The effect of air injection into a subcooled water flow on boiling heat transfer and a critical heat flux (CHF) was examined. The heat transfer was remarkably improved by introducing an air flow into a water single-phase flow. The present results were well correlated with the Lockhart-Martmelli parameter where the vapor phase was replaced with the air phase. The CHF was improved a little by the air introduction in the high water flow region However, that was rather greatly reduced in the low flow region. The air introduction into the subcooled water flow was a more profitable way to get the better heat transfer with less pump power increase than increasing only the water flow rate.

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The critical heat fluxes on inclined plates were investigated analytically by using macrolayer model and Kelvin-Helmholtz instability. In the present model, most dangerous wavelength and propagative velocity in Kelvin-Helmholtz instability were calculated to determine the length and the velocity of a coalesced bubble on a heating surface at CHF. The time covered over the heater was estimated as the calculated value with the length divided by the velocity. The predictions of the model agreed well with previous experimental data for CHF on inclined plates with 30 to 180 degree in orientation. The present model was developed to the CHF on a hemisphere surface.

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The fuel cell is very promising technology on view-points of the efficiency and the environment. This paper explains about the SOFC on its working mechanism, the structure of a stack and the current status of development. Many books and papers on the SOFC are already published. So anyone can get more details about the technology. I would be happy if this paper can make an opportunity to everyone to approach the SOFC technology.

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Effects of swirl number on flame tip oscillation of a Bunsen type premixed flame with burner rotation are experimentally investigated. The flame tip oscillation frequency v remains unchanged as the Swirl number S is bellow 0.11, and decreases with increasing S for S>0.11. This suggests that the effect of burner rotation on the flame tip oscillation frequency becomes significant as S exceeds 0.11. When S=0, value of St^<*2>/Ri almost coincides with an empirical correlation (St^<*2>/Ri=0.00028Re^<*2/3>, here, St^*, Rt, and Re^* are, the Strouhal number normalized by the heat release ratio, the Richardson number, and the Reynolds number normalized by the heat release ratio, respectively) proposed by Kostiuk and Cheng. As S is further increased, the gradient of the relationship between St^<*2>/Ri and Re^<*2/3> decreases and finally becomes flat as S exceeds around unity. These results indicate that the Swirl number plays an important role in determining the flame tip oscillation frequency as well as the Reynolds number.

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The flame images were measured by using laser tomography in a spark ignition engine. The curvatures of local flame fronts were computed at each flame boundary. The number of positive curvatures was probably equal to that of negative ones. The average values of positive and negative curvatures were comparable in all flame images. The averaged value of the flame curvatures was smaller than the curvature of equivalent flame radius. The positive and negative curvatures were distributed symmetrically around the zero value.

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CFD simulation was applied to describe the combustion processes in a high-speed hydrogen engine, based on the flame area evolution (FAE) combustion model. The simulated courses of in-cylinder pressure and heat-release rates significantly depend on the estimation of temperature effect on burning velocity. They can be well reproduced in a range of conditions including high-speed operations as long as the turbulent burning velocity is appropriately estimated as a function of pressure, temperature, mixture concentration and turbulence characteristics.

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A fiber optical heterodyne interferometry system was developed to obtain high temporal resolution temperature histories of unburned gas in an SI engine cylinder non-intrusively. The effective optical path length of the test beam changes with the gas density and corresponding changes of the refractive index. Therefore, the temperature history of the gas can be determined from the pressure and phase shift of the interference signal. The fiber optical heterodyne interferometry has the advantage of resisting the mechanical vibration. In this study, this system was applied to a homogeneous charge compression(HCCI) engine. The measured temperature history of unburned gas in a HCCI engine just before generation of cold flame was almost equal to the calculated value using the equation of state of ideal gas.

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The calculation error of IMEP depends on the number n of sampling pressure data and increases with decreasing n. It is also affected by numerical integration methods. In this study, the influences on the error are tested with continuous pressure data. The error of the proposed IMEP equation based on the Fourier series expansion is similar to that of Trapezoid rule and smaller than that of conventional method and Simpson's rule. Correlation coefficient is 0.99, even if n decreases to eighteen per cycle. The equation has advantage on calculation time as compared with Trapezoid rule and then can be recognized to be excellent more method.

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A dual-wavelength laser absorption-scattering (LAS) technique was developed to analyze the mixture formation process in a D.I. gasoline spray. P-xylene was used as a test fuel and the second harmonic (532nm) and the fourth harmonic (266nm) of an Nd:YAG laser were simultaneously illuminated the spray, which was injected into a high temperature and high pressure constant volume vessel. The dual-wave length LAS images were acquired by two CCD cameras and processed by a computer. The distributions of droplets and vapor concentrations in a D.I. gasoline spray were quantitatively analyzed.

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Quick mixing of fuel and air is one of the most essential factors to improve combustion and emissions in diesel engines. The paper investigates local diffusion phenomena in a wall impinging jet with focusing on scales of the heterogeneity. Analysis was made with entropic concept proposed in the previous paper; it analyses homogeneity degree and scales of the heterogeneity in a picture. The result of the entropy analysis shows that the heterogeneity scale increases gradually along the spray axis towards downstream, with containing smaller scales inside of the larger clouds. Such structural development is similar to a free jet, and no obvious difference in the diffusion intensity was observed between free and wall-impinging jets.

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A mixture formation from a direct injection gasoline spray plays an important role of combustion and emission formation processes. A spray shape, which is related to the mixture formation, is influenced by ambient pressure, ambient temperature, fuel temperature and so on. In this study, the ambient temperature in the constant volume bomb was changed to investigate the effect of surrounding on spray shapes. Also the fuel temperature was changed. Moreover, OH radical from spray combustion was visualized by chemiluminescence. As a result, the injected spray behavior with high fuel temperature and these combustion characteristics were made clear.

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To investigate the ignition process in a diesel spray, the ignition in a transient fuel spray is analyzed numerically by a discrete droplet spray model (DDM) coupled with the Shell kinetics model at various operating conditions. Predicted results show that the fuel mixture injected at the start of injection, which travels along midway between the spray axis and the spray periphery, contributes heavily to the first ignition in a spray. The equivalence ratio and temperature of the first ignited mixture are kept nearly constant until the start of hot ignition. The temperature of the first ignited mixture is kept at a constant value of higher temperature than the thermodynamic equilibrium temperature of the mixture before the hot ignition starts. The equivalence ratio of the first ignited mixture is around 1.6 at initial gas temperatures between 750 K and 850 K. When the initial gas temperature increases from 850 K to 1000 K, this equivalence ratio increases up to 2.5 through the effect of negative temperature coefficient region (NTC).

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The THC emissions from a DI diesel engine during increasing loads significantly increased to very high concentrations from just after the start of the load increase until around the 10th cycle, rapidly decreased until the 20th cycle, and then gradually decreased to a steady state value after 1000 cycles. The increase in THC is more significant with lower compression ratios and lower coolant temperatures. The dominant components present in the THC transient spike were lower hydrocarbons with carbon numbers less than eight. In particular, ethylene showed a much higher concentration than the other components.

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A computational fluid-dynamics simulation for a turbulent combustion is established using a stochastic approach, and applied to Diesel Combustion. The nonuniform states of turbulence mixing, ignition process and formation of Nitric oxide (NO) are statistically described using the probability density function (PDF). The results show that the courses of in-cylinder pressure is good agreement with experimental data and the rapid formation of NO in the beginning of the combustion is calculated. Furthermore, the local hot spots, which related to NO production, are well predicted.

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Predictions of the mixture formation process in gasoline DI engines are strongly required. Numerical simulations of free sprays are carried out on the basis of DDM. In this report, know problems such as settings of the initial conditions and droplet breakup model are discussed. Solutions to these problems are introduced in a condition with high ambient pressure. To improve the spray modeling quantitatively, both experimental and theoretical studies are still required.

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In order to conduct the three-dimensional numerical analysis of the mixture formation and combustion processes in diesel engines, submodels for fuel sprays, ignition and combustion had been investigated. In this paper, the Livengood-Wu's model or the Schreiber's reduced kinetic model was applied as an ignition model. As a combustion model, the Reitz's model was employed. These submodels were incorporated into the author's GTT code, and the combustion process in a direct-injection diesel engine and that in a premixed compression ignition engine were numerically analyzed using this code. The validity of the submodels was confirmed by comparing the calculated results with the experimental ones.

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This paper reviews the phnemenological mechanisms of the diesel combustion and the pnenomenological combustion modeling. A comparison of the detailed multidimentional models and the pnenomenological models are discussed. These include spray penetration, spray angle, drop size, ignition delay, nitric oxide and soot formation. The phenomenological models are particularly suitable for routine simulation exercises, and for extensive parametric studies of engine operating and emission characteristics.

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The heat conduction in finite length single walled carbon nanotubes (SWNTs) was simulated by the molecular dynamics method with the Tersoff-Brenner bond order potential. Temperature at each end of a SWNT was controlled by the phantom technique, and the thermal conductivity was calculated from the measured temperature gradient and the energy budgets in phantom molecules. The thermal conductivity was measured for two different diameter SWNTs with various lengths from 3 nm through 200 nm. Since the photon mean free path is estimated as order of lOOnm〜1μm, heat conduction of nanotubes with less than 1μm length should have the nearly 'ballistic' features with much less apparent thermal conductivity than infinitely long nanotubes. The Fourier's law of heat conduction may not be obeyed for these almost one-dimensional materials when rather high heat-flux conditions. The measured thermal conductivity did not converge to a finite value with increase in tube length, but an interesting power law relation was observed. The basic heat conduction mechanism was explored through the phonon dynamics extracted from the molecular dynamics simulations. The phonon density of states and photon dispersion relations were directly calculated from the simulated results.

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This paper aims to study diffusion mechanism of point defects such as vacancies and interstitials of silicon in silicon-germanium solid solution using molecular dynamics simulation. Moreover, equilibrium volume of the silicon, germanium and these alloys were also estimated by using two different schemes of constant volume. The calculation revealed that diffusion constants of the point defects are almost independent of external pressure. Furthermore, volume of the system changed almost isotropically.

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In the processes of nanotechnology or surface deoxidization by flame treatment, it is necessary to establish a fundamental method for controlling heat transfer and chemical reaction on surfaces in molecular scales. In the present study, we discussed the possibility of controlling reaction probability and energy transfer in molecular scales by laser excitation of molecular quantum states. In order to investigate effects of internal motion of oxygen molecules on reaction probability and energy transfer to metallic surface, we carried out a classical molecular dynamics simulation by using LEPS potential energy surface between an oxygen molecule and Ag surface. Reaction probability of oxygen molecules much depends on internal molecular motion, such as vibrational temperature and rotational temperature of oxygen molecules. With the increase of initial translational energy and vibrational temperature of an oxygen molecule, the probability of dissociative adsorption increases. With the increase of initial rotation temperature, the dissociative probability decreases substantially.

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MD seems to be one of promising tools to obtain thermal properties but it has not been recognized as a powerful one for estimating them with an adequate accuracy. This can be attributed to a quantitative inadequacy in MD simulation results and the main reason can be considered as an accuracy of intermolecular potentials. In MD simulations, intermolecular potentials are usually cited from references, therefore, even though the simulation result does not agree well with the experimental one, it is difficult to examine an accuracy of the potential used. In this study, the intermolecular potential of Ar or Oxygen was calculated using ab initio molecular orbital method and effects of basis sets and approximation level on its accuracy were examined.

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In the present paper, current states of the art of natural working fluids for heat pumps are overviewed. The coefficients of performance of ammonia and propane are as high as those of HCFC22 and HFC alternatives. Because of their flammability and toxicity, the use of these refrigerants is restricted for limited applications. Carbon dioxide has inherent disadvantage of low COP for air conditioning application. A high-performance water heater, in which carbon dioxide was used for a working fluid, was put on the market. Possibility of other natural refrigerants is discussed.

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The development clathrate hydrate has latent heat over the temp. range of 5〜12℃ and a mixture of clathrate hydrate and aqueous solution ( referred to as CHS ) has greater cooling capacity compared to cold water. The air-conditioning system utilizing the CHS is expected to reduce the pumping power consumption dramatically. This paper reports the results of a measured heat transfer characteristics of air conditioner using the CHS. The result of experiments, proved that CHS is capable for cold latent heat medium for air conditioning system.

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Experimental investigation on the phenomena of direct flowing out of cooled air from a thermoacoustic refrigerator was made. Cooled air in the acoustic refrigerator was blown naturally by pressure change in the refrigerator without any valve, the inside air was cooled by thermoacoustic effect and the air was blown out by acoustic pressure. The flow rate of the air increased with the power input to the acoustic driver and with the outlet diameter. On the other hand, the temperature difference decreased with their increase.

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As the use of environmentally acceptable refrigerant is required recently, CO_2 is proposed for one of alternatives and recommended in car air-conditioners and heat pumps for hot-water supply system. However, remaining unsolved problems are not small amont to develop the designing method of heat exchanger. In this study, to clarify the heat transfer characteristics of CO_2 in a small diameter tube of 1.8 mm I.D., the experiments were carried out on flow boiling and the local heat transfer coefficients are measured in the range of mass velocity from 100 to 250 kg/m^2s and of wallheat flux from 3.77 to 37.4 kW/m^2 at constant inlet pressure of about 3.5 MPa.

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This paper deals with a refrigeration system using CO_2 as the working fluid. The CO_2 refrigeration system has a cycle including trans-critical region at the high-pressure side due to its thermodynamic characteristics. This refrigeration system provides an advantage, when it is applied for both cooling and heating demand simultaneously in the temperature range from -30℃ to 80℃. Taking into account of operational data of a 40USRT CO_2 refrigeration system, which is installed at Waseda University, the effectiveness of the CO_2 refrigeration system applying to both cooling and heating demand at the same time in industries is discussed.

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This paper deals with the heat transfer and flow characteristics of the heat exchanger for a heat pump system using carbon dioxide as a working fluid. The heat exchanger designed as a gas cooler for high-pressure side is a counter-flow and shell-and-tube type one, 1m in length. Twenty-three copper capillary tubes, 2mm in O.D and 1.0mm in I.D., are assembled in the shell, which is a copper tube, 16mm in I.D. and 18mm in O.D. The experimental results show that the overall heat transfer coefficient of the heat exchanger is about 5 times higher than that of the concentric tube heat exchanger (comprised of a outer tube, 10.7mm in I.D., and a inner tube, 8mm in O.D.) and the pressure drop does not increase seriously.

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Mixing of gas and solution in a bubble type absorption system is better than that in a falling film type. Experimental study was performed on ammonia bubble absorption. Ammonia was provided through a single orifice into ammonia aqueous solution under system pressures of 0.1-0.4 MPa. Concentration of the solution was 0-0.3 kg/kg and temperature was at 295 and 313 K. System pressure had effects on the initial bubble diameter and mass transfer coefficient. It was clarified that bubble diameters increased with increasing ammonia flow rates and decreased with increasing system pressure. Experimental formulations of bubble diameter and mass transfer coefficient were obtained.

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From the viewpoint of the energy saving, it is an effective procedure to attempt the compactification and performance improvement of absorption water heater-chiller and is the improvement on heat and mass transfer characteristics of absorber and regenerator. In the physical method, the configuration improvement on absorbers and structure of generator and heating surface (tube), etc. of the shape is required. In this study, it was made that elementary process of heat transfer, which simultaneously, it is accompanied, by mass transfer in heat transfer process of plate type absorber, which established accordion pleated flow channel type was clarified to be purpose.

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For improving performance of the GHP system in summer season, an adsorption refrigeration cycle is useful to utilize the waste heat exhausted from the gas engine. We introduce a unit cell as a model of adsorber, which has a single tube bound by silica gel on the external surface, to make easy to analyze the phenomena of heat and mass transfer in the adsorbent. This paper deals effects of the fin pitch of the finned tube on progression rate of adsorption process. As a result of discussing about optimization of the adsorption process, it was found that the adequate fin pitch existed.

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In order to save energy and decrease environmental impacts of thermal energy utilization systems, a CaO/H_2O/Ca(OH)_2 chemical heat pump (CHP) can be applied for the systems by using the high-density heat storage and cooling/heating functions of the CHP. In this paper, the performance of the CHP for refrigeration and air-conditioning were examined based on the authors' experimental and theoretical over ten years studies on CaO/H_2O/Ca(OH)_2 CHPs. As a result, the CaO/H_2O/Ca(OH)_2 CHPs are found to work more efficiently than other heat pump systems in appropriate heat source conditions.

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When a hydration reaction can be operated reversibly by alternate removal and addition of the reaction heat, it is utilized for operating a multipurpose process with various capabilities of heat pumping, recovery of pure water, low temperature concentration, freeze concentration and so on. This paper deals with a fundamental study to develop multipurpose chemical heat pumps driven by the hydration reaction of calcium chloride, whose principle and potentialities are described in the first part. To elucidate the mechanism that the hydration reaction stopped at a low yield, the reaction rates were measured after performing short-period vacuum desorption of the surface water and the surface structure of the reacted particles was observed by SEM. Based on these investigations a reaction model has been proposed, which can simulate the reaction progress by taking account of the condensation of water molecules absorbed on the particle surface.

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From the viewpoints of global warming and depletion of ozone layer, natural working fluids are used in heat pumping technology. Water/ice system is selected as natural working fluid for cold heat storage and transportation. There are two big problems in use of water/ice system in cold heat storage and transportation system. They are supercooling phenomenon in ice crystal nucleating and agglomeration phenomenon of ice slurry in storage tank or pipe line. In this paper, the suppressing method of these phenomena by use of some additives, etc. is introduced.

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Addition of poly(vinyl alcohol) (PVOH) to ice slurries is expected to be effective in inhibiting recrystallization of ice. We evaluated the ability of recrystallization inhibition by the splat cooling method, using PVOH with different concentrations and molecular weights. The results showed that PVOH was effective in inhibiting recrystallization even at a low concentration of 0.01 mg/ml. Relatively small molecular weight decreased the ability of recrystallization inhibition, although molecular weight did not significantly affect the ability within the present experimental conditions. The recrystallization-inhibition ability of PVOH could be explained by the adsorption of PVOH molecules onto an ice surface, in the same manner as that of antifreeze protein.

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We developed the sealed type ice-making system that makes supercooling water in the direct expansion style ice making device unit and continuously change to iced water. Continuation supply and the long piping of iced water are possible with this system. This system was developed for the air-conditioning system using ice thermal storage. This paper reports the outline of the sealed type ice-making system continuously changed to iced water

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Abstracts A two-dimensional numerical study has been conducted to obtain fluid flow and heat transfer characteristics of Rayleigh-Benard natural convection in non-Newtonian Phase-Change-Material (PCM) slurries inside a rectangular enclosure with isothermal horizontal hot and cold plates and adiabatic side walls. Generally, a PCM slurry has the properties that its density draws down sharply but continuously with the melting of PCM and its specific heat capacity shows a peak value during melting. Some PCM slurries such as microemulsions can exhibit pseudoplastic non-Newtonian fluid behavior. This paper deals with the differences in natural convection and flow patterns between Newtonian and non-Newtonian fluids of which with or without PCM theoretically. Given in the paper are also some explanations and mechanisms about the results. The simulation is performed with the following parameters: a shear thinning pseudoplastic fluid for 0.8&le;n&le;1.0, Ra&le;2×10^6, Pr=70〜210, and the aspect ratio from 1:5 to 1:20.

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In respect of progress on the first utilization as ethanol brine and episode on the sales promotion of ethanol brine to the beer factories, lecturer reported on the story of experience. At a later period, application for the LNG liquefied gas of regenerator actualized as new adoption of ethanol brine system. Come to the conclusion it is necessary to prepare of ethanol brine data under the demonstration example, as the result, Japan Alcohol Association put together and published that research and development for 5 years as a trust business from Ministry of International trade and Industry. I'm very hopeful of practical use of those ethanol physical properties data as brine.

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Ethanol is a familiar substance to everybody, but its water solution is a mysterious substance in that it shows complex changes in many of its properties depending on ethanol concentration. Ethanol water mixture has a liquidus line and a solidus line that one separated, and therefore it can have both liquid and solid phases existing together. As result, with advances in low temperature technology in recent days, ethanol water mixture is attracting more and more attention as an environment-friendly coolant or as a thermal storage material. In the present work, we developed the fluid latent heat storage material using ethanol water mixture.

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In the present study, a new secondary refrigerant was investigated using urea-water mixture. And we developed the new fluid latent heat storage material. As the urea-water mixture is a binary solution, it can have a solid-liquid phase. But there are so few data available at present for describing the behavior of the urea-water mixture. In this study, the differential scanning calorimeter (DSC) was used to construct the phase diagram of the urea-water mixture and investigate the latent heat of ethanol water solution.

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This paper deals with the manuscript of TED-Conf'01 Proceedings. Intelligent property, talent, research environment are improved and must be strengthened in order to effectively efficiently carry out research and development. Various businesses are promoted for the sustainable development of science and technology of Japan in JST. The challenge to the technology transfer for the support for research and development with the aim of the commercialization and Modeling Project for New Concept of Technology which is the project in the initial stage for promoting research result to the commercialization are introduced.

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This paper describes that 21 of TLOs have founded with the authorization from the Ministry of Education, Culture, Sports, Science and Technology and the Ministry of Economy, Trade and Industry, and they have achieved about 70 cases of licensing and to set up 5 SMEs since the TLO law acted in force in 1998. University faculty, as the highest intellect group, are largely expected to make a contribution in the field of Technology Transfer, in order to create new industries and to activate the R&D oriented industrial needs. It presents you activities of TLO in view of faculty.

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Joint development of thermal-dynamic equipments between universities and companies has to change, from the universities doing the basic research and companies doing equipment application research, to joint research with the view of equipment application. The joint research should involve the customer for speedy development and application as well as minimization of risk. This paper reports on progress of actual joint research and development project between universities, customer and company.

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The new invention is a nozzle with a pressurized annular slit and a conical cylinder, typically attached to the entrance of a pipe. Pressurized air is forced through the sides of the device into the buffer area and then through the angled annular slit into the pipe. Due to the Coanda effect of annular jet's attaching to the nozzle walls, the flow down stream develops a spiral structure flow. In general, it is felt that this new spiral-flow nozzle has considerable potential for producing more stable and efficient industrial flows. The evolution from discovery to invention through spiral flow researches have been discussed; patent application, research originality guaranteed by patents and liaison for collaboration with company.

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Some new combustion phenomena have been found by use of microgravity field, and now microgravity is one of the most effective tools in combustion research. Promising experiments in the space station are near at hand, but it is necessary to reconsider what the microgravity experiment is and how the microgravity field should be effectively utilized, especially by showing several problems and expected subjects in combustion.

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The resupply technique of cryogenic liquid propellants under microgravity condition is a key technology to construct an infrastructure of space transportation system. Our study is on investigation of forced convective boiling of the cryogenic fluid for establishment of this technique. In the present experiment, we used the transparent heated tube, which can allow temperature measurements and visual recordings at the same time. It was conducted under Ig and microgravity (10^<-5>g) using Japan Microgravity Center (JAMIC). We succeeded in measuring heat flux and heat transfer coefficient on forced convective boiling of LN_2 using the tube under Ig and microgravity.

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To clarify fundamentals of gravity effect on the behaviors of two-phase flow, experiments were conducted onboard aircraft. Annular flow of air-water mixture was realized independent of gravity level varying along a parabolic trajectory. Effect of gravity on the pressure drop was clarified systematically for a vertical upward flow in a tube for different combinations of liquid and gas flow rates. Pressure drop becomes low when gravity is reduced, and the effect of gravity decreases with the increase of gas or liquid flow rate. The gravity effect was corresponded to the change of interfacial shear stress on the surface of annular liquid film, and a method to correlate the gravity effect on interfacial friction factor having direct influence on the pressure drop was introduced. To clarify gravity effect on two-phase forced convective heat transfer, distribution of velocity and temperature across the annular liquid film were analyzed in detail based on measured values of pressure drop under different gravity conditions.

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