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Volume 19 (2002)
- Issue 4 Pages 301-
- Issue 3 Pages 211-
- Issue 2 Pages 101-
- Issue 1 Pages 1-
Volume 19, Issue 2
Displaying 1-10 of 10 articles from this issue
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Review Article
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Hiroshi KITAMURA, Kosei OGUCHI2002 Volume 19 Issue 2 Pages 101-119
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSPresent status on the thermodynamic properties of experimental data and their correlations of both ammonia and aqueous solution of ammonia was introduced in this paper. The aqueous solution of ammonia is used for not only a working fluid in absorption refrigerator cycles but also working fluids in bottoming cycles of steam power plants and other heat recovering systems. Therefore, the thermodynamic properties of this substance are required in a wide range of temperatures, pressures and compositions. The experimental results of pVTx properties for ammonia and aqueous solution of ammonia and their comparisons with a formulation by Tillner-Roth and Friend1) were critically surveyed. The “Guideline on the IAPWS Formulation 2000 for the Thermodynamic Properties of Ammonia-Water Mixtures”, correlated by Tillner-Roth and Friend1), was approved on September, 2001, by the International Association for the Properties of Water and Steam (IAPWS) 2).View full abstractDownload PDF (1249K)
Papers
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Hirokazu SAKAI, Satoshi TOKUSHIGE2002 Volume 19 Issue 2 Pages 121-131
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSSuction wing row of the inner unit of an air conditioner as well as its function to cover the inside of the air conditioner are important components to determine the design quality. The draft resistance is determined by this complicated shape. Therefore, with the present development method, a prototype is installed on the main body to obtain an optimum shape by repeating performance of the experimental evaluation.
Thanks to the development of Computational Fluid Dynamics(CFD), we have a method to apply CFD to various developments. In this study, we studied the porous media for modeling the suction wing row. Then, we designed a method for analyzing individual draft resistance of the suction wing row in order to obtain the relation given to the porous media. Further, we analyzed the influence of design parameters of each suction wing row upon the draft resistance. Finally, we obtained an ideal shape of the suction wing row under certain conditions using CFD.View full abstractDownload PDF (933K) -
Shigeru BANDO, Eiji HIHARA2002 Volume 19 Issue 2 Pages 133-141
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSAmong the growing number of environmental issues, the global warming due to the increasing emission of greenhouse gases, such as carbon dioxide CO2, is the most serious one. In order to reduce CO2 emissions in energy use, it is necessary to reduce primary energy consumption, and to replace energy sources with alternatives that emit less CO2.One option of such ideas is to replace fossil gas for water heating with electricity generated by nuclear power, hydraulic power, and other methods with low CO2 emission. It is also important to use energy efficiently and to reduce waste heat. Co-generation system is one of the applications to be able to use waste heat from a generator as much as possible. The CO2 heat pump water heaters, the polymer electrolyte fuel cells, and the micro gas turbines have high potential for domestic energy systems. In the present study, the life-cycle cost, the life-cycle consumption of primary energy and the life-cycle emission of CO2 of these domestic energy systems are compare. The result shows that the CO2 heat pump water heaters have an ability to reduce CO2 emission by 10%, and the co-generation systems also have another ability to reduce primary energy consumption by 20%.View full abstractDownload PDF (548K) -
(Further Report : Evaluation of Ice Layer as Thermal Resistance)Kenichi HASHIZUME, Yuusuke MIYAMOTO, Takahiro MATSUE2002 Volume 19 Issue 2 Pages 143-149
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSAn experimental study was performed on ice formation around a brine-cooled tube embedded horizontally in a liquid-fluidized bed. It was found that the ice layer thickness evaluated from thermal resistance, equivalent thickness, is thinner than the actual average thickness, and that the ratio of the equivalent to the average thickness depends on a non-dimensional parameter consisted of Biot number and cooling temperature ratio for liquid single-phase flow, and additionally of the Archimedes number for liquid fluidized bed.View full abstractDownload PDF (368K) -
Takahisa KIDA, Hideo INABA, Akihiko HORIBE2002 Volume 19 Issue 2 Pages 151-161
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSThis paper deals with the optimum running conditions of honeycomb rotor composed of new polymer sorbent which was composed of the cross-linked polymer of sodium acrylate. At first, overall mass transfer coefficient of the honeycomb rotor for numerical computation was derived by the experimental results from the model experimental apparatus. Numerical simulations could predict the optimum running conditions of the honeycomb rotor such as the revolution number of the honeycomb rotor against the inflow air velocity and honeycomb length etc.View full abstractDownload PDF (608K) -
Taizo SATO, Tetsuhiro TSUKIJI2002 Volume 19 Issue 2 Pages 163-171
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSThe displacement of the suction valve in a compressor for automotive air-conditioning and the flow around the valve are investigated using a flow visualization technique. The visualization is conducted using the real compressor, which is improved to observe inside under the actual condition. Turbulent flow around the suction valve is solved using a computational fluid dynamics simulation. The flow is assumed to be an incompressible three-dimensional and viscous. The standard k-ε turbulent model is used Furthermore the pressure pulsations, the flow velocity and the displacements of the suction valves are analyzed numerically using the system simulation program we developed. The calculated results using a computational fluid dynamics are compared with the flow visualization results and the vibrations of the valve are discussed.View full abstractDownload PDF (4686K) -
Yoshinao YAGI, Sadanari MOCHIZUKI2002 Volume 19 Issue 2 Pages 173-180
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSThe modified single-blow transient testing technique was applied to evaluate heat transfer and pressure loss performances of actual louvered fin heat exchanger cores. A systematic measurement was conducted for the louvered fin surfaces varying transverse fin pitch in order to investigate the effect of the channel cross section shape as well as the Reynolds number, Re. In this study, the ratio of louver pitch and hydraulic diameter, l/dh, was used as a parameter to represent the channel cross section shape. Empirical equations were obtained for heat transfer and pressure loss performances in terms of Gz, Pr and l/dh.View full abstractDownload PDF (416K) -
Tsutomu HOZUMI, Akio SAITO, Seiji OKAWA, Kazuharu WATANABE2002 Volume 19 Issue 2 Pages 181-187
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSIn order to clarify effects of electric charge on freezing of supercooled water, experiments were carried out with various kinds of electrodes in supercooled water. Water sample was kept in a test tube and cooled down at a constant cooling rate. When the water sample was maintained under a supercooling state, an electric charge was applying to the water sample with a small electric current. The degree of supercooling was measured continuously. Then the degree of supercooling at freezing was determined. Six kinds of materials were used for electrodes. Those materials were Aluminum, Copper, Argentum, Aurum, Platinum and Carbon. It was found that the effects of electric charge were changed by each material of electrodes. The degree of supercooling at freezing is the lowest in the case of Aluminum. On the other hand, the highest value of the degree of supercooling at freezing is in the case of carbon. The reason for the difference of the degree of supercooling at freezing by six materials was discussed.View full abstractDownload PDF (427K) -
3rd Report: Study about the Effect of Mixing the Carbon Fiber and Driving Conditions on the System Refrigeration PerformanceSang-Chul BAE, Takahiro YABE, Masafumi KATSUTA2002 Volume 19 Issue 2 Pages 189-200
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSIn this paper, because the effective thermal conductivity of MH alloy bed is extremely low (about 1W /m•K), the mixing the carbon fiber into the MH bed is used to enhance the heat transfer performance. In addition, it is clear that the effective thermal conductivity of MH-2 alloy bed is higher than that of MH-l alloy. In order to clarify the effect of mixing carbon fiber, the effective thermal conductivity of the MH alloy bed with and without carbon fiber are measured and compared. Mixing carbon fiber is useful method for MH alloy's heat transfer enhancement. And, using the calculation model based on the one dimensional thermal diffusion equation and the demonstrational refrigeration system, the effects of driving conditions, heat source temperature, middle cooling temperature and initial system equilibrium pressure are discussed.
Finally, using the above calculation model, the influence of adding the carbon fiber on the refrigeration performance is analyzed.View full abstractDownload PDF (728K) -
-Effects of Composition of Water-Oil Emulsion on Ice Formation Process-Shinji NAKAGAWA, Daisuke TSUCHIDA, Maashi OKADA, Chaedong KANG, Koji M ...2002 Volume 19 Issue 2 Pages 201-209
Published: 2002
Released on J-STAGE: October 11, 2011
JOURNAL FREE ACCESSA water-oil emulsion which is a mixture of silanol-aqueous solution and silicone oil was cooled under stirring in a vessel in order to form ice particles without adhesion. A volume ratio of water in the emulsion was changed from 80vol.% to 100vol.% and the effects of the ratio on ice formation process were investigated. It was confirmed that oil in the emulsion restrained ice from adhesion to a cooling wall Water-oil emulsion with 80vol.% water is most effective in preventing ice adhesion under various cooling conditions examined. If a cooling temperature is higher and there is no ice adhesion, silanol-aqueous solution without oil can form ice with a higher heat transfer rate.View full abstractDownload PDF (654K)
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