Experimental investigation of multi-scale turbulent eddy adjustment in personal gasper flow with wedges
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摘要: 客机座舱个性化风口是座舱环控系统中重要的送风单元，其主要作用为快速通风、换热，对乘客的热舒适起到改善作用，但现有个性化送风常引起乘客头部的强烈吹风感。本文通过对现有个性化风口进行边缘加齿的优化设计，调控风口流场中不同尺度的湍涡成分，降低吹风感，从而获得使人体更为舒适的气流流场。实验中使用高时间分辨率热线风速仪，精细测量安装不同尺寸加齿喷嘴的风口流场，采用子波分析的方法对流场多尺度湍涡成分进行分析，对比不同尺寸大小的加齿喷嘴对个性化风口流场多尺度湍涡成分的调控效果，得出齿尖间距离为5mm时，个性化风口的送风使人体更舒适。个性化风口圆环射流经过加齿调控，增强了动量、能量和质量交换，降低了含能尺度的湍流强度，从而降低了吹风感，提高了流场的舒适性。Abstract: In aircraft cabin, the personal gasper plays a significant role in the environment control system. It improves the thermal comfort of passengers and enhances the ventilations and heat exchanges. However, the personal gasper currently in use always brings about uncomfortable draft sensation to the passenger's head. In this paper, the personal gasper is optimized by fixing wedges with different sizes at the nozzle, so that it can adjust and control the multi-scale turbulent eddy structures in the jet flow filed and reduce the uncomfortable draft sensation. The constant-temperature anemometer with the hot-wire probe was employed to finely measure the turbulent jet flow field with high time resolution and evaluate the turbulent level of the personal gasper with wedges. The acquired time series of the instantaneous velocity are decomposed by wavelet analysis to extract the multi-scale turbulent eddy structures, and the effects with and without wedges of different sizes are compared. The 5mm wedges structure is highlighted, which has the most optimal effect and the most comfortable sensation to passengers. By the adjustment and control of wedges, the momentum, energy, mass exchanges of the turbulent jet flow are enhanced, the turbulent level is reduced, the draft sensation deceases and the comfortability is improved.
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Key words:
- aircraft cabin /
- jet flow /
- personal gasper /
- constant-temperature anemometer /
- wavelet analysis
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图 4 有无加齿个性化风口射流中心线平均速度剖面
Figure 4. Comparison of mean velocity profiles in the axial direction of personal gasper jet flow with and without wedges
图 5 有无加齿个性化风口射流径向无量纲平均速度剖面
Figure 5. Comparison of non-dimensional mean velocity profiles in the radial direction of personal gasper jet flow with and without wedges
图 6 有无加齿个性化风口射流中心线湍流强度剖面
Figure 6. Comparison of turbulence level proliles of personal gasper jet flow on the central line with and without wedges
图 7 不加齿结构径向(x=13.13D0，r=40mm)与加齿结构x和y径向(z=13.13D0，y=40mm)能量随尺度分布对比
Figure 7. Comparsion of turbulent fluctuating kinetic energy evolutions across scales at x=13.13D0, r=40mm in personal gasper jet flow with and without wedges
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