联焰板宽度对单凹腔驻涡燃烧室冷态流场特性影响的试验研究

Experimental Researches on Unburnt Flow Field Performance of a Single-Cavity Trapped Vortex Combustor with Different Width of Radial Strut

关键词:  单凹腔驻涡燃烧室  冷态流场特性  试验研究

Key words:  Single-cavity trapped vortex combustor  Unburnt flow field performance  Experimental research

摘要:

为了研究联焰板宽度对单凹腔驻涡燃烧室冷态流场特性的影响，设计了一个带扩压器和机匣的单凹腔驻涡燃烧室，并在此基础上通过改变联焰板宽度进行了冷态流场试验。试验在常温常压状态下进行，试验中的主要研究参数如下：在保持联焰板数目不变时，联焰板宽度分别为40mm，30mm，20mm；在改变联焰板数目时，联焰板数目分别为1，3。研究结果表明：在主流中心(PM)截面上，凹腔内存在双涡流动结构，主涡位于凹腔的中间位置，约占凹腔区域面积的80%；副涡位于主涡与主流之间，约占凹腔区域面积的20%。在联焰板中心(PA)截面上，不同的联焰板宽度会形成两种不同的流线形态，当联焰板宽度较宽时，凹腔内为单涡流动结构，仅存在主涡结构，主涡回流气流沿联焰板向火焰筒下壁面流动；当联焰板宽度较窄时，凹腔内为双涡流动结构，主流气流卷入联焰板后。联焰板宽度对流场特性的影响可以总结为：当联焰板宽度减小时，在PM截面上，凹腔副涡涡心位置在轴向上向上游移动，在径向上向主流移动，主流气流向凹腔扩张程度变小；在PA截面上，联焰板后出现主流和旋涡结构。

Abstract:

In order to study the unburnt flow field performance of different width of radial strut, a single-cavity trapped vortex combustor with diffuser and casings was designed. Unburnt flow field experiments were carried out by changing the width of radial strut on the combustor. Experiments were accomplished at atmospheric pressure and temperature. The main parameters of the experiments were shown as follows: the width of radial strut was 40mm， 30mm， 20mm， respectively， while the number of radial strut was constant， and the number of radial strut was 1 or 3 while the number of radial strut was changeable. The results showed that on the central section of mainstream (PM), there were two vortices in the cavity. The main vortex was located in the middle of cavity, accounting for about 80% area of cavity, and the secondary vortex was located between the main vortex and mainstream, accounting for about 20% area of cavity. On the central section of radial strut (PA), different width of radial strut would form two different flow structures. When radial strut was wider, the cavity had a single-vortex flow structure, which meant that only the main vortex existed in cavity. The reflux airflow from main vortex flowed along the radial strut to the lower wall of the liner. When the width of radial strut was narrower, the cavity had a double-vortex flow structure, which meant that the mainstream flowed to the area behind the radial strut. The influence of the width of radial strut on the unburnt flow field characteristics could be summarized as follows: when the width of radial strut decreased, in PM plane, the center of secondary vortex moved upward in axial direction, and moved to the mainstream in radial direction. In PA plane, the mainstream and vortex appeared behind the radial strut.