The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Jamal Chaouki - One of the best experts on this subject based on the ideXlab platform.
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On the Axial Movement of Solids in Gas-Solid Fluidized Beds
Chemical Engineering Research and Design, 2000Co-Authors: Navid Mostoufi, Jamal ChaoukiAbstract:Solids Movement in a gas-solid fluidized bed was monitored by a Radioactive Particle Tracking (RPT) technique. The gas was air at room temperature and atmospheric pressure and the solid was sand or FCC powder. The experiments were done at superficial gas velocities from 0.5 to 2.8 ms−1 for sand, and 0.44 to 0.9 ms−1 for FCC, covering both bubbling and turbulent regimes. A variety of solids behaviours, including restricted Axial Movement and unrestricted Axial Movement of solids, were studied by processing the data in an appropriate manner. The variance test was performed on the Residence Time Distribution (RTD) of solids in the restricted upward and downward Movement. The results of the test clearly showed that upward Movement of solids could be explained by a diffusive mechanism, while the mechanism of downward Movement of solids should be considered as convective. The variance test for unrestricted Axial Movement of solids showed that this type of Movement cannot be explained by either of the two above mentioned mechanisms. In order to model the Axial Movement of the solids, it was assumed that solids move according to the two diffusive and convective mechanisms. By comparing the RTD of unrestricted Movement of solids with the unsteady state formulation of the solid Movement, it was found that the solid velocity in the convective term of the model have to be less than the velocity of a single particle moving in a fluidized bed at the same condition. This fact suggests that the solid particles do not move separately in the fluidized bed, butmove as part of a solid aggregate, or cluster, which exercises a drag force greater than that of a single particle and, therefore, moves at a lower velocity.
Guixiang Zhu - One of the best experts on this subject based on the ideXlab platform.
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Research on Turbulent Lubrication of Misaligned Journal Bearing Considering the Axial Motion of Journal
Journal of Tribology, 2019Co-Authors: Shaoyu Zhu, Jun Sun, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Abstract Based on the coordinate transformation method, the generalized turbulent lubrication equation considering the Axial motion of the journal is derived. The finite-difference method is used to solve the generalized turbulent lubrication equation. The variations of turbulent lubrication performance with Axial displacement for different Axial Movement velocity of the journal, journal misalignment angle, and initial mid-plane eccentricity ratio are obtained. The results show that when the Axial Movement velocity of the journal increases, the mid-plane eccentricity ratio of the bearing and the minimum film thickness remain unchanged, the average Reynolds number, maximum film pressure, load capacity, frictional power, and side leakage increases. As the Axial displacement of the journal increases, the greater the misalignment angle of the journal, the greater the degree of misalignment, maximum film pressure, load capacity, and misalignment moment of the bearing. The greater the initial mid-plane eccentricity ratio, the greater the degree of journal misalignment, maximum film pressure, load capacity, frictional power, and misalignment moment.
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Effect of the Axial Movement of misaligned journal on the performance of hydrodynamic lubrication journal bearing with rough surface
Mechanics & Industry, 2019Co-Authors: Jun Sun, Shaoyu Zhu, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Generally, the Movement of journal along the direction of bearing axis under the combined action of various factors is neglected in the lubrication study of bearing, which is quite different from the actual working condition of bearing in the shaft-bearing system. In this paper, with a comprehensive consideration of the Axial Movement of journal, the surface topography of journal and bearing and the misalignment of journal, a new model about the hydrodynamic lubrication of misaligned journal bearing is established based on the average Reynolds equation. Considering the effect of the Axial Movement of misaligned journal, the lubrication characteristics parameters of rough journal bearing is presented and mainly discussed. The results show that the Axial Movement of misaligned journal has a distinct effect on the bearing lubrication characteristics. The influence of the Axial Movement of misaligned journal on the bearing lubrication characteristics is slightly reduced when considering the surface roughness.
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Thermohydrodynamic lubrication analysis of misaligned journal bearing considering the Axial Movement of journal
Tribology International, 2019Co-Authors: Jun Sun, Shaoyu Zhu, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Abstract In the journal-bearing system, the journal inevitably moves along the bearing axis, and the Axial Movement of journal may affect the performance of misaligned journal bearing. In this article, a numerical model for the thermohydrodynamic lubrication of bearing considering the Axial Movement of journal is established, and based on which a comprehensive analysis on the performance of misaligned journal bearing is conducted by solving the generalized Reynolds equation, heat conduction equation and energy equation. The results show that Axial Movement of misaligned journal has more obvious influence on the bearing lubrication characteristics at the lower speed, larger inclination angle and eccentricity. The impact of Axial Movement on the bearing lubrication performance is greatly affected by the thermal effect and surface roughness.
Jun Sun - One of the best experts on this subject based on the ideXlab platform.
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Research on Turbulent Lubrication of Misaligned Journal Bearing Considering the Axial Motion of Journal
Journal of Tribology, 2019Co-Authors: Shaoyu Zhu, Jun Sun, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Abstract Based on the coordinate transformation method, the generalized turbulent lubrication equation considering the Axial motion of the journal is derived. The finite-difference method is used to solve the generalized turbulent lubrication equation. The variations of turbulent lubrication performance with Axial displacement for different Axial Movement velocity of the journal, journal misalignment angle, and initial mid-plane eccentricity ratio are obtained. The results show that when the Axial Movement velocity of the journal increases, the mid-plane eccentricity ratio of the bearing and the minimum film thickness remain unchanged, the average Reynolds number, maximum film pressure, load capacity, frictional power, and side leakage increases. As the Axial displacement of the journal increases, the greater the misalignment angle of the journal, the greater the degree of misalignment, maximum film pressure, load capacity, and misalignment moment of the bearing. The greater the initial mid-plane eccentricity ratio, the greater the degree of journal misalignment, maximum film pressure, load capacity, frictional power, and misalignment moment.
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Effect of the Axial Movement of misaligned journal on the performance of hydrodynamic lubrication journal bearing with rough surface
Mechanics & Industry, 2019Co-Authors: Jun Sun, Shaoyu Zhu, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Generally, the Movement of journal along the direction of bearing axis under the combined action of various factors is neglected in the lubrication study of bearing, which is quite different from the actual working condition of bearing in the shaft-bearing system. In this paper, with a comprehensive consideration of the Axial Movement of journal, the surface topography of journal and bearing and the misalignment of journal, a new model about the hydrodynamic lubrication of misaligned journal bearing is established based on the average Reynolds equation. Considering the effect of the Axial Movement of misaligned journal, the lubrication characteristics parameters of rough journal bearing is presented and mainly discussed. The results show that the Axial Movement of misaligned journal has a distinct effect on the bearing lubrication characteristics. The influence of the Axial Movement of misaligned journal on the bearing lubrication characteristics is slightly reduced when considering the surface roughness.
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Thermohydrodynamic lubrication analysis of misaligned journal bearing considering the Axial Movement of journal
Tribology International, 2019Co-Authors: Jun Sun, Shaoyu Zhu, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Abstract In the journal-bearing system, the journal inevitably moves along the bearing axis, and the Axial Movement of journal may affect the performance of misaligned journal bearing. In this article, a numerical model for the thermohydrodynamic lubrication of bearing considering the Axial Movement of journal is established, and based on which a comprehensive analysis on the performance of misaligned journal bearing is conducted by solving the generalized Reynolds equation, heat conduction equation and energy equation. The results show that Axial Movement of misaligned journal has more obvious influence on the bearing lubrication characteristics at the lower speed, larger inclination angle and eccentricity. The impact of Axial Movement on the bearing lubrication performance is greatly affected by the thermal effect and surface roughness.
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Experimental Research on a Three-Dimensional Journal Orbit of a Crankshaft Bearing for an Internal Combustion Engine
Journal of Tribology, 2014Co-Authors: Jun Sun, Xiao-hui Chai, Xinlong Zhu, Liang Zhang, Xianyi Wang, Wei Yin, Wei ShiAbstract:The current experimental researches on the orbit of a journal center of a crankshaft bearing for an internal combustion engine were usually focused on the 2D Movement locus of a crankshaft journal center in the cross section of the bearing. However, in the actual operation of an internal combustion engine, there exists the Movement of a crankshaft journal along the bearing axis under the effect of various factors, such as the crankshaft deformation acted by load. Obviously the tribological performance of a crankshaft bearing is affected inevitably by the Movement of the crankshaft journal along the bearing axis. In this paper, a four-stroke four-cylinder internal combustion engine was taken as the studying object, the 3D orbit (that includes the Movement in the cross section of the bearing and the Movement along the bearing axis) of the journal center of the crankshaft bearing for an internal combustion engine was measured under a number of operating conditions on the test bench of an internal combustion engine. The position of the journal in the crankshaft bearing was obtained by the measurement using eddy current gap sensors and the data post-process. The results show that there exists the Movement of the crankshaft journal along the Axial direction in the bearing for an internal combustion engine. The actual orbit of the journal center of the crankshaft bearing for an internal combustion engine is a 3D spatial curve. The orbit of the journal center of the crankshaft bearing in one operating cycle of an internal combustion engine is not a closed curve. There is relatively a large Movement of the journal along the Axial direction of the crankshaft bearing, and the numerical value of the Movement is greater than the radial clearance of the bearing. The greater the rotational speed of the internal combustion engine, the larger the amount of Axial Movement of the journal. The periodic variation exists in the Axial Movement of the bearing journal in one operating cycle of the internal combustion engine at low engine speed, and the varying periodicity equals the number of engine cylinders. There is no obvious varying rule of the Axial Movement of the bearing journal in one operating cycle of the internal combustion engine at high engine speed.
Navid Mostoufi - One of the best experts on this subject based on the ideXlab platform.
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On the Axial Movement of Solids in Gas-Solid Fluidized Beds
Chemical Engineering Research and Design, 2000Co-Authors: Navid Mostoufi, Jamal ChaoukiAbstract:Solids Movement in a gas-solid fluidized bed was monitored by a Radioactive Particle Tracking (RPT) technique. The gas was air at room temperature and atmospheric pressure and the solid was sand or FCC powder. The experiments were done at superficial gas velocities from 0.5 to 2.8 ms−1 for sand, and 0.44 to 0.9 ms−1 for FCC, covering both bubbling and turbulent regimes. A variety of solids behaviours, including restricted Axial Movement and unrestricted Axial Movement of solids, were studied by processing the data in an appropriate manner. The variance test was performed on the Residence Time Distribution (RTD) of solids in the restricted upward and downward Movement. The results of the test clearly showed that upward Movement of solids could be explained by a diffusive mechanism, while the mechanism of downward Movement of solids should be considered as convective. The variance test for unrestricted Axial Movement of solids showed that this type of Movement cannot be explained by either of the two above mentioned mechanisms. In order to model the Axial Movement of the solids, it was assumed that solids move according to the two diffusive and convective mechanisms. By comparing the RTD of unrestricted Movement of solids with the unsteady state formulation of the solid Movement, it was found that the solid velocity in the convective term of the model have to be less than the velocity of a single particle moving in a fluidized bed at the same condition. This fact suggests that the solid particles do not move separately in the fluidized bed, butmove as part of a solid aggregate, or cluster, which exercises a drag force greater than that of a single particle and, therefore, moves at a lower velocity.
Shaoyu Zhu - One of the best experts on this subject based on the ideXlab platform.
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Research on Turbulent Lubrication of Misaligned Journal Bearing Considering the Axial Motion of Journal
Journal of Tribology, 2019Co-Authors: Shaoyu Zhu, Jun Sun, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Abstract Based on the coordinate transformation method, the generalized turbulent lubrication equation considering the Axial motion of the journal is derived. The finite-difference method is used to solve the generalized turbulent lubrication equation. The variations of turbulent lubrication performance with Axial displacement for different Axial Movement velocity of the journal, journal misalignment angle, and initial mid-plane eccentricity ratio are obtained. The results show that when the Axial Movement velocity of the journal increases, the mid-plane eccentricity ratio of the bearing and the minimum film thickness remain unchanged, the average Reynolds number, maximum film pressure, load capacity, frictional power, and side leakage increases. As the Axial displacement of the journal increases, the greater the misalignment angle of the journal, the greater the degree of misalignment, maximum film pressure, load capacity, and misalignment moment of the bearing. The greater the initial mid-plane eccentricity ratio, the greater the degree of journal misalignment, maximum film pressure, load capacity, frictional power, and misalignment moment.
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Effect of the Axial Movement of misaligned journal on the performance of hydrodynamic lubrication journal bearing with rough surface
Mechanics & Industry, 2019Co-Authors: Jun Sun, Shaoyu Zhu, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Generally, the Movement of journal along the direction of bearing axis under the combined action of various factors is neglected in the lubrication study of bearing, which is quite different from the actual working condition of bearing in the shaft-bearing system. In this paper, with a comprehensive consideration of the Axial Movement of journal, the surface topography of journal and bearing and the misalignment of journal, a new model about the hydrodynamic lubrication of misaligned journal bearing is established based on the average Reynolds equation. Considering the effect of the Axial Movement of misaligned journal, the lubrication characteristics parameters of rough journal bearing is presented and mainly discussed. The results show that the Axial Movement of misaligned journal has a distinct effect on the bearing lubrication characteristics. The influence of the Axial Movement of misaligned journal on the bearing lubrication characteristics is slightly reduced when considering the surface roughness.
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Thermohydrodynamic lubrication analysis of misaligned journal bearing considering the Axial Movement of journal
Tribology International, 2019Co-Authors: Jun Sun, Shaoyu Zhu, Xiaoyong Zhao, Hu Wang, Qin Teng, Yanping Ren, Guixiang ZhuAbstract:Abstract In the journal-bearing system, the journal inevitably moves along the bearing axis, and the Axial Movement of journal may affect the performance of misaligned journal bearing. In this article, a numerical model for the thermohydrodynamic lubrication of bearing considering the Axial Movement of journal is established, and based on which a comprehensive analysis on the performance of misaligned journal bearing is conducted by solving the generalized Reynolds equation, heat conduction equation and energy equation. The results show that Axial Movement of misaligned journal has more obvious influence on the bearing lubrication characteristics at the lower speed, larger inclination angle and eccentricity. The impact of Axial Movement on the bearing lubrication performance is greatly affected by the thermal effect and surface roughness.
