具有加速和减速管道的喷气器对水力动力学特征和流场特性进行比较的短暂预测
Yunkai Zhou1,2, Jianping Yuan1,3, Giovanna Cavazzini2
1National Research Center of Pumps, Jiangsu University, Zhenjiang, 212013, China.
Scientific reports
|March 2, 2024
概括
通过先进的模拟来研究短暂的喷气行为. 管道的曲率和攻击角度显著影响水力动力学特性和流场,这对于海洋应用至关重要.
科学领域:
- 海洋工程 海洋工程
- 流体动力学 流体动力学
- 计算式水力动力学
背景情况:
- 喷气推进在海洋应用中至关重要,需要深入了解设计优化的短暂行为.
- 现有的研究往往侧重于稳定状态条件,使不同管道几何形状下的短暂流动动力学得到更少的探索.
研究的目的:
- 通过数值研究具有加速和减速管道的喷气机的短暂水力动力学和推进特性.
- 分析管道曲率 (f) 和攻击角 (α) 对流场,压力分布和推力波动的影响.
- 阐明不同管道配置下的流动不稳定性和尾行动态背后的机制.
主要方法:
- 采用雷诺兹-平均纳维埃-斯托克斯 (RANS) 方程与独立模拟 (DES) 模型相结合进行数值模拟.
- 与实验结果对比数字方法验证以确保准确性.
- 利用快速里埃转换 (FFT) 来分析时间域和频域数据,包括推力和压力脉冲.
主要成果:
- 加速管道显示出出口速度明显高于入口速度,与减速管道不同.
- 管道曲率 (f) 和攻击角度 (α) 的变化对管道模式产生了一致的影响,尽管不同的轮修改引起了相反的短暂流动特性.
- 对旋大小和旋的分析揭示了f和α对旋和定子尾随旋的显著影响,影响流动不稳定性.
结论:
- 管道的曲率和攻击角度是影响喷气短暂性能和流场动态的关键参数.
- 该研究提供了关于流动不稳定机制的见解,并为改进喷气设计提供了基础,以提高效率和稳定性.
- 这些发现对于优化各种海洋应用中的喷气性能至关重要.
相关概念视频
01:14Free Jet
161
Free jets describe the flow of liquid exiting a reservoir through an opening into the atmosphere without resistance. The velocity (v) of the liquid jet is derived using Bernoulli's principle and expressed as:
161
01:24Rapidly Varying Flow
62
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
62
01:11Velocity and Acceleration in Steady and Unsteady Flow
106
In fluid mechanics, velocity and acceleration are key concepts for analyzing particle motion in both steady and unsteady flow. Consider a fluid particle moving along a pathline, where its velocity depends on its position and time. The particle's acceleration is obtained by differentiating the velocity with respect to time.
The acceleration can be generalized to any point in the flow, and expressed as components along three perpendicular directions, representing changes in velocity over...
The acceleration can be generalized to any point in the flow, and expressed as components along three perpendicular directions, representing changes in velocity over...
106
01:07Laminar and Turbulent Flow
8.5K
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the...
8.5K
01:30Bernoulli's Equation for Flow Along a Streamline
969
Bernoulli's equation relates the energy conservation in a fluid moving along a streamline. The equation applies to incompressible and inviscid fluids under steady flow. For such a flow, Newton's second law is applied to a small fluid element, which experiences forces due to pressure differences, gravity, and velocity variations. The force balance leads to the following form of Bernoulli's equation:
969
01:17Accelerating Fluids
1.0K
When a fluid is in constant acceleration, the pressure and buoyant force equations are modified. Suppose a beaker is placed in an elevator accelerating upward with a constant acceleration, a. In the beaker, assume there is a thin cylinder of height h with an infinitesimal cross-sectional area, ΔS.
The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid:
The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid:
1.0K