Heat transfer and fluid flow characteristics of impinging jet using combined device with triangular tabs and synthetic jets
Heat transfer and fluid flow characteristics of impinging jet using combined device with triangular tabs and synthetic jets
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DOI：
10.1016/j.expthermflusci.2015.05.007
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发表时间：
2015-11
影响因子：
3.2
通讯作者：
T. Iwana;K. Suenaga;K. Shirai;Y. Kameya;M. Motosuke;S. Honami
中科院分区：
文献类型：
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作者：
T. Iwana;K. Suenaga;K. Shirai;Y. Kameya;M. Motosuke;S. Honami
研究了主被动组合装置冲击射流的流动与换热特性。该组合装置由三角形翼片和合成射流阵列组成，该合成射流阵列对射流的剪切层提供周期性扰动。基于喷嘴直径（D）的雷诺数为3.9 × 104，壁面间距（L/D）为2。将四个三角形突片附接到喷嘴出口。合成射流与主射流成30°角。在三角形调整片的作用下，主射流的纵向涡产生，横向涡崩溃。此外，主射流的速度增加，因为收缩的流动。在合成射流作用下，由于剪切层的不稳定性增加，横向涡的发展得到了促进。由于使用了合成射流，射流的周期性扰动得到加强。组合装置的运行导致主射流的速度幅值和周期性扰动的增加，因此，提高了速度波动的峰值RMS值和峰值局部Nusselt数附近的驻点增加了35%，与未使用该装置的情况相比。此外，面积平均努塞尔数是10%以上，没有该设备。热传递由射流的速度、RMS和周期性的速度波动决定。这些结果表明，冲击射流的流体流动和传热特性可以通过优化的主被动组合装置的驱动条件进行控制。
The fluid flow and heat transfer characteristics of an impinging jet with a combined active–passive device were investigated. The combined device consisted of triangular tabs and a synthetic jet array that provided periodic disturbance to the jet’s shear layer. The Reynolds number based on the nozzle diameter (D) was 3.9 × 104, and the nozzle-to-wall spacing (L/D) was 2. Four triangular tabs were attached to the nozzle outlet. The synthetic jets were issued at an angle of 30° against the primary jet. Under the triangular tab operation, the longitudinal vortices were generated and the transverse vortex of the primary jet collapsed. Moreover, the velocity of the primary jet increased because of contracted flow. Under the synthetic jet operation, the development of the transverse vortex was promoted due to the increased instability of the shear layer. The jet’s periodic disturbances strengthened because of the use of synthetic jets. The combined device operation led to increased velocity magnitude and periodic disturbance of the primary jet; thus, the peak RMS value of the velocity fluctuation was enhanced and the peak local Nusselt number near the stagnation point increased by 35% compared with cases where the device was not used. Additionally, the area-averaged Nusselt number was 10% larger than that obtained without the device. The heat transfer was governed by the jet’s velocity, RMS, and periodic velocity fluctuation. These results indicate that the fluid flow and heat transfer characteristics of an impinging jet could be controlled by optimizing the actuation conditions of the combined active–passive device.