To recovering a throttling loss by an expander is effective to improve the performance of a CO_2 refrigeration cycle. Leakage in the expander is dominant factor on the expander performance, and it is to be estimated correctly by an analytical model. Since the leakage in the expander flows from super-critical region to two-phase region, i.e. the trans-critical flow, the flow characteristic is complicated. In this study, the flow characteristics of the trans-critical flow are examined experimentally and analytically. It is found that oil circulating with refrigerant is separated and stratified in a pipe under the super-critical condition. The position where the transition from super-critical to two-phase condition occurs is identified by observation in the leakage path. The calculated result by an analytical model taking account of the oil effect agrees well with the experimental one.

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In this report, cooling effectiveness of sliding thrust bearing with forced lubrication system for screw compressor is studied. Lubricant heat generated at bearing surface is partly mixed with and dissipated by fresh lubricants through bearing grooves and the rest is carried over to the next bearing surface. Effect of the bearing groove arrangement of the thrust bearing on cooling effectiveness is experimentally investigated. As the results cooling effectiveness of the bearing with grooves on runner is superior than that with grooves on pad, which results in lower bearing temperature. Cooling effectiveness of the bearing with grooves on runner is found to be aborts 80%.

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The refrigeration and air conditioning industry is urgently required to develop environment friendly and energy conserving equipments because of problems related to ozone depletion and global warming. Natural refrigerants have attracted high interest in the industry because of their little effect on the environment. This paper reports on the development of heat pump system working with carbon dioxide as the refrigerant. Test results under different operating conditions are reported.

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While the concerns about global environmental issues are on the rise, natural refrigerants and heat pump systems of high efficiency attract attention as a measure to combat ozone layer depletion and global warming. This work presents the development work of a heat pump chiller for air-conditioning, using the natural refrigerant ammonia as the refrigerant. Using a newly developed evaporative condenser and a high efficient compressor, we attained a unit COP of 5.1/4.9 (at 50/60Hz) in the cooling operations. A sealing damper was used in order to raise the safety level of the chiller in the event of ammonia leakage. In addition, the installation space was drastically reduced by building an ammonia removal system in a unit. Japan, as an earthquake-prone country has imposed strict regulations on the use of ammonia refrigerant. With the construction of the present work, we have been able to produce an ammonia removal system, which is easy to use but less likely to cause concerns on ammonia leakage.

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In recent years, there is a growing need for the high-efficiency air conditioners as a means of preventing global warming, In response to this need, we have developed the highest efficiency multi-split air conditioners in industry for office building use by using the R410A refrigerant and by improving the efficiency of constituent main components. In addition, we have improved the partial load efficiency by using variable-speed compressors and driving them all flexibly by the system controller. As a result of this improvement, the annual energy consumption is reduced by half compared to the conventional model.

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The CITY MULTI ICE YkP ECO series corresponding to a new refrigerant(R410A) can contribute to reduction of CO_2 emissions by adopting highly efficient compressor, the optimal design heat exchanger, etc. And energy saving and the low running cost exceeding the conventional machine become realizable by performing load equalization of the amount of electric power use by ice thermal storage. Moreover, this system can perform comfortable heating by heating using thermal storage. It is expected that it can respond to the needs of various markets from now on.

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The commercial air conditioners which are now in common use are primarily designed to control temperature. In most cases it is not possible to control humidity with the same unit. However, with the increasing demand for IAQ improvements in recent years, the cooling/reheat method has been used to add full dehumidifying functions to standard models in the home air conditioner market. In order to meet this market need for commercial air conditioners as well, we have adapted the 3-way cooling/heating free multi system to develop the Desiccant Air Conditioner, an air conditioning system which allows more advanced control of temperature and humidity.

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By installing an additional condenser on the air-conditioning machine, a more efficient heat pump system could be operated with HCFC22 and HFC134a without changing mineral lubricant oil. It was shown that COP for cooling operation was improved when operating with HCFC22 and HFC134a. Based on the flow visualization experiment, it would be confirmed that HFC134a and the mineral lubricant oil normally circulate during operation even though they are not dissolved to each other.

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While various actions for prevention of global warming are carried out, higher efficient chiller development is expected. In this development, we adopted inverter control and Lorentz cycle in the field of lower-capacity screw chiller and aimed for performance of development machine to become equal with large-capacity chiller. It became clear that developed machine showed 1.3-1.5 times performance in comparison with conventional one at full load, 1.3-3 times performance at partial load and to have superior economical efficiency and environment friendly effect.

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High energy efficiency can be obtained by utilizing seawater as heat source water or cooling water of heat pumps. Then, we had developed the highly effective heat pump, which can use seawater directly as heat source or cooling water. In North Side Building of the Port of Nagoya Public Aquarium, the water temperature of huge pools for breeding orca, and belugas, etc, is adjusted with this highly effective heat pump system. In this paper, the energy saving performance, environmental preservation performance, and operation cost of the system are clarified by analyzing the operation data over a period of four fiscal years.

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In order to make practical use of energy-saving type cooling system which is possibly introduced into general buildings, an experimental evaluation with 1/2 model of the desiccant cooling system (1000CMH machine) that has 5kW cooling ability and can even use the low temperature energy at 70℃ level generated from small type power generator with 5-10kW class power generation amount was made and the performance evaluation results were reported.

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This review introduces the recent developments in the field of biomedical measurement and imaging using near infra-red light, including pulse oximeter, oxygen monitor, optical mapping (topography), diffuse optical tomography, retinal imaging, and fluorescence tomography.

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The purpose of this study is to develop a method to measure noninvasively the temperature distributions in tissues from the differences in sound speed before and after heating, using the characteristics that sound speed depends on the medium temperature. First, the phantom made of agar was placed in a water bath. We obtained the temperature distribution with the difference within 1℃ in phantom by subtracting the sound distribution before heating from that after heating. Then, we made the experiment with excised tissue in glucose solution. Tissue has to be placed in liquid which has the sound speed close to that in tissue in order to measure the small temperature difference. As a result, we measured the temperature difference below 1℃ in excised tissue.

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The aim of this study was to investigate the relationship between blood flow and skin temperature after water heating. Simultaneous measurements of skin temperature, blood pressure, and blood flow in hands and forearms exposed to the air were carried out after the test hands were immersed into the water at 40℃ for 2〜5 min. Temperatures were measured by an infrared thermography. Blood flow in the ulnar artery and blood perfusion in the fingertip were monitored by an ultrasound Doppler and laser Doppler velocimeter. Results indicate that water heating can induce the arterial blood flow in the forearm to either increase or decrease; when the thermal stress is raised to be above a critical value for different subjects, the arterial blood flow would be decreased. Additionally, the spectrum analyses of the sequential thermal images show that with the thermal stress increasing, the amplitude of some frequencies become stronger, which implies that the hemodynamic effect on the skin temperature tends to be stronger.

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A method to actively controlling crystallization is one of promising technique for cryopreservation. The object of this paper is to study the effects of ultrasonic irradiation on ice formation during freezing of biological materials. In the experiments, potato tissue was frozen under irradiation of ultrasound at frequency of 28kHz. Firstly, it was found that ultrasound enhanced the freezing rate. Secondary, the microscopic observation using Cryo-SEM suggested that mechanical damage of the tissue due to extracellular ice formation was reduced by ultrasonic irradiation. However, through impedance analysis, the Cole-Cole arc disappeared regardless of ultrasonic irradiation. Therefore, the effects of ultrasonic irradiation on freezing damage did not made clear quantitatively.

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Cell damage and death due to the hypertonic electrolyte solution under the unfrozen condition were investigated experimentally. The cells were exposed from an isotonic solution to hypertonic electrolyte solution (concentration C_m and exposure time τ) back to the isotonic solution. The membrane integrity was assessed by means of the dye exclusion test to estimate the cell viability. Influence of temperature on the cell viability as a function of τ and C_m was clarified. The results indicate that the cell damage and death proceed kinetically in the similar way. Also, an interesting dependency of the cell viability on temperature was found out.

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One of the most important techniques involved in the studies of stem cells or progenitor cells is harvesting and purification of target cells. In this paper, we proposed a new technique to harvest cells targeted under the microscope from cells cultured on a dish, which was coated with thermoresponsive polymers that is soluble in water below〜33℃. Using a device that allowed cooling the bottom of the dish locally beneath target cells, a cell or a small cell colony were detached from surface and harvested within about 30 seconds.

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Fluorescence image was investigated for development of a leukocyte counter for quality assurance tests of transfusion blood products. The standard leukocyte fluorescence image profile was established by averaging the actual fluorescence image of leukocytes. It was used for development of an optimum image analysis algorithm to avoid miss-counting of the dust contaminated from the environment. The centrifugal concentration process was investigated by a computer simulation, and it was found that this process caused leukocyte overlapping and limited the measurement range. We succeed in developing the leukocyte counter, with improving the accuracy and the measurement range up to 25 [WBC/μl].

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For the aqueous solution extracted from the evaporator, there were made model solutions included one, two or three components, i.e. sodium sulphate, sodium chloride and sodium hydroxide. For the solutions mentioned in two series of experiments bubble velocity, mass steam content of passing to the deteriorated heat transfer region and heat transfer at boiling in tank and vertical tube were studied.

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After TMI and Chernobyl accidents, many efforts have been made to enhance the nuclear safety with passive features. Among such passive features, the passive containment cooling system has been suggested. In case of a Loss of Coolant Accident (LOCA) occurred, Passive Containment Cooling System (PCCS) cools the core decay heat. The objective of this experimental study is to clarify the heat transfer characteristics of PCCS on a vertical pipe. In order to calculate overall heat transfer coefficient between the cooling water and atmosphere, cooling water flow rate, cooling water temperature and gas temperature are measured. The influence of the system pressure is clarified in the range of 0.1 to 0.4MPa(abs) of the system pressure at 0% of the air fraction. It is confirmed that increasing of the heat transfer coefficient is affected by increasing of the system pressure.

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For the purpose of clarifying the mechanism of CHF for saturated and subcooled pool boiling, boiling behaviors close to a heating surface were investigated with micro-sensors. Dryout process of the heating surface appearing near the CHF was measured with a high accurate conductance probe. The wall void fraction increased rapidly just when the CHF occurs, suggesting that the CHF is triggered by dryout of the liquid-rich layer formed beneath the vapor masses. Also, temperature beneath the vapor masses was measured with a micro-thermocouple to examine an effect of subcooling on the liquid-vapor structure close to the heating surface. It was found that the effective subcooling of the liquid adjacent to the heating surface remains within a considerably lower value than the subcooling of bulk liquid.

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The combination of burner and combustion chamber is one of important factors controlling flame characteristics, which has never been to our knowledge investigated systematically. In the present study, coaxial jet diffusion flames in cylindrical combustion chambers have been studied in terms of inner diameter of the combustion chamber, global equivalence ratio and turbulence in air flow. It has been found that the increase in the diameter of combustion chamber enhances the exhaust gas self-recirculation, as the result decreases the NOx emission.

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In a constant volume combustion chamber, a study of investigating for relationship between NOx emissions and a non-homogeneity distribution of methane-air mixture was conducted Non-homogeneity distribution was generated by varying a period after fuel injection and movement of perforated plate. Non-homogeneity distribution was measured by the acetone planar LIF technique and the heterogeneity index was defined. Initial pressure and temperature in the chamber was changed The effect of NOx and combustion efficiency on the heterogeneity index and the initial condition in the chamber was studied in detail. The trend of NOx and combustion efficiency was varied in different heterogeneity mixture at the same air fuel ratio.

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A standard addition LIF method for measuring nitrogen oxide concentration was applied to a quartz glass model of double-pipe type radiant tube burner. The measurement technique was developed for establishing a quick practical diagnostics to find the optimal conditions of the widely used burners. Nitrogen oxide of 90ppm was doped to the natural gas of fuel injector and the surrounding air. Mole fractions were determined comparing the LIF intensities of the doped and non-doped cases. Gas temperatures were also obtained using the two-line method. Horizontal distributions of temperature and NO mole fractions were obtained at the several different distances from the fuel injector. The temperature and NO emission level were higher in comparison with the usual diffusion burner because of the preheating effects of the burned gas in the outer annular space to the inlet gas mixture in the inner tube.

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Effects of the fuel partition between the rich and the lean flames and the air ratios of the lean and the rich flames on the characteristics of the rich-lean combustion under low-load condition were investigated in order to develop a new type of a domestic boiling water heater and a warm heater with low emission of NOx, high TDR and high thermal efficiency. It is clarified from the results of the analysis of the burned gas, the thermal efficiencies and the temperatures of the burner plates that the optimum conditions under low-load combustion are X_R:X_L=30:70 for the fuel partition between the rich and the lean flames and around λ_L=1.46 and λ_R=0.49 for the air ratios of the lean and the rich flames, respectively.

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Effects of the velocity and the air ratio of the mixture supplied into the boundary region between the rich and lean flames on the characteristics of flame stabilization of the rich-lean combustion were investigated in order to develop a new type of a domestic boiling water heater and a warm heater with low emission of NOx and high TDR. The characteristics of stabilization of the rich-lean flames are substantially improved when the stoichiometric, the lean mixture and the air are supplied at the low velocity into the boundary region between the rich and lean flames, but not improved when the rich mixture is supplied into the boundary region between the rich and lean flames. The optimum velocity of the lean mixture supplied into the boundary region between the rich and lean flames exists for improving substantially the stability limits of the rich-lean flames. It is possible to develop the new type of burners with high performance of further low emission of NOx and high TDR by controlling the velocity and the air ratio of the mixture supplied into the boundary region between the rich and lean flames.

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Based on a folded heat exchanger sheet design, we made a unique, small scale diesel particulate filter (DPF) that can transfer the heat generated in the DPF to the exhaust gas in the upstream of the DPF. By this function, the temperature of the inner part of DPF (position F in Fig. 1) was much more raised than the adiabatic temperature rise expected from the concentration of PM or H_2 artificially added for heating. With a maximum heat recovery rate of 87%, we succeeded in maintaining the inner temperature of DPF at around 500℃ and continuously removing more than 90% of PM, with a supply of only small amount of H_2.

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In the present work, optical measurement of soot particles has been performed to evaluate emission characteristics of a newly designed tubular flame burner for heavy-oil. Principles of measurement system were based on thermography, infrared spectroscopy, and laser extinction. The furnace in which the tubular flame burner was installed has a cross-section of 3m×3m and its total length is about 6m. The experimental results show that thermographic images of soot particles, soot temperature and kcl can be obtained in the practical scale furnace by the present measurement system. Volumetric soot concentration measured by laser extinction method agrees well with that estimated from output of a smoke meter placed in the exhaust tunnel of the furnace.

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A numerical simulation of turbulent spray combustion including soot and NO formation was carried out. The validity of the calculated results was demonstrated by comparing with experimental data. The effect of diameter and number of inlet nozzle on the combustion behavior was discussed. When inlet nozzle diameter decreases, the high temperature region shifts towards upstream because the increase in the inlet velocity causes the improvement of mixing of spray and air. As a result, the NO concentration in the exhaust gas decreases. The number of inlet nozzles has little influence on the temperature distribution. However, when the number of nozzle decreases, the NO concentration in the exhaust gas increases since the increase in the fluctuation of temperature results in the increase in the peak temperature.

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Although diesel engines have an advantage of low fuel consumption in comparison with gasoline engines, several problems must be solved. One of the major concerns is that diesel exhaust gas has more particle matters (PM) including soot, which are suspected to be linked to human carcinogen. As one of the key technologies, a diesel particle filter (DPF) has been developed to reduce particle matters (PM) in the after-treatment of exhaust gas. In this study, we simulate soot deposition in porous media by Lattice Boltzmann method. Results show that the flow pattern is largely changed when the soot is accumulated. When the soot concentration is higher at the inlet, the accumulated soot is expectedly increased.

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This study is made to attempt to establish a prediction model of turbulent burning velocity for hydrogen mixtures based on the mean local burning velocity estimated by taking the preferential diffusion into consideration S_L, instead of the laminar burning velocity S_<LO>. The S_L is estimated for the specific mixtures having the same S_<LO> by adding nitrogen to hydrogen-air mixtures, where S_<LO> as well as the equivalence ratio are varied extensively, in order to confirm the effect of u'/S_<LO>. It is found that accuracy of the proposed simple mode can be improved by using S_L with respect to u'/S_<LO>.

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Numerical simulation is applied to analyze the unsteady counterflow premixed flame. The influence of equivalence ratio is investigated. Fuel lean and stoichiometric mixtures (equivalence ratios are 0.75, 0.85 and 1.0) are considered in this study. Methane-air premixed gas and air are spouted from each plane. The spout velocity is varied in a sine function. As a result, it is shown that the characteristics of flame structure are correlated with the progress variable and its gradient at flame front. It is defined by mass fraction of oxidizer and corrected by mass fraction rate of fuel.

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Diode-laser absorption spectroscopy for measurements of temperature and H_2O mole fraction by scanned-wavelength method and fixed-wavelength method has been applied to monitoring of exhaust from swirl-stabilized turbulent combustor for the detection of high frequency combustion oscillation and noise. The fluctuations of temperature and H_2O mole fraction were detected by scanned-wavelength method, and peak frequencies of power spectra of these quantities coincide with those of pressure fluctuation in the combustor. Furthermore, under the control by secondary fuel injection, the energy at peak frequency of power spectra of temperature and H_2O mole fraction decreases in accordance with noise reduction. As for the fixed-wavelength method, similar results were obtained. These results suggest that the diode-laser absorption sensor is a strong candidate for sensors for the active controls of turbulent combustion.

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Experiments were performed for turbulent premixed flames of methane/CO_2-diluted-air mixture at pressure ranging from atmospheric pressure to high pressure up to 1.0MPa and mixture temperatures of 300K and 573K, which covers the typical operating conditions of premixed-type gas-turbine combustors. Bunsen-type flame was stabilized in a high pressure chamber and OH-PILF visualization was performed. Using the OH-PLIF images, contours of the mean progress variable were determined assuming flamelet regime, and turbulent burning velocity and time-and-space-averaged fuel consumption rate in the flames were measured. Results showed that the time-and-space averaged fuel consumption rate became small by the CO_2 dilution. It is mainly due to the increase in the volume of flame region, meaning suitable conditions for eliminating the combustion instability in premix-type gas turbine combustors.

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In order to cut down the fossil consumption and exhaust emission of an existing oil-burning boiler by renewable biomass energy, this paper establishes a method to combust the wood powder and A-heavy oil mixture fuel, and experimentally studies the combustion temperature and exhaust emissions. The experiments are carried out in a furnace equipped with a mixture fuel burner at different wood powder mass ratios. Compared with A-heavy oil, the mixture fuel produces less net CO_2 to provide same amount of heat. The CO concentration decreases. The NO and NO_X concentrations increase. The PM+Ash and DS+Ash concentrations increase, but the SOF concentration decreases. The experimental results show that the mixture fuel improves the combustion efficiency and lowers some exhaust emission concentrations.

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A bubble of hydrogen/air mixture is ignited in water by electric spark in the present experiment. The present study has achieved more ideal experimental condition in terms of uniform heat loss than our previous study, owing to newly developed experimental setup. Influence of the effect of heat loss to the gas-liquid interface, which increases with decreasing size of bubble, on the combustion efficiency is investigated. It is shown that the combustion efficiency of hydrogen/air mixture in a bubble with various equivalence ratio (φ=0.4, 0.6, 0.8, 1.0, 2.0) decreases as the mean diameter of bubble decreases. This result shows that the heat loss to the low temperature gas-liquid interface characterizes the combustion in micro bubble.

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Thermal recycling of wasted plastic-resin is focused in this investigation. Polyethylene terephthalate resin powder is employed and a high temperature oxidizing atmosphere is generated downstream an annular burner. Temperature and O_2 concentration fields downstream the annular burner are first examined by varying the slit and nozzle jet velocities with both equivalence ratios kept constant and without PET-powder supply. PET-powder and stoichiometric propane-air mixture are then issued into the high temperature oxidizing atmosphere. Variation of O_2 concentration contours and isothermals due to PET-powder combustion is also measured in the PET-powder flame. According to the results, the relationship between the high temperature oxidizing regions and the unburnt rate of PET-powder is finally discussed.

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Development of the integrated gasification combined cycle power generation of various gasifying methods has been preceded in the world. The gasified fuels are chiefly characterized by the gasifying agent and the synthetic gas clean-up method, and divided roughly into four types. The calorific value of gasified fuel differs according to the type of gasification agent. On the other hand, to improve the thermal efficiency, it is necessary to use a hot/dry type synthetic gas clean-up, but ammonia originated from nitrogenous compounds in coal is not removed. And then it forms fuel-NOx. For these reasons, the combustion technology for each gasified fuel is important. In this paper, we investigate influences of fuel compositions and calorific value on combustion emission characteristics, and effect of two-stage combustion on NOx emission characteristics through experiments using a small burner.

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The instability of hydrogen-air premixed flames with heat loss is investigated by two-dimensional, unsteady calculations of reactive flows. The numerical model contains detailed hydrogen-oxygen combustion with 17 elementary reactions of 8 reactive species and a nitrogen diluent, compressibility, viscosity, heat conduction, molecular diffusion, and heat loss of Newtonian type. Estimating the diffusive-thermal effect on the instability of premixed flames, the equivalence ratio is varied 0.75 to 1.25. A sufficiently small disturbance is superimposed on a planar flame to obtain the dispersion relation and linearly most unstable wave number. To investigate the characteristics of cellular flames, the disturbance with the linearly most unstable wave number, i.e., the critical wave number, is superimposed. The superimposed disturbance evolves owing to intrinsic instability, and then the cellular-flame front forms. With an increase in heat-loss parameter, the burning velocity of a cellular flame becomes monotonously smaller, which is due to the decrease in thermal expansion. However, the burning velocity of a cellular flame normalized by that of a planar flame at the equivalence ratio of 0.75 becomes larger near the quenching point.

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In this study, experimental and numerical investigations on the baroclinic torque, which is produced by pressure gradient and density gradient are made in two dimensional heterogeneous density flow field with interaction between a vortex pair and low density region. First high speed photograpy and PIV measurement with pulsed YAG laser and CW laser in order to observe the vortex-heterogeneous-denstiy-flow interaction between two dimensional vortex pair and low density region. Next numerical simulation using discrete vortex method is performed taking the baroclinic torque into consideration.

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The validation and proposal of SGS combustion model for turbulent premixed flames are conducted by using direct numerical simulation data. The conventional SGS combustion model, which represents the SGS turbulent burning velocity as a monotonically increasing function of SGS turbulence intensity, fails to represent the filtered DNS data. From the hierarchical structures of turbulent premixed flames, a strong correlation of SGS flame surface area with GS strain rate of turbulent velocity field has been clarified. A new SGS combustion model has been proposed under assumptions of fractal characteristics of flame fronts and the scale separation of turbulence. The predicted results by the proposed model coincide very well with DNS results.

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In present study, the instantaneous three-dimensional distribution of the chemiluminescence light emission image of turbulent premixed "blue" flame is captured as a fuel consumption rate distribution by a newly proposed technique; "instantaneous three-dimensional scanless computerized tomography (3D-CT) technique" with a custom-made multi (40)-lens camera. The results for a propane-air fuel-rich-premixed turbulent flame show that the flame front is observed to be a thin wrinkled luminous region of 0.6mm in thickness and that the cusps observed in horizontal cross-sections correspond to ridges of the three-dimensional flame front. It is also found that the luminosity distribution is quenched along the ridges. The maximum value of local fuel consumption rate is estimated to be 0.23 g/s/cm^3.

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Extinction stretch rates of premixed counterflow flames of DME/air mixtures were numerically and experimentally investigated. The extinction stretch rate of the DME fuel showed the intermediate value between those of CH_4 and C_2H_4 fuels. This experimental result did not coincide with numerical simulation with full chemical kinetics of DME reactions. The extinction of DME/air flame occurred when the local Kalrovitz number (Ka^L) evaluated from the local burning velocity and the local flame thickness of the stretched flame became almost unity as the same as other hydrocarbon fuels.

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To examine the evaporative cooling effects due to droplet group combustion, we conducted direct numerical simulations of combustion processes of n-decane polydisperse spray entering into a gaseous flat-flame stabilized in a laminar 2D counterflow configuration. Firstly, we investigated the effects of energy exchange between droplets and gaseous phase and the latent heat. The latent heat had stronger influence on the evaporative cooling effect in the droplet group combustion region. Secondly, parcel model on numerical simulations of spray combustion were examined. We found that the use of the parcel approach has a risk of causing a delay of combustion reaction, since the partial fuel vapor pressure increases at limited locations, which suppresses the global droplet evaporation rate.

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