排序方式: 共有12条查询结果,搜索用时 15 毫秒
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上游斜坡对气膜孔换热特性影响的数值研究 总被引:1,自引:0,他引:1
为了获得气膜孔上游放置斜坡对气膜孔换热特性的影响规律,采用数值模拟方法研究了斜坡的台阶高度分别为0.3D,0.5D和0.75D(D为气膜孔直径)时在不同吹风比下的流动过程和换热特性分布情况,并与常规气膜孔冷却结构形式进行了对比。研究表明:在气膜孔上游设置斜坡,延缓了主流通过反向涡对对冷却气流的掺混作用,反向涡对强度减弱,冷却气流出流后的贴壁效果更好,提高了气膜孔出口下游的冷却效率和换热系数,并且随着斜坡高度的增高,效果更为显著。吹风比M=1.0时,斜坡对气膜孔出口下游换热系数的改善作用更强。 相似文献
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Investigation of flame structure in plasma-assisted turbulent premixed methane-air flame 总被引:1,自引:0,他引:1
The mechanism of plasma-assisted combustion at increasing discharge voltage is investigated in detail at two distinctive system schemes (pretreatment of reactants and direct in situ discharge).OH-planar laser-induced fluorescence (PLIF) technique is used to diagnose the turbulent structure methane-air flame,and the experimental apparatus consists of dump burner,plasma-generating system,gas supply system and OH-PLIF system.Results have shown that the effect of pretreatment of reactants on flame can be categorized into three regimes:regime Ⅰ for voltage lower than 6.6 kV;regime Ⅱ for voltage between 6.6 and 11.1 kV;and regime Ⅲ for voltage between 11.1 and 12.5 kV.In regime Ⅰ,aerodynamic effect and slower oxidation of higher hydrocarbons generated around the inner electrode tip plays a dominate role,while in regime Ⅲ,the temperature rising effect will probably superimpose on the chemical effect and amplify it.For wire-cylinder dielectric barrier discharge reactor with spatially uneven electric field,the amount of radicals and hydrocarbons are decreased monotonically in radial direction which affects the flame shape.With regard to in situ plasma discharge in flames,the discharge pattern changes from streamer type to glow type.Compared with the case of reactants pretreatment,the flame propagates further in the upstream direction.In the discharge region,the OH intensity is highest for in situ plasma assisted combustion,indicating that the plasma energy is coupled into flame reaction zone. 相似文献
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空气放电等离子体中活性粒子数浓度演化规律分析 总被引:3,自引:1,他引:2
为获得空气放电等离子体中活性粒子的演化规律,耦合了组分浓度方程和能量传递方程以及Boltzmann方程,建立了空气放电等离子体动力学模型,对空气中单次和重复放电进行了数值计算,分析了空气放电等离子体中活性粒子数浓度随电子数浓度和约化场强以及放电频率的变化趋势。结果表明,放电等离子体中的活性粒子数浓度随电子数浓度的增加而大幅增加,当电子数浓度为1.0×104cm-3时,放电产生的O原子粒子数浓度最大值约5.0×107cm-3,而当电子数浓度增加到1.0×108和1.0×1012cm-3时,O原子粒子数浓度的最大值则相应地提高到5.0×1011cm-3和5.0×1014cm-3;约化场强的提高,获得的活性粒子数浓度增加;随着驱动电压频率的增加,氧原子O的周期变化达到稳定所要经历的放电次数增加,O原子的粒子数浓度最大值随放电频率的增加而增加。 相似文献
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基于支持向量机的滚动轴承故障诊断研究 总被引:3,自引:2,他引:1
在分析支持向量机多分类算法和滚动轴承故障诊断特征向量的基础上,建立了基于支持向量机的滚动轴承故障诊断模型,并对模型进行了鲁棒性研究.对建立的数学模型进行了试验验证,结果表明,建立的诊断模型对轴承故障诊断具有良好的诊断效果. 相似文献
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Lei ZHANG 《等离子体科学和技术》2023,25(3):35502-147
A gliding arc plasma fuel atomization actuator suitable for aeroengines was designed, and a gliding arc plasma fuel spray experimental platform was built to address the fuel atomization problem in aeroengine combustion chambers. The spray characteristics for different airflows,fuel flows, and discharge voltages were analyzed using laser particle size analysis. The research shows that the fuel atomization effect is improved from the increased airflow. The decreased fuel flow not only reduces the ... 相似文献
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