Recently, the demand of high power lithium-ion batteries has become higher. If lithium-ion batteries are used in high power application, the battery capacity degradation due to heat generated from inside of the batteries becomes a problem. Therefore, we have studied about cooling structure of lithium-ion battery modules to increase the power of lithium-ion batteries. The lithium-ion Battery module that we developed has two important points. Firstly, we applied the aluminum die-casting case having flow paths as a module case. Secondly, we applied the thermally conductive compound. The results of the experiment, we verified that the battery module can be used in the 6C(C-Rate) charge-discharge cycle.

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Lithium-air battery attracts great attention because of its high energy density. The great advantage of an aqueous type is that discharge reaction products can be soluble in electrolytes. However, it precipitates in the positive electrode when the concentration of the electrolyte excesses its solubility. It is considered that the discharge reaction products cause cell performance degradation and its precipitation mechanism needs to be clarified. In this study, we observed the discharge reaction product in the positive electrode by using low energy X-ray computed tomography (CT). As a result, it was clearly shown that the discharge reaction products were mainly produced in the positive electrode near the electrolyte.

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Lithium air batteries receive significant interest because of their extremely high theoretical energy density. However, low solubility of oxygen in aqueous electrolyte limit oxygen transport to the reaction site, and effects of dissolved oxygen concentration on battery performance have to be understood fundamentally. In this study, oxygen concentration in aqueous electrolyte and thickness of the positive electrode were changed. As a result, strong impact of dissolved oxygen concentration on discharge characteristics were observed, and importance of enhancement of the oxygen transport to the reaction site was suggested.

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Lithium air batteries have received much attention recently. However, they have a problem with their low output density due to insufficiency of oxygen. In this study, we focused on lithium air batteries with an electrolyte flow which were considered to promote oxygen transfer. We calculated an electrolyte flow and oxygen transport in the cathodes by Lattice Boltzmann Method (LBM). Then, we compared output performances and pump performances, which achieve the target output (70 kW), between various structures of the cathodes. As a result, it is considered that reducing the flow rate of the pumps is strongly required to realize the reasonable performances of lithium air flow batteries.

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This paper carries the numerical analysis on dynamic behaviour of a tubular Solid Oxide Fuel Cell (SOFC), particularly relating the operational parameter of the fuel utilization (FU) given as a ratio of fuel consumption to its supply. The transient response of the voltage to the change in the current was studied in several FU levelled conditions. The response lag due to diffusion of hydrogen in a fuel flow channel has a certain consequence in elongate the voltage response. It was also found that the difference in diffusion model does not result in the voltage response, but the voltage performance.

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A two-dimensional comprehensive CFD model for anode-supported planner solid oxide fuel cells (SOFCs) is developed to study the performance the cells. The electrode microstructures of the anodes are quantified using FIB-SEM measurements and implemented to the simulation. The model is verified from a short stack experiment with a standard power output of 100W. The simulation results have a good agreement with experimental data, and reveal the relationships between the cell performance and the electrode microstructure. In addition, effects of temperature on the potential loss are presented.

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Cost reduction is the key challenge for commercialization of fuel cell vehicles, and reduction of Platinum amount in catalyst layer without sacrificing performance is essential. To understand the effect of Platinum loading on the transport phenomena within the cathode catalyst layer, performance test and cyclic voltammetry were carried out. Results suggested that local transport loss within the cathode catalyst layer was not fully captured with a normalized Platinum surface area. Furthermore, effect of Platinum loading on nanoscopic structure of the catalyst layer, and more detailed investigation is required to understand the phenomena within the cathode catalyst layer.

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Several studies have reported that oxygen transport in ionomer in a PEFC catalyst layer (CL) is the rate determining process. To understand oxygen transport phenomena in ionomer in detail, diffusion-limited currents were measured by using the model electrode which simulates the system near platinum in CL under various film thickness, relative humidity and equivalent weight conditions, and oxygen transport properties were examined in this report. The presence of transport resistance which does not depend on the film thickness, dissolution resistance at the interface, was confirmed from results. Furthermore, it was found that dissolution process for ionomer thin film in CL is the rate determining process and oxygen diffusivity and solubility improve with an increase in the water content of ionomer.

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Single-layer electrodes (SLEs) were used instead of the conventional multi-layer electrodes for polymer electrolyte fuel cells (PEFCs). The cell consists of a polymer electrolyte membrane, catalyst layers and separators with a microchannel. Removing microporous layers and gas diffusion layers has a potential to enhance the through-plane mass transfer efficiency. The largest challenge is degradation of in-plane diffusivity of gas and water under the ribs. In this study, two types of the cell were developed for the fundamental understanding of gas and water transport in the SLE-PEFCs. The cells indicated that overpotential under rib is much larger than that under the channel of the cathode.

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In this study, three-dimensional, non-isothermal, and unsteady numerical model considering liquid water in gas channel and GDL have been developed to investigate effect of water transport on cell performance. In addition, a novel gas channel with micro grooves is improved the liquid water discharge from GDL to gas channel, and have a high limiting current density. Thus, the effect of liquid water in the flow channel with micro grooves on the unsteady responses of PEFCs membrane resistance was discussed. As a result, accumulated liquid water in the flow channel has a significant influence on time responses of membrane resistance to prevent the gas transport.

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The water management has a significant effect on power generation performance of the Polymer electrolyte fuel cell (PEFC). Water distribution and temperature distribution give interaction, then the temperature distribution is required for optimizing the water management. Thus to obtain the temperature distribution by the multipoint measurements are important. We have developed the thin film thermocouples by using Micro Electronic Mechanical Systems (MEMS) technology, and the thermocouples are inserted and measured multipoint of local temperature in cells. Finally, we measured temperature difference of 2 degrees between the current collector and the CL.

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Water management is very important in the development of the PEFC with high performance and high reliability. The purpose of this paper is to present a new method for utilizing the generated water to humidify the polymer membrane actively. We have developed a humidity control porous rib system. The rib is made of a humidity control material, for example, a diatomite. We consider it is possible to reuse condensed water at the outlet side for humidifying the inlet air by switching the inlet and the outlet of the gas. In this study, experimental and numerical examinations were carried out to understand the effect of the humidity control porous rib on the water behavior and the cell performance of the PEFC.

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Performance degradation of polymer electrolyte fuel cells (PEFCs) is caused by water flooding and plugging on cathode side. In this paper, the liquid water behavior in the cathode channel of a PEFC was observed directly by using cross-sectional visualization technique. Furthermore, the effect of hydrophilic treatment of the channel wall on the through-plane liquid water transport and performance characteristics was discussed considering operating conditions.

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To improve power density of polymer electrolyte fuel cells (PEFCs), it is essential to understand oxygen transport mechanism inside fuel cell. We have investigated the possibility of applying tunable diode laser absorption spectroscopy (TDLAS) technique to measuring oxygen concentration within micro-channel of fuel cell. In this study, the fiber-optic laser spectroscopy system for high-speed and high-sensitive detection of oxygen gas was developed based on TDLAS method, and the oxygen concentration in a gas cell was tentatively measured using this system. It was noted that the long optical path length of 200 mm enables the high-accurate monitoring of oxygen concentration.

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The object of this paper is to study the improvement of performance in a looped-tube-type thermoacoustic cooler with branch resonator by additional bypass-looped tube with stack as the double loop-tube-type thermoacoustic cooler. By measuring the pressure in the tube using two-sensor method and numerical simuration using FDTD method, pressure, particle velocity, and phase difference were made clear in relation to the stack structures. The calculated results showed the traveling wave component increased in the original looped tube by connecting bypass-looped tube. The higher cooling performance of the double loop thermoacoustic cooler was indicated experimentally in comparison with the single looped type.

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We aim at investigating a mathematical model for a desiccant rotor heated directly by concentrated solar irradiation using a non-imaging Fresnel lens in the desorption process. The ray irradiates along with narrow channel in the rotor. The model considered the distribution of solar irradiation in the rotor based on the measurements. In addition, the experiment for measuring dehumidifying rate was performed to compare with the calculation and to confirm the validity of the model. According to this model, the total dehumidifying rate of rotor was predicted by numerical simulation. Finally, the influences of operation parameters such as flow rate, input energy, temperature and humidity on the rate were clarified.

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Using biogas that is generated from the gasification furnace as fuel (diameter 6mm, 15mm in length) wood pellets was driving a small spark ignition engine (290cc). When performing the analysis of the combustion product gas as fuel small spark-ignition engine, stable operation of the engine is determined. However, composition and flow rate of the product gas will to some extent vary, can not be expected a stable operating the rotational speed of the engine also fluctuates. Therefore, the gas holder is installed between the gasifier and the engine was investigated the effect of the volume of the gas holder has on the rotational speed of the stability of the engine.

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This paper describes the performance (generated electric voltage and current) of thermoelectric conversion system under the condition of continuous heating (200 hours) and cyclic heating (300 cycles). In this experiment, the Seebeck element was used as the thermoelectric conversion element. When the setting temperature of the heating side was 180 ℃, the generated power was maximum. When the module was heated for 200 hours at 180 ℃ (heating side), the output voltage declined 5 %, and the current value reduced or increased about 10% by 200 hours heating. However, the ratio of reduction is not constant at each temperature and the relationship between the temperature difference, the voltage and current were sometimes not proportional. The temperature difference between each element was increased to 80 ℃ by using a cooling fan. When the module was heated from room temperature to 180 ℃ with 40 minutes interval for 300 times, the output voltage and current fell about 15 %.

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An in situ viscosity measurement can enhance both quality and efficiency of production process by detailed observation of the phenomenon in the process through monitoring real time viscosity fluctuation. In the present study, prototype of optical hand-held viscosity sensor has been developed in order to attempt easy and quick hand-held measurement. The proposed sensor enables non-contact high speed viscosity sensing based on an optical measurement method called laser-induced capillary wave method. In order to robustly detect the intensity of the first-order diffracted signal which contains the information of the viscosity, the surface tracking system and distance monitoring system has been developed and integrated on the sensor. The experiment using the proposed hand-held sensor to detect the signal while controlling the incident angle of laser and timing of measurement has been performed.

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Surface tension of any fluid is crucial for multiphase systems and is often manipulated during industrial processes by introducing surfactants. Normally, water used in an industry includes impurity such as salt. In this study, effect of sodium chloride concentrations, microwave power and time on surface tension of aqueous solution was investigated under microwave irradiation. It has found that surface tension decreased quickly, while temperature increased during microwave. Once the radiation is turned off, the temperature returns rapidly as expected. However, surface tension recovery was much slower than temperature. Moreover, the recovery and reduction amounts by non-thermal effect depend on the power and concentrations.

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This paper reports formation of the gas-containing semiclathrate hydrate from tetra-n-butylammonium (TBA) carboxylates + CH_4 gas. Formation conditions of the gas hydrates were measured by the isochoric method using the high pressure autoclave. The TBA acrylate formed gas hydrates with CH_4 gas. Four stages of the hydrate formation were observed, which means that four hydrate phases may exist in the system. The phase diagram showed that there is the phase property-change depending on the formation pressure. Characterization of the TBA acrylate + CH_4 hydrate phase was also performed by the single crystal X-ray diffraction measurement. The crystal structure was identical with the TBA acrylate hydrate formed in the absence of gas, however, CH_4 molecules were found in the dodecahedral cage.

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The comparison method of measuring thermal conductivity is simple in construction of apparatus and measurement theory. So it has been widely used to measure thermal conductivity of various kinds of materials. In this study, the contact thermal resistance between standard material and specimen was examined by using numerical simulation, when the thermal conductivity of SUS304 was measured by using copper cylinders as the standard material. The thermal conductivity of SUS304 measured by using our apparatus was lower than the reference value over 30 %. The reason of the different between measurement and reference values was explained by assuming to have respectively different thermal resistances on the contact surfaces of specimen. A dimensionless number which can show the effect of the contact thermal resistance was also derived.

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In measuring thermal conductivity of a glass fiber, thermal radiation may have a large influence on its accuracy. In this research, the influence was closely investigated to find proper experimental conditions for the measurement. As a result, by inserting a fiber into a radiation shield maintained at about the average temperature of the fiber, it was found that the influence could be reduced to within 5 %. By measearing the thermal conductivity of E-type glass fiber under such a condition, those of 0.2 W/(m・K) and 0.9 W/(m・K) at 20 K and 94 K, respectively were obtained.

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Total knee arthroplasty (TKA) is a surgery to replace the damaged surface of knee joint with a prosthesis. In the surgery, polymethylmethacrylate bone cement is used between the prosthesis and bone tissue. Although temperature rise during polymerization of the bone cement has a risk of thermal damage to the surrounding tissue and cells, it has not been elucidated. Therefore, we performed 3D heat conduction analysis based on CT images to evaluate temperature distribution during bone cement polymerization. The result showed that the maximal temperature rise reached 50℃ at the interface between bone cement and tissue, which was high enough to induce thermal damage to osteocytes. However, the damaged region was very restricted to immediately beneath the tibial tray of the prosthesis.

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Cryosurgery is a surgical technique that applies a low temperature source into the human tissue so as to remove the tumor. Cryosurgery includes several heat transfer mechanisms such as blood perfusion, phase change, and metabolic rate. Blood perfusion affects the size of the ice ball during cryosurgery. Commonly, the bio-heat equation needs to be solved to consider the blood perfusion effect. The objective of this study is therefore to investigate the possibility of using an effective thermal conductivity instead of solving the bio-heat equation. Based on the calculated temperature distribution, the effective thermal conductivity can be used under certain conditions.

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Cryoprotective effect of dimethylsulfoxide, as the most useful cryoprotectant, and pressurized dissolution of Xenon gas was used together, and the enhancing effect of damage reduction in cryopreservation of cells was investigated. Human dermal fibroblast of monolayer culture in a culture dish was prepared for a test sample. Dimethylsulfoxide concentration was 10%. Four samples were piled and placed into a pressure-resistant chamber, Xenon gas was pressurized at approximately 0.5 MPa for dissolution, and then decompressed to atmospheric pressure. The samples were frozen from -5 to -40℃ at 0.1-1℃/min, cooled to below -150℃, and then thawed. Post-thaw cell activity was evaluated using the water-soluble tetrazolium salts assay. As a result, the effect was enhanced by pressurized Xenon gas on the conditions of a cooling rate lower or higher than 0.3℃/min, as the optimal cooling rate.

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Active enhancement of supercooling is one of the promising techniques for high-quality cryopreservation. The object of this paper is to study the effects of alternating electric field on a supercooling of biological cell. In the experiments, onion skin cells were cooled at constant cooling rate using a directional solidification stage, with applying alternating electric field at frequency of 1kHz. As a result, it was found that the load effects of low electric current on cell enhance supercooling degree, but also those of high electric current reduce supercooling degree. The effects of electric field on surface-catalyzed nucleation on cell membrane were discussed in relation to electric current and cooling rate.

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We have investigated experimentally the turbulent diffusion processes of ethylene emitted from a point source in the upstream region of a two-dimensional hill model installed in a flat-plate turbulent boundary layer. The mean concentration distributions around the hill model were measured by a homemade flame ionization detector (FID), and the effects of flow characteristics of the incoming boundary-layer on the concentration field are discussed. Depending on the boundary layer thickness just upstream of the hill model, a maximum-value location of the mean concentration distribution in the downstream region of the model moves vertically with respect to the dividing streamline of the separation bubble, and the spanwise distribution becomes wider as the boundary-layer thickness is thinner than the hill height.

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A technique using high-speed infrared thermography was used to measure the spatio-temporal heat transfer to a pulsating flow in a circular pipe. Rectangle-shaped pulsating flow was generated by solenoid valve installed at downstream of test section. The flow was turbulent (Re_D = 13000) at maximum flow rate and early turbulent (Re_D = 3000) at minimum flow rate. At the time of deceleration, complicated heat transfer structure appeared, and which remained with spreading toward streamwise. Thus heat transfer coefficient decreased gradually although flow rate decreased rapidly. On the other hand, at the time of acceleration, heat transfer coefficient was kept low value until flow turbulence was generated although flow rate increased rapidly. Then heat transfer coefficient increased rapidly with growing turbulent.

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The heat transfer of natural convection from upward facing-horizontal heated surface which a heated annular duct was placed above was investigated experimentally. The relationship of the heat transfer to the distance of between the horizontal heated surface and the heated ducts was examined. The flow fields around the heated surface and heated ducts were visualized. With decreasing the distance, the ascending flow velocity in the heated ducts becomes low and the reverse flow occurs. The heat transfer increases with decreasing the distance. Inserting a heated inner duct enhances the heat transfer.

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A numerical study has been performed for combined natural convection and thermal radiation heat transfer in the air-filled enclosed space. Finite volume method and SIMPLE algorithm has been applied for computation. A radiative Nusselt number increases with increase of emissivity, in addition, a natural convection is enhanced by thermal radiation and convective Nusselt number also increases. When the temperature of the heating surface is high, convective Nusselt number and radiative Nusselt number are about the same order and the total Nusselt number becomes very large.

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Direct numerical simulations of a spectral method were performed to study turbulent structure and heat transfer mechanism in Couette flow at transitional region under stable system rotation. To compare the flow structure, we also calculate the same friction Reynolds number flow without any rotations. The Prandtl number is 0.71 to assume air. A stable system rotation makes the flow relaminarising, turbulent stripes are observed near the walls, though the stripe is not observed in the flow at same friction Reynolds number condition without system rotation. The turbulent region enhances both friction and heat transfer, and temporal oscillations were occurred due to the advection of the turbulent region.

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Totally enclosed motor for traction motors of the train and industrial motors can prevent intruding dust and extend the period of disassembly and cleaning. It is difficult to radiate the heat which generate inside the motor during operation. For further cooling performance improvement, the cooling structure by which inner air agitation and the outside ventilation are possible by using one fan was considered. Moreover, cooling performance was improved by the structure which cooling wind was inhaled in both sides of the motor and was exhausted at an iron core center. This paper describes the result evaluated by CFD about the coil temperature of the motor.

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Vortex structure behind highly heated cylinder in a pulsating air flow is investigated experimentally. The pulsating flow is generated by a loud speaker up to 0.6m/s while the main flow sets 1m/s. The heat flux of the heated cylinder sets up to 72.6kW/m^2 then the maximum surface temperature of the cylinder reaches to about 600℃. In the non-heating condition, the generating vortex frequency follows the pulsating main flow velocity. However, in the highly heated condition, the vortex frequency cannot follow the pulsating flow.

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When a depressurization accident occurs in the Very-High-Temperature Reactor (VHTR), a mixing process of different kind of gases occurs. Then, in order to research mixing process of two component gases and flow characteristics of localized natural convection, we have carried out the numerical analysis using three dimensional CFD code. The numerical model was consisted of a reverse U-shaped vertical slot and a storage tank. The left side slot was consisted of a heated wall and a cooled wall. The right side slot was consisted of two cooled walls. The heavy gas was transported to the slot by the molecular diffusion and localized natural convection. And then, natural circulation generated through the reverse U-shaped slot. As a result of three dimensional analysis, gas mixture was promoted by flow of depth direction and natural circulation generated faster than that of two dimensional analysis.

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In this study, two-phase immiscible polymer blend with selective radiation heating by infrared laser is studied numerically. The phase-field model of a non-isothermal flow, which accounts for laser induced temperature field, two-phase flow with interfacial tension and Marangoni effect, was developed. This model was used to simulate a droplet deforming in shear flow with various shear rate, droplet size and laser irradiation power. Based on the simulation results the effect of the selective radiation heating by infrared laser to the droplet deformation, the break-up situation and the micro-structure of the polymer blend was discussed. The paper concludes with suggestions for future research and potential applications.

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LES is a promising tool for predicting local entropy production in turbulent flows. Currently, there is no numerical model available for industrial design with an acceptable cost and prediction accuracy. Therefore the purpose of this research is modeling the entropy production in turbulent heat transfer fields, based on the filtered transport equations for LES. The entropy production in turbulent flows occurs in two ways: viscous dissipation and heat conduction. In our earlier work, the production by viscous dissipation was in quantitative agreement, but the production by heat conduction was not. In this paper, we introduced improved models for the production by heat conduction. One of the three models that were considered in this paper shows a smaller difference between DNS and LES.

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It is important to predict temperatures in tunnels accurately in order to find a way for reducing power consumption by ventilation fans placed in tunnels or by air conditioners placed in underground train stations. RTRI has been developing a method of simulating the thermal environment in tunnels. To improve the simulation accuracy, modeling of the heat transfer by the groundwater flowing in the surrounding earth of the tunnel and that of heat generation in the tunnel has been modified. We found the difference between the results of the simulation and the field test becomes smaller in consequence of the improvement of the model.

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The objective of this study is to investigate an entrance region of thermal field in turbulent flow having various wall thermal conditions, thermal stratifications and pressure gradients via direct numerical simulation (DNS), in which both the internal and the external turbulent flows are carried out. In this study, DNS clearly provides distributions of local Nusselt and Standton numbers in an entrance region of thermal field of turbulent flow having various wall thermal conditions, thermal stratifications and pressure gradients. The different distributions of these numbers are observed, and understanding of turbulent characteristics of thermal entrance region is expanded.

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In wall jet region of impingement jet, installation of rib turbulator is an effective technique to prevent rapid decay of local heat transfer. Two-dimensional impingement jet cooling on ribbed walls has been studied by Concurrent-LES to reveal the effect of rib-height on heat transfer enhancement. As a result of simulations, higher rib-height was found to be effective to enhance heat transfer. The use of Concurrent-LES and correlation coefficient realized the direct and quantitative comparison of instantaneous turbulent structure among two different ribs. It was confirmed that turbulent structures are not affected by the rib height in the upstream, but much affected in the downstream.

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This study searched for the possibility of hydrogen generation by oxidizing metal with high temperature super-heated steam (SHS). The temperature of SHS was set to 573, 873 and 1173K. And we used 3g of Fe powder as the object of oxidation. The results showed that it was possible to generate hydrogen by oxidizing Fe powder with SHS and that the higher the temperature of SHS was the bigger the amount of generated hydrogen became. We will inspect the amount of hydrogen generated by oxidizing metal with SHS at a temperature higher than 1173K in the future.

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Solid-liquid interfacial thermal resistance is thermal resistance defined for temperature jump at the interface between solid and liquid which have different temperatures. Solid-liquid interfacial thermal resistance is a microscopic phenomenon that of elucidation of the heat transfer mechanism is needed. Therefore, in the precedent study, in the case of a nanoparticle layer accumulated on to a heat transfer interface, effects of thermal conductivity of the nanoparticle layer, its thickness, and wettability on solid-liquid interfacial thermal resistance has been investigated by the molecular dynamics analysis. However, about this study, the quantitative evaluation by experiments is not performed yet. Therefore, our goal is to experimentally evaluate thermal resistance using a nanoparticle layer and compare the result with the simulation. In this study, we experimentally and quantitatively investigated the thermal resistance of an interface between a molten salt nanofluid and stainless-steel heat transfer surface, where zirconia nanoparticles accumulated having an enough temperature gradient.

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To confirm the possibility of aluminum use on PHE plate for ocean thermal energy conversion (OTEC), the corrosivity and heat transfer tests using PEEK resin and WIN KOTE film coated aluminum blocks under ammonia or ammonia/water environment were performed. These coated blocks were immersed ammonia or ammonia/water during 2 months at saturated pool boiling condition. After these immersing test, these heat surface conditions were not or slightly changed, and these heat transfer coefficients were not also changed during 2 months. Then, it is found that these aluminum coating methods are available for using ammonia boiling environments such as PHE of OTEC.

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Characteristics of particles of thermo-sensitive gel in temperature-stratified polymer solution have been observed. Porous gel of N-isopropylacrylamide (NIPA) which generally has volumetric transition temperature around 32 ℃ in pure water was synthesized as porous medium and then covered by a layer of hydrophilic hydrogel. The rates of both particle-wall and inter-particles adhesion were decreased compared with those of gel particles without the outer layer. The particles in the polymer solution where temperature varied vertically between 10 to 40 ℃ periodically moved up and down at a period of about 15 minutes which is longer than that of particles without the outer layer.

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This paper proposes new heat removal devices utilizing unidirectional porous media against extremely high heat flux conditions. Before that, we discuss effective thermal conductivity, permeability, and contact thermal resistance etc. for several porous media. The discussion suggests to utilize the unidirectional porous media from the view point of its higher thermal conductivity, direct supply of cooling liquid toward the heat transfer surface, discharge of vapor, reduction in flow resistance and the thermal contact resistance.

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We compared four kinds of heat exchangers made of porous material. Moreover, we proposed a new model which predicts the performance of the porous metal fins. Heat transfer coefficient of porous metal fins can be predicted within an error of 10% by our model. The predictive model has two assumptions. One is that the perimeter in the porous metal fin per cross-sectional area of that is independent of the heights of fins and number of porous cells. Another assumption is that heat transfer coefficient of porous metal fin is also independent of the heights of fins and number of porous cells.

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Based on biphasic mixture model including swelling effect, frost heaving for swelling soils has been investigated theoretically. For both periods of freezing and no freezing, the calculated results for swelling pressure were compared with the experimental results using bentonite particles. In period of freezing, the increase in swelling pressure is related to the increase in the solid fraction due to separating of particles from freezing front. In period of no freezing, the increase in swelling pressure is related to the equalization of the solid fraction distribution due to the diffusion of swelling particles combined solid and liquid attributes.

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In this study, the steam generation by using the porous media was reported. We have been developed a superheated steam generator using tubular flame for household use. However, it needed a long start-up time due to the large capacity of the pool water surrounding the heat source. In this study, the porous media was used for a rapid steam generation by setting around the heat source instead of the pool water. Water was absorbed by the capillary force and the steam was generated successively by the heat conduction through the porous media. In this report, the absorption water level is estimated by a capillary tube model.

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Effective thermal conductivity with contact resistance is analyzed by a homogenization method that can precisely represent the microstructure of a packed bed. The homogenization used in this study explains the heat transfer due to conduction through the solid, the fluid phase, and the contact area between particles, and radiation between solid surfaces. In particular, the effects of parameters, such as the hardness, contact pressure, roughness, temperature, and particle size of the packed bed, on conductivity are estimated in order to clarify the thermal conduction mechanism for the complex packed structure. Heat transfer with thermal contact resistance does not dominate if the Biot number is near 100. Moreover, thermal radiation in the bed becomes more important for larger particles (>1 mm) and contact resistance can be neglected.

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Large eddy simulation (LES) of conjugate heat transfer in a porous medium is performed by the lattice Boltzmann method to discuss on the unknown terms of the double averaged energy equation for modeling those terms. The D3Q19 SRT model with the regularization procedure is applied to the temperature fields in a cube matrix while the D3Q27 MRT model is applied to the velocity field in this study. The behaviors of turbulent and dispersion heat fluxes are studied by using LES data.

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