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Please use this identifier to cite or link to this item: http://hdl.handle.net/1974/1526

Title: Numerical Investigation of the Scavenging Flow in a Two-Stroke Engine with Passive Intake Valves
Authors: Oliver, Philip Jozef

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Keywords: Two-Stroke
Computational Fluid Dynamics
Fluid-Structure Interaction
Issue Date: 2008
Series/Report no.: Canadian theses
Abstract: The development of a numerical model of a two-stroke engine is undertaken to study the scavenging characteristics of the engine. The engine design is unique in its use of 16 passive intake valves in the cylinder head which, along with the exhaust ports located at bottom centre (BC), give the engine a top-down uniflow-scavenged configuration. Each valve constitutes a small stainless steel platelet within a cavity in the cylinder head which reacts to the pressure difference across the cylinder head. The principle focus of this study is the transient simulation of the scavenging flow using dynamic meshing to model the piston motion and the response of the passive intake valves to the scavenging flow for varied engine speed and peak pressure. A flowbench study of the steady flow through the cylinder head into a duct is incorporated as a step in the development of the transient numerical model. Validation of the numerical predictions is undertaken by comparing results from an experimental flowbench for the steady case and using a cold-flow scavenging rig for the transient simulations. Both the steady flow through the cylinder head and the unsteady flow within the cylinder indicate the presence of a recirculation region on the cylinder axis. As a result, short-circuiting of scavenging gas becomes considerable and leads to scavenging characteristics comparable to Hopkinsonā€™s perfect mixing one-dimensional scavenging model.
Description: Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2008-09-26 18:38:53.375
URI: http://hdl.handle.net/1974/1526
Appears in Collections:Queen's Theses & Dissertations
Mechanical and Materials Engineering Graduate Theses

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