The ground source heat has recently attracted considerable attention as the renewable energy. The temperature of the underground less than 100m depth is constant by geothermal energy throughout the year. Thus, the ground source heat pump (GSHP) is one of saving energy systems. The GSHP system radiates heat at the cooling mode to the underground and extracts heat at hte heating mode from the underground. This paper describes the influence that operation of the GSHP system gives to the underground temperature. As a result of the experiment, it was found that both the cooling and heating mode gave only less than 2℃ change of the underground temperature.

抄録全体を表示

Absorption characteristics of water vapor into a LiBr aqueous solution falling down along a cooled vertical wall have been investigated experimentally. Metal foam is attached to the cooled wall, and a hydrophobic membrane covers the metal foam surface to prevent the solution splashing. In the case without membrane the mass flux of vapor absorption increases with increasing the solution flow rate or lowering the inlet solution temperature. The mass transfer coefficient for the case with membrane was less by approximately 50% than that without membrane.

抄録全体を表示

This paper describes the performance of GSHP (Ground Source Heat Pump) system that uses the direct expansion method. In the experimental apparatus, a borehole is 30 m in depth and R410A is used as a refrigerant. The ground source heat pump was operated continuously for 48 hours with the cooling mode. Temperature and pressure of the refrigerant were measured at 5 positions. Air temperature at the entrance and exit of an indoor unit were also measured. As a result of the experiment, the coefficient of performance (COP) of the GSHP became 12 when the set value of the room temperature is 27℃.

抄録全体を表示

This papeO

抄録全体を表示

This paper investigates critical heat flux (CHF) in saturated pool boiling for water and nanofluid on a 7 mm diameter vertical copper surface at pressures 0.1 to 0.8MPa. The nanofluid was prepared by dispersing TiO_2 nanoparticles with the concentration of 0.002wt% in deionized water. The CHF of the nanofluid was enhanced 2.4 times the CHF in water boiling at atmospheric pressure. With increasing pressure, however, the CHF enhancement effect by the nanofluid is decreased, and disappeared at pressures higher than 0.6MPa. It was also found that the well-known CHF correlations by Zuber and Lienhard predict considerably smaller CHF values than the present data for water boiling at high pressures.

抄録全体を表示

Focusing on the heat transfer mechanism of the MEB we are trying to express the heat transfer characteristics of subcooling boiling based on the microlayer model. This paper presents an estimation of bubble-formation and condensation period on the heating surface with high-superheat under the larger subcooling conditions. The heat transfer rate is estimated for higher heat flux than the CHF and compared to the experimental data for wire heating. The comparison indicates that there is a possibility to express the heat transfer of MEB by the microlayer model for subcool boiling.

抄録全体を表示

An effect of dissolved air on bubble growth from hydrophobic spots has been experimentally studied. Experiments were conducted using pure water at a subcooling of 20 K and the atmospheric pressure. Dissolved air produces negative wall superheats at the bubble incipience from hydrophobic spots and enhances bubble growth. The shape of bubbles attaching on the hydrophobic spots are also different between an open and closed conditions. It is assumed that this difference is caused by existence of air inside the bubble. In the open condition, the bubble consists of vapor and air and saturated temperature of the bubble is lower than saturated temperature of pure vapor, therefore the bubble grows over superheated liquid layer.

抄録全体を表示

This study aims to elucidate the break characteristics of liquid film formed between approaching bubbles in the process of bubble coalescence. The coalescence of horizontally contacting twin bubbles was experimentally studied in isothermal system. The bubbles were generated at the outlets of two pipes that face each other horizontally. Liquid film thickness formed between approaching bubbles were measured by the modified laser extinction method. The variation and the distribution of liquid film thickness between bubbles were investigated. The air flow rate, sample liquids and the measuring position of liquid film thickness were adopted as the experimental parameters.

抄録全体を表示

This study evaluated boiling heat transfer in a quasi-two dimensional space by visualizing both flow structure near a heat transfer surface using particle image velocimetry and liquid film beneath bubbles using back light method, simultaneously. In isolated bubble region at low heat flux, a single bubble pushed aside superheated liquid near a heat transfer surface and a rising bubble formed a wake and a vortex to enhanced convection on the surface. In coalesced bubble region at high heat flux, the evaporation of liquid film took place mainly while detaching coalesced bubbles induced relatively fast downward flow occasionally. Estimated liquid film thickness decreases as heat flux increases in agreement with earlier studies.

抄録全体を表示

The present paper investigated an effect of pressure on boiling heat transfer mechanism by using the MEMS technology. Steady state pool boiling experiments were conducted by using a copper thin-film for the test heater and pure water at atmospheric condition for the test liquid. The system pressure was 0.010 and 0.10 MPa, respectively. The heaters were made of a printed circuit board and a quartz glass with sputtering copper film. The test heaters had an artificial cylindrical-cavity. The cavities were fabricated by using the MEMS technology, i.e., wet etching technology. The mechanism of critical heat flux on a single boiling bubble was examined through observations of the present experiments.

抄録全体を表示

This study has been investigated characteristics of phase change heat transfer at the liquid-vapor interface around a boiling bubble using laser interferometry. Initially, to evaluate measurement accuracy of the used interferometric temperature measurement technique, a temperature field of water around a heated fine wire was measured and the temperature data was compared to the result of a transient heat conduction simulation. It was indicated that laser interferometry was available for temperature measurement in fast and local heat transfer phenomena such as liquid phase heat transfer in boiling. In the boiling experiment, a temperature field around a spherical bubble growing in the superheated water was measured. Over 80% of heat flux calculated from temperature gradient was measured with an uncertainty of ±30%.

抄録全体を表示

Subcooled flow boiling experiment was conducted using a MEMS sensor with high spatiotemporal resolution in temperature measurement in order to investigate the heat transfer mechanisms and also collect a benchmark data for validation of numerical simulations. The local wall temperature beneath boiling bubble was measured at a sampling frequency 50 kHz and a spatial resolution 40 μm. The developed MEMS sensor successfully grasped the fundamental heat transfer phenomena beneath a bubble rapidly departed from the heated wall in 3 ms, such as rapid evaporation and dry-out of the microlayer and rewetting of the dry-out area.

抄録全体を表示

Pool boiling heat transfer experiments were performed for deionized water at 0.101 MPa to examine the elemental process of pool nucleate boiling. The heat transfer surface was made from a copper printed circuit board. Direct current was supplied to the heat transfer surface to heat it up. The Bakelite plate of the backside of the copper layer was taken off at the center portion of the heat transfer surface. The instantaneous variation of the backside temperature of the heat transfer surface was measured with an infrared radiation camera. Bubble behavior was recorded with a high speed video camera. The variations of the surface temperature and the surface heat flux with time were obtained two-dimensionally for the isolated boiling region. The bound of the area affected by the boiling bubble was approximately 1.8 mm from a cavity.

抄録全体を表示

Experimental investigations were made on the vaporizing behavior of water droplet on heated brass surfaces with different polish finishes; rough polish #400 to extremely fine polish #15000 in comparison to previous studies. The surfaces were nickel & gold plated for good experimental reproducibility. Familiar lifetime curve with LFP was obtained in the case of intermediate polish, and the surfaces of rough polish required higher LFP, as was reported in previous studies. However, the droplet showed curious manner, bound with splashing fine droplets, and vaporized faster on the finely polished surface at surface temperatures just above LFP.

抄録全体を表示

This paper reports experimental results of both visual observation for liquid-solid contact situations and surface temperature measurement when liquid spray cooled superheated surface. A single crystal sapphire plate was cooled by HFE-7100 liquid spray from film boiling to transition boiling situation. The obtained results show that wetting initiation temperature was affected by initial surface temperature, liquid flow rate density and spray nozzle position. Wetting initiation temperature ranged between Leidenfrost temperature and spontaneous nucleation temperature of HFE-7100.

抄録全体を表示

The objective of this study is to clarify the role of ambient gas on hydrothermal waves in evaporating volatile droplets and evaporation. Experiments were conducted in a large chamber where the temperature and relative humidity of water can be controlled. An infrared camera and a CCD camera were used to determine the temperature distribution inside evaporating droplet and the profile of droplet, respectively. The liquids used here are ethanol and methanol. The minimum temperature in the droplet captured by infrared camera increased with relative humidity. Residual liquid was observed after evaporation of a volatile droplet whose volume increased with relative humidity.

抄録全体を表示

It is well known that the wet compression technique is effective to improve the performance of gas turbines. A thorough understanding of the droplet behavior within compressor is important to achieve full potentials of the wet compression. A model has been developed to investigate the evaporation time of a water droplet. The temperature of a water droplet has been calculated by treating the droplet as a lumped thermal mass with one representative temperature uniformly distributed in the droplet. It is assumed that the change of the water droplet temperature is caused by convective heat transfer through the droplet surface. Then the evaporation time of a water droplet has been calculated based on either evaporation or boiling conditions.

抄録全体を表示

Wicked heat pipe is well-known heat transfer device, operated with a two-phase working fluid. This operating principle is based on evaporation and condensation of working fluid, and circulation by capillary force. In this study, we visualized the fluid behavior inside the flat-plate heat pipe, especially at the evaporation region. The heat pipe performance depends on a number of factors, then we focus on the inner wall wettability and made different degrees of wetting conditions by coating the hydrophilic material. We will discuss how the wettability at the evaporation region affect the heat pipe performance.

抄録全体を表示

This paper numerically investigated the self-oscillating mechanism of the vapor-liquid two-phase flow in 1-turn oscillating heat pipe. The phase change is simulated by using the temperature-recovery method which is combined with the VOF(Volume of Fluid) method. It is found that difference of bubble rate between left and right channel and average vertical flow velocity have positive correlation. Thus, the self-oscillating mechanism is related to the difference of bubble rate between left and right channel which is caused by phase change. Furthermore, heat transport performance of methanol shows higher than that of ethanol due to the higher latent heat.

抄録全体を表示

An efficient numerical method for large scaled parallel computation is developed to investigate mechanism of Oscillating Heat Pipe (OHP). The flow inside OHP is approximated as compressible flow due to effect of pressure wave propagation from large temperature difference. Interface between gas and liquid phases is expressed by level-set and Heaviside functions. In this paper, effect of numerical dissipation of advection term is investigated to keep volume of a rising bubble. An innovative algorithm to solve acoustic system in the current time marching scheme should be considered to realize rapid large scaled parallel computation of OHP as a future work.

抄録全体を表示

A long - term change of nucleate boiling heat transfer coefficients in water and ammonia have been measured when a surface active agent was added into water and those have been measured on a heated wire that PEEK (Poly Ether Ether Ketone) resin was coated in ammonia. The experiment has been carried out using a thermosyphon with a plain heated surface and a pool boiling vessel with a heated fine wire. The effect of the surface - active agent and PEEK coating on the nucleate boiling heat transfer coefficient and time variation of the nucleate boiling heat transfer coefficient were investigated experimentally for the surfactant concentration, Cs=0 and 1000 ppm. The result shows that the nucleate boiling heat transfer coefficient never changes for a month in pure water and in ammonia with the heated wire coated by PEEK resin. On the other hand, the boiling heat transfer coefficient decreases gradually till the end of operation in water with the surfactant. The surfactant incresed the nucleate boiling heat transfer and PEEK resin decreased one.

抄録全体を表示

Expected to improve heat flux and to downsizing of power module cooler, by use of forced convective boiling heat transfer. However, about 100mm length was required for heat transfer surface and reduction of heat flux occurred in downstream area. Heat flux reduction was caused by inhibition of subcooled boiling. This study examined Enhancement of forced convective boiling heat transfer using spiral flow. By making liquid flow path layout and providing a step, spiral flow was generated. Results of the boiling heat transfer test by using the spiral flow path, temperature rise of the downstream was suppressed and length of subcooled boiling area became 1.8 times the straight flow path.

抄録全体を表示

The operating condition of the distillation column is strongly restricted by the flooding condition. Thus, several investigations of the flooding phenomena have been widely conducted so far, but most of those investigations were based on the experimental results in round tube with water-air two-phase flow. In this investigation, the flooding velocity was measured in an actual structured packing with air-water / air-HCFC(R-225) two-phase flow. In the experiment, the distribution of the liquid hold up was also evaluated by using X-ray radiography. Experimental results were evaluated by Wallis's equation, and the influence of the liquid surface tension clearly appeared as the fluid distribution and the flooding velocity.

抄録全体を表示

Understanding of reflooding phenomena under oscillatory flow condition in natural circulation loop is required for the development of emergency core cooling system of a LWR, simplified BWR and so on. In this investigation, the reflooding experiment was conducted with a natural circulation loop by using liquid nitrogen as working fluid. A heating section was made of the stainless steel tube and had a 4.0 in inner diameter, 5.0 in outer diameter and 1700 mm in heating length. In this experiment, a quench propagation velocity and wall temperature fluctuations were obtained. A surface heat flux and a heat transfer has been evaluated by one-dimensional heat balance.

抄録全体を表示

Heat transfer rate was evaluated in the heat exchanger that was consists of a heat transfer tube and a condensation tank. Thermal stratification affects the heat transfer rate when steam is injected into a tube through the condensation tank. Thermocouples were installed in the condensation tank to observe the temperature distribution inside. The heat transfer rate was evaluated by temperature distribution in the tank. As a result, the relation between the heat transfer rate due to steam condensation and surrounding cooling water temperature was obtained experimentally, and the behavior of heat transfer with thermal stratification has been revealed.

抄録全体を表示

From the viewpoints of advances in Electronic Devices, various cooling systems by air cooling and liquid cooling have been studied. However, these systems have some difficulty in downsizing because of the increase in power consumption and system structure. Chemical Heat Pump (CHP) can drive only by the device exhaust heat and downsize for the simple structure. In this work, we performed experiments and simulation of CHP using hydration/dehydration of CaSO_4/CaSO_4・1/2H_2O. As a result, the experiments and simulation showed the possibility of cooling of electronic devices using CHP driven only by the device exhaust heat.

抄録全体を表示

A high-height thermo siphon cooling apparatus for high-density packaging ICT racks has been developed. An evaporator is provided at the side face of the server, a heat exchanger with cooling water is set on the ceiling of the rack. The evaporator is connected to the heat exchanger each other by the grooved tube which vapor and condensed water pass through. A heat transfer plate of 3mm thick is vertically arranged in the evaporator. The grooves of equal pitch of groove radius 0.1mm are provided on this boiling heat transfer surface. The water in the evaporator could be supplied to the boiling heat transfer surface by the capillarity. The heat transfer coefficient K of the evaporation surface is more than 10kW/(m^2K) at heat input 200W. A temperature difference between vapor and the heater surface was 4℃ or less.

抄録全体を表示

Recently, it has become necessary to propose new cooling technology that can operate at both a high power and high heat density. We developed the JEST type loop heat pipe (JEST-LHP) that has a water cooled heat exchanger, and we conducted experiments. Moreover we examined the cooling performance and characteristics. As a result, when the size of the heating element was 707mm^2 (φ30), the maximum amount of heat transport was about 850W. Also the thermal resistance was about 0.07t/W, within ±5% error independent of the filling amount of refrigerant.

抄録全体を表示

The influence of flow path shape on the thermal performance of ultra-thin polymer pulsating heat pipe (PPHP) was experimentally investigated. We compared the thermal performances among three types of PPHP with different flow path structure: open end flow path with a flat cross section, closed loop flow path with a flat cross section, and closed loop flow path with slope and step structures. We found that the slope and step structures realized continuous supply of the working fluid to the heating section by producing circulating flow and improved thermal performance at a higher heat load.

抄録全体を表示

In order to measure the time-dependent pressure change in Oscillating Heat Pipe (OHP), we used the flow path of glass tube which has three branches for pressure measurement. Three temperatures at the glass tube surface and three pressures in OHP were measured at the same time. We verified that the pressures increase by about 2 to 15 kPa just before large movement of liquid column in the whole of flow path. We assume that this pressure increase is due to rapid vaporization of small droplet of working fluid at heating section. It changes the pressure balance in OHP and lead to large movement of liquid column.

抄録全体を表示

As smart phones become more complex, higher in performance and smaller in size, heat concentration at localized areas is becoming a problem. Phase change materials (PCM) have drawn attention as passive thermal management. In this study, simple experiments using PCM were conducted. The results showed that the saturation time increased with increase in the mass of PCM, and a relationship between the saturation time and the mass of PCM was a linear relation. Furthermore, the saturation time increased with decrease in the melting temperature of PCM. As a result, PCM is effective for the thermal management of smart phones.

抄録全体を表示

Temperature of X-ray tube is very high in operation. Therefore, information of detailed temperature distribution is indispensable for developing of the new X-ray tube. This study is conducted to obtain the detailed temperature distribution on the basis of the unsteady numerical analysis. Temperature near the target center became nearly 2000K immediately after the input. Maximum temperature with intensity distribution at the target was about 2310K. The maximum temperature was about 20% higher than uniform input case for target. Temperature gradient was steep near the target, and temperature was about 700K at a distance of 1 mm from the target center.

抄録全体を表示

A new concept of thermal switch with liquid metal driven by electrowetting-on-dielectic (EWOD) was proposed in the first report. The thermal switch is expected to play a role of controlling both heat insulation and transfer in a heat transport system. Gallium alloy in place of mercury was utilized as liquid metal in this report. A treatment to inhibit oxide film formed in the surface of gallium alloy droplet was firstly evaluated. It was clarified that the method of putting a drop of diluted HCl in the surface of Gallium alloy droplet was effective in inhibition of oxide film. Then it was confirmed that a gallium alloy droplet was driven back and forth by EWOD.

抄録全体を表示

Parametric studies to predict the conditions of the onset of natural convection in fluidic optical devices are given. Thermal lens effect in fluidic optical devices induced by CW laser heating may accompany the onset of the natural convection closely associated to the characteristics of the devices. When natural convection occurs in fluidic optical devices, it cannot be used as laser beam shaper because laser beam is distorted. It has been investigated that the onset of the natural convection is strongly dependent on configuration of fluidic optical device. In particular, the optical thickness of the cell, in which liquid medium is filled, has significant effect on the onset of the natural convection.

抄録全体を表示

In electrophotographic printers and copiers, the fuser fixes resin particles of graphics on sheets of paper by pressure and heating. It is known that curl is generated after the fusing process. One of the main factors of the curl generation is the temperature difference between paper surfaces in the heating. We have revealed the generating mechanism of the curl, and developed the method to predict the amount of the curl. In the recent year, there are many brands of paper, which are imported or recycled, sometimes generate large curl that causes the degradation of printed quality. We start to study a prediction method considering paper properties that are possible to describe the differences among paper brands. Permeability is the most influencing parameter of the curl, and the amount of curl of ten paper brands are calculated by three methods to lead permeability. The result is that the prediction of the curl difference between paper brands is good at the experiment when the permeability is calculated from the porosity to be led by ash ratio of paper.

抄録全体を表示

This study tries an application of pulsating airflow to a novel cooling method of electronic equipment using fans. In this report, the flow and heat transfer characteristics around a cylindrical obstruction, which simulates electronic components, mounted in a rectangular enclosure was investigated experimentally in order to evaluate the effectiveness of the pulsating airflow. Through heat transfer experiment and flow visualization, it was found that the pulsating airflow achieved almost same heat transfer performance as the steady airflow when the integrated flow rate of the steady airflow was 15% smaller than that of the pulsating flow. Therefore, we conclude that the pulsating airflow is effective for cooling electronic equipment when the airflow is generated in an appropriate manner.

抄録全体を表示

This paper introduces a technique of iterative calculation to obtain thermal spreading resistance and thermal local resistance along heat transfer paths. First, the one-dimensional thermal network with average temperature nodes is explained. Second, a technique by iterative calculation which employs the simplified boundary conditions is introduced. After that, the effectiveness of the technique is explored by utilizing a simple model assuming a microprocessor system with heat sink fan. The calculated result is compared to a three-dimensional heat conduction simulation result. It is found that the introduced technique matches the three-dimensional heat conduction simulation result well.

抄録全体を表示

In make and break of relay, arc is generated in the cut off in general. The temperature reaches several thousand degrees at the contact point. Heat generated by the arc causes the consumption of contact and leads to the premature failure. It is known that consumption of contact is strongly related to the contact volume from previous experiences. On the other hand, cost of contact material is a large proportion among the relay. So it is inversely proportional to the contact cost and life. In this paper, a simplified one-dimensional unsteady-state thermal analysis has been examined, and the contact volume which satisfies both cost and a life is able to be optimized by using this technique.

抄録全体を表示

In general, power semiconductors are highly sensitive to thermal stress, and thus are required to be highly reliable. Some typical failure modes of the power semiconductors are caused by thermal stress. One example of such mode is cracks in joints. There arises a need for an effective method for non-destructive and quantitative evaluation of cracks, to identify possible deterioration of semiconductors over time and to reduce man-hours required for the evaluation. Conventionally, crack evaluations are based on changes in electric resistance and in temperature of semiconductor components. However, the accuracy of such evaluation is insufficient, which is a great concern. This research focuses on changes in transient thermal resistance caused by cracks. Especially, discussion is made on the correlation between the changes in transient thermal resistance and the crack propagation rate. Consequently, the research reveals a close correlation between these two elements. The research also shows that the discussed approach allows measurement of cracks, including those in the early phase of semiconductor deterioration, with high accuracy.

抄録全体を表示

Plate Type Heat Exchanger has been developed for Low-grade thermal energy conversion (LTEC) and heat pump, etc. It is used as the two phase flow phenomena in the plate type heat exchanger for LTEC and heat pump. The configuration of surface on plate is influenced on the performance of heat transfer. Due to design the best configuration of surface of plate, it is investigated on visualization of evaporation and condensation in the plate heat exchanger made by 3-D printer.

抄録全体を表示

In this study, experimental research on the performance evaluation and flow visualization of the pulsating heat pipe (PHP) has been carried out. The PHP made of aluminum plate and consists of 24 parallel square channel with 2×2 mm^2. The working fluids used were water and 1-Butanol aqueous solution (so-called self-rewetting fluids). Self-rewetting fluids show unique surface tension behavior which causes the fluids heat transfer enhancement. The experimental results indicate that heat transfer performance of the PHP using 1-Butanol aqueous solution was enhancement. And liquid slugs moving between heating and cooling sections contained considerable minute air bubbles by improving boiling phenomenon.

抄録全体を表示

Loop heat pipe (LHP) is heat transfer devices whose operation principle is based on the evaporation and condensation of working fluid, and use the capillary forces to ensure the fluid circulation. In this study, we proposed a new flat evaporator structure and micro LHP with the evaporator thickness of 3mm and one-way transport length of 200mm and a PTFE porous material as a wick was designed, fabricated and tested. From the results, stable operation in heat load amount of target and operation at maximum heat load of 12W has been confirmed.

抄録全体を表示

This paper reports design, fabrication, and test results of a long-distance loop heat pipe (LLHP) with 10m heat transport distance. The previous LLHP could transport heat up to 160W for 10m with a thermal resistance between evaporator to condenser of 0.12 K/W. From the calculation of pressure drop, it reveals that the pressure drop in the liquid line is the largest among all elements of the LLHP. A new LLHP was re-designed with the same wick size. The test results agreed well with the calculated result. The effect of the gravity was also evaluated by changing its height.

抄録全体を表示

Here we detail a study into the thermo-physical properties of a solution of ethylene glycol. We demonstrate how viscosity varies smoothly with glycol mole-fraction, but thermal conductivity less-so. The thermo-physical properties of liquids depend on the molecular composition, both in terms of the structure of the molecules and the interactions between them, and molecular simulation is a useful tool to extract this information. Consequently we conduct molecular dynamics simulations to elucidate the reasons for the non-smooth variation of thermal conductivity, showing the important role that disruption of water-water interaction by the glycol plays.

抄録全体を表示

Molecular dynamics simulations (MD) are carried out in order to investigate the wettability and pore size dependence of the saturation pressure of the water molecules in nanocylinder and to verify the Kelvin equation. The Kelvin equation quantitatively coincides to the MD results for the nanocylinders with the diameter of 4.2 and 5.2 nm in the case of the intermediate-wetting and hydrophilic nanocylinders. In the case of the hydrophobic nanocylinder, the saturation pressures are at most 10% higher than the estimation of the Kelvin equation with the diameter from 2.2 nm to 5.2 nm.

抄録全体を表示

In this study, we evaluated the density fluctuation of diatomic fluids around the critical point. We performed Molecular Dynamics (MD) simulation against 2-Center-Lenard-Jones (2CLJ) fluids that have molecular elongation as a parameter. We compared the density fluctuation of each fluid to evaluate the principle of corresponding state of density fluctuation. We evaluated the density fluctuation by dispersion of number of molecules, static structure factor, and intermediate scattering function. As the results, in 2CLJ fluids that have shorter molecular elongation comparatively, the principle of corresponding state of static fluctuation structure was satisfied.

抄録全体を表示

Poly(3,4-ethylenedioxythiophene) (PEDOT), a technologically important thermoelectric material, is modeled to analyze its thermal properties using molecular dynamic simulation. Three different models are constructed to reproduce a state of PEDOT film where PEDOT are layered in one direction. The models differ in the number of layers with 1, 2 and 6 layers, respectively. To investigate inter-molecular and intra-molecular thermal transport, vibration-mode analysis is conducted. The results show that effects of inter-molecular force increase as the number of layers increasing, producing a change in the characteristic frequencies of vibration. This result indicates that variation in thermal conductivity can be expected.

抄録全体を表示

Molecular dynamics simulations were conducted for a liquid film on a solid surface with and without a slit pore, using SPC/E potential, and the effects of the thickness of the liquid film, nanostructure and calculation accuracy of the coulomb interactions, on the density distribution of the liquid film, were investigated so as to elucidate the dominant factors on state of the liquid film. The interaction between the liquid molecule and solid atom is assumed to be the 12-6 Lennard-Jones form. The results showed the thickness of the liquid film and the calculation accuracy of the coulomb interactions did not have a significant effect on the density distribution of the liquid film on the flat solid surface. The same tendency was observed even in the model of liquid film on the solid surface with a slit pore.

抄録全体を表示

In this paper, thermal conductivity of liquid n-alkanes in the vicinity of three crystal planes of a-quartz substrate terminated with H and OH-groups have been investigated using nonequilibrium molecular dynamics simulations. Methane and decane molecules are considered as alkane molecules in this study. It is found that the thermal conductivity fluctuates in an oscillating manner in the solid-liquid interface region. These fluctuations are typically in proportion to the oscillations in the density profile.

抄録全体を表示

The surfactant is expected as a kinetic inhibitor of ice crystal growth. Molecular dynamics simulations were applied to ice/water coexistence system with the surfactant to clarify the mechanism of ice growth inhibition. We found that ice grow was inhibit by the surfactant which was near ice/water interface.

抄録全体を表示