Browsing by Author "Huang, Yun"

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An investigation of compressible forced convection in a three dimensional tapered chimney by CUDA computation platform
(2011-07-01)
Fu, Wu-Shung
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Wang, Wei-Hsiang
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Huang, Yun
;
Li, Chung-Gang
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機械工程學系
Compressible forced convection in a three dimensional tapered chimney is investigated numerically. Schemes of Roe and preconditioning are adopted to resolve compressible flow problem under a low speed velocity situation. Coordinates transformation of algebraic grid generation and non-reflecting boundary condition is used to execute the coordinated transformation of the tapered duct and decrease the computation domain, respectively. Computing procedures are performed on the CUDA computation platform which is developed recently and is a very effective tool. Due to the variation of the geometry of three dimensional tapered chimney, the flow velocity increases in the central region and decreases near the corner region. Therefore, heat transfer rates are enhanced remarkably in the central region and become inferior abruptly near the corner region. The efficiency of CUDA computation platform is marvelous, and the possibility of capability of super computation of individualization may be realized by using the CUDA computation platform. (C) 2011 Elsevier Ltd. All rights reserved.
An Investigation of Compressible Turbulent Forced Convection by an Implicit Turbulence Model for Large Eddy Simulation
(2013-12-01)
Fu, Wu-Shung
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Li, Chung-Gang
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Tsubokura, Makoto
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Huang, Yun
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Domaradzki, J. A.
An investigation of compressible turbulent forced convection in a three-dimensional channel flow is studied numerically by an implicit turbulence model for large eddy simulation (LES). Because of a high temperature difference between two walls and turbulent flow, the compressibility and viscosity of fluid should be taken into consideration simultaneously. Methods of the Roe scheme, preconditioning, and dual time stepping coordinating an implicit turbulence model for LES are used for resolving the effect of the compressibility of fluid on a low speed flow field. The magnitudes of Re-tau based on the friction velocity changing from 180 to 940, with the high temperature difference of two walls of 500k are conducted. The results of the mean velocity profiles and turbulent intensities are in good agreement with the benchmark DNS data obtained by spectral codes from a low Reynolds number (Re-tau =180) to a high Reynolds number (Re-tau = 940). Besides, the larger the Re-tau is, with the exception of acquirement of larger average Nusselt number, the more drastic variation of local instantaneous Nusselt number is observed.
An investigation of flow reversal of mixed convection in a three dimensional rectangular channel with a finite length
(2013-09-01)
Fu, Wu-Shung
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Lai, Yu-Chih
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Huang, Yun
;
Liu, Kuan-Lan
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機械工程學系
An investigation of flow reversal of mixed flow in a three dimensional channel is studied numerically. At a high Richardson number, natural convection dominates the flow and thermal fields of mixed convection. Behaviors of the residual mass flow rate produced by the difference of the strength of natural and forced convections coexisting in mixed convection are worthy to be examined deeply for industrial applications. Due to the necessity of considering the fluid compressibility, methods of the Roe scheme, preconditioning and dual time stepping are adopted to solve governing equations. The results show that at a high Richardson number situation, via the outlet in large quantities of fluids are sucked into the channel from the outside that causes the flow and thermal fields in the channel to be unsteady and vice versa. (C) 2013 Elsevier Ltd. All rights reserved.
An investigation of natural convection in a three dimensional tapered chimney without Boussinesq assumption
(2012-04-01)
Fu, Wu-Shung
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Huang, Yun
;
Wang, Wei-Hsiang
;
機械工程學系
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Department of Mechanical Engineering
Natural convection in a three dimensional tapered chimney is investigated numerically. In order to investigate the natural convection under a high temperature difference situation. Boussinesq assumption is not adopted instead of consideration of the compressibility of fluid. Methods of Roe scheme, preconditioning and dual time stepping are used to solve governing equations for a low speed compressible flow. Coordinates transformation of algebraic grid generation and non-reflecting boundary condition are used to facilitate computation processes. The results reveal that in the expanding duct local Nusselt numbers distributed around the corner region are larger than those distributed around the central region. An available correlation equation is proposed and is well consistent with the numerical results. (C) 2012 Elsevier Ltd. All rights reserved.
Enhancement of mixed convection heat transfer in a three-dimensional horizontal channel flow by insertion of a moving block
(2012-01-01)
Fu, Wu-Shung
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Chen, Chung-Jen
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Wang, Yuan-Ying
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Huang, Yun
;
機械工程學系
Enhancement of mixed convection heat transfer rate of a heat surface in a three dimensional horizontal channel with insertion of a moving block is studied numerically. Bossinique assumption is not adopted, then methods of Roe scheme, preconditioning, and dual time stepping are needed to solve the governing equations. Contributions of important parameters of Gr/Re-2 and moving block velocity to the heat transfer rate are validated. Due to the consideration of natural convection, under situations of large magnitude of Gr/Re-2 a counter-effect for promotion of heat transfer rate is observed. Oppositely, under situations of small magnitude of Gr/Re-2, the enhancement of heat transfer rate is remarkably achieved. (C) 2011 Elsevier Ltd. All rights reserved.