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首页> 外文期刊>International Journal of Heat and Mass Transfer >Thermal characterization of a heating cylinder under ultrasonic effects
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Thermal characterization of a heating cylinder under ultrasonic effects

机译：超声波效应下加热缸的热表征

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Ultrasonic effects were investigated on the heat transfer characteristics of a vertical cylinder releasing a constant heat flux of 14,150 W/m~2 in distilled water. A triple-frequency ultrasonic transducer was installed at the center of the lateral wall of the cubic test section to emit 40, 80, and 120 kHz ultrasonic waves. The thermal characterization was investigated by varying the distance (5, 10, and 15 cm) between the ultrasonic transducer and the heating surface. The surface temperature of the heater, detected using 12 thin-leaf thermocouples, decreased rapidly because of the ultrasonic effect, leading to an increase in the Nusselt number. An infrared camera and a video camera were used for the visualization and investigation of acoustic streaming and acoustic cavitation. The results showed that ultrasound enhanced heat transfer to the maximum level of 82.4% using 40 kHz waves at a distance of 5 cm. At distances of 10 and 15 cm, 120 kHz ultrasonic waves produced the highest heat transfer enhancement levels of 74.2% and 59.7%, respectively. The heat transfer enhancement ratio decreased with increasing incident angle of the wave beam as well as with the distance between the ultrasonic transducer and the heating surface. The key mechanisms leading to the enhancement of heat transfer in the near and far fields were identified and discussed. Finally, an accurate prediction formula was proposed for the overall heat transfer enhancement ratio, depending on the ultrasonic frequency and distance.
机译：对垂直圆筒的传热特性研究了超声波效应释放蒸馏水中的恒定热通量为14,150W / m〜2的恒定热通量。三频超声换能器安装在立方试验部分的侧壁的中心，以发射40,80和120kHz超声波。通过改变超声换能器和加热表面之间的距离（5,10和15cm）来研究热表征。使用12薄叶热电偶检测到加热器的表面温度，由于超声波效应，迅速下降，导致营养数增加。红外相机和摄像机用于声学流和声学空气的可视化和调查。结果表明，使用40kHz波在5厘米的距离下，超声增强的热传递到82.4％的最大水平。在10和15厘米的距离处，120 kHz超声波的热传递增强水平分别为74.2％和59.7％。随着波束的入射角以及超声换能器与加热表面之间的距离，传热增强比率降低。鉴定并讨论了导致近距离场中传热增强的关键机制。最后，提出了一种精确的预测公式，用于整体传热增强比，这取决于超声波频率和距离。

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