Experimental study of vortex-flame interaction in a gas turbine model combustor
Experimental study of vortex-flame interaction in a gas turbine model combustor
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DOI：
10.1016/j.combustflame.2012.03.020
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发表时间：
2012-08
影响因子：
4.4
通讯作者：
M. Stöhr;I. Boxx;C. Carter;W. Meier
中科院分区：
文献类型：
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作者：
M. Stöhr;I. Boxx;C. Carter;W. Meier
对燃气轮机模型燃烧室中螺旋进动涡核（PVC）与湍流旋流火焰的相互作用进行了实验研究。燃烧器在大气压下使用空气和甲烷运行，热功率为 10 至 35kW。使用粒子图像测速 (PIV) 测量流场，并使用适当的正交分解确定主要的非定常涡流结构。对于所有操作条件，在内再循环区 (IRZ) 的剪切层中都会检测到 PVC。此外，还发现了外剪切层（OSL）中的同向旋转螺旋涡流和源自排气管的中心涡流。 OH 化学发光 (CL) 图像显示火焰主要稳定在内剪切层 (ISL) 中，PVC 也位于该层。 OH-CL 的相位平均图像显示，在所有条件下，热量释放的主要部分发生在与 PVC 耦合的螺旋区域中。然后，使用重复率为 5kHz 的同步 PIV 和 OH-PLIF 测量，研究 P=10kW 情况下 PVC 与火焰之间相互作用的机制。测量结果表明，PVC 会导致火焰卷起、已燃烧气体和未燃烧气体的混合以及随后 ISL 中混合物的点燃的规律序列。这些效应与周期性涡旋运动直接相关。流场的相位平均分析进一步表明，PVC 会产生平均流场中不存在的不稳定下驻点。驻点的运动与 PVC 的周期性进动有关。接近这一点时，燃烧的气体和未燃烧的气体正面碰撞，并释放大量的热量。该点附近的火焰动力学也与 PVC 相关。通过这种方式，反应区的一部分被周期性地从驻点拉入ISL，从而充当该层中反应的点火源。总的来说，ISL 和停滞点的影响表明 PVC 在湍流漩涡火焰的稳定机制中起着至关重要的作用。与 PVC 不同，OSL 中和排气管附近的涡流对火焰没有直接影响，因为它们位于火焰区域之外。
The interaction of a helical precessing vortex core (PVC) with turbulent swirl flames in a gas turbine model combustor is studied experimentally. The combustor is operated with air and methane at atmospheric pressure and thermal powers from 10 to 35kW. The flow field is measured using particle image velocimetry (PIV), and the dominant unsteady vortex structures are determined using proper orthogonal decomposition. For all operating conditions, a PVC is detected in the shear layer of the inner recirculation zone (IRZ). In addition, a co-rotating helical vortex in the outer shear layer (OSL) and a central vortex originating in the exhaust tube are found. OH chemiluminescence (CL) images show that the flames are mainly stabilized in the inner shear layer (ISL), where also the PVC is located. Phase-averaged images of OH-CL show that for all conditions, a major part of heat release takes place in a helical zone that is coupled to the PVC. The mechanisms of the interaction between PVC and flame are then studied for the case P=10kW using simultaneous PIV and OH-PLIF measurements with a repetition rate of 5kHz. The measurements show that the PVC causes a regular sequence of flame roll-up, mixing of burned and unburned gas, and subsequent ignition of the mixture in the ISL. These effects are directly linked to the periodic vortex motions. A phase-averaged analysis of the flow field further shows that the PVC induces an unsteady lower stagnation point that is not present in the average flow field. The motion of the stagnation point is linked to the periodic precession of the PVC. Near this point burned and unburned gas collide frontally and a significant amount of heat release takes place. The flame dynamics near this point is also coupled to the PVC. In this way, a part of the reaction zone is periodically drawn from the stagnation point into the ISL, and thus serves as an ignition source for the reactions in this layer. In total, the effects in the ISL and at the stagnation point showed that the PVC plays an essential role in the stabilization mechanism of the turbulent swirl flames. In contrast to the PVC, the vortices in the OSL and near the exhaust tube have no direct effect on the flame since they are located outside the flame zone.