船用滑油冷却器运行性能分析及流致振动研究

为研究船用滑油冷却器流致振动和微振磨损问题,清晰滑油冷却器易发生振动破损的薄弱部位。建立滑油冷却器壳侧及管侧的三维计算模型,采用流固耦合计算方法计算滑油冷却器壳侧滑油和管侧冷却水的耦合压力场、耦合流速场及耦合温度场,获得压力、流速、温度等关键运行参数的分布规律,基于管壳式换热器流致振动的诱发机理,揭示与流致振动密切相关的壳侧流体流动能量分布规律。由于滑油横向冲刷换热管束,促使壳侧流体掺混剧烈,导致壳侧流体压力场和速度场剧烈脉动,温度场不均匀分布,壳侧对流传热系数呈先降低再快速升高变化规律。根据滑油流动能量分布图谱,判定滑油冷却器进、出口区域的换热管束承受流致振动破损较为严重,其中进口区域换热管承受流致振动破损最严重。

Analysis and Study on Operation Performance and Flow Induced Vibration of Marine Lubricating Oil Cooler

In order to study flow induced vibration and fretting wear problems for lubricating oil cooler, the weak parts of it susceptible to vibration damage would be cleared. A three-dimensional model of lubricating oil cooler coupled with shell side and tube side was established. The coupled pressure, velocity, and temperature field were calculated within the lubricating oil cooler based on the fluid-solid coupled method. The key operating parameters distributions, such as pressure, velocity and temperature, were obtained. According to the flow induced vibration mechanism of shell and tube heat exchangers, the shell side fluid flow energy distribution that was closely related to flow induced vibration was revealed. Because the oil cross flow heat exchanger tube bundles, the shell side fluid mixed violently, which lead to intense pulse of pressure field and velocity field and uneven distribution of temperature field. The shell side heat transfer coefficient decreased firstly and then increased rapidly. According to the picture of the flow energy distributions, tube bundles subjected to flow induced vibration damages were more serious near inlet and outlet regions within the lubricating oil cooler. Meanwhile, flow induced vibration damages for tubes were the most serious in the inlet regions of lubricating oil cooler.