Experimental investigation on flow characteristics and unsteady heat transfer of noncircular impinging synthetic jets
Experimental investigation on flow characteristics and unsteady heat transfer of noncircular impinging synthetic jets
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非圆形冲击合成射流流动特性及非定常传热实验研究
DOI：
10.1016/j.ijheatmasstransfer.2022.122760
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发表时间：
2022
影响因子：
5.2
通讯作者：
Wang Jin-jun
中科院分区：
文献类型：
--
作者：
Wang Lei;Feng Li-hao;Xu Yi;Xu Yang;Wang Jin-jun
本文研究了非圆形合成射流冲击加热平板的流动特性和非稳态传热。采用热成像荧光测温技术和时间分辨粒子图像测速技术分别获得壁面温度和流场的定量信息。在壁温为80 °C的条件下，在恒定的孔壁距离（H/De= 7.5）下，检查了五种孔结构（圆形、方形、纵横比（AR）为3的椭圆形以及AR为3和5的矩形）。小孔结构对合成射流冲击换热和旋涡特性有重要影响。由于冲击速度更大、穿透壁面剪切层更深，方形孔板表现出更好的滞止冷却性能，相对于圆形孔板，最大滞止冷却系数提高了42%。在椭圆形和矩形孔口撞击到壁面上之前，检测到涡环的轴切换。与圆形孔相比，轴向切换增强了椭圆孔和矩形孔的近壁混合和湍流动能，从而增强了传热。此外，更强的涡流和更深的渗透到壁剪切层中观察到的长轴平面比在短轴平面，导致在长轴方向上的传热增强。特别是，矩形孔与AR为5诱导强烈的二次结构的尾射流后的主涡环，这些是负责的双峰分布的壁面温度在主轴方向。这是首次报道非圆形冲击合成射流的双峰温度分布。AR为5的矩形孔在短轴方向上也产生较大的横流速度，表明壁射流较强。因此，在本研究所考虑的情况下，与AR = 5的矩形孔实现了最佳的冷却性能和最大时均冷却面积达到14倍以上的射流孔面积。
This study investigates the flow characteristics and unsteady heat transfer of noncircular synthetic jets impinging on a heated plate. Thermographic phosphor thermometry and time-resolved particle image velocimetry are used to acquire quantitative wall temperature and flow field information, respectively. At a constant orifice-to-wall distance (H/De= 7.5), five orifice configurations (circular, square, elliptic with aspect ratio (AR) of 3, and rectangular with ARs of 3 and 5) are examined at a wall temperature of 80 °C. The orifice configuration has a significant effect on the heat transfer and vortex behavior of the impinging synthetic jets. The square orifice displays better stagnation cooling performance with 42% increase in the maximum stagnation cooling coefficient relative to the circular case due to the larger impinging velocity and deeper penetration into the wall shear layer. Axis-switching of the vortex rings is detected for both the elliptic and rectangular orifices before they impinge onto the wall. The axis-switching enhances the near-wall mixing and turbulent kinetic energy in the elliptic and rectangular orifices, and thus heat transfer compared with the circular case. Additionally, stronger vortices and deeper penetration into the wall shear layer are observed in the major-axis plane than in the minor-axis plane, leading to enhanced heat transfer in the major-axis direction. In particular, the rectangular orifice with an AR of 5 induces strong secondary structures in the trailing jet following the primary vortex ring, and these are responsible for the double-peak distribution of wall temperature in the major-axis direction. This is the first time a double-peak temperature distribution has been reported for noncircular impinging synthetic jets. The rectangular orifice with an AR of 5 also yields a larger cross-stream velocity in the minor-axis direction, indicating a stronger wall jet. Thus, among the cases considered in this study, the rectangular orifice with AR = 5 achieves the optimal cooling performance and the maximum time-averaged cooling area reaches more than 14 times the jet orifice area.
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影响因子：
3.2
作者：
Alan McGuinn;R. Farrelly;T. Persoons;D. Murray
通讯作者：
Alan McGuinn;R. Farrelly;T. Persoons;D. Murray
影响因子：
2.4
作者：
J. Brübach;A. Dreizler;J. Janicka
通讯作者：
J. Brübach;A. Dreizler;J. Janicka
DOI：
10.1016/j.ijheatmasstransfer.2015.06.065
发表时间：
2015-11
影响因子：
5.2
作者：
Xiao-ming Tan;Jing-zhou Zhang;Shan Yong;G. Xie
通讯作者：
Xiao-ming Tan;Jing-zhou Zhang;Shan Yong;G. Xie
影响因子：
3.7
作者：
Chih-Ming Ho;E. Gutmark
通讯作者：
Chih-Ming Ho;E. Gutmark
雷诺数对撞击固体壁的合成射流涡环影响的实验研究
影响因子：
2.4
作者：
Xu Yang;He GuoSheng;Kulkarni Varun;Wang JinJun
通讯作者：
Wang JinJun