上海交通大学学报

上海交通大学学报

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船用燃气轮机网垫级进气滤清器二次夹带影响机理（网络首发）

  

  1. 1. 北京理工大学宇航学院2. 中国船舶工业系统工程研究院
  • 基金资助:
    国家自然科学基金（12372228）资助项目；

Influence mechanism of the droplet reentrainment in wire mesh filter for marine gas turbine

  1. (1. School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China;2. Systems Engineering Research Institute of China State Shipbuilding Cooperation, Beijing 100094, China)

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摘要： 船舶燃气轮机进气过滤部件内的液滴二次夹带严重影响进气品质以及燃气轮机的安全运行，对此研究了网垫级内液滴二次夹带形成及影响机理，对比分析了不同进气流速、不同液滴直径对网丝表面液膜厚度以及二次夹带质量的影响规律。结果表明：受速度梯度以及惯性的影响，进口液滴趋于先在丝网段上游沉积形成液膜；液膜剥离是船舶行驶工况下二次夹带的主要形式，其发生的临界进气流速在4～4.5 m/s区间内；相邻丝网层紧凑型排列对通过气流起到加速作用，加剧了对液膜的剪切，使得液膜剥离质量升高，在网垫级加工中应尽量避免；随着进气流速的增大，液膜厚度整体减小，液膜剥离质量整体增大；液滴直径的增大使得孔隙易于堵塞且局部膜厚增大，最终导致液膜厚度减小，液膜剥离质量升高，严重影响过滤效率，在d=20 μm时过滤器失效。

关键词: 燃气轮机进气系统, 网垫级滤清器, 二次夹带, 液膜分布, 液膜剥离

Abstract: The droplet re-entrainment in Marine intake filtration components seriously affects the gas intake quality and the safe operation of gas turbines. Given the above problem, the formation and influence mechanism of the droplet re-entrainment inside the wire mesh filter were studied, and the effects of different inlet air velocities and different droplet diameters on the liquid film thickness on the surface of the mesh and the mass of re-entrained droplets were compared and analyzed. The results show that droplets at the inlet tend to deposit and form the liquid film first upstream of the mesh segment due to the velocity gradient and inertia; Liquid film stripping is the main form of reentrainment under ship driving conditions, and the critical inlet air velocity is in the range of 4~4.5 m/s. The compact arrangement of adjacent wire mesh layers accelerates the airflow, intensifies the shear effect on the film, and increases the film stripping mass, which should be avoided as far as possible in mesh processing. With the increase of the inlet air velocity, the liquid film thickness decreases on a whole, and the film stripping mass increases; The increase of droplet diameter makes the pores easy to block, and the local film thickness increases, which eventually leads to the overall decrease of film thickness and the increase of film stripping mass, which seriously affects the filtration efficiency. When d=20 μm , the filter is close to failure.

Key words: Gas turbine intake system, Wire mesh filter, Droplet re-entrainment, Liquid film distribution, Film stripping

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