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燃烧室出口辐射对气膜冷却传热影响研究 总被引:2,自引:0,他引:2
燃气轮机高温透平中包含对流/导热/辐射等复杂传热现象。本文依托高温流热固耦合实验台,提出燃烧室与透平联合计算的方法,采用数值模拟和实验对比的方式分析了平板气膜冷却的对流/导热/辐射传热特性。同时研究了不同燃气吸收系数以及不同进口辐射条件对于平板气膜冷却的表面温度分布的影响。结果表明:辐射传热是燃气轮机首级高温叶片传热特性的重要影响因素,辐射传热使得实验平板温度抬升50~70 K,燃烧室/透平联合计算方法有效地分析了燃烧室出口辐射强度对高温平板气膜冷却辐射传热的影响;高温燃气辐射特性对于平板温度分布具有明显影响。 相似文献
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采用颗粒离散元方法和持续同调理论,研究了内排土场堆叠至不同高度时的边坡稳定性。为便于研究,现采用一水平金属板向下施加压力,代替不同厚度土层的重力荷载,对边坡在竖向荷载作用下的失稳破坏过程进行了颗粒离散元模拟。研究了二维边坡土颗粒速度总矢量、边坡失稳破坏时滑移开裂面的角度以及边坡坡顶y方向的平均速度等宏观响应过程,并构建了自然堆积下边坡堆积体颗粒的法向力链无向网络模型。最后,用持续同调方法对边坡坡顶颗粒接触力链网络的拓扑特征进行分析,获得条码图,建立了岩体结构持续同调特征与失稳演化的关系。本文为研究边坡失稳拓扑识别提供了一种新方法,从而可以有效预测边坡的失稳破坏。 相似文献
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An experimental investigation on swirl effects on inhomogeneous confined jet mixing in a combustor configuration is reported. The confined swirling flow was simulated by a swirler with a central jet mounted in a cyclindrical tube. Helium and air jets set at different velocities were injected into the confined swirling air flow. The resulting flow fields due to two vane swirlers with constant vane angles of 35° and 66° were compared. Results show that the 35° vane swirler produces a solid-body rotation core with a slope about twice that created by the 66° vane swirler. It is the behavior of this solid-body rotation core that determines jet mixing rather than the swirler vane angle. Consequently, the coaxial jet decays much faster, the mixing is more intense, and the turbulence intensities are higher for the 35° vane swirler. In view of these results, combustor designers should be more concerned with behavior of the solid-body rotation core produced by the swirler, instead of the swirler vane angle. 相似文献
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This study reports on experimental investigations on isothermal and reacting swirled non-premixed flows under varying pressure
conditions. In this configuration, a central high speed fuel jet was surrounded by a heated swirling air flow. For the reacting
case natural gas served as fuel whereas for isothermal conditions fuel was replaced by a mixture of helium and air to achieve
Reynolds-similarity. The optically accessible combustor allowed for application of laser diagnostics. Here we report on Laser
Doppler Anemometry and planar laser-induced fluorescence (PLIF) experiments used to characterize the flow field and visualize
selected scalars, respectively. Acetone served as a fluorescence marker for mixture fraction investigations. The hydroxyl
radical was used to provide general features of the reaction zone such as flame shape and mean stabilization. To expose the
influence of pressure on the flame structure three different operating points were investigated varying the combustor pressure
between 2 and 6 bar while the inflow bulk velocities remained the same. Striking features of the present configuration are
a detached flame, multiple recirculation zones, and complex coherent flow structures. 相似文献
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F. Flemming C. Olbricht B. Wegner A. Sadiki J. Janicka F. Bake U. Michel B. Lehmann I. Röhle 《Flow, Turbulence and Combustion》2005,75(1-4):3-27
In order to evaluate the direct and indirect contributions to the total combustion noise emission, a combustion chamber consisting
of a swirl burner and an exit nozzle of Laval-shape, representing a gas turbine combustor, is investigated by means of experiments
and large eddy simulation. Focused on the isothermal flow case first and encouraged by a good overall agreement between the
LES and the experimental data for the flow field, a first characterisation of the flow with respect to noise sources is performed.
To analyse acoustic properties of the flow, time and length scales are evaluated inside the combustor. Furthermore, the evidence
for the existence of a precessing vortex core (PVC), typical for configurations with swirl, is revealed. Finally, the effect
of the PVC on the flow inside the Laval nozzle is discussed. 相似文献
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This paper constitutes an experimental study of the separation performances of a gas–liquid cylindrical cyclone (GLCC) separator that interests the oil industry. The global hydrodynamics behavior in the GLCC is characterized by flow visualization under various inflow operating conditions. The effect of the inlet nozzle design on the performances of the separator is studied by using three different nozzles, and it proves to be a key parameter. With an insufficient nozzle restriction, low swirl intensity is imparted to the flow. Due to inadequate centrifugal effects, liquid is prematurely carried over by the gas as flooding occurs in the separator upper part. High amounts of gas are also carried under by the liquid stream. On the other hand, with a too severe nozzle convergence, the important drag applied by the gas leads to liquid “short circuiting” the cyclone toward the gas outlet. In addition to the nozzle design, the separator performances are influenced by phenomena such as liquid bridging or the occurrence of the slug flow regime at the cyclone inlet. This paper leads to a better understanding of the links between the hydrodynamics in the GLCC and its operational limits, which is necessary to enable reliable scaling up tools. 相似文献
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