併排雙Tsuji燃燒器火焰交互影響之實驗觀測與量測

Abstract

本文可分類為二個部分。第一部分即觀察在單一圓柱上火焰結構（S = 180ο）的雙重現象以及遲滯現象。藉由不同的操作過程（進氣速度增加與遞減），發現火焰的雙重現象存在於不同的過程中。即在任何一個燃料噴率之下（除了最小的燃料噴率之外），於某進氣速度範圍，皆會有二種不同的火焰型式的存在，也就是所謂的雙重現象。此外，遲滯現象往往存在於許多的非線性系統中，其中包含了雙重現象的不可逆過程；這種現象的發生往往取決於系統的操作情況與起始狀態。第二部分為主要的研究領域，利用圓柱間中心線溫度的量測(Uin = 0.48m/s,VW = 2.6cm/s)，觀察水平放置的兩個燃燒器其火焰交互作用的影響。研究發現，火焰交互作用是造成在雙圓柱間氧氣量缺乏的主要原因。當圓柱間距大於2.5D的時候，由於中心線溫度近乎維持著室溫，表示並沒有明顯的火焰干涉的情形；然而，當雙圓柱彼此靠近的時候，其交互作用越明顯，同時火焰交接處（merge point）會逐漸往上游移動。另一方面，在不同的圓柱間距之下，藉由轉變速度的變化，也可了解交互作用與圓柱間距的關係。當圓柱間距為1.2D £ L£ 2.5D時，火焰會有較大的轉變速度；相對地，當L > 2.5D的時候，由於沒有火焰干涉的影響，其火焰的轉變速度會保持著一個定值。

This thesis consists of two parts. The first part is to observe the duality and hysteresis phenomena over a porous cylinder, in which the fuel is ejected from the forward half surface. It indicates that the duality phenomenon of counterflow flame exists in the different processes, such as increasing or reducing inflow velocity. The state of such system is decided by the operating procedures and the initial conditions of the system. The second part investigates the interference phenomena of twin Tsuji Burner flames. The temperature profiles along the centerline between two burners for specific spacing (L) are used to depict the flame interaction. The inflow velocity is fixed at Uin = 0.48 m/s and the fuel ejection rate is at Vw = 2.6 cm/s. As L > 2.5D (diameter of cylindrical burner), the temperatures along the centerline are equal to ambient temperature, implying that the two flames do not interact each other. When the spacing is decreased from 2.5 D to 1.2D, the flame interference gradually becomes apparent and the merge point moves toward the upstream. It is followed by the measurements of the transition velocity as a function of intercylinder spacing under Vw = 1.23 cm/s. It is found that the transition velocity is higher as the separation distance is smaller between 1.2D £ L£ 2.5D. As L > 2.5D, the transition velocity is found to retain a constant value due to no interaction between the twin flames.