Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2470
標題: 等截面積不同展弦比之單對衝流場三維數值模擬與分析
Three-Dimensional Numerical Simulation and Analysis of the Impinging Flow Fields at Equal Cross-sectional Area and Different Aspect Ratios
作者: 陳建利
關鍵字: single jet;單噴射;impinging flow;three-dimensional flow field;hybrid effect;對衝流;三維流場;混合效果
出版社: 機械工程學系
摘要: 
本文利用計算流體力學軟體FLOTHERM對三維、不可壓縮之單噴射對衝紊流流場進行混合效果及流體行為作探討與分析。在數值計算方面,採用交錯式格點系統(Staggered Grid System)、混合體系(Hybrid Scheme)及SIMPLEST求解程序來求解。紊流模式則使用Lam&Bremhorst ε−k雙方程式。在固定截面積下,本文分別就入口紊流雷諾數(RE)、展弦比(Ar)等參數變化下,分析它們對流場壓力、速度、溫度及結構的影響。
經數值計算結果顯示,當上下入口紊流雷諾數在1:1時,其值大小對流場的混合效果影響不大。當改變雷諾數比值(Rr)所得到的混合效果均較改變雷諾數(RE)值時要佳。又當展弦比(Ar)愈大時,其對整個流場的混合效果愈佳。在同時兼顧混合效果較佳及所需的軸向混合長度最短之情形下,本文建議以Rr≠1、Ar>1組合時為最佳,此可提供產業界在設計各種混合器或燃燒器時之參考。
關鍵字:單噴射、對衝流、三維流場、混合效果

In this study, a computational fluid dynamics(CFD) code of FLOTHERM was used to calculate the three-dimensional, incompressible, impinging single-jet turbulence flow field in order to understand the mixing effects and flow behavior. The Staggered Grid System, Hybrid Scheme and SIMPLEST algorithm were employed in this numerical simulation. The Lam & Bremhorst k-ε two-equation turbulence model was used in present study. The parameters of inlet Reynolds number(Re) and aspect ratio(Ar) are employed to analyze the effected pressure, velocity, temperature and structure in the flow field for fixed cross-section.
The calculated results have shown that the effect was minor when the inlet Reynolds number ratio(Rr) between upper and down nozzle as 1: 1. The mixing effect was better when the parameters of the Reynolds number ratio change from 1: 1 to 1: 2. The mixing effect of the flow field was better when the aspect ratio(Ar) change from Ar<1 to Ar>1. From the present numerical results, it shows that the mixing effect was best when the parameters were Rr≠1, Ar>1. The present results can also provide the reference for the design of mixer or burner in the industry.
Keywords: single jet, impinging flow, three-dimensional flow field, hybrid effect.
URI: http://hdl.handle.net/11455/2470
Appears in Collections:機械工程學系所

Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.