| 刘坤,颜建国,郭鹏程,李文博,赵莉.微小通道内非定常空化流动可视化研究及热力学效应分析[J].水利学报,2025,56(7):945-957 |
| 微小通道内非定常空化流动可视化研究及热力学效应分析 |
| Visualization study and thermodynamic effect analysis of unsteady cavitation flow in microchannels |
| 投稿时间：2024-06-03 修订日期：2025-03-07 |
| DOI：10.13243/j.cnki.slxb.20240331 |
| 中文关键词: 空化 非定常流动 热力学效应 微小通道 可视化 |
| 英文关键词: cavitation unsteady flow thermodynamic effect microchannels visualization |
| 基金项目:国家自然科学基金项目(51909213); 陕西省自然科学基础研究计划项目(2024JC-YBMS-330); 陕西省技术创新引导计划项目(2024QCY-KXJ-050); 西安市科技局高校院所人才服务企业项目(23GXFW0039) |
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| 中文摘要: |
| 为分析温度、流速和压力等因素对非定常空化演化过程的影响，并定量评价空化流动中的热力学效应，采用高速摄影可视化等方法，开展了25~65℃范围内的空化实验研究。实验获取了非定常空化流动图像数据，分析结果表明，随着温度的升高与空化数减小，空化区域空腔特征尺寸增大，且空化发展持续时间更长。回射流的持续流动促进云空化进一步脱落，且脱落分离过程体现出准周期性，而随着温度升高，腔体表现出更晚的脱落和更剧烈的溃灭射流现象。使用FFT变换计算得到了云状空化振荡主频率和无量纲斯特劳哈尔数St,证明了空腔最大特征长度是云脱落振荡频率的主导因素。空化均值图像信息表明，温度是决定空腔尺寸变化的主要因素。随着温度升高，平均空腔尺寸增加，随后因热力学效应抑制作用而减小，并通过无量纲参数CSP,表征热力学效应的抑制作用，超过特定温度后，热力学效应逐渐显著，进一步抑制了空化发展。随着空化数减小，准稳态的片空化分布逐渐转变为准周期性脱落云空化。 |
| 英文摘要: |
| In order to analyze the influence of temperature,flow rate and pressure on the evolution of unsteady cavitation,and to evaluate the thermodynamic effect of cavitation flow quantitatively,cavitation experiments were carried out in the temperature range of 25-65 ℃ by using high-speed photographic visualization methods.Unsteady cavitation flow image data were obtained.The results indicate that as the temperature increases and the cavitation number decreases,the characteristic scale of the cavitation area increases and the duration of cavitation development becomes longer.The continuous flow of the return jet promotes further detachment of the cloud cavitation,and the detachment and separation process exhibit quasi-periodicity.As the temperature increases,the cavity exhibits a later detachment and more violent jet collapsing jet phenomena.The main frequency of oscillation in the cloud cavitation and the dimensionless Strouhal number（St） are calculated by using FFT transformation,proving that the maximum characteristic length of the cavity is the dominant factor for the cloud shedding oscillation frequency.Cavitation mean image information indicates that temperature is the primary factor determining the variation in cavitation intensity.As temperature rises,the average cavity size initially increases and then decreases due to the inhibitory effect of thermodynamic effects.The dimensionless parameter CSP is used to characterize the inhibitory effect of thermodynamic effects.Beyond a specific temperature,the thermodynamic effects become more pronounced,further inhibiting cavitation development.As the cavitation number decreases,the quasi-steady sheet cavitation distribution gradually transitions to quasi-periodic shedding cloud cavitation. |
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