Study on Calculation Method for Droplet Drag Coeffient Based on Dynamic Simulation and P Control
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摘要: 液滴的曳力系数是影响液滴行为的关键因素,尚未有成熟的通用计算公式。提出一种计算液滴曳力系数的方法:动态模拟液滴在均匀气流中的运动,通过加入动量方程的体积力源项,对液滴质心位置进行控制,使液滴做近似简谐运动,根据运动过程中的位置变化估算曳力系数。采用流体体积函数(VOF)方法模拟液滴-气体两相流,实现了此方法。通过几个算例,验证了此方法,计算结果表明,与高效的比例积分微分(PID)控制方法相比,此方法具有参数选取简便,计算效率更高的优点。Abstract: Droplet drag coefficient is the key factor which affects the droplet behavior. And there is no mature and general drag correlation for droplets. The present work proposed a new approach to calculate the droplet drag coefficient: the single droplet motion in the uniform flow is simulated dynamically. By adding the body force source item to the momentum equation, the position of the droplet centroid is controlled leading to its approximative simple harmonic motion. The droplet drag coefficient is estimated by analyzing its position change. The present approach was realized by using VOF method to simulate the droplet-gas two-phase flow and validated by several example cases. Results showed that compared with the efficient PID control method, the present approach is more convenient to select the control parameter and even more efficient in the calculation.
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Key words:
- Droplet /
- Drag coefficient /
- Dynamic simulation /
- P Control /
- VOF
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