Optimisation of low energy cooling through phase variation between adjacent piezoelectric fan blades
Optimisation of low energy cooling through phase variation between adjacent piezoelectric fan blades
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DOI：
10.1016/j.ijheatmasstransfer.2019.05.004
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发表时间：
2019-08
影响因子：
5.2
通讯作者：
A. Hales;Xi Jiang
中科院分区：
文献类型：
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作者：
A. Hales;Xi Jiang
压电风扇是一种高效、低耗能的空气推进器。该技术可用于降低一系列电力电子产品中热管理系统的功率需求。了解多个叶片有益耦合的压电风扇阵列对研究领域具有至关重要的意义。在本研究中，建立了一个由两个压电风扇叶片组成的数值模型，并与以往的实验工作进行了验证。该模型用于研究相位变化的影响，φ，两个相邻的压电风扇叶片在面对面的方向，在一个通道内操作。当ϕ≠0°，180°时，观察到一个不对称的流域。考虑到从φ = 0°的相位变化的增量增加，当φ≥60°时，下游速度剖面的偏度大大增加，而平均下游速度的大小仅在φ≥75°时增强。产生的倾斜归因于一个旋涡的优势，在相邻的叶片面之间，在他们的开启期间。在峰值偏度（φ = 75°）时，相位前导叶片后面的涡流比其对应的涡流大101%。两个叶片之间均匀匹配的涡是产生峰值传质的最佳选择。这是在叶片处于反相时观察到的，ϕ= 180°。本研究的结论建立在先前发表的结论的基础上，并与之很好地一致。
Piezoelectric fans are highly efficient and low energy air-movers. The technology may be applied to reduce the power requirements of thermal management systems in a range of power electronics. The understanding of piezoelectric fan arrays, in which multiple blades are beneficially coupled, is of paramount importance for the research field. In the present research, a numerical model consisting of two piezoelectric fan blades is developed and validated against previous experimental work. The model is used to investigate the effect of phase variation, ϕ, between two adjacent piezoelectric fan blades in face-to-face orientation, operating within a channel. When ϕ≠ 0°, 180°, an asymmetrical flow domain is observed. Considering an incremental increase of phase variation from ϕ= 0°, the skewness of the downstream velocity profile is increased heavily when ϕ⩽ 60°, whilst the magnitude of the average downstream velocity is only enhanced when ϕ⩾ 75°. The generated skew is attributed to the dominance of one vortex over another between the adjacent blade faces during their opening period. At peak skewness (ϕ= 75°), the vortex behind the phase leading blade is 101% larger than its counterpart. Evenly matched vortices between the two blades are optimal for generating peak mass transfer. This is observed when the blades are in counter-phase, ϕ= 180°. Conclusions in the present study build upon and are in good agreement with those previously published.