A model for diffusing flow loss in numerical 1D gas dynamics simulations

Gibbes, G; Hong, G

A model for diffusing flow loss in numerical 1D gas dynamics simulations

Gibbes, G Hong, G

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Publisher:: Cultural & Communication Publisher
Publication Type:: Conference
Citation:: Gibbes Gregory and Hong Guang 2009, 'A model for diffusing flow loss in numerical 1D gas dynamics simulations', , Cultural & Communication Publisher, Hanoi, Vietnam, , pp. APAC15-216/1-APAC15-216/8.
Issue Date:: 2009

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Field	Value	Language
dc.contributor.author	Gibbes, G	en_US
dc.contributor.author	Hong, G	en_US
dc.contributor.editor	Scientific & Technical Commitee	en_US
dc.date	20091026	en_US
dc.date.accessioned	2012-02-02T11:08:44Z
dc.date.available	2012-02-02T11:08:44Z
dc.date.issued	2009	en_US
dc.identifier	2009004919	en_US
dc.identifier.citation	Gibbes Gregory and Hong Guang 2009, 'A model for diffusing flow loss in numerical 1D gas dynamics simulations', , Cultural & Communication Publisher, Hanoi, Vietnam, , pp. APAC15-216/1-APAC15-216/8.	en_US
dc.identifier.issn	912-2009/CXB/11-119/	en_US
dc.identifier.other	E1	en_US
dc.identifier.uri	http://hdl.handle.net/10453/16377
dc.description.abstract	A new model for flow though rapidly expanding ducts is proposed. Experiments by others have shown that unstcady flows deviate from quasi steady behavior, in particular that rapidly increasing (ie impulsive) flows exhibit less flow separation than equivalent steady flows. This unsteady effect is analyzed here from the perspective of pressure recovery. This approach differs from others as it does not directly involve tuning flow area coefficients. Three common models for flow in expanding ducts are presented and described, namely the isentropic flow model, the constant pressure (or equal pressure) model and the momentum equation model. A fourth model is developed using the energy equation. The model is called the deceleration model and contains a term for the local acceleration of the flow in order to account for the unsteadiness of the flow. The four alternative models are then compared to experimental results for a single flow pulse through ducts with rapid increase in area. lhe deceleration model performs the best of all the models although the momentum model is also generally good. Finally the four alternative models arc compared to one another in a full simulation of a two stroke engine with a tuned exhaust pipe. The differences between the models results are small though noi insignificant. It is hoped that the insights presented here stimulate further thinking on the issue and yield improvement in ID gas dynamics simulations of difficult-to-model regions such as diffusers, valves, throttles, ports, and multi pipe junctions.	en_US
dc.language	English	en_US
dc.publisher	Cultural & Communication Publisher	en_US
dc.relation.ispartof	APAC 2009 - Proceedings of 15th Asia Pacific Automotive Engineering Conference	en_US
dc.relation.ispartof	Verified OK	en_US
dc.relation.isbasedon	NA	en_US
dc.subject	ID gas dynamics, unsteady, flow separation, pressure recovery	en_US
dc.subject.classification	Automotive Engineering	en_US
dc.title	A model for diffusing flow loss in numerical 1D gas dynamics simulations	en_US
dc.type	Conference
utslib.location	Hanoi, Vietnam	en_US
utslib.citation.startpage	APAC15-216/1	en_US
utslib.citation.endpage	APAC15-216/8	en_US
utslib.identifier.org	FEIT.School of Elec, Mech and Mechatronic Systems	en_US
utslib.for	090200	en_US
utslib.percentage	100	en_US
dc.location.activity	Hanoi, Vietnam	en_US
utslib.copyright.status	closed_access

Abstract:

A new model for flow though rapidly expanding ducts is proposed. Experiments by others have shown that unstcady flows deviate from quasi steady behavior, in particular that rapidly increasing (ie impulsive) flows exhibit less flow separation than equivalent steady flows. This unsteady effect is analyzed here from the perspective of pressure recovery. This approach differs from others as it does not directly involve tuning flow area coefficients. Three common models for flow in expanding ducts are presented and described, namely the isentropic flow model, the constant pressure (or equal pressure) model and the momentum equation model. A fourth model is developed using the energy equation. The model is called the deceleration model and contains a term for the local acceleration of the flow in order to account for the unsteadiness of the flow. The four alternative models are then compared to experimental results for a single flow pulse through ducts with rapid increase in area. lhe deceleration model performs the best of all the models although the momentum model is also generally good. Finally the four alternative models arc compared to one another in a full simulation of a two stroke engine with a tuned exhaust pipe. The differences between the models results are small though noi insignificant. It is hoped that the insights presented here stimulate further thinking on the issue and yield improvement in ID gas dynamics simulations of difficult-to-model regions such as diffusers, valves, throttles, ports, and multi pipe junctions.

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http://hdl.handle.net/10453/16377