【摘要】：在燃燒場中,溫度是最為重要的參數(shù),如何準確且快速的獲取溫度信息具有重要的實際意義,可以為建立有效的燃燒模型、深入地了解燃燒的物理和化學過程以及改進現(xiàn)有的燃燒系統(tǒng)提供重要的參考。在燃燒測溫領域,測溫方式分為熱電偶等接觸式測量及CARS等激光光譜非接觸測量手段。其中,接觸式測量易受環(huán)境條件限制,且不適用于高溫測量;激光光譜非接觸式測量不受測溫環(huán)境條件的限制,且能實現(xiàn)對高溫領域高度的時間和空間分辨。本課題即利用非接觸式測溫中的飛秒單脈沖CARS光譜技術研究Hencken火焰結構對其溫度定標擬合過程的影響。本文先對Hencken型燃燒器和CARS光譜技術的研究現(xiàn)狀進行介紹;對丙烷/空氣的平焰擴散火焰特征進行定性研究;以及用熱電偶測溫方法對燃燒場的軸向及不同橫截面的溫度分布規(guī)律進行研究;其次,用飛秒單脈沖CARS光譜技術對Hencken燃燒器燃燒場中的一維溫度分布進行測溫研究,并分析該Hencken燃燒器不同測點溫度與理論CARS光譜最佳擬合溫度的擬合誤差。根據(jù)以上研究思路,設計了符合實驗所需的Hencken型平焰燃燒器,搭建了S型熱電偶測溫裝置,研究了不同當量比、平均流速、氧氣濃度等因素對溫度分布的影響規(guī)律。實驗結果表明,火焰呈近正四棱錐形,火焰的高度及燃盡情況主要取決于燃料的流量,且當量比為0.471時,隨著軸向高度的增加,測點溫度近正弦曲線般波動而后逐漸降低,平均的降溫幅度為0.5℃/mm,整個軸向高度方向的所有測點的溫度平均值為1131℃,比理論計算溫度低1.4%,即該工況測溫結果和理論計算溫度最接近;隨著甲烷流量的升高,軸向溫度隨高度的升高逐漸呈現(xiàn)出先減小再增大后降低的現(xiàn)象,整體呈現(xiàn)波動變化的規(guī)律;當氧氣濃度為21%時,在測量范圍內,軸向溫度隨著高度的增加基本無變化。同時,搭建了一套基于啁啾脈沖的飛秒單脈沖CARS光譜實驗裝置,以Hencken燃燒器產(chǎn)生的高溫火焰為探測樣品。實驗結果表明,利用飛秒CPP-CARS光譜技術對火焰溫度一維分布的測量,測量溫度在1350K和1450K之間,和熱電偶測量的結果較為符合,而且可以看出從火焰的一側到另一側火焰溫度呈現(xiàn)現(xiàn)增大后減小的趨勢,在火焰中心溫度最高;且與所測得的CARS光譜進行擬合的理論CARS光譜的最佳模型參數(shù)基本無變化,擬合誤差主要集中在0.01和0.02附近。
[Abstract]:In the combustion field, temperature is the most important parameter. How to obtain the temperature information accurately and quickly has important practical significance, which can be used to establish an effective combustion model. An in-depth understanding of the physical and chemical processes of combustion and the improvement of existing combustion systems provide important references. In the field of combustion temperature measurement, the temperature measurement can be divided into thermocouple contact measurement and laser spectrum non-contact measurement such as CARS. The contact measurement is easy to be restricted by the environmental conditions and is not suitable for high temperature measurement. The laser spectrum non-contact measurement is not limited by the environmental conditions of the temperature measurement and can realize the time and space resolution of the height of the high temperature field. In this paper, femtosecond monopulse CARS spectroscopy in non-contact temperature measurement is used to study the effect of Hencken flame structure on the fitting process of temperature calibration. In this paper, the research status of Hencken burner and CARS spectroscopic technology is introduced, and the characteristics of flat flame diffusion flame of propane / air are studied qualitatively. The temperature distribution of combustion field in axial direction and different cross section is studied by thermocouple method. Secondly, the one-dimensional temperature distribution in the combustion field of Hencken burner is studied by femtosecond monopulse CARS spectroscopy, and the fitting error between the temperature of different measuring points of the Hencken burner and the optimum fitting temperature of theoretical CARS spectrum is analyzed. According to the above research ideas, the Hencken type flat flame burner is designed, and the S type thermocouple temperature measuring device is built. The influence of different equivalent ratio, average flow rate and oxygen concentration on the temperature distribution is studied. The experimental results show that the flame is nearly quadrilateral, the height and burnout of the flame mainly depend on the flow rate of the fuel, and the equivalent ratio is 0.471. With the increase of the axial height, the temperature of the measuring point fluctuates like a sinusoidal curve and then decreases gradually. The average temperature of all the measuring points in the direction of the whole axial height of 0.5 鈩，

本文編號：2388811