Blowout limits of inclined nonpremixed turbulent jet flames
Blowout limits of inclined nonpremixed turbulent jet flames
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DOI：
10.1016/j.proci.2022.11.009
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发表时间：
2022-12
影响因子：
3.4
通讯作者：
Qiang Wang;Xu Liang;Aquan Lu;Ben Wang;O. Fujita;S. Chung;L. Hu
中科院分区：
文献类型：
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作者：
Qiang Wang;Xu Liang;Aquan Lu;Ben Wang;O. Fujita;S. Chung;L. Hu
通过在-90°~ 90°范围内改变射流倾斜角，研究了倾斜非预混湍流射流火焰的喷灭行为，并对不同喷嘴直径、不同燃料和不同倾斜角下的喷灭极限临界射流速度进行了实验量化。数值模拟强调了正、负倾斜角度下的流场差异。进行了物理模拟，考虑了倾斜角度对井喷行为的影响。主要研究结果包括：(1)负倾斜射流火焰比正倾斜射流火焰表现出更强的黄色亮度和更大的烟尘区；(2)喷流极限随着喷流倾斜角的增大而明显减小，而喷流倾斜角的减小幅度较小；(3)对倾斜射流的流动发展进行了物理分析，发现倾斜角度越小，火焰沿射流轨迹的中心线速度下降越快。负倾斜射流火焰的下降速率相对较大；(4)在分析气流发展及特征速度随倾斜角变化的基础上，建立了考虑射流倾斜角影响的Damköhler数（Da）模型来表征倾斜射流火焰的喷灭极限。该模型成功地关联了实验数据。本文的研究结果为非预混倾斜射流火焰井喷极限提供了新的数据和基本的标度规律，揭示了射流动量与浮力相对角的影响。
The blowout behavior of inclined nonpremixed turbulent jet flames is investigated by varying the jet inclined angle in the range of -90° to 90° The critical jet velocity at blow-out limit is quantified experimentally for various nozzle diameters, different fuels and inclined angles. Numerical simulations are performed to emphasize the flow field difference for the positive and negative inclined angles. Physical modeling is conducted to incorporate the effect of the inclined angle on blow-out behavior. Major findings include: (1) The negatively inclined jet flames show more intense yellow luminosity with larger sooting zones than the positively inclined jet flames; (2) The blowout limit decreases appreciably with the jet inclined angle for the negatively inclined flames, while for the positively inclined jet flames, this decrease is relatively small; (3) Physical analysis of the flow development of inclined jets is conducted, indicating the centerline velocity along the jet trajectory decreases faster for the flame with smaller inclined angle. And the decrease rate is relatively larger for the negatively inclined jet flames; (4) Based on the analysis of the flow development as well as the characteristic velocity with the inclined angle variation, a model based on the Damköhler number (Da) accounting for the effect of jet inclined angle is developed to characterize the blowout limits of inclined jet flames. The proposed model successfully correlates the experimental data. The present findings provide new data and a basic scaling law for the blowout limit of nonpremixed inclined turbulent jet flames, revealing the effect of the relative angle between the jet momentum and buoyancy.