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Analysis of the transient atomization characteristics of diesel spray using time-resolved PDPA data 总被引:1,自引:0,他引:1
The transient atomization characteristics of a single-hole diesel spray were investigated to clarify the time-dependent droplet
formation process of the spray through time-resolved analysis of the droplet size data acquired by using a 2-D PDPA (phase
Doppler particle analyzer). Comparisons among the three single-hole diesel nozzles on the atomization characteristics were
made to confirm the effects of the hole-diameter. The hole diameter of the single-hole diesel nozzles varied with dn=0.22, 0.32 and 0.42 mm. The time-resolved diameter, SMD (Sauter mean diameter) and AMD (arithmetic mean diameter) of droplets
in diesel spray injected into still ambient air were measured. The SMD and AMD decreased with decreasing nozzle hole diameter.
The SMD distribution along the spray centerline steeply decreased with increasing axial distance before reaching a constant
value. In the time-dependent analysis of the SMD of the whole flow field, the SMD gradually increased with time after the
initiation of injection, reached a maximum value, and then decreased. 相似文献
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针对高速移动环境下多业务多用户正交频分多址(OFDMA)系统下行链路提出一种动态资源分配方案。针对具有不同时延要求的多种类型数据包的数据流,提出了一种考虑多种时延服务质量(QoS)要求的动态资源分配算法。通过应用排队论原理,将用户的时延要求转化为速率约束,结合多普勒频移产生的中断概率的约束,形成一个高速移动环境下考虑用户不同QoS要求的最优化问题。该优化问题为混合整数非线性规划,直接求解的复杂度非常高。为了解决原问题,提出了次优方法。仿真结果表明,在高速移动环境下,提出的方法在保障用户各种QoS时延要求的同时,有效地提高了系统的容量。 相似文献
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