode was found to be independent of surface temperature. Additionally, it was determined that the surface temperature of EB-PVD TBC has a perfectly inverse linear relationship with coating life. This finding implies that the derived linear regression line from the burner rig test can be directly used to predict coating life for any untested surface .temperature.

In this study, we developed a new vertical thermal gradient rig that uses methane-oxygen fuel. We conducted thermal gradient testing on a thermal barrier coating system, with a flame temperature of 1,900℃. Our results showed that the maximum surface temperature reached 1,065℃, while the temperature difference between the surface temperature and the temperature of the middle substrate (ΔT) was 70oC. Using the same torch as in this study, our finding suggest that the total flow rate of the flame should be above 12.4 LPM, and the gun distance should be less than 8 cm, to simulate a surface temperature of 1,300℃, while keeping the substrate temperature below 1,000℃. This will ensure that the flame is wide enough to cover the entire surface area of the thermal barrier coating.

The high voltage direct current (HVDC) device has been used to transmit electrical power with an advanced technology of semiconductors. The sustainable energy generation technologies of solar power and windmills are demanding that the HVDCs have high performance and reliability. In this regard, the cooling performance of the HVDC becomes a significant research topic because the temperature increase affects the operation of the device. The evaluation system to assess the cooling performance has been developed and is proposed in this paper. The experimental apparatus is presented in detail. Our experiments have shown the accuracy of flow rates, pressure drops, and the temperatures in the desired measurement points. We have successfully developed an evaluation system of the cooling performance of the HVDC device which has 2.48 kW of heat dissipation.

Reactors are needed to produce polymeric polymers as materials for OLED (Organic Light Emitting Diode). There are many types of reactors that assist in producing chemical reactions. One type, called a coil type, is a continuous reactor that has many advantages compared to other reactors. It can not only manufacture products continuously, but is cheaper and therefore cost efficient. A continuous coil type reactor was designed and manufactured for this study. A precise flow rate cannot be determined because of the numerous variables. An experimental flow rate is obtained when combining the following information: the valve opening angle, the revolution velocity of the screw and the temperature of the reaction. As a result, the study is considered that people who use this device will refer to this to control flow rate and time for reaction.

Recently, demands for difficult-to-cut materials with high mechanical properties have been increased in various industrial fields, such as the aerospace and automobile industries. Because difficult-to-cut materials have high mechanical properties, it is difficult to achieve conventional machining. Therefore, many researchers have been studying the machining methods for difficult-to-cut materials. One of the many studies of how to cut difficult-to-cut materials involves plasma-assisted machining (PAM) is a machining method that softens difficult-to-cut materials by a plasma heat source to remove by the cutting tool. PAM has various machining conditions, and it is very important to determine the optimal conditions to improve machining accuracy and efficiency. In this study, the cutting force was analyzed by using a gas flow rate and power which are the easiest to control in the PAM system. The results of this study can be applied to PAM data under optimum conditions.