摘要
为了研究湍流模型对热敏介质空化流数值模拟精度的影响,结合滤波器模型(Filter-based model,FBM)和密度修正模型(Density-corrected model,DCM),基于局部网格尺度和气液两相混合密度,修正了3种湍流模型(k-ε、RNG kε和SST k-ω)的湍流粘度,并分别采用原始湍流模型和修正湍流模型,以不同温度的水为介质,对NACA0015翼型进行了单相和气液两相数值模拟。通过与实验数据比较,验证了数值模拟结果的准确性。研究结果表明,修正的kε模型消除了湍流尺度的影响,通过修正的RNG kε模型计算得到的空泡发展规律与实验结果一致。修正后的RNG kε模型揭示了空化与温度变化的规律,反映出较好的修正效果,可为低温热敏介质空化流数值模拟提供理论参考。
The size of turbulence is of great significance to the accuracy of numerical calculation.In addition,the variation of gas-liquid two-phase mixed density in the cavitation zone has a great influence on the cavitation development process.In order to investigate the effect of turbulence models on numerical simulation of cavitating flows in thermo-fluids,combined filter-based model(FBM)with density-corrected model(DCM),three turbulence models(k-ε,RNG k-εand SST k-ω)were modified based on the local mesh size and the density of vapor-liquid mixture.The original turbulence models and modified models were used in the numerical simulation of single-phase flow and gasliquid two-phase flow around the NACA0015 hydrofoil in varying temperatures water.The numerical results were compared with experimental data.The results showed that the modified k-εmodel eliminated the effect of turbulence scale.In addition,the law of development of cavity was well consistent with the experimental results,according to the results calculated by the modified RNG k-εmodel.The modified RNG k-εrevealed the law of cavitation with temperature variation simultaneously,i.e.as the temperature of the fluid increased,the vapor volume fraction was decreased,the cavitation intensity was weakened,and the cavity area became smaller.The adverse pressure gradient became smaller in the closed region of the cavity tail,and the gasliquid interface became blurred,which reflected better corrected effect.According to validation calculations and composite comparison with the experiment,the modified RNG k-εwas applicable for numerical simulation of gas-liquid two-phase flow in thermo-fluids which can provide theoretical basis and guidance for numerical simulation of low temperature thermal cavitating flow.
作者
张德胜
冯健
万福来
李俊峰
施卫东
ZHANG Desheng;FENG Jian;WAN Fulai;LI Junfeng;SHI Weidong(National Research Center of Pumps,Jiangsu University,Zhenjiang 212013,China;School of Mechanical Engineering,Nantong University,Nantong 226019,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2020年第5期134-141,共8页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51776087)
江苏省“333”人才工程项目(2016Ⅲ-2731)
江苏省“六大人才高峰”项目(HYGC-008)
江苏省青蓝工程中青年学术带头人项目。
关键词
热敏介质
湍流模型
空化
翼型
数值模拟
修正
thermosensitive media
turbulence model
cavitation
hydrofoil
numerical simulation
modify