擴散體增強型川流發電機之設計與分析

Design and Analysis of an Augmentation Device for a River Current Turbine

秉天(Bryan Steven Nelson)

指導教授 ： 姜庭隆

國立屏東科技大學/工學院/機械工程系所/碩士(2009年)

https://doi.org/10.6346/NPUST.2009.00185

摘要

本研究中利用計算流體力學來設計及分析擴散體增強型川流發電機。首先以二緯軸對稱模型探討擴散器幾何參數對質量流量的影響，再建構三緯模型。二緯軸對稱模型以多孔跳躍(porous-jump)來模擬旋轉翼，三緯葉片幾何以葉片元素動量理論來設計。使用之翼型為NACA 4412。本文係運用商用軟體Gambit建構流場的網格，Fluent進行流場的解析。根據模擬結果顯示擴散體增強型川流發電機之增強係數跟擴散器面積比例相同。

關鍵字

計算流體力學 ； 擴散體增強型川流發電機 ； 多孔跳躍 ； 葉片元素動量理論 ； NACA 4412

並列摘要

This report documents the CFD-based design and analysis of a diffuser augmented river current turbine. In order to investigate the effects of various geometric design parameters on the flow through the diffusing duct, several two-dimensional axisymmetric models were analysed, for the two cases of ‘rotored’ and ‘rotorless’ ducts, with the 2-D rotor modelled by employing a ‘porous-jump’ to simulate the pressure drop through the rotor plane. Based on these preliminary results, a one-third (by periodic symmetry) three- dimensional model, with a single blade, designed by application of the blade element momentum (BEM) theory, for a NACA 4412 airfoil geometry, was generated and analysed. The degree of augmentation was determined by comparing these results with those of an identical blade in open flow (i.e. unducted). The model geometries were generated in Gambit, and the meshes exported to the Fluent 6.3 Computational Fluid Dynamics software package for solution of the flow-fields. Analysis of the results revealed augmentation factors roughly equal to the exit/throat area ratio of the diffusing duct.

並列關鍵字

CFD ； diffuser augmented river current turbine ； porous-jump ； blade element momentum theory ； NACA 4412

參考文獻

[1] IPCC, “About IPCC”, Intergovernmental Panel on Climate Change Available at: www.ipcc.ch/about/index.htm, Accessed 7 May, 2009

[5] UNFCCC, “Kyoto Protocol”, United Nations Framework Convention on Climate Change, Available at: http://unfccc.int/2860.php, Accessed 7 May, 2009

[7] G. van Bussel, 2007, “The science of making more torque from wind: Diffuser experiments and theory revisited,” Journal of Physics, Conference Series, Denmark

[8] Jamieson, 2008, Beating Betz – Energy Extraction Limits in a Uniform Flow Field, Garrad Hassan & Partners, Ltd., U.K.

[11] D. Phillips, R. Flay, T. Nash, 1999, Aerodynamic analysis & monitoring of the Vortec7 Diffuser-Augmented Wind Turbine, Vortec Energy Ltd. and University of Auckland