The theoretical and experimental study is carried out to investigate the static characteristics of the liquid annular seals with a square-hole pattern in seal stator. The momentum equations with turbulent coefficients and the continuity equation, which are averaged across the film thickness, are numerically solved to obtain the pressure distributions in the seal clearance and the leakage flow rate. Semi-empirical pressure jump coefficients are used for evaluation of both pressure jumps due to the expansion at the passage of the fluid from the land to the square-hole region and the contraction from the square-hole to the land region. The numerical results of the pressure distribution and the leakage flow rate agree well with the experimental results, which proves the validity of the numerical analysis. The pressures decrease in the axial direction and their distribution has periodical unevenness due to the square-hole pattern in the seal stator. The square-hole pattern seal as well as the parallel-grooved annular seal yields a lower leakage flow rate than conventional seals with smooth surfaces. This reduction of the leakage flow rate is attributed to the pressure jump phenomena with energy loss induced by the axial flow passage across each step between the land and the square-hole region.
{"title":"Dynamic Characteristics of Liquid Annular Seals with Square-Hole Pattern","authors":"S. Kaneko, H. Taura, Noriyoshi Ueda, Kota Henmi","doi":"10.1299/KIKAIC.74.2171","DOIUrl":"https://doi.org/10.1299/KIKAIC.74.2171","url":null,"abstract":"The theoretical and experimental study is carried out to investigate the static characteristics of the liquid annular seals with a square-hole pattern in seal stator. The momentum equations with turbulent coefficients and the continuity equation, which are averaged across the film thickness, are numerically solved to obtain the pressure distributions in the seal clearance and the leakage flow rate. Semi-empirical pressure jump coefficients are used for evaluation of both pressure jumps due to the expansion at the passage of the fluid from the land to the square-hole region and the contraction from the square-hole to the land region. The numerical results of the pressure distribution and the leakage flow rate agree well with the experimental results, which proves the validity of the numerical analysis. The pressures decrease in the axial direction and their distribution has periodical unevenness due to the square-hole pattern in the seal stator. The square-hole pattern seal as well as the parallel-grooved annular seal yields a lower leakage flow rate than conventional seals with smooth surfaces. This reduction of the leakage flow rate is attributed to the pressure jump phenomena with energy loss induced by the axial flow passage across each step between the land and the square-hole region.","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127851895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The new type of heat exchanger, in which fuel gas flows inside thin tubes and water is shell-side, was proposed to develop the performance and compactness of shell & tube type heat exchanger for latent heat recovery from flue gas. The effects of tube diameter (1.0~5.0 mm) and heat exchanging length (7~100 mm) on the heat transfer characteristics of a single tube were systematically investigated by measuring the gas outlet temperature, the pressure loss of the gas, and the condensation rate for moist air. It was shown that the usage of thinner tubes was remarkably effective to achieve the high performance. That is, the rapid temperature drop near inlet occurred and high heat transfer rate was realized for thinner tubes of 1.0mm and 2.0mm in inner diameter compared with thicker tubes because of small heat capacity flow rate and high heat transfer coefficient. In addition, the increase in the volumetric heat transfer area in thin tube type heat exchanger contributed to the compactness. Furthermore, although the pressure drop increased with decreasing tube diameter, it was possible to keep it within the tolerance level for the heat exchanger of domestic hot water supply for practical use because of shorter length of thin tubes. It was shown that one twentieth of heat exchanging volume was possible to be downsized by changing small tubes of 1.0mm from 5.0mm.
{"title":"High performance heat exchanger for latent heat recovery from flue gas","authors":"Junpei Yamashita, Y. Utaka, M. Kobayashi, Y. Sano","doi":"10.1299/KIKAIB.79.1363","DOIUrl":"https://doi.org/10.1299/KIKAIB.79.1363","url":null,"abstract":"The new type of heat exchanger, in which fuel gas flows inside thin tubes and water is shell-side, was proposed to develop the performance and compactness of shell & tube type heat exchanger for latent heat recovery from flue gas. The effects of tube diameter (1.0~5.0 mm) and heat exchanging length (7~100 mm) on the heat transfer characteristics of a single tube were systematically investigated by measuring the gas outlet temperature, the pressure loss of the gas, and the condensation rate for moist air. It was shown that the usage of thinner tubes was remarkably effective to achieve the high performance. That is, the rapid temperature drop near inlet occurred and high heat transfer rate was realized for thinner tubes of 1.0mm and 2.0mm in inner diameter compared with thicker tubes because of small heat capacity flow rate and high heat transfer coefficient. In addition, the increase in the volumetric heat transfer area in thin tube type heat exchanger contributed to the compactness. Furthermore, although the pressure drop increased with decreasing tube diameter, it was possible to keep it within the tolerance level for the heat exchanger of domestic hot water supply for practical use because of shorter length of thin tubes. It was shown that one twentieth of heat exchanging volume was possible to be downsized by changing small tubes of 1.0mm from 5.0mm.","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130692481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To measure true values of kinetic friction coefficient in a force balance between the frictional force and spring force, an anti-vibration tribometer (AVT) has been developed. The AVT utilizes a novel principle that an angular misalignment between the two velocities (i.e., the driving velocity of one of contact surfaces and the moving velocity of the other surface) produces a positive damping effect to stabilize the equilibrium point and suppress frictional vibration autonomously. For example, when a sliding contact between a steel ball and a steel plate is lubricated by glycerin, the AVT provides a force balance situation at a misalignment angle φ = 30° (i.e., an anti-vibration setting), although strong frictional vibration occurs at φ = 0° (i.e., a conventional setting). By comparing the kinetic friction coefficients obtained at φ = 0° and 30°, it has been found that frictional vibration can lead to a serious error of measuring kinetic friction coefficient (e.g., a 35% underestimation at a low driving speed).
{"title":"Measurement error of kinetic friction coefficient generated by frictional vibration","authors":"N. Kado, C. Tadokoro, K. Nakano","doi":"10.1299/KIKAIC.79.2635","DOIUrl":"https://doi.org/10.1299/KIKAIC.79.2635","url":null,"abstract":"To measure true values of kinetic friction coefficient in a force balance between the frictional force and spring force, an anti-vibration tribometer (AVT) has been developed. The AVT utilizes a novel principle that an angular misalignment between the two velocities (i.e., the driving velocity of one of contact surfaces and the moving velocity of the other surface) produces a positive damping effect to stabilize the equilibrium point and suppress frictional vibration autonomously. For example, when a sliding contact between a steel ball and a steel plate is lubricated by glycerin, the AVT provides a force balance situation at a misalignment angle φ = 30° (i.e., an anti-vibration setting), although strong frictional vibration occurs at φ = 0° (i.e., a conventional setting). By comparing the kinetic friction coefficients obtained at φ = 0° and 30°, it has been found that frictional vibration can lead to a serious error of measuring kinetic friction coefficient (e.g., a 35% underestimation at a low driving speed).","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114385931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kensuke Ishikawa, K. Nakazawa, Taku Yamazaki, Satoru Furugori, T. Suetomi, Y. Matsuoka
The purpose of this study is reduction of both fuel consumption and battery deterioration by the suboptimal control for hybrid electric vehicles (HEV) which can be adapted for various driving situations and drivers as part of the emergent control system. From the rising price of fossil fuels and growing concerns on the environmental protection, HEVs are recently attracting attention. The HEV control system requires reduction of fuel consumption and battery deterioration, as well as adaptivity to dynamic environment and various drivers. However no conventional methods have taken this in account. Consequently in this paper, we use genetic network programming (GNP) as a method to find a suboptimal control of HEVs for various situations. GNP is one of the evolutionary computing methods, which has a network structure as its solution and is effective to dynamical problem because it implicitly depends on past information. We validated the proposed method by applying it to the driving simulation. Comparison to the conventional method proved the advantage of the new proposed method. We introduced new evaluation criterion “driving cost [¥/km]” in order to consider all the cost needed to drive; not only the fuel cost nor the battery cost. In addition, we validated the adaptivity to various driving situation and various drivers.
{"title":"Reduction of the Driving Cost for Capacitor-Battery Combined HEV by Using Genetic Network Programming","authors":"Kensuke Ishikawa, K. Nakazawa, Taku Yamazaki, Satoru Furugori, T. Suetomi, Y. Matsuoka","doi":"10.1299/KIKAIC.79.2259","DOIUrl":"https://doi.org/10.1299/KIKAIC.79.2259","url":null,"abstract":"The purpose of this study is reduction of both fuel consumption and battery deterioration by the suboptimal control for hybrid electric vehicles (HEV) which can be adapted for various driving situations and drivers as part of the emergent control system. From the rising price of fossil fuels and growing concerns on the environmental protection, HEVs are recently attracting attention. The HEV control system requires reduction of fuel consumption and battery deterioration, as well as adaptivity to dynamic environment and various drivers. However no conventional methods have taken this in account. Consequently in this paper, we use genetic network programming (GNP) as a method to find a suboptimal control of HEVs for various situations. GNP is one of the evolutionary computing methods, which has a network structure as its solution and is effective to dynamical problem because it implicitly depends on past information. We validated the proposed method by applying it to the driving simulation. Comparison to the conventional method proved the advantage of the new proposed method. We introduced new evaluation criterion “driving cost [¥/km]” in order to consider all the cost needed to drive; not only the fuel cost nor the battery cost. In addition, we validated the adaptivity to various driving situation and various drivers.","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"333 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134544253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Doan, Y. Akamine, Naoki Iwatani, M. Kohno, K. Fushinobu
Bessel beam has been gaining strong attention from various applications. In this study, a new concept for generating zero-order Bessel beams was studied theoretically and experimentally. The principle of the generation of a Bessel-like beam is discussed based on Fourier optics. A preliminary model is proposed that accounts for heat conduction and diffraction effect. Analytical modeling results indicated that Bessel beam can be generated by using a thermal lens and a convergent lens. A simple and flexible method to convert a Gaussian laser beam into a Bessel-like beam with a long and narrow focal line by using a thermal lens effect is demonstrated experimentally. Experimental and calculated results show a good agreement for generation and characteristics of Bessel-like beam. Experimental results also show that the focal depth of the Bessel beam can be controlled by adjusting some parameters in the thermal lens system. The paper concludes with suggestions for further research and potential applications for the work.
{"title":"Generation of Bessel Beam by Using Thermal Lens","authors":"H. Doan, Y. Akamine, Naoki Iwatani, M. Kohno, K. Fushinobu","doi":"10.1299/KIKAIB.79.1354","DOIUrl":"https://doi.org/10.1299/KIKAIB.79.1354","url":null,"abstract":"Bessel beam has been gaining strong attention from various applications. In this study, a new concept for generating zero-order Bessel beams was studied theoretically and experimentally. The principle of the generation of a Bessel-like beam is discussed based on Fourier optics. A preliminary model is proposed that accounts for heat conduction and diffraction effect. Analytical modeling results indicated that Bessel beam can be generated by using a thermal lens and a convergent lens. A simple and flexible method to convert a Gaussian laser beam into a Bessel-like beam with a long and narrow focal line by using a thermal lens effect is demonstrated experimentally. Experimental and calculated results show a good agreement for generation and characteristics of Bessel-like beam. Experimental results also show that the focal depth of the Bessel beam can be controlled by adjusting some parameters in the thermal lens system. The paper concludes with suggestions for further research and potential applications for the work.","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127707487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Sugano, Kazuto Yokoyama, Takuma Suzuki, Masaki Takahashi
A mobile inverted pendulum (MIP) draws attention as a next-generation energy saving vehicle especially for urban life because it is energy-efficient to transport a person and has a small footprint. It is important for the MIP to run safely on various types of roads. However, there are few studies on the MIP considering slopes or steps. We focus on a change of slope angle and aim to improve safety when the MIP runs on such a road. To achieve this goal, a simulation model of the MIP which runs on a road with a change of slope angle is constructed. This simulation model introduces constraint contact formulation to consider change of a contact point between the wheel and the ground. Motion of the MIP is analyzed when it runs up or down the road. The results of the analyses indicate differences of motion caused by running velocity and feedback gains. Based on the results, we show the existence of the feedback gain which has good controlled performance focusing on behavior of pendulum angle, acceleration of human body and running velocity, and the guideline of control system design considering running on a road with a change of slope angle.
{"title":"Modeling and motion analysis of a mobile inverted pendulum considering a change of slope angle","authors":"T. Sugano, Kazuto Yokoyama, Takuma Suzuki, Masaki Takahashi","doi":"10.1299/KIKAIC.79.1441","DOIUrl":"https://doi.org/10.1299/KIKAIC.79.1441","url":null,"abstract":"A mobile inverted pendulum (MIP) draws attention as a next-generation energy saving vehicle especially for urban life because it is energy-efficient to transport a person and has a small footprint. It is important for the MIP to run safely on various types of roads. However, there are few studies on the MIP considering slopes or steps. We focus on a change of slope angle and aim to improve safety when the MIP runs on such a road. To achieve this goal, a simulation model of the MIP which runs on a road with a change of slope angle is constructed. This simulation model introduces constraint contact formulation to consider change of a contact point between the wheel and the ground. Motion of the MIP is analyzed when it runs up or down the road. The results of the analyses indicate differences of motion caused by running velocity and feedback gains. Based on the results, we show the existence of the feedback gain which has good controlled performance focusing on behavior of pendulum angle, acceleration of human body and running velocity, and the guideline of control system design considering running on a road with a change of slope angle.","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133561114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Gait measurement system using laser range finder","authors":"Mayumi Ozawa, Ayanori Yorozu, Tetsuya Matsumura, Masaki Takahashi","doi":"10.1299/KIKAIC.79.1550","DOIUrl":"https://doi.org/10.1299/KIKAIC.79.1550","url":null,"abstract":"","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134174798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Legged locomotion is high environmental adaptability by the effect of ability to choose landing positions freely, but low transfer efficiency. Because, the output is consumed by supporting upper body. In this paper, we propose a passive walking assist device with two air cylinders and surge tanks. This new device has three advantages in comparison with conventional devices. (1): The proposed device can effectively assist than conventional devices that are arranged spring element series to leg, because it has a twist arranged spring in parallel without interfering swing motions. (2): The weight is very light (1.5kg) and assist force is powerful (about 20~40 N / leg), using the system it runs by air. (3): The assist force is not from the electricity, from the loss of walking. Demonstrating these effects, we create the device and measured feelings and assist powers, Feeling are measured throughout the walking motion and bends by each load condition. Assist power are measured by a device that reproduces the walk. From result of this, it is expected that leg power can be assisted effectively.
腿式运动通过自由选择落脚位置的能力，具有较高的环境适应性，但传递效率较低。因为，输出是由支撑上半身消耗的。本文提出了一种由两个气缸和调压箱组成的被动行走辅助装置。与传统装置相比，这种新装置有三个优点。(1):所提出的装置比传统的弹簧元件串联的装置更能有效地辅助腿部，因为它有一个平行的扭曲排列的弹簧，不干扰摆动运动。(2):重量非常轻(1.5kg)，辅助力强大(约20~40 N /腿)，采用空气运行的系统。(3):辅助力不来自电，来自行走的损失。为了演示这些效果，我们创建了设备并测量了感觉和辅助力量，在每个负载条件下测量了整个行走运动和弯曲的感觉。辅助力量是通过一个再现行走的装置来测量的。从这一结果可以预期，可以有效地辅助腿部力量。
{"title":"Development of walking assist device by regenerating the upper body position energy from vertical oscillation of the upper body","authors":"Yasuyuki Yamada, T. Morita","doi":"10.1299/KIKAIC.79.2025","DOIUrl":"https://doi.org/10.1299/KIKAIC.79.2025","url":null,"abstract":"Legged locomotion is high environmental adaptability by the effect of ability to choose landing positions freely, but low transfer efficiency. Because, the output is consumed by supporting upper body. In this paper, we propose a passive walking assist device with two air cylinders and surge tanks. This new device has three advantages in comparison with conventional devices. (1): The proposed device can effectively assist than conventional devices that are arranged spring element series to leg, because it has a twist arranged spring in parallel without interfering swing motions. (2): The weight is very light (1.5kg) and assist force is powerful (about 20~40 N / leg), using the system it runs by air. (3): The assist force is not from the electricity, from the loss of walking. Demonstrating these effects, we create the device and measured feelings and assist powers, Feeling are measured throughout the walking motion and bends by each load condition. Assist power are measured by a device that reproduces the walk. From result of this, it is expected that leg power can be assisted effectively.","PeriodicalId":337733,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. C","volume":"154 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115622491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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