基于Fluent亥姆霍兹自振空化喷嘴流场的数值模拟
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摘要
根据Fluent流体计算软件和亥姆霍兹自振空化喷嘴内流场的特点,基于流体力学的基本理论,对不同结构尺寸的亥姆霍兹型自振空化喷嘴进行了模拟研究。通过数值模拟计算,得到了各个亥姆霍兹型自振空化喷嘴流场内速度与压力分布云图及轴线的速度压力分布曲线等。模拟结果表明,在射流进入振荡腔后产生了明显的负压区,当压力低于液体的饱和蒸气压时,空化气泡产生;在自振空化喷嘴的扩张段处存在速度的最大值,并且随着腔长的增加,扩张段处速度最大值减小。在特定的参数下(入口直径d_1=3.4mm,振荡腔直径D_c=15mm,扩张段扩张角α_2=60°),振荡腔长度L_c=3mm,撞击角α_1=180°,出口直径d_2=4mm时,喷嘴内部产生较强的空化作用。
Simulation study for Helmholtz shaped cavitation jet nozzle with various structures was carried out according to the fluid simulation software-Fluent and characteristics of internal flow field of Helmholtz shaped cavitation jet nozzle based on hydrodynamics theory. Cloud diagram of velocity and pressure distribution in flow field and velocity and pressure distribution curve on axis were obtained through numerical simulation. The simulation results show that there is an obvious negative pressure region when the jet enters the oscillation chamber and when the pressure is lower than the saturated vapor pressure of the liquid, the cavitation bubbles produce. There is a maximum velocity at the expansion section of the self-oscillating cavitation jet nozzle, and the maximum velocity decreases with the increase of cavity length.Under certain parameters(inlet diameter d_1=3.4 mm, oscillating cavity diameter D_c=15 mm, expansion angle α_2=60°), oscillating cavity length L_c=3 mm, impact angle α_1=180° and outlet diameter d_2=4 mm, strong cavitation can be produced in the jet nozzle.
Simulation study for Helmholtz shaped cavitation jet nozzle with various structures was carried out according to the fluid simulation software-Fluent and characteristics of internal flow field of Helmholtz shaped cavitation jet nozzle based on hydrodynamics theory. Cloud diagram of velocity and pressure distribution in flow field and velocity and pressure distribution curve on axis were obtained through numerical simulation. The simulation results show that there is an obvious negative pressure region when the jet enters the oscillation chamber and when the pressure is lower than the saturated vapor pressure of the liquid, the cavitation bubbles produce. There is a maximum velocity at the expansion section of the self-oscillating cavitation jet nozzle, and the maximum velocity decreases with the increase of cavity length.Under certain parameters(inlet diameter d_1=3.4 mm, oscillating cavity diameter D_c=15 mm, expansion angle α_2=60°), oscillating cavity length L_c=3 mm, impact angle α_1=180° and outlet diameter d_2=4 mm, strong cavitation can be produced in the jet nozzle.
引文
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