脉冲热控下微尺度沸腾不稳定性实验

Experiment on Pulse Thermal Controlled Microscale Boiling Instability

微通道沸腾不稳定性引起传热恶化,造成设备疲劳损坏。设计入口集成种子汽泡发生器的并行三角形硅基微通道热沉,搭建同步可视化测量实验台。研究高热流密度下不同触发频率种子汽泡抑制微通道内流动沸腾不稳定性,验证种子汽泡主动式控制微通道内沸腾不稳定性的思路。实验结果表明,种子汽泡可有效抑制微通道内沸腾不稳定性,降低壁面温度,将微通道内混乱无序的汽泡动力学转换为规则有序的汽泡动力学。低频下,种子汽泡热控能够有效抑制压力和温度波动;高频下,沸腾不稳定性得到完全抑制,加热膜上温度均匀性得到明显改善,换热显著加强。

Boiling instability in the microchannel can cause the heat transfer deterioration, and lead to the fatigue damages of the equipment. The parallel triangle silicon microchannel heat sink integrated with the seed bubble generator in the channel entrance was designed, and the synchronous visual measurement test bench was set up. The flow boiling instability in the microchannel controlled by seed bubbles with different triggering frequencies under the high heat flux condition was studied, and the idea that the seed bubbles actively control the boiling instability in micro- channels was verified. The experimental results show that the seed bubbles can effectively control the boiling instability in the microchannel and reduce the wall temperature, thus the chaotic bubble dynamics in microchannels is transformed to the orderly bubble dynamics. At the low triggering frequency, the fluctuations of the pressure and temperature were restrained effectively by the seed bubble thermal control; at the high triggering frequency, the boiling instability was suppressed completely, and the temperature uniformity of the heating film was improved significantly, the heat transfer was enhanced significantly.