We have developed a Micro Optical Diffusion Sensor (MODS) using laser-induced dielectrophoresis, enabling small sample volume and high-speed measurement without any additives or pretreatments. All optical components are integrated in a small chip by using MEMS fabrication technique. A micro channel of MODS consists of a pair of transparent electrodes and a photoconductive layer. AC voltage is applied between transparent electrodes sealing the liquid sample, and two excitation lasers which generate the light intensity distribution are intersected on the photoconductive layer. The electric conductivity distribution of the photoconductive layer is generated by the photoconductive effect. A non-uniform electric field is formed followed by generating the dielectrophoresis, and then the sinusoidal concentration distribution is induced in a micro channel. After cutting the AC voltage, the mass diffusion occurs, and the diffusion coefficient can be obtained by observing the diffusion process of one-dimensional concentration distribution. In this paper, we have utilized the transient grating method as a detecting method of the mass diffusion because of its simplicity of integration. When probing laser enters the concentration distribution, the diffracted light is generated. The decay of the concentration distribution can be detected by the intensity change of the diffracted light, and the diffusion coefficient can be obtained from the time constant of decay. In order to verify the proposed method, preliminary experiments were conducted, and the applicability of MODS was successfully confirmed.
{"title":"Study on Micro Optical Diffusion Sensor using laser-induced dielectrophoresis (preliminary experiment of optical detection system for integrated micro optical device)","authors":"K. Itani, Y. Taguchi, Y. Nagasaka","doi":"10.1299/KIKAIB.77.1567","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.1567","url":null,"abstract":"We have developed a Micro Optical Diffusion Sensor (MODS) using laser-induced dielectrophoresis, enabling small sample volume and high-speed measurement without any additives or pretreatments. All optical components are integrated in a small chip by using MEMS fabrication technique. A micro channel of MODS consists of a pair of transparent electrodes and a photoconductive layer. AC voltage is applied between transparent electrodes sealing the liquid sample, and two excitation lasers which generate the light intensity distribution are intersected on the photoconductive layer. The electric conductivity distribution of the photoconductive layer is generated by the photoconductive effect. A non-uniform electric field is formed followed by generating the dielectrophoresis, and then the sinusoidal concentration distribution is induced in a micro channel. After cutting the AC voltage, the mass diffusion occurs, and the diffusion coefficient can be obtained by observing the diffusion process of one-dimensional concentration distribution. In this paper, we have utilized the transient grating method as a detecting method of the mass diffusion because of its simplicity of integration. When probing laser enters the concentration distribution, the diffracted light is generated. The decay of the concentration distribution can be detected by the intensity change of the diffracted light, and the diffusion coefficient can be obtained from the time constant of decay. In order to verify the proposed method, preliminary experiments were conducted, and the applicability of MODS was successfully confirmed.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131691888","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}
L. Ruan, Y. Iguchi, M. Noda, Yasuo Marumo, Y. Kawamura
The major problem for forging of magnesium alloy is the lack of process ductility at the low temperature. The Mg96Zn2Y2 is a high strength magnesium alloy material developed by Mr. Kawamura in Japan. Mg96Zn2Y2, a newly developed high strength magnesium alloy material is expected as forged parts of the automobile and materials for aerospace applications. It is necessary to clarify forging process characteristics of this material. The purpose of the present study is to examine increasing of ductility of forging process for the Mg96Zn2Y2 material. For this purpose, cylinder upsetting tests were performed by this method of two stages. In addition, the deformation resistance and ductility of the material were examined. The two stages forging process is effective for an increase of ductility of the material.
{"title":"Examination of Ductility Increase on Forming of Magnesium Alloy","authors":"L. Ruan, Y. Iguchi, M. Noda, Yasuo Marumo, Y. Kawamura","doi":"10.1299/KIKAIA.77.1061","DOIUrl":"https://doi.org/10.1299/KIKAIA.77.1061","url":null,"abstract":"The major problem for forging of magnesium alloy is the lack of process ductility at the low temperature. The Mg96Zn2Y2 is a high strength magnesium alloy material developed by Mr. Kawamura in Japan. Mg96Zn2Y2, a newly developed high strength magnesium alloy material is expected as forged parts of the automobile and materials for aerospace applications. It is necessary to clarify forging process characteristics of this material. The purpose of the present study is to examine increasing of ductility of forging process for the Mg96Zn2Y2 material. For this purpose, cylinder upsetting tests were performed by this method of two stages. In addition, the deformation resistance and ductility of the material were examined. The two stages forging process is effective for an increase of ductility of the material.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115389125","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}
One of the important factors of cell performance in polymer electrolyte fuel cell (PEFC) is moisture control in gas diffusion layer (GDL). It is necessary to clarify the mass transfer characteristics in GDL. The oxygen diffusion coefficient in GDL is measured with a galvanic battery type oxygen absorber. Particularly, measurement in high accuracy of oxygen diffusion coefficient in GDL becomes important. In the previous study, the measurement of the effective oxygen diffusivity in the microporous GDL using the galvanic cell type oxygen absorber was proposed. In addition, the measurement of the effective oxygen diffusivity in the microporous GDL containing moisture was proposed and shown to be an effective technique for measurement of the effective oxygen diffusivity in microporous media. However, because the diffusion resistance of dry GDL is small, the error margin of tens of percent existed in the result of a measurement of the oxygen diffusivity. In the present study, the objective of this study is high precision measurement of the oxygen diffusion coefficient in GDL by specifying the error factors and improving them.
{"title":"High precision measurement of oxygen diffusion coefficient in micro porous media using a galvanic cell type oxygen absorber","authors":"Ryo Koresawa, T. Daitoku, Y. Utaka","doi":"10.1299/KIKAIB.77.2191","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.2191","url":null,"abstract":"One of the important factors of cell performance in polymer electrolyte fuel cell (PEFC) is moisture control in gas diffusion layer (GDL). It is necessary to clarify the mass transfer characteristics in GDL. The oxygen diffusion coefficient in GDL is measured with a galvanic battery type oxygen absorber. Particularly, measurement in high accuracy of oxygen diffusion coefficient in GDL becomes important. In the previous study, the measurement of the effective oxygen diffusivity in the microporous GDL using the galvanic cell type oxygen absorber was proposed. In addition, the measurement of the effective oxygen diffusivity in the microporous GDL containing moisture was proposed and shown to be an effective technique for measurement of the effective oxygen diffusivity in microporous media. However, because the diffusion resistance of dry GDL is small, the error margin of tens of percent existed in the result of a measurement of the oxygen diffusivity. In the present study, the objective of this study is high precision measurement of the oxygen diffusion coefficient in GDL by specifying the error factors and improving them.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128436644","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 development of a polymer electrolyte fuel cell (PEFC) without external humidification is one of the most important issues to increase total efficiency and reduce cost. In the present study, we have developed hybrid pattern gas channels consisting of interdigitated and serpentine gas flow channels for PEFCs. The effects of gas flow channels at the anode and cathode on PEFC performance without external humidification were investigated. The PEFC performance was significantly deteriorated when a conventional triple serpentine channel was used at both the anode and cathode. However, when using the serpentine hybrid flow channel in the cathode, the performance was improved because of preventing the water from exhausting from the cathode. Moreover, the gas which flowed through the low pressure serpentine flow channel in the serpentine hybrid flow channel possibly promoted spreading water vapor over the whole active area. The triple serpentine flow channel in the anode was indicated to enhance spreading the water to whole of active area. Accordingly, IR overpotential was decreased and thereby PEFC performance was enhanced.
{"title":"サーペンタインハイブリッド形流路を有するPEFCに関する研究（第４報 両極無加湿運転における発電特性）","authors":"和人 津田, 康隼 髙園, 辰巳 北原, 裕典 中島","doi":"10.1299/KIKAIB.77.1138","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.1138","url":null,"abstract":"The development of a polymer electrolyte fuel cell (PEFC) without external humidification is one of the most important issues to increase total efficiency and reduce cost. In the present study, we have developed hybrid pattern gas channels consisting of interdigitated and serpentine gas flow channels for PEFCs. The effects of gas flow channels at the anode and cathode on PEFC performance without external humidification were investigated. The PEFC performance was significantly deteriorated when a conventional triple serpentine channel was used at both the anode and cathode. However, when using the serpentine hybrid flow channel in the cathode, the performance was improved because of preventing the water from exhausting from the cathode. Moreover, the gas which flowed through the low pressure serpentine flow channel in the serpentine hybrid flow channel possibly promoted spreading water vapor over the whole active area. The triple serpentine flow channel in the anode was indicated to enhance spreading the water to whole of active area. Accordingly, IR overpotential was decreased and thereby PEFC performance was enhanced.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129241285","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 noise reduction radiated from a centrifugal compressor with vaned diffuser using hooked and tapered diffuser vane are discussed by experiments and CFD. Most dominant noise of the centrifugal compressor is interaction tone noise between impeller-discharged flow and diffuser leading-edge. Thus, the shape of diffuser leading-edge is important to reduce the noise level of interaction tone noise. In the experiments, the compressor performance by using hooked diffuser vane is deteriorated because of increase of the leakage-flow passing through the hooked portion while the hooked diffusers are able to reduce the noise level effectively. On the other hand, tapered diffuser vanes are able to reduce the noise and to maintain high compressor performance simultaneously. In the CFD, the twin vortices are generated by the leakage-flow passing through the tapered portion and the vortices induce secondary flow near the pressure surface at diffuser leading-edge and suppress the flow separation from the diffuser leading-edge.
{"title":"Effects of diffuser leading-edge geometries on performance and noise characteristics of a centrifugal compressor","authors":"T. Goto, Y. Ohta, E. Outa","doi":"10.1299/KIKAIB.77.1229","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.1229","url":null,"abstract":"The noise reduction radiated from a centrifugal compressor with vaned diffuser using hooked and tapered diffuser vane are discussed by experiments and CFD. Most dominant noise of the centrifugal compressor is interaction tone noise between impeller-discharged flow and diffuser leading-edge. Thus, the shape of diffuser leading-edge is important to reduce the noise level of interaction tone noise. In the experiments, the compressor performance by using hooked diffuser vane is deteriorated because of increase of the leakage-flow passing through the hooked portion while the hooked diffusers are able to reduce the noise level effectively. On the other hand, tapered diffuser vanes are able to reduce the noise and to maintain high compressor performance simultaneously. In the CFD, the twin vortices are generated by the leakage-flow passing through the tapered portion and the vortices induce secondary flow near the pressure surface at diffuser leading-edge and suppress the flow separation from the diffuser leading-edge.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132913884","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}
Masato Odagawa, Yuriko Takeshima, I. Fujishiro, G. Kikugawa, T. Ohara
When visualizing large-scale particle systems, it is difficult to maintain adequate framerates because we have to render dynamic scenes with a large number of small spheres. For the control of trade-offs between the overall image quality and total rendering speed, we propose a new rendering scheme which uses a fast method based on shaded texture mapping and a high-quality implicit surface method in a combined way. The shaded texture mapping, which generates a pseudo-texture through alpha-blending a proper portion of template texture for shade and highlight onto a base spherical texture, can render a particle faster than the implicit surface method. However, a weakness of the texture mapping lies in its poor shading quality. In contrast, the implicit surface method is accurate enough for analyzing particle systems visually. Actual method to render each particle is decided according to the viewing distance; the high-quality method is chosen only when the distance is smaller than a threshold, to allow the user to observe the region of interest closely. We use a molecular dynamics simulation dataset to evaluate the effectiveness of our scheme empirically. In addition to this, we also consider the extensibility of our scheme in terms of framerate stability, scalability, and expressiveness.
{"title":"GPU-based adaptive visualization for particle systems","authors":"Masato Odagawa, Yuriko Takeshima, I. Fujishiro, G. Kikugawa, T. Ohara","doi":"10.1299/KIKAIB.77.1767","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.1767","url":null,"abstract":"When visualizing large-scale particle systems, it is difficult to maintain adequate framerates because we have to render dynamic scenes with a large number of small spheres. For the control of trade-offs between the overall image quality and total rendering speed, we propose a new rendering scheme which uses a fast method based on shaded texture mapping and a high-quality implicit surface method in a combined way. The shaded texture mapping, which generates a pseudo-texture through alpha-blending a proper portion of template texture for shade and highlight onto a base spherical texture, can render a particle faster than the implicit surface method. However, a weakness of the texture mapping lies in its poor shading quality. In contrast, the implicit surface method is accurate enough for analyzing particle systems visually. Actual method to render each particle is decided according to the viewing distance; the high-quality method is chosen only when the distance is smaller than a threshold, to allow the user to observe the region of interest closely. We use a molecular dynamics simulation dataset to evaluate the effectiveness of our scheme empirically. In addition to this, we also consider the extensibility of our scheme in terms of framerate stability, scalability, and expressiveness.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123814049","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}
A passive pitch-angle control system for a small horizontal axis wind turbine (HAWT) has been proposed in our previous study. The main component of the system is the rubber pipe reinforced by metal fibers arranged with oblique angle, and the system is installed at the root of the blade. When the rubber pipe is subjected to centrifugal force due to the rotation of the rotor, the oblique fibers cause the torsional deformation of the pipe and the change in the pitch-angle of the blade. In this study, FEM analyses for the fiber-reinforced rubber pipe are carried out, and the influences of the structural specifications on the torsional deformation are examined. Additionally the electric power generation of the turbine with the system is estimated in order to confirm the effectiveness of the proposed system for the prevention of the overspeed of the turbine. Through the study, it is found that the fiber-angle of the fiber-reinforced rubber pipe affects the torsional deformation remarkably, and the influences of the dimensions of the rubber pipe on the torsional behavior can be simply shown as a relation between the average stress and the average shear strain. It is also confirmed that the proposed pitch-angle control system prevents the overspeed of the turbine in the strong wing condition and the stall control is more effective than the feather control.
{"title":"Estimation of performances of a HAWT with passive pitch-angle control system using fiber-reinforced rubber","authors":"D. Yanagihara, H. Iwashita, Yukio Watanabe","doi":"10.1299/KIKAIB.77.2379","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.2379","url":null,"abstract":"A passive pitch-angle control system for a small horizontal axis wind turbine (HAWT) has been proposed in our previous study. The main component of the system is the rubber pipe reinforced by metal fibers arranged with oblique angle, and the system is installed at the root of the blade. When the rubber pipe is subjected to centrifugal force due to the rotation of the rotor, the oblique fibers cause the torsional deformation of the pipe and the change in the pitch-angle of the blade. In this study, FEM analyses for the fiber-reinforced rubber pipe are carried out, and the influences of the structural specifications on the torsional deformation are examined. Additionally the electric power generation of the turbine with the system is estimated in order to confirm the effectiveness of the proposed system for the prevention of the overspeed of the turbine. Through the study, it is found that the fiber-angle of the fiber-reinforced rubber pipe affects the torsional deformation remarkably, and the influences of the dimensions of the rubber pipe on the torsional behavior can be simply shown as a relation between the average stress and the average shear strain. It is also confirmed that the proposed pitch-angle control system prevents the overspeed of the turbine in the strong wing condition and the stall control is more effective than the feather control.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123609550","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. Iwase, Tetsuya Hioki, Yoshihiko Kato, Taro Tanno, Osamu Sekiguchi, M. Furukawa
Influence of interaction with a tangential lean blade and a box type casing on blade passing frequency (BPF) noise level in small axial-flow fans was investigated by measurement and computational fluid dynamics (CFD). Noise level of five fans having different tangential lean angles was measured. By increasing tangential lean angle, BPF noise level and broadband noise level reduced. An unsteady CFD simulation of tangential lean angle 31-degrees and 63-degrees was conducted to analyze the cause of BPF noise reduction. By increasing tangential lean angle, the inward blade force of the 63-degrees blade was increased compared to the 31-degrees blade. The increase of the inward blade force decreased centrifugal flow in radial direction at the exit of casing, because the inward blade force gave a momentum to the flow in radial inward direction. The decrease of the centrifugal flow suppressed interaction of the flow with the casing wall. The suppression of the interaction reduced static pressure fluctuation for BPF of the casing wall. The reduction of static pressure fluctuation for BPF was found to have a great influence on the BPF noise reduction. It is therefore clarified that increasing tangential lean angle was effective in reduction of the BPF noise.
{"title":"Influence of interaction with tangential lean blade and box type casing on blade passing frequency noise level in small axial-flow fans","authors":"T. Iwase, Tetsuya Hioki, Yoshihiko Kato, Taro Tanno, Osamu Sekiguchi, M. Furukawa","doi":"10.1299/KIKAIB.77.1620","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.1620","url":null,"abstract":"Influence of interaction with a tangential lean blade and a box type casing on blade passing frequency (BPF) noise level in small axial-flow fans was investigated by measurement and computational fluid dynamics (CFD). Noise level of five fans having different tangential lean angles was measured. By increasing tangential lean angle, BPF noise level and broadband noise level reduced. An unsteady CFD simulation of tangential lean angle 31-degrees and 63-degrees was conducted to analyze the cause of BPF noise reduction. By increasing tangential lean angle, the inward blade force of the 63-degrees blade was increased compared to the 31-degrees blade. The increase of the inward blade force decreased centrifugal flow in radial direction at the exit of casing, because the inward blade force gave a momentum to the flow in radial inward direction. The decrease of the centrifugal flow suppressed interaction of the flow with the casing wall. The suppression of the interaction reduced static pressure fluctuation for BPF of the casing wall. The reduction of static pressure fluctuation for BPF was found to have a great influence on the BPF noise reduction. It is therefore clarified that increasing tangential lean angle was effective in reduction of the BPF noise.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126813927","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}
Pressure-sensitive paint (PSP) is a useful measurement technique to obtain the pressure distribution on a surface, and has been applied to many measurements in wind tunnel testing. The measurement error of PSP has not been discussed in most reports, while the evaluation of the error is very important for quantitative measurements. In this study, we propose the calibration method which enables us to find the defect of PSPs or the failure of the calibration tests easily. Based on the first- and second-order polynomial Stern-Volmer equations, the propagation of error is analyzed. As a result, it is clarified that the experimental values must be fitted by the Stern-Volmer equations with the constraint condition of (p/pref, Iref/I) = (1, 1) at T = Tref , and the relative error in pressure can be reduced. It is also shown that the error becomes quite large when p/pref ≈ -B/2C in the second-order polynomial Stern-Volmer equation. We propose an indicator for the choice of the polynomial order of the Stern-Volmer equation at T/Tref ≈ 1, p/pref ≈ 1.
{"title":"Error analysis of pressure-sensitive paint measurement","authors":"Y. Matsuda, H. Yamaguchi, Y. Egami, T. Niimi","doi":"10.1299/KIKAIB.77.1189","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.1189","url":null,"abstract":"Pressure-sensitive paint (PSP) is a useful measurement technique to obtain the pressure distribution on a surface, and has been applied to many measurements in wind tunnel testing. The measurement error of PSP has not been discussed in most reports, while the evaluation of the error is very important for quantitative measurements. In this study, we propose the calibration method which enables us to find the defect of PSPs or the failure of the calibration tests easily. Based on the first- and second-order polynomial Stern-Volmer equations, the propagation of error is analyzed. As a result, it is clarified that the experimental values must be fitted by the Stern-Volmer equations with the constraint condition of (p/pref, Iref/I) = (1, 1) at T = Tref , and the relative error in pressure can be reduced. It is also shown that the error becomes quite large when p/pref ≈ -B/2C in the second-order polynomial Stern-Volmer equation. We propose an indicator for the choice of the polynomial order of the Stern-Volmer equation at T/Tref ≈ 1, p/pref ≈ 1.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121354224","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}
Atsushi Teraji, M. Nishida, T. Morikawa, T. Ishihara, Y. Kaneda
Two-dimensional direct numerical simulation (DNS) was applied to auto-ignition of n-heptane/air mixture. The diffusion of intermediate species was studied in terms of the influence on the ignition delay. The chemical reaction process. The simplified reaction mechanism was used in this study. Likewise, the influence of turbulence was investigated by comparing the results of 0 dimensional simulation and two-dimensional direct simulation of non-turbulence condition. In conclusions, the ignition delay was strongly affected by the different diffusion speeds of intermediate species. It was shown that the outflow of OH radical having larger diffusion coefficient decreases the reaction rate at the high temperature point. On the contrary, the reaction rate was enhanced by the influx of OH radical at the low temperature point.
{"title":"Numerical Analysis of Intermediate Species Diffusion Effect on Low Temperature Oxidation in a Homogeneous n-Heptane Mixture","authors":"Atsushi Teraji, M. Nishida, T. Morikawa, T. Ishihara, Y. Kaneda","doi":"10.1299/KIKAIB.77.1592","DOIUrl":"https://doi.org/10.1299/KIKAIB.77.1592","url":null,"abstract":"Two-dimensional direct numerical simulation (DNS) was applied to auto-ignition of n-heptane/air mixture. The diffusion of intermediate species was studied in terms of the influence on the ignition delay. The chemical reaction process. The simplified reaction mechanism was used in this study. Likewise, the influence of turbulence was investigated by comparing the results of 0 dimensional simulation and two-dimensional direct simulation of non-turbulence condition. In conclusions, the ignition delay was strongly affected by the different diffusion speeds of intermediate species. It was shown that the outflow of OH radical having larger diffusion coefficient decreases the reaction rate at the high temperature point. On the contrary, the reaction rate was enhanced by the influx of OH radical at the low temperature point.","PeriodicalId":331123,"journal":{"name":"Transactions of the Japan Society of Mechanical Engineers. B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126793980","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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