Analyzing Static and Dynamic Characteristics of Supercritical CO2 Turbine Shaft Cooling Device
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摘要: 以超临界二氧化碳(SCO2)透平机主轴冷却装置为研究对象,基于流体域圆柱曲面展开法建立了流体域压力分布的数学模型,推导出压力分布及承载力的函数表达式;采用CFD分析方法,针对进气压力、主轴转速、偏心率等不同条件下的流场压力、承载力、刚度进行了分析研究。研究结果表明:主轴低速对气膜压力影响极小,轴向压力以冷却装置轴向中心截面呈对称分布;相同偏心率下,承载力随进气压力的提高而增大;进气压力恒定条件下,气膜承载力随偏心率的增大逐渐增大;冷却装置刚度与偏心率呈非线性关系,随偏心率的增大,冷却装置刚度增大,到达极值点后开始减小,极值点出现在偏心率0.35位置。
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关键词:
- 超临界二氧化碳(SCO2) /
- 冷却装置 /
- 压力场 /
- 承载力 /
- 刚度
Abstract: The supercritical carbon dioxide (SCO2) turbine main shaft cooling device was studied. The mathematical model of pressure distribution in the fluid domain was established with the cylindrical surface expansion method. The functional expressions of pressure distribution and bearing capacity were deduced. The computational fluid dynamics (CFD) method was used to analyse the flow field pressure, bearing capacity and stiffness under different conditions such as inlet pressure, rotation speed and eccentricity. The results show that the low speed of the main shaft has little influence on the film pressure and that the axial pressure is symmetrically distributed along the axial central section of the cooling device. Under the same eccentricity, the bearing capacity increases with the increase of intake pressure; under the condition of constant inlet pressure, the bearing capacity of the film increases with the increase of eccentricity. The stiffness and eccentricity of the cooling device are non-linear. The stiffness of the cooling device increases with the increase of eccentricity and begins to decrease after reaching the limit point, and the extreme point appears at the eccentricity of 0.35.-
Key words:
- supercritical carbon dioxide (SCO2) /
- cooling device /
- pressure field /
- bearing capacity /
- stiffness
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表 1 冷却装置结构参数
参数及单位 数值 长度 L/mm 30 主轴直径 2R/mm 30 进气节流孔直径 d/mm 2 平均气膜间隙 h0/mm 0.5 节流孔与端面距离 l/mm 15 节流孔排数 1 表 2 数值仿真计算工况
参数及单位 参数 进气口压力P/MPa 7.0,7.5,8.0,8.5,9.0 出气口压力p0/MPa 0.1 进气温度/K 310 主轴偏心率 0,0.1,0.2,0.3,0.4,0.5 主轴转速/103(r·min−1) 0,2,4,6,8,10 表 3 不同网格数量承载力对比
压力P/MPa 偏心率 承载力W/N 20万网格 40万网格 66万网格 92万网格 7.5 0.1 204.5 186.05 142.89 145.63 0.3 599.1 531.74 363.99 362.05 0.5 818.2 670.10 639.24 645.75 8.5 0.1 202.2 198.67 152.56 150.64 0.3 641.3 575.9 405.93 404.89 0.5 924.5 778.42 749.14 744.34 -
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