Ming He, Lianyu Wang, Yong-Lei Li, Lijia Zhao, Zhouhua Jiang, Qiang Wang
{"title":"A model to predict coil temperature evolution during the whole thermal cycle process of ladle with a novel steel teeming technology","authors":"Ming He, Lianyu Wang, Yong-Lei Li, Lijia Zhao, Zhouhua Jiang, Qiang Wang","doi":"10.1299/jtst.22-00259","DOIUrl":"https://doi.org/10.1299/jtst.22-00259","url":null,"abstract":"","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66345555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Isothermal chamber is filled with a certain density of high thermal conductivity porous material, which has a wide range of applications in the flow measurement of pneumatic field, and its isothermal characteristic is critical to its application results. In this paper, in order to improve the numerical calculation accuracy of the isothermal characteristics during discharge process, a discharge model of isothermal chamber with fractal effective thermal conductivity (ETC) for determining the isothermal characteristic is reported. Firstly, the stuffer in isothermal chamber is considered as porous random fiber bundle, and an ETC prediction model of anisotropic porous random fiber bundle in both vertical and horizontal directions is established by fractal theory. This model with two directions is in good agreement with the experimental results, and the relative root mean square errors (RRMSE) are 3.94% and 9.85%, respectively. Secondly, the discharge model with fractal ETCs is built, and the isothermal characteristics of isothermal chambers with three different porosities are determined by numerical simulation. Finally, experiments to determine the isothermal characteristic are carried out. The numerical simulation results are in good agreement with the experimental results, and the relative errors are less than 3%. It could be concluded that accurately determining the ETC of the stuffer in isothermal chamber can improve the numerical calculation accuracy of the isothermal characteristic. Moreover, compared with the experimental method, numerical method is energy-saving and timesaving.
{"title":"Modeling and simulation of the discharge process of isothermal chamber to determine the isothermal characteristic","authors":"Hangming Shen, Lihong Yang, Guoxiang Meng","doi":"10.1299/jtst.21-00353","DOIUrl":"https://doi.org/10.1299/jtst.21-00353","url":null,"abstract":"Isothermal chamber is filled with a certain density of high thermal conductivity porous material, which has a wide range of applications in the flow measurement of pneumatic field, and its isothermal characteristic is critical to its application results. In this paper, in order to improve the numerical calculation accuracy of the isothermal characteristics during discharge process, a discharge model of isothermal chamber with fractal effective thermal conductivity (ETC) for determining the isothermal characteristic is reported. Firstly, the stuffer in isothermal chamber is considered as porous random fiber bundle, and an ETC prediction model of anisotropic porous random fiber bundle in both vertical and horizontal directions is established by fractal theory. This model with two directions is in good agreement with the experimental results, and the relative root mean square errors (RRMSE) are 3.94% and 9.85%, respectively. Secondly, the discharge model with fractal ETCs is built, and the isothermal characteristics of isothermal chambers with three different porosities are determined by numerical simulation. Finally, experiments to determine the isothermal characteristic are carried out. The numerical simulation results are in good agreement with the experimental results, and the relative errors are less than 3%. It could be concluded that accurately determining the ETC of the stuffer in isothermal chamber can improve the numerical calculation accuracy of the isothermal characteristic. Moreover, compared with the experimental method, numerical method is energy-saving and timesaving.","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66344603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ryo Koyama, K. Inokuma, A. Murata, K. Iwamoto, H. Saito
{"title":"Machine learning-based prediction of heat transport performance in oscillating heat pipe","authors":"Ryo Koyama, K. Inokuma, A. Murata, K. Iwamoto, H. Saito","doi":"10.1299/jtst.21-00413","DOIUrl":"https://doi.org/10.1299/jtst.21-00413","url":null,"abstract":"","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66344688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable energy-based microgrid systems are widely being studied as electrification methods for rural communities in developing countries. Waste heat generated by the components of the microgrid systems, such as the biogas driven generators (BDG), presents the potential of utilizing the low-grade heat in a way that can contribute to the sustainability of such energy systems. From the points of view of affordability, local manufacturability, and applicability for agriculture, thermally driven pumps (TDP) may be attractive for coupling with such microgrid systems. Therefore, the current study has focused on the development of a new type of thermally driven pumping system as a potential waste heat utilization component for microgrid applications in rural areas. A liquid piston-type TDP concept without moving parts, except few valves, was developed and parametric experimental investigations were carried out. The performance and characteristics of the system were studied, which revealed that the proposed system has a superior performance compared to the literature. It was also found that the system performance strongly depends on the heat addition rate and delivery capacity of the system, which are suitable characteristics for the intended application. Hence, the experimental data were used to estimate whether the proposed system can pump enough water that needs to be supplied for the biogas production to supply a 10 kW BDG unit of a microgrid. It was found that 87 – 93% of the total pumped water (13 – 27 m 3 ) would be available for agricultural and other purposes while only 6 – 13% would need to be fed to the biogas digester. Generally, the results seem to be promising, and yet there are potentials for the optimization and improvement of the proposed system, hence they have been pointed out.
{"title":"Experimental investigation of a thermally driven pumping system for a potential application with a microgrid system for rural communities","authors":"Y. Abirham, F. Mikšík, K. Thu, T. Miyazaki","doi":"10.1299/jtst.21-00323","DOIUrl":"https://doi.org/10.1299/jtst.21-00323","url":null,"abstract":"Renewable energy-based microgrid systems are widely being studied as electrification methods for rural communities in developing countries. Waste heat generated by the components of the microgrid systems, such as the biogas driven generators (BDG), presents the potential of utilizing the low-grade heat in a way that can contribute to the sustainability of such energy systems. From the points of view of affordability, local manufacturability, and applicability for agriculture, thermally driven pumps (TDP) may be attractive for coupling with such microgrid systems. Therefore, the current study has focused on the development of a new type of thermally driven pumping system as a potential waste heat utilization component for microgrid applications in rural areas. A liquid piston-type TDP concept without moving parts, except few valves, was developed and parametric experimental investigations were carried out. The performance and characteristics of the system were studied, which revealed that the proposed system has a superior performance compared to the literature. It was also found that the system performance strongly depends on the heat addition rate and delivery capacity of the system, which are suitable characteristics for the intended application. Hence, the experimental data were used to estimate whether the proposed system can pump enough water that needs to be supplied for the biogas production to supply a 10 kW BDG unit of a microgrid. It was found that 87 – 93% of the total pumped water (13 – 27 m 3 ) would be available for agricultural and other purposes while only 6 – 13% would need to be fed to the biogas digester. Generally, the results seem to be promising, and yet there are potentials for the optimization and improvement of the proposed system, hence they have been pointed out.","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66344896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical simulation of methane-hydrogen premixed flames on a Bunsen burner","authors":"T. Moriyama, K. Yamamoto","doi":"10.1299/jtst.22-00129","DOIUrl":"https://doi.org/10.1299/jtst.22-00129","url":null,"abstract":"","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66345377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Higuchi, Y. Nunome, Satoshi Takada, Ryoma Yoshikawa, Taku Kudo, A. Hayakawa, Hideaki Kobayashi
{"title":"Quantitative OH concentration measurement using OH(2,0) band bi-directional LIF method for high-pressure and high-temperature symmetrical flames","authors":"Y. Higuchi, Y. Nunome, Satoshi Takada, Ryoma Yoshikawa, Taku Kudo, A. Hayakawa, Hideaki Kobayashi","doi":"10.1299/jtst.22-00216","DOIUrl":"https://doi.org/10.1299/jtst.22-00216","url":null,"abstract":"","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66345517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ayaka Kamiyama, K. Inokuma, A. Murata, Shohei Yamamoto, K. Iwamoto, Taketo Konno
{"title":"Multi-objective optimization of multi-stage heat sink of electric aircraft using three-dimensional thermal network analysis","authors":"Ayaka Kamiyama, K. Inokuma, A. Murata, Shohei Yamamoto, K. Iwamoto, Taketo Konno","doi":"10.1299/jtst.21-00421","DOIUrl":"https://doi.org/10.1299/jtst.21-00421","url":null,"abstract":"","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66344704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Flow field and local burning velocity affected by stretch in swirl flow of turbulent premixed flames","authors":"K. Yamamoto, Kenta Yamamori, Hiromu Suzuki","doi":"10.1299/jtst.22-00327","DOIUrl":"https://doi.org/10.1299/jtst.22-00327","url":null,"abstract":"","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66346186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Inthavideth, N. Sekishita, S. Phommachanh, Y. Nakamura
This study aims to investigate the hot-smoke dispersion behavior released from a chimney in a cross flow experimentally using specially designed wind tunnel. An artificially obtained quasi-isotropic turbulence was generated using an active turbulence generator developed by Makita. A heated jet and an unheated jet with smoke are injected into the cross flow from the vertically-oriented chimney installed in the test section. Smoke motion was captured by high-speed camera to obtain instantaneous patterns of the smoke dispersion. Six-kinds of the featured patterns are clearly identified, such as; (I)(II) bifurcated vortex tubes with and without a strong mutual interaction, (III) connected hairpin-type vortices, (IV)(V) the mixture of the coherent and turbulent vortices, (VI) downwash-type structure. These smoke pattern in the downstream field from the chimney are found to be depended on buoyancy, turbulent motion, and inertia forces. Under the quasi-isotropic turbulence, the smoke dispersion prefers to exhibit a meandering pattern (Mode V) under wide range of adopted flow velocities, which is hardly observed using the grid turbulent test device. Interestingly, as compared to the unheated jet, the meandering smoke structure with heated jet ejection was also observed even at the lower jet velocities and the higher cross flow velocities, suggesting that the buoyancy force shall play an important role on appearance of meandering motion and control the smoke dispersion. Direct smoke exposure case (Mode VI) is preferred to be observed when the quasi-isotropic turbulence is imposed, although the trend of appearance depending on the jet temperature can be predicted even using grid turbulent device. It is concluded that using grid turbulence would not be suitable to predict on the smoke dispersion problem in the actual scale. The time averaged smoke concentrations profiles are analyzed at locations along the cross flow direction and it is revealed that the effective diffusion becomes stronger when the quasi-isotropic turbulence is imposed in the cross wind. Further, it is confirmed that the smoke dispersion behavior can be well-characterized by the existing prediction method based on the point source model.
{"title":"Experimental study on the effect of turbulence on hot-smoke dispersion ejecting in a cross flow","authors":"X. Inthavideth, N. Sekishita, S. Phommachanh, Y. Nakamura","doi":"10.1299/jtst.21-00296","DOIUrl":"https://doi.org/10.1299/jtst.21-00296","url":null,"abstract":"This study aims to investigate the hot-smoke dispersion behavior released from a chimney in a cross flow experimentally using specially designed wind tunnel. An artificially obtained quasi-isotropic turbulence was generated using an active turbulence generator developed by Makita. A heated jet and an unheated jet with smoke are injected into the cross flow from the vertically-oriented chimney installed in the test section. Smoke motion was captured by high-speed camera to obtain instantaneous patterns of the smoke dispersion. Six-kinds of the featured patterns are clearly identified, such as; (I)(II) bifurcated vortex tubes with and without a strong mutual interaction, (III) connected hairpin-type vortices, (IV)(V) the mixture of the coherent and turbulent vortices, (VI) downwash-type structure. These smoke pattern in the downstream field from the chimney are found to be depended on buoyancy, turbulent motion, and inertia forces. Under the quasi-isotropic turbulence, the smoke dispersion prefers to exhibit a meandering pattern (Mode V) under wide range of adopted flow velocities, which is hardly observed using the grid turbulent test device. Interestingly, as compared to the unheated jet, the meandering smoke structure with heated jet ejection was also observed even at the lower jet velocities and the higher cross flow velocities, suggesting that the buoyancy force shall play an important role on appearance of meandering motion and control the smoke dispersion. Direct smoke exposure case (Mode VI) is preferred to be observed when the quasi-isotropic turbulence is imposed, although the trend of appearance depending on the jet temperature can be predicted even using grid turbulent device. It is concluded that using grid turbulence would not be suitable to predict on the smoke dispersion problem in the actual scale. The time averaged smoke concentrations profiles are analyzed at locations along the cross flow direction and it is revealed that the effective diffusion becomes stronger when the quasi-isotropic turbulence is imposed in the cross wind. Further, it is confirmed that the smoke dispersion behavior can be well-characterized by the existing prediction method based on the point source model.","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66344792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Higashi, K. Fukutani, T. Kawaguchi, I. Satoh, T. Saito
{"title":"Effect of shear-thinning behavior on interface renewal in partially filled single rotor mixing","authors":"K. Higashi, K. Fukutani, T. Kawaguchi, I. Satoh, T. Saito","doi":"10.1299/jtst.22-00020","DOIUrl":"https://doi.org/10.1299/jtst.22-00020","url":null,"abstract":"","PeriodicalId":17405,"journal":{"name":"Journal of Thermal Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66344803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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