Silicon sheets are utilized for electrical device cooling in terms of electrical insulation, thermal conductivity characteristics, and deformability. To reduce the contact thermal resistance between the silicon sheet and electrical device, a compressed flexible silicon sheet is used. The compressed silicon sheet realizes a higher thermal conductivity than uncompressed. In this paper, a relationship between compressive load and thermal resistance of silicon sheet is investigated. The test method is proposed, and measured. The thermal resistance of compressed silicon sheet is derived by an input heat flow for temperature controller and heat going through silicon sheet.

If dry-ice can be generated in the CO₂ refrigeration system and the endotherm by sublimation can be used, the system can achieve a low temperature range of -50ºC or less. However, when the conventional horizontal evaporator was used, the problem that the inside of the evaporator was blocked by dry-ice and the system stopped often occurred. Therefore, a cyclone separator-evaporator was newly introduced into the system. By the introduction, the blocking is suppressed and made it possible to lower the condensation temperature. As a result, more dry-ice could be produced and then lower temperature range could be obtained.

The effect of avoiding active-transport stop on viability during cold storage of cells and protective effect by pressurized dissolution of xenon gas were investigated. Rat cardiac myocyte was selected as an experimental cell. The cultured monolayer cell in culture medium preserved at 4-8°C for 6-24 h. Cell viability was evaluated by tetrazolium salts assay. Moreover, samples were preserved at 4 and 6°C for 24 h, then the cell viability was evaluated by the pressurized xenon gas (0.5 MPa) or absence (0 MPa). Results showed that cell viability at 6-8°C in each storage time was higher than that at 4 and 5°C; and the viability was close to 100% at both 4 and 6°C in pressurized dissolution of xenon gas.

According to the NEDO fuel cell/hydrogen technology development roadmap, high temperature condition over 90 ℃ is the target operating temperatures of PEFC systems (stationary and automotive) from 2020 to 2025. Power generation experiment using a single cell of PEFC was carried out at 90 ℃ and 100 ℃) using two types of PEMs and GDLs having different thicknesses. The power generation data was acquired by changing the presence/absence of MPL and the inflow gas flow rate/relative humidity. In addition, the temperature distribution on the back of separator was measured by a thermograph. Based on the obtained results, the effects of PEM and GDL thicknesses as well as MPL on various characteristics were discussed in this study.

This paper describes feasibility of a pyroelectric power generator (PEG) for powering sensors in IoT devices. This generator utilizes the pyroelectric effect, which is a change in polarization with temperature variation. The PEG devices have a simple structure and can generate electricity from exhaust heat, such as from an engine and a compressor. In this study, a simple power generation analysis and a proof-of-concept experiment were conducted to clarify the relationship between temperature change and amount of generated power of PEG. As a result, it became clear that the PEG can be used as a power source of the IoT devices.

Thermosyphons can be one solution to dissipate high density heat from heavily loaded semiconductors installed in limited spaces. To improve boiling heat transfer and critical heat flux of thermodyphons, various aluminum boiling surfaces fabricated by laser micro-texturing are tested. The tested surface having grid grooves exhibited much stronger surface wicking force than others having random cavities. The fabricated surfaces show higher heart transfer coefficient in nucleate boiling. This is rationalized by visualization results: LISS surface generates smaller but large number of bubbles.

In this study, we studied the characteristics of fingering of miscible fluids associated with gel formation between skimmed milk and citric acid solution. Mixing of skimmed milk and citric acid solution leads to form viscoelastic gel, i.e., yogurt, at interface of two fluids. We observed the fingering patterns induced by viscoelastic gel formation at the interface in a Hele-Shaw cell for various concentrations and flow rates. At high citric acid solution concentration, mixing of two fluids is suppressed and unique fingering patterns which are resemble to the sequence of bubbles appear. The distinctive structure like connected bubbles was formed by sequential rupture of gel membrane surrounding bubbles. The thickness of the membrane is modelled mathematically by the competition between the extension of the membrane and the diffusion through it.

The ultra-supercritical variable pressure operation once-through boiler with vertical furnace waterwall can be expected to improve load change characteristics and reliability by reducing the mass velocity of furnace wall tubes. On the other hand, when the mass velocity is lowered, there is a concern to suppress excessive temperature rise of furnace wall tubes due to heat transfer deterioration or departure from nucleate boiling. We tackled these issues and succeeded in improving the load change characteristics and reliability of the boiler. This report introduces the analysis/experiment and design technique applied to solve the problems, and the latest ultra-supercritical variable pressure once-through boiler put on the market using them.

This paper describes performance analysis of the oxygen-hydrogen combustion power generation system with respect to the effect of non-condensable gas, oxygen purity, and oxygen production energy. Residual oxygen and nitrogen concentrations at the combustor outlet by diluted H2O circulation are concentrated to 1.7 times higher compared to the case of the chemical reaction on oxygenhydrogen combustion when equivalence ratio is 0.9. A small amount of nitrogen (1% by volume) in purified oxygen is considered to result in the formation of NOx. Oxygen production energy slightly increases as the oxygen purity becomes higher from 95% to 99.6%. However, the energy of noncondensable gas removal decreases and the impact of NOx becomes smaller.

It is desired to improve the storage/release rate to shorten the heat exchange time in the latent heat storage system. This study is aimed at latent heat storage materials including the carbon nanotube (CNT) dispersoid with high thermal conductivity. Carbon nanotubes (CNTs) can be expected to increase the apparent thermal conductivity when dispersed in latent heat storage materials. In addition, since it is a dispersed system, it does not interfere with convection during heat storage in the melt. As the CNT dispersed latent heat storage material, tetracosane (melting point 50.6°C) was used as a continuous phase, and a sample containing multi-walled CNT in the range of 0.25 to 1.00 mass% was used. This paper deals with the evaluation results of temperature rising melting and temperature falling solidification characteristics using a differential scanning calorimeter (DSC).

This study deals with an experimental investigation of heat transfer characteristics of nanosuspension as a heat medium. Nanosuspension is a fluid that uses nano-sized latent heat storage material having a melting point temperature higher than normal temperature as a dispersoid. Tetracosane (melting point 50.6 °C) is selected for the dispersoid as a latent heat storage material. A non-ion surfactant polioxyethylencetylether is used for the dispersion stability of the dispersoid in the distilled water that is a dispersion medium. The dispersoid composition ratio of the nanosuspension is measured in the range of 10 to 20 mass%. This paper shows the results on the condition that nanosuspension with nonNewtonian flows in a straight circular tube. The heat transfer coefficient was measured and evaluated in each temperature range of the liquid phase of dispersoid (>melting point) and the solid phase of dipersoid (<melting point).

This paper deals with the experimental study of melting heat storage process of the carbon nanotube (CNT) dispersed latent heat storage material in rectangular tank with horizontal heating surface on the bottom. A heat transfer fluid in which CNT is solubilized and dispersed has the potential to greatly improve heat exchange performance because of its thermal conductivity raising. Dispersing CNT can increase the thermal conductivity, and since it does not hinder convection, it can be expected to promote heat transfer. The experiment was performed using CNT dispersed latent heat storage material while changing the heating surface temperature. It was observed that the total melting time of CNT dispersed latent heat storage material was longer than that without CNT. It is shown that the increase in viscosity due to CNT dispersion suppresses the generation of convection and does not lead to the promotion of melting heat transfer.

High-speed and small-amplitude pressure wave propagating with almost sound speed in a pure water was observed by a shock tube experiment (Ohtani & Sugiyama, Shock Waves, 2005). The present study derives a nonlinear effective equation for weakly nonlinear propagation of such a pressure wave in bubbly liquids with a special attention to a thermal effect (i.e., thermal conduction, liquid viscosity, and so on). As a result, the nonlinear Schrödinger type equation with some correction terms was derived. The thermal effect contributed not only the dissipation effect but also the nonlinear effect. The thermal conduction strongly increased the wave dissipation. On the other hand, the dissipation due to liquid viscosity was considerably small.

This study aims to develop a new guideline for hyperthermia using the laser. Hyperthermia by laser is drawing attention as a cancer treatment method. Laser treatment of skin cancer has a problem that it destroys healthy tissues. In order to solve this problem, it is necessary to control the depth of the heating area. In this study, a sin wave laser and Peltier cooling were introduced to control the depth of the heating region. The validity of the heating area control of the proposed method was evaluated by calculating the temperature distribution using the analytical solution.

Source of error in measurement of heat flux sensor using a Peltier module (PHFS) was experimentally and numerically investigated. A series of measurement tests using a cone heater was carried out. It is confirmed that the estimated heat flux was overestimated when the temperature difference within the module was not zero. It is suggested the excess heat flux is generated due to the overcurrent through the module under the condition. Numerical simulation validated that the excess heat flux can be given as a function of the temperature difference. Based on the result, a correction formula to

In a natural ventilation system of buildings, the radiation affects the convection due to the scale effect of convection region. To control the natural convection field using radiation, it is necessary to understand large-scale natural convection heat transfer phenomena in a building. The final objective of this study is to quantify the combined heat transfer of radiation and natural convection in a building using OpenFOAM. In order to achieve of the objective study, it is necessary to understand the accuracy of the radiation analysis library in OpenFOAM. In order to evaluate the reliability of this library, the dependence of the optical thickness per mesh of the coupled analysis method is evaluated.

In a semiconductor light emitting device such as an LED, when a voltage is applied to increase the chemical potential of photons, a thermodynamically nonequilibrium state is generated, and light emission may be different from Planck's law black body radiation. In this study, we focus on Thermophotonic power generation system composed of LED and PV cell, and discuss the mechanism of non-equilibrium thermal radiation via fluctuational electromagnetic simulation.

We numerically studied thermocapillary convection in a rectangular free liquid film and investigated several types of flow patterns as basic steady flows. In a liquid film with a volume ratio of 1.0, which means the liquid film is essentially flat in the absence of convection, a double-layered flow (DLF) occurred even in such a thin liquid film. On the other hand, a smaller volume ratio than the unity resulted in one or more vortex pairs were generated in the plane of the liquid film, called as single-layered flow (SLF). We also found that, even in the SLF, there existed DLF-like vortices on the cold wall. The size and number of vortex cells of SLF depended on the liquid film shape, aspect ratio, and volume ratio. The Nusselt number was obtained to determine its depend on the size and number of cells.

The spray flash desalination system has attracted attention because of its application in ocean thermal energy conversion plants. The spray flash desalination system, which is composed of a flash chamber, plate condenser, fresh water tank, and vacuum pump. In this study, the new herring-bone aluminum plate was configured and surface treated the plate by the anodic oxidation method. We measured the overall and condensation heat transfer coefficients. The experiment shows that the overall heat transfer coefficient is increasing with an increase in cold water velocity and the condensation heat transfer is also increasing with an increase in water vapor velocity.

This paper describes effectiveness of Bayesian optimization (BO) for thermal design of electronic devices. Recently, as the heating power density of electronic devices has increases due to miniaturization and performance enhancement, more effective thermal design is required. However, it is difficult to optimize the thermal design due to need to consider various trade-offs associated with packaging and non-steady heating power of components. In this study, we applied a method which combined BO with lumped-capacitance thermal circuit network model to chip layout optimization of a printed circuit board.

The self-water supply organic Rankine cycle (ORC) is a power generation system using the low enthalpy heat water by a distillation to feed the product water into the cooling water system. The lowpressure steam produced by the flash evaporation in the vacuumed condition enters into the ORC as the heat input. The process, because seawater will not flow to the heat exchanger directly, allows to prevent the scaling in heat exchanger caused by the supersaturated Ca, Si, and so on. In this study, the parametric analysis of a novel self-water supply ORC is conducted to uncertain the basic power generation and water production performance. The results show the available power generation capacity and the possibility to feed sufficient water to the cooling water circuit for contentious operation.

Along with higher performance and smaller size of electronic devices, the use of high-power components and the higher density of component mounting are being promoted. When the heat generation density increases and the temperature of the mounted component rises, the component malfunctions and becomes unstable. Therefore, it is necessary to efficiently dissipate the heat generated in the component. Further, in order to secure the mounting reliability of the component, it is necessary to enhance the heat dissipation from the component and at the same time reduce the difference in thermal expansion between the component and the substrate. Therefore, we are developing a new printed circuit boards that has both high heat dissipation and low thermal expansion.

As concerns over the environmental impact of rising CO2 emissions such as global warming, CCUS (CO2 capture, utilization and storage) is becoming important. While there are various ways to capture and separate CO2 from gas streams, physical adsorption methods with packed beds are a promising approach because the methods provides high purity CO2. In this study, we have developed a physical model of the packed bed column for CO2 capturing to understand heat and mass transfer occurring inside the column. By calculating and analyzing the model, we found that the temperature field inside the column determines characteristic profiles of breakthrough curves. As a result, an effective usage of adsorption capacity has strong dependence on the column diameter under constant space velocity of inlet gas.

In recent years, with the development of industrial technology, interest in technologies that utilize the evaporation of multiple droplets, such as thin film formation technology and spray coating, has been growing. It is used for applications and further progress is expected. However, most of the studies on droplet evaporation that have been conducted so far focus on the evaporation phenomenon of a single droplet, and the knowledge about evaporation of multiple droplets is still limited. In the present study, we carried out the evaporation experiment of the droplet which placed adjacent to a wall to simulate multiple droplets, and studied the evaporation behavior.

The interface between stearyl trimethylammonium (STAC) and palmitic acid (PA) vibrates spontaneously because of chemical nonequilibrium. This dynamic motion of the interface is often referred as “blebbing,” and explained as the gel formation and the change in its thickness with time. In this paper, the influence of gel formation by the chemical reaction and blebbing at the interface on the displacement process has been investigated in Hele-Shaw cell. Gel formation at the interface stabilizes the fingering with an increase in the injection rate, in contrast to normal viscos fingering associated with the viscosity ratio. In injected aqueous phase, unique residual oil blobs which grow from the web-like structure at the interface was found. This oil residual process was similar to spinodal water repellent. When injecting the oil phase into the water phase, blebbing was observed at the interface. This blebbing causes a decrease in the replacement area.

Moderate or Intense Low-oxygen dilution (MILD) combustion was studied by utilizing data driven techniques. It was found that MILD combustion yields relatively small scalar gradients whereas intense reaction zones were predominantly observed. This could be caused due to local ignition and flame interactions in the combustion field. Such zones are identified in direct numerical simulation (DNS) field with appropriate thresholding of scalar gradient and reaction rate. Then, a data driven model for predicting local combustion modes was proposed and validated for large eddy simulation (LES) context, using filtered DNS data at various filter sizes.

The delay of the heat transfer increase against the rapid acceleration of the pipe flow was investigated through the measurement of fluctuations of flow and heat transfer. Immediately after the rapid acceleration of the flow, the pressure loss increases due to an increase in the wall velocity gradient. However, since the turbulence in the pipe is almost the same as before the acceleration, the heat transfer coefficient is almost unchanged. Then, after a short delay, generation of turbulent spots increases the heat transfer coefficient. By systematically changing the Reynolds number, it was revealed that the delay until the turbulent spots generate after the acceleration strongly depends on the turbulence intensity before the acceleration.

A Magnus wind turbine having the rotating cylindrical blades with fins has a high performance. Previous studies have shown that the lift characteristics change depending on the fin shape. In this research, the fluid force and the flow field for a rotating cylinder with a straight fin were measured to understand the effect of a fin on the lift force fluctuation. The results showed that the vortices generated by a fin enhanced the circulation around the rotating cylinder with a straight fin. Therefore, the lift variation is affected by the vortices behavior.

Ocean thermal energy conversion (OTEC) is a system, which uses the seawater temperature difference between the surface and the deep to generate electricity. The balance of performance of components will determine the net power output from OTEC. Previously, the finite-time thermodynamics (FTT) models has been constructed for calculating the maximum net power of OTEC heat engines. This research evaluates the power output characteristic of 15kW OTEC system using cross-flow plate heat exchangers by comparing the exceptional data with the theoretical maximum power output based on FTT. In the experiment, the Rankine cycle using pure ammonia as a working fluid was used. As the results, the analysis of the experimental results show the power generation characteristic and the overall internal irreversibility of heat engine.

The effects of core material on the extinction characteristics of the flame spreading over electric wires have been investigated. The theoretical analysis reveals that heat loss in the unburned zone has a negative feedback mechanism for the flame spread process. The reduction of the flame spread rate increases heat loss in the unburned zone and induces the quenching extinction as a result of extended thermal diffusion length. It is also found that a highly conductive wire increases heat loss rather than poorly conductive wire even under the same flame spread rate. Lastly, applicable conditions of the model are discussed based on the correlation between the thermal boundary layer and the stand-off distance of the spreading flame.