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Volume 22 (2005)
- Issue 4 Pages 369-
- Issue 3 Pages 193-
- Issue 2 Pages 95-
- Issue 1 Pages 1-
Volume 22, Issue 4
Displaying 1-9 of 9 articles from this issue
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Osamu MAKISHI, Hiroshi HONDA2005 Volume 22 Issue 4 Pages 369-378
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSA stratified flow model and an annular flow model of evaporation heat transfer in horizontal microfin tubes have been proposed. In the stratified flow model, the contributions of thin film evaporation and nucleate boiling in the groove above a stratified liquid were predicted by a previously reported numerical analysis and a newly developed correlation, respectively. The contributions of nucleate boiling and forced convection in the stratified liquid region were predicted by the new correlation and the Carnavos equation, respectively. In the annular flow model, the contributions of nucleate boiling and forced convection were predicted by the new correlation and the Carnavos equation in which the equivalent Reynolds number was introduced, respectively. A flow pattern transition criterion proposed by Kattan et al. was incorporated to predict the circumferential average heat transfer coefficient in the intermediate region by use of the two models. The predictions of the heat transfer coefficient compared well with available experimental data for ten tubes and four refrigerants.View full abstractDownload PDF (585K) -
Akane KAWASHIMA, Yuki HAMADA, Kazufumi OSAKO, Katsuyasu TACHIBANA, Yuk ...2005 Volume 22 Issue 4 Pages 379-4384
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSThe gel forming properties and low temperature torelance of dusky spinefoot as raw materials of kamaboko were evaluated during contact icing and frozen storage ( -25°C ) in round. Kamaboko was prepared at definite periods, and its jelly strength ( J. S. ) water holding capacity and whiteness, and Ca-ATPase activity of the myofibrils of the fish were analyzed. As a result of this study, it was considered That dusky spinefoot meat immeadiately after catch is suitable for raw materials of kamaboko making. However, J.S. and Ca-ATPase activity decreased with the extention of storage period. The limits for the icing and frozen storage periods of the round fish as raw materials of kamaboko were two days and one day, respectively. This suggests that more study should be necessary for long term low temperature storage.View full abstractDownload PDF (389K) -
Shigeru KOYAMA, Daisuke ITO, Sang-Mu LEE, Ken KUWAHARA, Chikara SAEKI2005 Volume 22 Issue 4 Pages 385-393
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSIn this study, experiments on the flow boiling of nearly pure CO2 and CO2-PAG oil mixture are carried out using a 2.064 m long double-pipe counter-flow heat exchanger, in which the refrigerant flows inside the inner tube and the heat source water flows counter-currently in the outer annulus. A smooth copper tube and a micro-fin copper tube are used as the inner tube. In case of nearly pure CO2, the present experimental results of heat transfer coefficient in smooth tube with rough surface agree well with the predicted results using Yu et al. correlation [5], in which the surface roughness effect is taken into account. It is also confirmed that the values of heat transfer coefficient for both smooth and micro-fin tubes are almost analogous, while the values of pressure drop for micro-fin tube are slightly higher than those of smooth tube. By comparing the experimental results between nearly pure CO2 and CO2-oil mixture, it is confirmed that the oil concentration effects on heat transfer coefficient and pressure drop in micro-fin tube have different characteristics from those of smooth tube.View full abstractDownload PDF (555K) -
Naoki KOBAYASHI, Atsushi FUKUI, Hironori HORIGUCHI, Yoshinobu TSUJIMOT ...2005 Volume 22 Issue 4 Pages 395-402
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSIn scroll compressors for air conditioners, there is a compressor with back-pressure chamber spaced by seal ring behind orbiting scroll. High pressure in the backpressure chamber presses the orbiting scroll to fixed scroll. In the case that lubrication oil and refrigerant gas with high pressure and temperature in the backpressure chamber leak to low pressure chamber through the seal ring, the efficiency of compressor decreases and the oil circulation rate can increase.
In the present study the leakage characteristics of lubrication oil from the backpressure chamber to the low pressure chamber were investigated. In experiment, it was found that the oil leakage is larger for higher rotational speed of rotating disk, higher viscosity of oil and smaller pressure difference between the backpressure and low-pressure chambers. This could be explained by the calculation in which the seal ring was assumed to have a tilt angle. It was also found in the calculation that oil leakage is larger due to the thicker oil film between the seal ring and the rotating disk in the case of higher rotational speed of the disk, higher viscosity of oil and smaller pressure difference between the backpressure and low-pressure chambers.View full abstractDownload PDF (479K) -
Mitsuteru KUSHIBE, Yasuyuki lKEGAMI, Masanori MONDE, Haruo UEHARA2005 Volume 22 Issue 4 Pages 403-415
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSThe performance test of three types of plate type evaporators for spring thermal energy conversion and ocean thermal energy conversion carried out. Ammonia is utilized as working fluid and warm water is utilized as heat source. An empirical correlation is proposed in order to predict the mean evaporation heat transfer coefficient of ammonia and heat transfer coefficient of warm water for plate type evaporators. The mean heat transfer coefficient and friction factor of warm water were compared with other researches.View full abstractDownload PDF (915K) -
Takuya TSUJIGUCHI, Akio KODAMA2005 Volume 22 Issue 4 Pages 417-428
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSDesiccant cooling system can be driven with a low temperature heat such as around 80°C obtained from exhaust gas and so on. Among the configuration of the cooling cycle, honeycomb rotary adsorber is the most important part to achieve higher cooling performance. By means of computer simulation, angular and axial distributions of the amount of adsorbed water, air humidity, air temperature and adsorbent temperature inside the desiccant rotor at various operating conditions were investigated. In the mathematical model, lumped mass transfer coefficient was used and its value were derived from the fitting with experimental results to improve the reliability of discussion about the simultaneous heat/mass transfer in the desiccant rotor. It was found that the part of honeycomb rotary adsorber which is close to the regeneration air inlet cannot work well as an adsorbent at higher regeneration temperature regardless of outside air condition and regeneration air humidity. On the other hand, since the driving force was extremely low throughout all the axial positions, water vapor was adsorbed gradually at the whole axial position of rotor under a lower regeneration temperature. Consequently, this study could clarify the importance of the optimization of the rotor in terms of its length depending on the operating and air conditions.View full abstractDownload PDF (720K) -
Kenji YOSHIMURA, Shigeru KOYAMA, Hiromi YAMAMOTO2005 Volume 22 Issue 4 Pages 429-436
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSOzone has the capability of sterilization and deodorization due to high oxidation power. It is also effective for the conservation of perishable foods and purification of water. However, ozone has a disadvantage, that is, conservation of ozone is difficult because it changes back into oxygen. Recently, ice containing ozone is taken attention for the purpose of its conservation. The use of ice containing ozone seems to keep food fresher when we conserve and transport perishable foods due to effects of cooling and sterilization of ice containing ozone. In the present study, we investigated the influence of temperatures of water dissolving ozone on the timewise attenuations of ozone concentration in water. We also investigated the influence of cooling temperature, ice diameter, initial temperatures of water dissolving ozone and container internal pressure of the water dissolving ozone on ozone concentration in the ice. In addition, we investigated the influence of the ice diameter on the timewise attenuations of ozone concentration in the ice. It was confirmed that the solidification experimental data can be adjusted by a correlation between ozone concentration in the ice and solidification time.View full abstractDownload PDF (540K) -
Masao GOTO, Norihiro INOUE, Keiko SIROMOTO, Yukiyasu EMOTO, Yu LI, MAs ...2005 Volume 22 Issue 4 Pages 437-447
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSAn experimental study of heat transfer in single-phase turbulent flow inside an internally helical-grooved tube was carried out using thirteen different kinds of grooved tubes and a smooth tube with 6.35mm outer diameter and1000mm working length. The range of geometric parameters of grooved test tubes were number of grooves (45 to 65), helix angle (10 t o 35deg.) and fm height (0.15 to 0.3 mm). In the experiments, each of test tubes was heated at constant heat input of 1.4 kW by an electric heater. The inlet cooling water temperature was kept between 16 and 18 °C, and the flow rate was varied from 0.03 to 0.11kg/s. The obtained data indicated that heat transfer coefficients were from110 to 200% higher than those of smooth tube and increased with increasing the ratio of inner surface area of grooved tube to that of smooth tube and helix angle, while decreased with increasing the number of grooves. The correlations to predict the heat transfer coefficients were developed based on the measured data, which predicted the experimental data within ±20% and correlated the data reported in literature within ±30% and the analogy between heat transfer and pressure drop for the grooved tube was discussed.View full abstractDownload PDF (616K) -
Masafumi KATSUTA, Tomoya SHINDO, Kouichiro SAITO, Takero SHINOHARA, Ah ...2005 Volume 22 Issue 4 Pages 449-456
Published: 2005
Released on J-STAGE: March 14, 2012
JOURNAL FREE ACCESSRecently, the newly developed flat type micro heat pipe (,,HP) attracts attention, because of easy installation in PC and the assurance of the enough contact area. In this research, an experimental study is done to investigate the heat transfer steady characteristics of this heat transfer device in detail and finally, a prediction method of maximum heat transfer capacity is proposed. Since the heat pipe operation must be started from the ambient temperature in practice, depending on the needs of a designer, heat transfer transient characteristic is also a matter of concern. Therefore in order to observe the response of heat pipe to a step heat input, transient tests are done.View full abstractDownload PDF (436K)
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