The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser

Diffusing S-shaped ducts are critical components in modern vehicle, primarily employed in directing the airflow to the engine. It links the air box and the engine in a very restricted place. The air flow through an S-duct is complex in nature, which perhaps includes boundary layer separation, second...

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Main Authors: Abd. Halim, M. A., Mohd., N. A. R. N., Mohd. Nasir, M. N., Dahalan, M. N.
Format: Article
Language:English
Published: Universiti Malaysia Pahang 2018
Subjects:
Online Access:http://eprints.utm.my/79724/1/NikMohd2018_TheEvaluationofkandkTurbulence.pdf
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author Abd. Halim, M. A.
Mohd., N. A. R. N.
Mohd. Nasir, M. N.
Dahalan, M. N.
author_facet Abd. Halim, M. A.
Mohd., N. A. R. N.
Mohd. Nasir, M. N.
Dahalan, M. N.
author_sort Abd. Halim, M. A.
collection ePrints
description Diffusing S-shaped ducts are critical components in modern vehicle, primarily employed in directing the airflow to the engine. It links the air box and the engine in a very restricted place. The air flow through an S-duct is complex in nature, which perhaps includes boundary layer separation, secondary flow, and total pressure loss effects that influences the engine performance. In this work, the flow and performance of S-shaped duct was predicted and analysed using computational fluid dynamics. The main objective is to evaluate the performance of the realizable k-ε and k-ω SST models qualitatively and quantitatively in modelling flow of a highly bend duct where a high stress distorted flow may have developed in proximity the duct wall leading to stall. CFD computations were performed for the flow entering the diffuser at Reynolds number of 80,000 cases. The results obtained suggested that the k-ω SST model reasonably predicts the flow characteristics qualitatively and quantitatively. The realizable k-ε turbulence model however poorly captures the actual magnitudes of the calculated flow features. The growth of the stream-wise velocity profile was calculated at three stream-wise stations and point out a smooth down the interior profile of the divergent section. An extreme flow distortion and a shift of the region of flow with the highest velocity were developed toward the outer wall of the first bend of the diffuser. A significant pressure recovery potential with no flow separation arise over the diffuser tube range was predicted well by the simulations.
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spelling utm.eprints-797242019-01-28T06:37:52Z http://eprints.utm.my/79724/ The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser Abd. Halim, M. A. Mohd., N. A. R. N. Mohd. Nasir, M. N. Dahalan, M. N. TJ Mechanical engineering and machinery Diffusing S-shaped ducts are critical components in modern vehicle, primarily employed in directing the airflow to the engine. It links the air box and the engine in a very restricted place. The air flow through an S-duct is complex in nature, which perhaps includes boundary layer separation, secondary flow, and total pressure loss effects that influences the engine performance. In this work, the flow and performance of S-shaped duct was predicted and analysed using computational fluid dynamics. The main objective is to evaluate the performance of the realizable k-ε and k-ω SST models qualitatively and quantitatively in modelling flow of a highly bend duct where a high stress distorted flow may have developed in proximity the duct wall leading to stall. CFD computations were performed for the flow entering the diffuser at Reynolds number of 80,000 cases. The results obtained suggested that the k-ω SST model reasonably predicts the flow characteristics qualitatively and quantitatively. The realizable k-ε turbulence model however poorly captures the actual magnitudes of the calculated flow features. The growth of the stream-wise velocity profile was calculated at three stream-wise stations and point out a smooth down the interior profile of the divergent section. An extreme flow distortion and a shift of the region of flow with the highest velocity were developed toward the outer wall of the first bend of the diffuser. A significant pressure recovery potential with no flow separation arise over the diffuser tube range was predicted well by the simulations. Universiti Malaysia Pahang 2018 Article PeerReviewed application/pdf en http://eprints.utm.my/79724/1/NikMohd2018_TheEvaluationofkandkTurbulence.pdf Abd. Halim, M. A. and Mohd., N. A. R. N. and Mohd. Nasir, M. N. and Dahalan, M. N. (2018) The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser. International Journal of Automotive and Mechanical Engineering, 15 (2). pp. 5161-5178. ISSN 2229-8649 http://dx.doi.org/10.15282/ijame.15.2.2018.2.0399 DOI:10.15282/ijame.15.2.2018.2.0399
spellingShingle TJ Mechanical engineering and machinery
Abd. Halim, M. A.
Mohd., N. A. R. N.
Mohd. Nasir, M. N.
Dahalan, M. N.
The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser
title The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser
title_full The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser
title_fullStr The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser
title_full_unstemmed The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser
title_short The evaluation of k-ε and k-ω turbulence models in modelling flows and performance of S-shaped diffuser
title_sort evaluation of k ε and k ω turbulence models in modelling flows and performance of s shaped diffuser
topic TJ Mechanical engineering and machinery
url http://eprints.utm.my/79724/1/NikMohd2018_TheEvaluationofkandkTurbulence.pdf
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