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摘要:
针对甩油盘启动过程中的流动特性,采用三维数值模拟方法研究甩油盘内外两相流场流动特性,并结合高速摄影实验结果、理论结果进行综合分析。结果表明:甩油盘的总出流量随时间发生明显变化,幅度较大。在短时间内,甩油盘各孔流量差异巨大,各孔对应的索泰尔平均直径(SMD)值相差不大,SMD主要取决于转速。各孔流量不同,雾化场分布不均匀,实验结果验证了这一现象。
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关键词:
- 航空发动机甩油盘 /
- 仿真模拟 /
- 高速摄影 /
- 索泰尔平均直径(SMD) /
- 非均匀特性
Abstract:Aimed at the flow property in the start-up process of fuel slinger, three-dimensional numerical simulation was used to study the flow property of the inner and outer two-phase flow field of fuel slinger. Combined with the experimental results of high-speed photography and theory, comprehensive analysis was carried out. The results show that the total out mass-flow rate varies with time largely. Each hole's out mass-flow rate is also different to a great extent within short time period. The Sauter mean diameter (SMD) difference for different holes is relatively small compared with the SMD difference caused by rotation rate. The SMD is mainly determined by rotary speed. The spatial distribution of the spray is uneven as the result of different single holes' out mass-flow rate. The experimental results confirm the simulation outcomes.
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表 1 内部流动数值计算方法
Table 1. Numerical simulation methods for internal flow
计算方法类型 计算方法具体内容 计算域 全盘 网格划分方式 非结构化网格 湍流模型 k-episilon 两相流模型 VOF 进口边界条件 流量进口 出口边界条件 压力出口 甩油盘壁面边界条件 无滑移旋转壁面 表 2 外部雾化区域的数值计算方法
Table 2. Simulation methods for outer atomization field
计算方法类型 计算方法具体内容 计算域 甩油盘外流场 网格划分方式 结构化网格 湍流模型 k-episilon 两相流模型 DPM 进口边界条件 速度进口 射流进口边界条件 压力雾化喷嘴 出口边界条件 速度出口 甩油盘壁面边界条件 无滑移旋转壁面 表 3 不同转速下孔流量统计
Table 3. Statistics of mass flow rates of holes under different rotation rates
转速/% 孔流量状态 孔流量/(kg·s-1) 与孔平均流量差值/% 60 最大值 6.72×10-3 88.24 中位数 3.72×10-3 4.20 平均值 3.57×10-3 0 最小值 4.68×10-4 86.89 70 最大值 7.60×10-3 112.89 中位数 5.44×10-3 52.38 平均值 3.57×10-3 0 最小值 1.20×10-3 66.39 80 最大值 2.35×10-2 263.78 中位数 5.76×10-3 10.84 平均值 6.46×10-3 0 最小值 4.02×10-3 37.77 90 最大值 1.91×10-2 120.05 中位数 7.75×10-3 10.71 平均值 8.68×10-3 0 最小值 1.36×10-4 98.43 100 最大值 2.00×10-2 33.33 中位数 1.70×10-2 13.33 平均值 1.50×10-2 0 最小值 1.00×10-2 33.33 表 4 试验台的技术指标
Table 4. Technique parameters of experiment rig
指标 内容 实验介质 水 介质温度 常温 供水压力 0 ~0.6MPa 介质清洁度 不低于6级(GJB 420B—2015) 流量调节精度 ±0.2% 供水流量 0~1200kg/h(连续可调) 甩油盘转速范围 0~22000kg/min(连续可调) 最大振动限定值 ≤1g 转速调节精度 ±100r/min 加速时间 从10500~22000r/min≤10s 连续工作时间 ≥1h 表 5 高速摄像机性能
Table 5. Functionality of high-speed photography
参数 数值 最大分辨率/(像素×像素) 1280×1024 最大拍摄频率(@分辨率1280×16)/(帧·s-1) 62000 最大拍摄频率(@最大分辨率)/(帧·s-1) 2550 工作温度/℃ -40~50 传感器类型 CMOS 传感器规格/in 1 注:1in=2.54cm。 -
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