In this study, focusing on the sensible heat transport of the main heat transport in OHP, we compared the relationship between heat transport and liquid position using a model using numerical simulation based on particle method. By comparing with heat transport by dream pipe effect, we showed propriety of this analysis method. Moreover, the heat transfer was evaluated when the amplitude of the wall oscillation was large and frequency is small. As a result, we showed that the heat transport amount increases by increasing the frequency, but the increasing rate decreased by increasing the frequency. In other words, it is considered that there is a peak structure in the temporal change of the heat transport amount. It was also found that the amount of heat transport changes depending on the difference in the initial position of the system. It is considered that the influence on the heat flowing in the system is different for initial position of the liquid.

Bubble-actuated circulating heat pipe, BACH, is one of new types of heat pipe, utilizing buoyancy force of vapor bubbles generated at bubble-generation part for liquid circulation. In the former report, bottom-heat BACH consisting of heated section and cooled section and top-heat BACH consisting of heated section, cooled section and intermediate cooled section were presented. The heat transport model of the each of them showed the basic characteristics in the past research. However, there are some problems such as consideration that the heating section is only horizontally placed and setting of several parameters in heat transfer formulas in order to adjust the predicted heat transport rate, moreover, bubble-generation part is not taken into account in these heat transfer models. Therefore, the models don’t have the versatility. In this study, the authors modified these models in order to solve the problems and establish general heat transfer modeling of BACH.

Materials manufacturing process are very expensive and this process use very high energy, so recent year TMCP technology is used to save energy in steel materials manufacturing process. Accordingly, we became possible to manufacture toughness and high-tensile steel without process and alloy. In TMCP, we exactly control cooling temperature near MHF point. However near MHF point is still not clear because MHF point is start point of transition boiling region. The region has nuclear boiling and film boiling, the two boiling region is temporally spatially mixed. In this study, we investigate the expansion situation of liquid-solid contact. To investigate the situation, we make visible of the wetting start position by high-speed video camera and measure the wetting start temperature by thermocouple. An experimental piece which is made of single crystal sapphire is superheated. After superheated, the solid surface is cooled by HFE-7100. These obtained results show that wetting initiation temperature was not affected by pool thickness when same spray boiling cooling through liquid pool.

Taylor vortex flow bifurcates to multiple modes depending on the two variables Reynolds number (Re) and aspect ratio (Γ). One example of the bifurcation phenomenon is transition from the Taylor vortex flow to the Wavy Taylor vortex flow with increasing Reynolds number. Through experiment, the critical Reynolds number at which the Taylor vortex flow bifurcated to the wavy Taylor vortex flow has been clarified. In addition, that of the numerical analysis also has been done. However, verification between the numerical results and experimental values is not necessary enough. In this study, the critical Reynolds number in Taylor vortex flow fixed at both ends with the aspect ratio was clarified. In the numerical analysis, the axial velocity change of the Taylor vortex flow which located to the bottom layer was embedded as an attractor in 3-dimensional topological space. The trajectory of attractor made a determination the mode whether the Taylor vortex flow or the wavy Taylor vortex flow. Finally the critical Reynolds number was clarified with the Reynolds number and the aspect ratio from 1.0 to 6.5. The numerical results and experimental results were similar for the two-cell mode, but the quantitative difference were found in the specific region of the aspect ratio for the four- and six- cell modes in the Taylor vortex flow.

The surface wave motion of the viscous fluid circulating between the concentric rotating cylinders was investigated using experimental approach. The outer cylinder and the bottom end wall of the cylinder are fixed, and the inner cylinder is rotating. The working fluid is an aqueous glycerin solution. The upper end of the working fluid is a free surface. In this condition, the characteristic flow pattern appeared on the free surface with increasing Reynolds number. In order to visualization, the free surface flow was taken with the video camera, and then the image processing was done by using a personal computer. The variation of the liquid level was measured by using an ultrasonic displacement sensor with a resolution of 0.1mm in order to quantify. In addition, the frequency distribution of the variation of the liquid level was derived by FFT analysis. These experiments were conducted by changing the Reynolds number. As a result of the experiment, the relationship of the area ratio between the inner flow region and the outer flow region was clarified. Moreover, the variation of the liquid level and the frequency of vibration on free surface were shown in detail. By increasing the Reynolds number, it was clarified that the complex surface wave was occurring.

In recent years, reciprocating engines or motors are mainstream as a power source for small unmanned aerial vehicles. The reciprocating engine has large vibration and large size. Even in the case of electric driving, the cruising distance becomes remarkably short because the battery is heavy. In this paper, in order to solve these problems, we have experimented by establishing a hybrid system that generates power using a high power, low vibration gas turbine and turns the motor with that electricity.

In this study, we suggest the functional mold applying boiling cooling that can control mechanical properties at the same time. This mold is comprised of the high melting point layer which does not break in the casting process and the low boiling point layer which performs cooling by boiling/disappearing. Particularly, the mold wall structure such as a material and thickness of the low boiling point layer is important factor in cooling characteristic control. However, the relationship between this structure and a cooling characteristic has not been clarified yet. Therefore, the relationship between the mold wall structure and a cooling characteristic was grasped and quantified by boiling experiment using the mixed layer of particles(alumina) - water and estimation by the heat transfer model.

In order obtain better understanding of the mechanisms of particle entrainment due to a propagating shock wave, we visualized particle-cloud formation process in a shock tube facility by the shadowgraph technique coupled with a high-speed video camera. In the present experiments, limestone particles (nominal average diameter of 1.9 μm) with a layer thickness of 12.7 mm were subjected to incident shock waves with a propagating Mach number of 1.3. Temporal evolutions of the height of particle cloud were then obtained from the shadowgraph images. The present visualization experiments revealed that (1) the boundaries of particle clouds were smoothly distributed just behind incident shock waves, but ripples appeared near the boundaries about 0.2 ms after shock passage, and (2) the ripples grew into small clusters of particles.