The Experts below are selected from a list of 8382 Experts worldwide ranked by ideXlab platform
Jerzy T. Sawicki - One of the best experts on this subject based on the ideXlab platform.
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Pumping Loss of Shrouded Meshed Spur Gears
Journal of Engineering for Gas Turbines and Power, 2020Co-Authors: Michael J. Hurrell, Jerzy T. SawickiAbstract:Abstract High speed rotorcraft transmissions are subject to load-independent power Losses consisting of drag Loss and Pumping Loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent Losses. However, tightly conforming axial shrouds can result in an increase in the Pumping Loss component. Quantifying the Pumping Loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating Pumping Loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag Loss and Pumping Loss of a shrouded spur gear pair have been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamics (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating Pumping power Loss of shrouded gear transmissions.
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Pumping Loss of Shrouded Meshed Spur Gears
Volume 10B: Structures and Dynamics, 2020Co-Authors: Michael J. Hurrell, Jerzy T. SawickiAbstract:Abstract High speed rotorcraft transmissions are subject to load-independent power Losses consisting of drag Loss and Pumping Loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent Losses. However, tightly conforming axial shrouds can result in an increase in the Pumping Loss component. Quantifying the Pumping Loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating Pumping Loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag Loss and Pumping Loss of a shrouded spur gear pair has been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamic (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating Pumping power Loss of shrouded gear transmissions.
Max Burgess - One of the best experts on this subject based on the ideXlab platform.
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Intake characteristics and Pumping Loss in the intake stroke of a novel small scale opposed rotary piston engine
Journal of Cleaner Production, 2020Co-Authors: Jianbing Gao, Guohong Tian, Phil Jenner, Max BurgessAbstract:Abstract Compact and high power density internal combustion engines are attracting much attention for the applications to hybrid vehicles, aiming at decreasing fuel consumption and exhaust emissions. A novel opposed rotary piston engine, whose cyclic period is 360° crank angle, is designed as the power of hybrid vehicles. Intake process of the internal combustion engines significantly affects brake thermal efficiency and rated power. In this paper, 3D simulation of a opposed rotary piston engine is conducted over different engine speeds of 3000 and 5000 RPM, in order to analyze the intake characteristics and Pumping Loss in the intake stroke. The results indicate that the in-cylinder pressure distributions change significantly in the intake process, which results from the variations of cylinder volume and fresh air flow rates. The minimum in-cylinder pressure is approximately 0.3 and 0.2 bar for 3000 and 5000 RPM, respectively, with the combustion chamber volume (corresponding to minimum pressure) being ∼0.04 L correspondingly. The maximum velocity of the fresh air in the intake process is higher than 150 m/s. Intake valves 2 and 3 dominate the mass flow of the combustion chambers, in addition, the contribution of mass flow from intake valve 1 decreases with the engine speed. The pump Loss in the intake process increases from 1.35 to 4.39 kW when the engine speed increases from 3000 to 5000 RPM.
Michael J. Hurrell - One of the best experts on this subject based on the ideXlab platform.
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Pumping Loss of Shrouded Meshed Spur Gears
Journal of Engineering for Gas Turbines and Power, 2020Co-Authors: Michael J. Hurrell, Jerzy T. SawickiAbstract:Abstract High speed rotorcraft transmissions are subject to load-independent power Losses consisting of drag Loss and Pumping Loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent Losses. However, tightly conforming axial shrouds can result in an increase in the Pumping Loss component. Quantifying the Pumping Loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating Pumping Loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag Loss and Pumping Loss of a shrouded spur gear pair have been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamics (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating Pumping power Loss of shrouded gear transmissions.
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Pumping Loss of Shrouded Meshed Spur Gears
Volume 10B: Structures and Dynamics, 2020Co-Authors: Michael J. Hurrell, Jerzy T. SawickiAbstract:Abstract High speed rotorcraft transmissions are subject to load-independent power Losses consisting of drag Loss and Pumping Loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent Losses. However, tightly conforming axial shrouds can result in an increase in the Pumping Loss component. Quantifying the Pumping Loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating Pumping Loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag Loss and Pumping Loss of a shrouded spur gear pair has been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamic (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating Pumping power Loss of shrouded gear transmissions.
Hans-erik Ångström - One of the best experts on this subject based on the ideXlab platform.
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Externally divided exhaust period on a turbocompound engine for fuel saving
Proceedings, 2018Co-Authors: Habib Aghaali, Hans-erik ÅngströmAbstract:To improve exhaust heat utilization of a turbocharged engine, divided exhaust period (DEP) and turbocompound are integrated. The DEP concept decreases Pumping Loss created by the turbocompound. In ...
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Performance Sensitivity to Exhaust Valves and Turbine Parameters on a Turbocompound Engine with Divided Exhaust Period
SAE International Journal of Engines, 2014Co-Authors: Habib Aghaali, Hans-erik ÅngströmAbstract:Turbocompound can utilize part of the exhaust energy on internal combustion engines; however, it increases exhaust back pressure, and Pumping Loss. To avoid such drawbacks, divided exhaust period ...
Jianbing Gao - One of the best experts on this subject based on the ideXlab platform.
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Intake characteristics and Pumping Loss in the intake stroke of a novel small scale opposed rotary piston engine
Journal of Cleaner Production, 2020Co-Authors: Jianbing Gao, Guohong Tian, Phil Jenner, Max BurgessAbstract:Abstract Compact and high power density internal combustion engines are attracting much attention for the applications to hybrid vehicles, aiming at decreasing fuel consumption and exhaust emissions. A novel opposed rotary piston engine, whose cyclic period is 360° crank angle, is designed as the power of hybrid vehicles. Intake process of the internal combustion engines significantly affects brake thermal efficiency and rated power. In this paper, 3D simulation of a opposed rotary piston engine is conducted over different engine speeds of 3000 and 5000 RPM, in order to analyze the intake characteristics and Pumping Loss in the intake stroke. The results indicate that the in-cylinder pressure distributions change significantly in the intake process, which results from the variations of cylinder volume and fresh air flow rates. The minimum in-cylinder pressure is approximately 0.3 and 0.2 bar for 3000 and 5000 RPM, respectively, with the combustion chamber volume (corresponding to minimum pressure) being ∼0.04 L correspondingly. The maximum velocity of the fresh air in the intake process is higher than 150 m/s. Intake valves 2 and 3 dominate the mass flow of the combustion chambers, in addition, the contribution of mass flow from intake valve 1 decreases with the engine speed. The pump Loss in the intake process increases from 1.35 to 4.39 kW when the engine speed increases from 3000 to 5000 RPM.
