The Experts below are selected from a list of 34320 Experts worldwide ranked by ideXlab platform
Jongsoo Kim - One of the best experts on this subject based on the ideXlab platform.
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A Rotordynamic, Thermal, and Thrust Load Performance Gas Bearing Test Rig and Test Results for Tilting Pad Journal Bearings and Spiral Groove Thrust Bearings
Journal of Engineering for Gas Turbines and Power, 2017Co-Authors: Aaron M. Rimpel, Giuseppe Vannini, Jongsoo KimAbstract:A high-speed gas Bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas Bearings being developed for an oil-free turboex- pander. The radial Bearings (RBs) tested in this paper were tilting pad journal Bearings with radial compliance features that allow the Bearing bore to increase to accommodate shaft growth, and the thrust Bearings (TBs) were a spiral groove type with axial compli- ance features. The TB accounts for over 90% of the Combined Bearing power consump- tion, which has a cubic relationship with speed and increases with case pressure. RB circumferential pad temperatures increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady-state Bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the TB showed a significant increase in temperature with higher case pressure. The TBs were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been pro- posed to better understand the TB thermal behavior and to improve the TB design. Finally, the RBs tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas Bearings tested in the literature.
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A Rotordynamic, Thermal, and Thrust Load Performance Gas Bearing Test Rig and Test Results for Tilting Pad Journal Bearings and Spiral Groove Thrust Bearings
Volume 8: Microturbines Turbochargers and Small Turbomachines; Steam Turbines, 2016Co-Authors: Aaron M. Rimpel, Giuseppe Vannini, Jongsoo KimAbstract:A high speed gas Bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas Bearings being developed for an oil-free turboexpander. The radial Bearings tested in this paper were tilting pad journal Bearings with radial compliance features that allow the Bearing bore to increase to accommodate shaft growth, and the thrust Bearings were a spiral groove type with axial compliance features. The thrust Bearing accounts for over 90% of the Combined Bearing power consumption, which has a cubic relationship with speed and increases with case pressure. Radial Bearing circumferential pad temperature gradients increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady state Bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the thrust Bearing showed a significant increase in temperature with higher case pressure. The thrust Bearings were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been proposed to better understand the thrust Bearing thermal behavior and to improve the thrust Bearing design. Finally, the radial Bearings tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas Bearings tested in the literature.© 2016 ASME
Aaron M. Rimpel - One of the best experts on this subject based on the ideXlab platform.
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A Rotordynamic, Thermal, and Thrust Load Performance Gas Bearing Test Rig and Test Results for Tilting Pad Journal Bearings and Spiral Groove Thrust Bearings
Journal of Engineering for Gas Turbines and Power, 2017Co-Authors: Aaron M. Rimpel, Giuseppe Vannini, Jongsoo KimAbstract:A high-speed gas Bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas Bearings being developed for an oil-free turboex- pander. The radial Bearings (RBs) tested in this paper were tilting pad journal Bearings with radial compliance features that allow the Bearing bore to increase to accommodate shaft growth, and the thrust Bearings (TBs) were a spiral groove type with axial compli- ance features. The TB accounts for over 90% of the Combined Bearing power consump- tion, which has a cubic relationship with speed and increases with case pressure. RB circumferential pad temperatures increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady-state Bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the TB showed a significant increase in temperature with higher case pressure. The TBs were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been pro- posed to better understand the TB thermal behavior and to improve the TB design. Finally, the RBs tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas Bearings tested in the literature.
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A Rotordynamic, Thermal, and Thrust Load Performance Gas Bearing Test Rig and Test Results for Tilting Pad Journal Bearings and Spiral Groove Thrust Bearings
Volume 8: Microturbines Turbochargers and Small Turbomachines; Steam Turbines, 2016Co-Authors: Aaron M. Rimpel, Giuseppe Vannini, Jongsoo KimAbstract:A high speed gas Bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas Bearings being developed for an oil-free turboexpander. The radial Bearings tested in this paper were tilting pad journal Bearings with radial compliance features that allow the Bearing bore to increase to accommodate shaft growth, and the thrust Bearings were a spiral groove type with axial compliance features. The thrust Bearing accounts for over 90% of the Combined Bearing power consumption, which has a cubic relationship with speed and increases with case pressure. Radial Bearing circumferential pad temperature gradients increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady state Bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the thrust Bearing showed a significant increase in temperature with higher case pressure. The thrust Bearings were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been proposed to better understand the thrust Bearing thermal behavior and to improve the thrust Bearing design. Finally, the radial Bearings tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas Bearings tested in the literature.© 2016 ASME
Giuseppe Vannini - One of the best experts on this subject based on the ideXlab platform.
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A Rotordynamic, Thermal, and Thrust Load Performance Gas Bearing Test Rig and Test Results for Tilting Pad Journal Bearings and Spiral Groove Thrust Bearings
Journal of Engineering for Gas Turbines and Power, 2017Co-Authors: Aaron M. Rimpel, Giuseppe Vannini, Jongsoo KimAbstract:A high-speed gas Bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas Bearings being developed for an oil-free turboex- pander. The radial Bearings (RBs) tested in this paper were tilting pad journal Bearings with radial compliance features that allow the Bearing bore to increase to accommodate shaft growth, and the thrust Bearings (TBs) were a spiral groove type with axial compli- ance features. The TB accounts for over 90% of the Combined Bearing power consump- tion, which has a cubic relationship with speed and increases with case pressure. RB circumferential pad temperatures increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady-state Bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the TB showed a significant increase in temperature with higher case pressure. The TBs were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been pro- posed to better understand the TB thermal behavior and to improve the TB design. Finally, the RBs tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas Bearings tested in the literature.
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A Rotordynamic, Thermal, and Thrust Load Performance Gas Bearing Test Rig and Test Results for Tilting Pad Journal Bearings and Spiral Groove Thrust Bearings
Volume 8: Microturbines Turbochargers and Small Turbomachines; Steam Turbines, 2016Co-Authors: Aaron M. Rimpel, Giuseppe Vannini, Jongsoo KimAbstract:A high speed gas Bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas Bearings being developed for an oil-free turboexpander. The radial Bearings tested in this paper were tilting pad journal Bearings with radial compliance features that allow the Bearing bore to increase to accommodate shaft growth, and the thrust Bearings were a spiral groove type with axial compliance features. The thrust Bearing accounts for over 90% of the Combined Bearing power consumption, which has a cubic relationship with speed and increases with case pressure. Radial Bearing circumferential pad temperature gradients increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady state Bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the thrust Bearing showed a significant increase in temperature with higher case pressure. The thrust Bearings were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been proposed to better understand the thrust Bearing thermal behavior and to improve the thrust Bearing design. Finally, the radial Bearings tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas Bearings tested in the literature.© 2016 ASME
Mark Cassidy - One of the best experts on this subject based on the ideXlab platform.
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Physical and numerical study of the Combined Bearing capacity of hybrid foundation systems
Ocean Engineering, 2019Co-Authors: Ning Cheng, Christophe Gaudin, Mark CassidyAbstract:Abstract In the search for enhanced alternatives to the conventional footings of jack-up platforms, the offshore industry has turned to novel types of shallow foundations. A recent hybrid foundation concept was proposed that merges a skirted footing with a deeper caisson, with the motivation to mobilise higher Bearing capacities and increase the foundation stiffness. Defining the behaviour of this hybrid foundation under Combined vertical, horizontal and moment loadings is crucial to understanding the overall response of the offshore structure. This paper presents a study of the Combined Bearing capacity of a hybrid foundation system both experimentally and numerically. Centrifuge tests were performed at an acceleration of 200 times that of Earth's gravity on three different hybrid foundations resting on soft clay and subjected to Combined vertical, horizontal and moment loads. Combined loads were applied using a novel apparatus, which enables independent vertical, horizontal and rotational movements of the footing. Then numerical studies were conducted by adopting the soil properties measured in the test. Experimental results revealed that the central caisson's dimension plays an important role in the determination of the Combined Bearing capacities. It also showed that for skirted foundations, the Combined Bearing capacity is nearly identical once the footing has been pushed to the depth of its skirt, even if the vertical capacity is not fully preloaded. When comparing the numerical and experimental prediction of the Combined Bearing capacity, a reasonable agreement was achieved across all hybrid footing types.
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A plasticity model for spudcan foundations in soft clay
Canadian Geotechnical Journal, 2014Co-Authors: Youhu Zhang, Mark Cassidy, Britta BienenAbstract:A plasticity model for predicting the load displacement behaviour of a typical spudcan foundation for offshore jack-up platforms under Combined vertical, horizontal, and moment loading in soft clay is presented. Results from geotechnical centrifuge experiments of a spudcan embedded vertically to 0.7, 1.0, and 1.45 footing diameters are described. Augmented with finite element results, these centrifuge experiments are used to evaluate the plasticity model components. As a result of soil backflow on top of the spudcan, enhanced Combined Bearing capacity was measured and this is reflected in increased yield surface size. A tensile vertical load capacity is also incorporated. The excellent predictive capabilities of the model are demonstrated by retrospectively simulating a selection of centrifuge tests.
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Undrained Bearing capacity of deeply embedded foundations under general loading
2011Co-Authors: Youhu Zhang, Mark Cassidy, Britta Bienen, Susan GourvenecAbstract:The foundations of offshore mobile jack-up drilling rigs are subject to Combined vertical (V), horizontal (H) and moment (M) loading conditions. In soft soil, spudcans penetrate deeply (up to 2.5 diameters) and soil flows back on top of the foundations. This is generally believed to provide additional Bearing capacity. However, the current industry guideline evaluates Bearing capacity based on shallow foundation mechanisms regardless of the spudcan penetration, and the potential benefits associated with deep failure mechanisms are unaccounted for. This results in conservatism within site-specific assessments. In this study, the Combined undrained Bearing capacity of a deeply embedded spudcan foundation in normally consolidated clay is investigated using small strain finite element analyses. The effects of footing shape and aspect ratio on the failure mechanisms and Combined Bearing capacity are highlighted. To conclude, a closed-form expression is proposed to describe the shape of the VHM failure envelopes.
Youhu Zhang - One of the best experts on this subject based on the ideXlab platform.
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A plasticity model for spudcan foundations in soft clay
Canadian Geotechnical Journal, 2014Co-Authors: Youhu Zhang, Mark Cassidy, Britta BienenAbstract:A plasticity model for predicting the load displacement behaviour of a typical spudcan foundation for offshore jack-up platforms under Combined vertical, horizontal, and moment loading in soft clay is presented. Results from geotechnical centrifuge experiments of a spudcan embedded vertically to 0.7, 1.0, and 1.45 footing diameters are described. Augmented with finite element results, these centrifuge experiments are used to evaluate the plasticity model components. As a result of soil backflow on top of the spudcan, enhanced Combined Bearing capacity was measured and this is reflected in increased yield surface size. A tensile vertical load capacity is also incorporated. The excellent predictive capabilities of the model are demonstrated by retrospectively simulating a selection of centrifuge tests.
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Undrained Bearing capacity of deeply embedded foundations under general loading
2011Co-Authors: Youhu Zhang, Mark Cassidy, Britta Bienen, Susan GourvenecAbstract:The foundations of offshore mobile jack-up drilling rigs are subject to Combined vertical (V), horizontal (H) and moment (M) loading conditions. In soft soil, spudcans penetrate deeply (up to 2.5 diameters) and soil flows back on top of the foundations. This is generally believed to provide additional Bearing capacity. However, the current industry guideline evaluates Bearing capacity based on shallow foundation mechanisms regardless of the spudcan penetration, and the potential benefits associated with deep failure mechanisms are unaccounted for. This results in conservatism within site-specific assessments. In this study, the Combined undrained Bearing capacity of a deeply embedded spudcan foundation in normally consolidated clay is investigated using small strain finite element analyses. The effects of footing shape and aspect ratio on the failure mechanisms and Combined Bearing capacity are highlighted. To conclude, a closed-form expression is proposed to describe the shape of the VHM failure envelopes.