Erythritol slurry attracts attention as a heat transfer medium for medium to low temperature thermal utilization. We investigated relationship between Reynolds number and inner wall of tube of erythritol slurry flowing in cooled tube, to avoid the blockage in the pipe transportation of erythritol slurry. It found that when Reynolds number is less than 1100, erythritol crystals sinks the bottom of the tube, and it causes blockage because of accumulation of sinking crystals. When Reynolds number is over 1100 and it forms heterogeneous flow, erythritol crystals adheres on the top of the tube. When Reynolds number is larger and it forms homogeneous flow, the accumulation of the crystals does not occur even after crystal adhesion, and the erythritol slurry can flow continuously. As a result, it can be said that the blockage condition depends on not only flow velocity and cooling temperature but also flow pattern.

W We have conducted a deposition experiment of SiO₂ film in HMDSO - O₂ - N₂ system using thermal CVD method. The effects of deposition temperature, material concentration, operating pressure and O₂ concentration on growth rate distribution were investigated. In the surface reaction controlled region, the film growth rate distribution continuous in the flow direction was evaluated by using a differential reactor, and created Arrhenius plot. It was found that it was represented by one correlation line regardless of the change of the experimental conditions. In addition, the activation energy was 221 kJ/mol. (9 point, about 100 words)102 words

Effects of permeability and porosity of the porous metal fins installed in a rectangular enclosure on the solidification process are investigated by dimensionless numerical analysis. Specifically, the thermal storage capacity in PCM and the time to complete freezing are examined in this paper. Comparing porous metal fins and solid fins, Porous fins with large porosity was inferior to solid fins, however we confirmed that porous metal fins with small porosity have an advantage in thermal storage. In addition, we researched about an optimal porous metal fins geometry on thermal storage capacity, as compared with the case where whole enclosure is filled with a porous metal

In this study, experiments were carried out using a one-turn pulsating heat pipe having a visualization flow channel. Deionized water, ethanol and ethanol aqueous solution were used as the working fluid. As a result, it was found that by using the ethanol aqueous solution, the effective thermal conductivity increases compared with deionized water and ethanol. Heat transport performances of the pulsating heat pipe were evaluated in terms of the liquid column oscillation and the liquid film formed in the flow channel.

The authors have proposed dispersing Calcite nanoparticles in to the stratosphere to decrease solar irradiation without changing earth's emission by long infrared. We may achieve the dispersion of the particles by launching 10-tons of particles 19 times per day from 100 launch sites located in the world. In this report, a feasible design of a projectile is proposed to disperse 10 tons of nanoparticles at the altitude of 30 km. We can accelerate the 20 m long, 15 tons of projectile in an acceleration vacuum tunnel of 34 km up to 1000 m/s by using superconducting linear motors. When the projectile is launched at the altitude of 3500 m. By unfolding sailwings at the altitude, the projectile can keep level flight during dispersing the particles in the stratosphere.

In recent years, the heat flux of electronics has been increased due to the miniaturization of electric devices. Accurate thermal management is required to protect electronics from performance degradation and life span reduction. Thermal contact resistance is one of the important parameters for accurate thermal design. Numerical analysis is attractive method to predict thermal contact resistance. However, estimation of thermal contact resistance is difficult because it is dependent on several parameters. In this study, thermal contact resistance was estimated by numerical analysis. As a result, max height roughness has possibility to predict thermal contact resistance. However, further experiments and numerical analysis are necessary in our future works.

Mushrooms are the only organisms capable of completely degrading wood components. It is thought that elucidating the ecology of mushrooms will lead to the development of new applications of wood biomass. However, the ecology of mushrooms is often unclear and the formation mechanism of fruiting bodies has not been elucidated. The fruit body is composed of 80% to 90% of moisture, but it does not have a water route like a conduit held by a plant. Therefore, if it becomes possible to visualize from where to how a large amount of moisture is moving inside the fruit body, it is thought that it will lead to the elucidation of the fruiting body formation mechanism of mushrooms. So we aim to visualize the moisture path inside fruiting body of mushroom using fluorescence.

To investigate near-wall flame behavior including effect of the surface reaction, two-dimensional direct numerical simulations (DNS) of methane/air, hydrogen/air and n-heptane/air premixed ignition and propagation between two parallel walls are conducted under several thermochemical conditions. From the DNS results, the flame front position defined by the OH gradient, and the flame displacement speed defined by the temporal evolution of the position are evaluated. The present analysis revealed following characteristics. (i) The flame speed takes a local minimum value near the wall. (ii) Under the conditions where the wall temperature equals unburnt gas temperature, this local minimum value corresponds to the laminar flame speed of the initial thermochemical condition. (iii) These characteristics do not depend on the ignition position, equivalence ratio, fuel types and presence/absence of surface reaction.

This paper proposed a promising method to increase the critical heat flux during the boiling of water in narrow gap. Materials with different thermal properties were alternately arranged near the heat transfer surface in heat transfer block and a temperature distribution is given to heat transfer surface in saturated pool boiling in narrow gaps for water. It was expected that critical heat flux was enhanced by mutual interference of different boiling modes. Such an enhanced method of CHF was proposed. Measurement was carried out for 20 mm rectangular heat transfer surface, gap size of 0.5 - 2.0 mm.

CHF was enhanced approximately up to 70% was obtained, showing its effectiveness.

This study is a basic research to validate the application of a laminated resin to an outer cylinder of a stack in a thermoacoustic device. A loop-tube type thermoacoustic device was selected. The looped tube having the length of 3 m and the inner diameter of 40 mm was used. The device consists of two engine parts in which heat is converted to sound and one cooler part in which sound is converted to heat and thereby cooling effect can be generated. A honeycomb ceramic was used as the stack in the device. It was confirmed that the heat loss in the laminated resin is reduced as compared with conventional stainless steel outer cylinders. In addition, the heat resisting property usable as an outer cylinder of a stack was shown.

In the heat treatment of alloy materials, it is very important to understand the film boiling minimum heat flux (MHF) point temperature quantitatively. The platinum small ball heated high temperature has been quenched into water and into an aqueous polymer solution in an arc shape. MHF point temperature tends to increase with increasing water subcooling. In quenching in the aqueous polymer solution, the MHF point could be clearly discriminated on the boiling curve. However, in the concentration below 15 vol%, striking change on the MHF point temperature was not recognized.

In recent years, further consideration on heat is required due to high performance and high density of electronic circuits. Switch mode power supply (SMPS) also required design including heat protection protection. In this paper, we confirmed the system in which the heat dissipation path from the switching element to the outside was constituted by the thermal resistance network by using VHDL-AMS corresponding to multi domain. Then, we show the problem of modeling and the solution which connects from the heating point to the thermal shutdown circuit by the thermal resistance network.

In recent years, with a large-capacity power conversion device, it is required to consolidate and cool the power modules due to restrictions on installation environment and installation space. The problem is temperature leveling in the large heat transfer area. The purpose of this development is to establish a highly efficient natural circulation cooling system utilizing boiling cooling in the large heat transfer area. Operation verification with a simulator of 2 MW level was carried out using HFE-7200 as a working fluid, and pressure dependence of heat transfer characteristics and flow characteristics was clarified.

To investigate the influence of outer and inner diameter of cylindrical solid fuel on the flaming “End face combustion” behavior, highly densified cylindrical biomass briquette was burned from the one end to the other in this study. The average mass loss rate per unit outer circumference length decreases with decreasing the ratio of the briquette outer circumference length to the sectional area (L/A) and was smaller with smaller briquette outer diameter (40 mm o.d.) than that with larger one (45 mm o.d.). It is observed that the decrease rate of mass loss rate with decreasing the briquette outer diameter is larger than that with decreasing L/A.

In order to elucidate heat and mass transfer during the torrefaction of woody biomass, component in the biomass, higher heating value, time course of temperature and generated gas flow rate in the packed bed of biomass powder have been measured. The kinds of biomass were Bamboo, Douglas fir and Bark. Remarkable exothermic chemical reaction was observed during bamboo torrefaction. The char after bamboo torrefaction had a higher heating value than that of other biomass due to this exothermic chemical reaction. On the other hand, the exothermic chemical reaction during Douglas fir torrefaction was milder than that during Bamboo torrefaction. From the component analysis, mass fraction of Cellulose and Lignin in the Bamboo was as almost same as that in Douglas fir. Xylan was highest in Hemicellulose of Bamboo while Mannan was major component in Hemmicellulose of Douglas fir. Therefore, it is suggested that the difference of the component could occur the change in the exothermic chemical reaction and higher heating value.

Non-equilibrium molecular dynamics (NEMD) simulations have been carried out to obtain new evidence for the inverted temperature profile. The inverted temperature profile is confirmed in the vicinity of the condensing surface at 90K and 100K. However, this profile disappears near the condensing surface at 120K. Thus, the velocity distribution is obtained from the results of NEMD simulations and it is found that the velocity distribution shows a good agreement with that for the equilibrium condition at 120K. In order to obtain the new evidence, behaviors of reflected molecules are examined from a view point of collision frequency.

Steel is the most fundamental material used everywhere. In steelmaking, precise control of steel temperature during spray cooling process has a great influence on the quality of the product. In order to obtain a desired material, it is necessary to accurately understand the effect of spray (water temperature and flowrate) and the surface conditions. In the previous work, focusing on the surface properties, we conducted spray cooling experiments on steel plates coated with each of five distinct oxide layers with different thickness. Furthermore, we observed the behavior of a single droplet impinging onto the surfaces with high speed camera, in order to capture the fundamental cooling process of in detail.

We report numerical simulations for assessing the effect of the shape of an underground magazine model on blast-wave propagation outside the magazine. The magazine model was divided into chamber and passageway sections. The internal diameters of the chamber and passageway sections were 38.8 mm and 19.8 mm, respectively. The length ratio between the chamber and passageway lengths varies from 0.125 to 2.0. Numerical simulations provide the azimuthal distributions of peak overpressure, and a narrow passageway greatly mitigates the peak overpressure outside the magazine, but the ratio of the chamber to the passageway length shows no effect on the peak overpressure.

Adequate thermal management of power semiconductor devices is vital for downsizing and power saving of power electronics systems. However, in many cases, temperature prediction is conducted based on a specific boundary condition, which is different from one real system faces without considering its influence on temperature prediction result. This paper investigates package thermal resistance of DPAK package as one of important standard power semiconductor device packages to understand temperature prediction result difference by boundary conditions. Through investigation with the case that heat flows from top and bottom surface of the package, it is found that package thermal resistance varies by heat transfer coefficient value set to bottom surface.

It is important to know the flow of the cooling fluid inside the product. In the case of a motor, in order to make compact and lightweight, efficient cooling of the motor must be performed. However, it is difficult to see the flow. In this study, in-house code written by fortran language is used to visualize the flow in the motor. At that time, simulation of cooling was performed under the condition that the same rotation as the actual operating situation was added, and how each core was cooled was investigated. As a result, it was found that each core was not evenly cooled.

Effect of the heated cylindrical pipe with the slit on natural convection heat transfer from the horizontal heated surface was investigated experimentally. The flow fields around the horizontal heated surface and the heated cylinder were visualized. With decreasing the distance of between the heaters, the induced flow rate decreases and reversed flow occurs. Reversed flow develops with increasing the width of the slit. When reversed flow reaches the heater, the heat transfer coefficients at the center are promoted.

The Nusselt number is proportional to the modified Rayleigh number at the power in general.

The thickness of a liquid film formed with liquid column oscillation was investigated experimentally. The liquid column was oscillated sinusoidally to simulate the flow phenomena in pulsating heat pipes. A vertically located circular glass tube with an inner diameter of 2 mm was used as the test channel. The average liquid film thickness during liquid column oscillation varied as a function of the average capillary number. The experimental results were compared to those in the horizontal pipe. The results showed that the gravity affected the thickness of the liquid film.

Diffusers are extensively used in many industrial aspects. So, diffusers with high efficiency are desired under both spatial and cost's limitations. In our previous studies, we proposed a flow deflector inside the diffuser-part of an automotive catalytic converter, in order to reduce energy loss and to improve thermal uniformity. In this study, we experimentally and numerically investigate the influence of the downstream substrate upon the effectiveness. As a result, it is revealed that the flow deflector is effective for diffusers as well as catalytic converters. By computation, we have shown the flow inside the diffuser with the flow deflector.

The in-cylinder flow in diesel engines significantly affects fuel-air mixing, combustion, and emissions. In the present study, the in-cylinder gas flow velocities in an optical single-cylinder diesel engine were measured using the high speed PIV under different opening area of intake port. Two kinds of intake ports were used which are known as the helical port and the tangential port, and the various experiments were conducted by changing the opening area of helical port. Using the obtained velocity data, the swirl ratio was calculated, which is an index showing the strength of swirl flow, and the center position of the swirl flow was identified during intake and compression strokes. It was found that the center position of swirl flow was moved in the in-cylinder and the opening area of intake ports greatly influences the swirl flow formation. When the opening area of helical port was increased, the center of swirl flow was away from the center of cavity, and the swirl ratio became smaller.

It is important for the generation of fire whirl to know how a swirling flow around a flame affects the flame behavior, and therefore it is very useful to investigate the flame behavior and the transient local distributions of physical property such as velocity, pressure, temperature, etc. around the flame by using a numerical analysis. In the present study, numerical calculations by a finite volume method are performed for an axisymmetric methane jet diffusion flame behavior which a swirling flow affects. The physical property change around the flame is investigated in the generation of fire whirl, and the effects of swirling flow on the flame behavior is elucidated.

In this research, silicon dioxide/DI water nanofluid was used as the working fluid in a cylindrical heat pipe to experimentally investigate its effect to enhance the heat transfer performance. In the experiment, the one end of the heat pipe was heated using a nichrome wire heater and the other end was cooled using a fan. In addition, effects of pre-coating of the screen mesh and the inside wall of the heat pipe with nanoparticles on heat transfer performance were explored. The experimental results showed that in comparison with the normal heat pipe BBW (bare tube / bare mesh / pure water), the thermal resistance of BNW (bare tube / nanoparticle-coated mesh / pure water) is reduced by 2-8% for the input power of 3-9W. When the power was increased to 9-25W, however, the thermal resistances of NXW (nanoparticle-coated tube / no mesh / pure water) and NBW (nanoparticle-coated tube / bare mesh / pure water) decreased 13-32%. This corresponded to the heat transfer enhancement of 15-40%.

The microtube heat exchanger performs heat exchange by setting up alley tube group in a duct. In the conventional analysis, since the wall thickness of the pipe is thin, the analysis was performed by applying isothermal conditions to the side of the pipe. However, in recent years, as the processing technology is digitized, the increase in the wall thickness with respect to the pipe diameter becomes remarkable. Therefore, in this analysis, numerical analysis of the flow channel with tubes with different wall thicknesses was conducted, and the flow characteristics of the fluid and the heat transfer characteristics inside the tube were investigated.

For improvement of thermal efficiency of diesel engines, it is effective to control the fuel injection by using the model-based control (MBC) on the ECU (on-board) with cycle-by-cycle calculation. The authors previously developed an on-board in-cylinder wall temperature prediction model and wall heat transfer prediction model for MBC. For the validation of the developed models, the present study measured the time evolution of local wall temperature and pressure in the combustion chamber and calculated wall surface heat flux and evaluated the errors of heat loss results obtained from model. Also, the polytropic index prediction model was evaluated using the result of in-cylinder pressure. As a result, it was confirmed that heat loss results during compression and expansion strokes show 1.3% errors and polytropic index prediction model shows 0.1% errors comparing with experiment data.

In this study, specific heat and heat of dilution of solution were measured to estimate effective latent heat of fusion of the solute in its aqueous solution. Erythritol solution and mannitol solution were used as a sample. In the measurement of heat of dilution, pure water was mixed into the solution, and temperature variations of the solution due to the dilution of the solution was measured. From the temperature variation, heat of dilution of the solution can be calculated. As a result, it was found that the influence of dilution of the aqueous solution on the effective latent heat of fusion of erythritol and mannitol was small.

Recent micronized machines require high advanced cooling systems because of its high heat generation density. Main conventional cooling systems have been air cooling and water cooling, but heat transfer is restricted with these techniques. Therefore, this study is focused on boiling phenomena with a large heat transfer coefficient utilizing the phase change as a further heat transfer means. Metal 3D printers can be stacked accurately without processing regardless complicated shapes. In this study, boiling phenomena and heat transfer coefficient characteristics at the low heat flux condition in the laser sintering and laminated structure by metal 3D printers were observed.

A ground source heat utilization system is considered to have higher energy saving performance compared with air heat utilization, and as a renewable energy is also positioned. Despite the features mentioned above, this system requires installation of the ground heat exchanger, so the cost increase therefor is inevitable. Therefore, we propose the system with pile heat exchangers, which is easy to install at low cost, and develop technologies to lower price and improve efficiency of the system for small buildings, especially housing market. Here, the outline of its research and development and its outcome prospects is introduced.

This paper compares the performances of 5kW-class “Air source heat pump system (ASHP) and Ground source heat pump system (GSHP)” at the same time and the same condition at semi-cold region. GSHP is more efficient than ASHP, but there is little evidence. As a result, the total energy consumption efficiency of ASHP was 29% to 40% higher than the that of GSHP. Therefore, 5kW-class heat pumps should be improved the efficiency.

A ground source heat utilization system is considered to have higher energy saving performance compared with air heat utilization. However, the initial installation cost is high due to many components and construction processes. Reducing the initial installation cost is important to expand spread. Therefore, in order to lower the installation cost of a ground source heat utilization system for general houses, the installation of pile heat exchangers, detailed design of piping and prefabricated assembling method were carried out. As a result, the prospect of realizing the initial introduction cost of 1.5 million yen / (5 kW heat output) by the prefabricated assembling method was obtained.

In nucleate boiling of nanofluids, heat transfer coefficient and CHF change due to nanoparticle layer formation on the heated surface. It is considered that the nanoparticle layer causes the changes of wettability and roughness of the heated surface. In this study, influences of the total mass of nanoparticle layer and properties of the heated surface were experimentally investigated parametrically changing the nanoparticle concentration and the heat flux during nanoparticle layer formation. The heated surface material was copper and the material of nanoparticles was titanium-dioxide, alumina, and silica. The influencing parameter for the total mass of the nanoparticle layer was elucidated experimentally.

A GSHP system with pile heat exchangers in Okinawa Prefecture in 2016. We undertook refurbishment from 2017 to 2018. After renovation, a cooling test was conducted and evaluation was carried out. The examination went on in July. COP was about 4.0, which was improved by about 1.7 compared to the same period last year. Moreover, by increasing the underground heat exchanger, fluctuation of the soil temperature could be reduced. We believe that it will be possible to evaluate the possibility of dissemination in warm regions by further solving the problem.

In order to elucidate the rewetting phenomenon in detail, it is important to know the distribution of the heat transfer coefficient in the vicinity of the rewetting front. However, the distribution of the heat transfer coefficient is not yet known in detail, and there are few data that directly measured its distribution. In this study, the temperature distribution of the wall surface temperature when the liquid film flows down was measured using a high-speed infrared camera, and the distribution of heat transfer coefficient was directly measured from the temperature data. We tried to experimentally determine the dominant factors influencing the heat transfer coefficient by changing experiment parameters.

In this study, thermogravimetory and differential thermal analysis (TG-DTA), time course of temperature and generated gas flow rate during pyrolysis of polystyrene (PS), polyethylene (PE) and polypropylene (PP) powders have been investigated using an isothermal reactor. From the results of TG-DTA, the pyrolysis was endothermic reaction for all samples and there was no char after pyrolysis at 1200 °C as with previous studies. Time course of temperature for plastic powder packed bed had a plateau because of the endothermic chemical reaction. The maximum gas flow rate for PS was slower than that for PE and PP. Mass of tar for PS didn't change with temperature while those for PE and PP decreased with one. In other words, the secondary decomposition of tar could not occurred for PS because a styrene monomer with a benzene ring, which was required a large energy to decompose into other small molecular substances, would be formed after PS pyrolysis.

Actual equipment incorporating newly developed design technology and elements was installed in the housing in Yamagata prefecture and operation started. SCOP averaged 3.5, 26% in terms of energy consumption efficiency. There is only economic consumption efficiency of 1.00 due to the difference in energy unit price, and there is almost no difference in running cost when considering it on a unit price basis. If it is the current energy unit price structure, unless the heat source side SCOP is 3.5 or more, there will be no operational cost difference. Discussion from an economic point of view is important not only from the viewpoint of energy, but also from the viewpoint of future.

This paper describes measurement of soil thermophysical property of the Reference Map for designing GSHP System. We measured thermal properties of 57 boring core samples in wet condition. They were collected in Okinawa, Fukushima and Kochi. 61% of all samples fell within the range of heat capacity 1.9 to 2.7 MJ/(m³K) and thermal conductivity 1.7 to 3.2 W/(mK). In the sample of the same classification, the heat capacity difference was 0.9 to 1.4 MJ/(m³K) and the thermal conductivity difference was 0.7 to 1.5 W/(mK). It is necessary to put numerical values in the map that consideration of safety factor by increasing the number of samples.

In this paper, we describe the peak cut by the brine type heat pump system with the thermal storage device. Selecting air-conditioning equipment according to the peak load at general housing leads to excessive equipment, which leads to increases in equipment cost and contract power capacity. We conducted an experiment that gives a cooling peak load to the ground source heat pump (rated 5 kW) pseudo system with the thermal storage device. As a result, that was able to supply 7 kW of cold heat for about 80 minutes. Therefore, the combination of the ground source system and the thermal storage device have the effect of reducing the equipment scale.

Recently polymer electrolyte fuel cells (PEFCs) spread on wide range of fields. However, PEFCs need a humidification system to avoid drying membranes during operating. Moreover, the use of humidifiers causes the decrease of the system’s efficiency and the flooding/plugging phenomena. Therefore, we proposed the self-water management separator (SWMS) with a bypass channel. We have already confirmed that was water transported by the capillary phenomena and the water concentration diffusion through the bypass channel. This paper aims to optimize a resupply position and to select a filler of the bypass channel. As a result, although the bypass channel functioned as a drain channel under full-humidifying condition, the wet condition was kept by returning excess water to dry part through the bypass channel. Moreover, PVA was suitable material as the fuller of the bypass channel.

In this study, numerical analysis is performed to consider a method for reducing the pressure loss over backward-facing step in low Reynolds number range. We attempted to reduce pressure loss with a heated small obstacle that is installed on the downstream wall of the step side. As a result, strength of backward flow behind the small obstacle in vortex is reduced due to buoyancy force, compared with the case where the small obstacle is not heated. Therefore, the pressure drop is further reduced by a heated obstacle.

We considering cost down of hydrogen stations in order to spread fuel cell vehicles. The PSA device included in the hydrogen station to occupies 30% of the construction cost. Therefore, we proposed the cost down by replacing the PSA and CO shift converter with a membrane reactor composed of CO₂ facilitated transport membrane and CO shift converter. We aim to enhance the membrane performance by keeping water in the membrane. Therefore, we added graphite as porous materials and silica gel as water absorption grains to the membrane. However, Graphite has water repellency. Hence, it is necessary to modify surface of graphite with surfactants AcetyrenolE00. As a result, we found the optimum amount of graphite and silica gel in experiments.

This study investigates conjugate heat transfer problem for honeycomb structure under concentrated irradiation. This simulation model focuses on a unit rectangular channel made by stainless steel. The problem assumes the condition that the honeycomb structure is installed in vertical orientation and heated up by beam-down concentrated irradiation, and simultaneously air flows through honeycomb channel. Discrete Ordinates radiation model calculates discretized radiative transfer equation and solves mutually interaction of radiation, convection, and conduction. For investigating the heat transfer phenomena, the beam width, power on aperture, and air mass flow rate are changed.

Newly Oil coolers with a highly efficient have developed using CFD and Experimental Study. Because in Engine lubrication sub-system, improvement of the efficiency, Pressure Drop Degree and High Heat Transfer are very important for vehicle fuel economy, environmental performance and next generation electrification system. The main core flow has eliminated from an oil passage, as a results heat exchange between a passage surface and an oil has performed in a temperature boundary layer without any fin devices. That oil cooler has both an increase in heat exchange and a suppression of pressure drop.

The compression ignition mechanism of PRF90/air mixture assisted by a non-equilibrium plasma has been clarified by 0-dimensional computational simulation. In a compression ignition process of fuel-air mixture, the heat release rate shows three peaks. The primary peak is caused by O radical generation from a thermal dissociation reaction of O₃. With increase of input energy density, gas temperature linearly elevates. While mole fraction of NO_x exponentially rises, O₃ shows maximum value at 4.0 mJ/cm³ and then gradually decreases due to thermal dissociation.

An experimental study was conducted to investigate the influences of external radiative heating and materials geometry and opacity on the flammability limits of electric wires. Firstly, overall characteristics of flame behavior over each sample wire were investigated based on the direct observation. It was found that downward spreading flame shows distinct types of unstable flame spread depending on the shape of wire at near extinction conditions and results in different extinction mechanisms. Among the results it was also found that external radiative heating extends the flammability limits of wire samples. Comparison were also made to examine the effect of metal core and materials opacity on the flammability of electric wires.

It is known that flow drag reduction effect (DR effect) is caused by adding a small amount of surfactant in a flow in a pipeline for a liquid. The effect of drag reduction by the surfactant solution flow has attracted attention as an efficient use of energy, such as reducing the power of the pump. When the surfactant solution flow is applied to a heat exchanger such as a factory or a building, not only a straight pipe but also a different diameter pipe and a curved pipe are used for the pipe. In this study, we investigated drag reduction flow characteristics of curved pipe and different diameter pipe at 500 ppm concentration of surfactant solution flow using square cross section acrylic pipe with dimensions 40 × 40 and 60 × 60 mm from the pressure distribution.

This paper describes numerical investigation of effect of pore size disorder on the capillary evaporator performance of loop heat pipes (LHP) by pore network simulation. Porous samples with different pore radius distribution but the same macroscopic porous property are generated and liquid-vapor two-phase heat transfer in the evaporator is simulated. The simulation reveals that moderate disorder enhances the heat-transfer coefficient and three-phase contact line within the case, liquid, and vapor phases and liquid saturation are correlated as phase interfacial characteristics on the performance enhancement. Design method of the wick and evaporator structure are discussed based on the simulation results.

This paper presents a numerical solution for shape optimization problem to achieve stiffness maximization in unsteady-state thermo-elastic fields. Mean compliance is used as an objective functional for the shape optimization problem. Shape gradient of the shape optimization problem was derived theoretically using the adjoint variable method, the Lagrange multiplier method and the formulate of the material derivative. Reshaping was accomplished using a traction method that was proposed as a solution to shape optimization problems. A numerical analysis program for the shape optimization was developed based on FreeFem++, and the validity of proposed method was confirmed by results of 2D numerical results.