二維文氏管內氣流數值模擬分析研究

Numerical studies of air flow in the two-dimensional Venturi tube

邱怡樺(HASH(0xef0e9f0))

指導教授 ： 李嘉塗

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00228

摘要

實驗測量方法是理論分析和數值方法的基礎，然而，實現往往受到模型尺寸、流場環境、人為因素和測量精準度的限制，且還需投入相對較多的經費、人力和物力。CFD方法克服了理論分析與實驗研究的弱點，利用電腦計算，方便快速的展現氣體流動情形。在自然環境中和工程裝置中的流動通常是湍流流動，根據所建立的模型所需要的微分方程式的數目，可以分為零方程式模型(代數方程式模型)、單方程式模型和雙方程式模型。本模擬研究使用FLUENT-2D求解器計算，是以一個二維漏斗型噴管，利用兩端高低壓力差，採用Spalart-Allmaras單方程式湍流模型，藉以觀察噴管內氣體流動的各種狀態。
研究結果顯示，入口處的大氣壓力越大，噴管內氣流的壓力也就越大；在入口處的壓力設置越大，氣流在通過中央噴口處後，氣壓雖然下降，但是壁面壓力上升；噴管壁面所承受的壓力較長管組低且組較長氣流在噴管內流動的速度會比組較短的噴管快；在噴管內流體溫度方面，均呈現在噴嘴處流體速度雖是管內最快速，但平均溫度卻是管內最低；在噴管內流體濃度方面，喉管的部分流體濃度是全噴管中最低的部份；流體在噴管內的壓力與濃度有著顯著關聯性。

關鍵字

FLUENT ； CFD ； 湍流模型

並列摘要

Experimental me surements are theoretical analysis and numerical methods based, howeer, tend to be the model to achieve and numerical size, flow field environment, human factors and measurement accuracy limitations, and the need to invest relatively more funding, manpower and material resources.CFD method overco es the theoretical analysis and experimental study weaknesses, using computer calculations, convenient and fast to show the gasflow situations. In the natural environment and engineering
pparatus flow is usually turbulent flow, according to the model of the required number of differential equations, equation model can be divided into the zero (algebraic

equation model), both single programming model and the

model equations.The simulation studies using FLUENT-2Dsolver,based on a two-dimensional funnel-shaped nozzle, the use of low pressure difference at both ends, using the Spalart-Allmaras one equation turbulence model, in

order to observe the gas flow in the nozzle of the various states.

The results show that the greater the atmospheric pressure inlet, nozzle air pressure inside the greater; pressure setting at the entrance to the greater airflow through the central vents, the air pressure although the decline, but the
wall pressure rise; spray the pressure on the wall surface of a long tube group

and the group of low

flow in the nozzle long flowing faster than shorter

I

nozzle set fast; fluid temperature inside the nozzle side, showed now though is the fluid velocity at the nozzle tube fastest, but the average temperature is the lowest tube; fluid concentration in the nozzle, the throat of the nozzle part of the fluid density is the lowest part of the whole; fluid pressure inside the nozzle has a significant correlation with the concentration of sex.

並列關鍵字

HASH(0xef196f0) ； HASH(0xef19790) ； HASH(0xef19830)

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