离心叶轮几何形变对气动性能的影响  

Influence of Centrifugal Blade Deformation on Impeller Aerodynamic Performance

作　　者：王宏亮[1] 席光[1] 

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2009年第5期46-50,共5页Journal of Xi'an Jiaotong University

基　　金：国家高技术研究发展计划资助项目(2006AA05Z250)

摘　　要：将数值流场分析方法与有限元方法相结合，利用流固耦合技术，由黏性流场分析得到流场的压力分布，并将其作为气动载荷施加于叶片表面进行应力应变分析．再对叶轮施加离心力载荷，分析离心叶轮叶片的变形情况，从结果中提取网格结点变形量，对叶片坐标进行修正得到工作状态下叶片的型线，并再次进行流场分析．为研究叶轮工作状态下叶顶间隙的变化对叶轮性能的影响，在固定转速下分别计算了3种叶顶间隙分布情况下的叶轮性能．研究表明：气动载荷下的叶片形变量仅占总体载荷下形变量的1％到3%左右，工作状态下叶片最大形变位置为叶顶叶尖；变形的叶根与叶顶向轮盖靠近，造成叶顶间隙减小；在叶顶间隙为0．5mm时，叶轮出口间隙减小量最大达到原间隙的50％；由于叶顶间隙以及叶片型线的变化，使得离心叶轮等熵效率在小流量时下降0．9％～1．8％．The fluid field pressure distribution was obtained using the fluid-solid interaction technology with the combination of computational fluid dynamics （CFD） flow analysis and finite ele- ment method （FEM） structure analysis. The aerodynamic loads were exerted on the solid blade surfaces to analyze strain and stress. Then the centrifugal force was added as another load to the blade and the deformation of the centrifugal blade under working condition was achieved. The running blade profile was gained by calculating the deformation magnitude of the solid grid nodes,and the fluid field in the deformed blade passage was analyzed. To evaluate the influence of deformation on the impeller performance with tip clearance variation, the calculations of three kinds of tip clearance distributions were conducted. The results show that the deformation under the aerodynamic load is only about 1%-3% of that under the total load and the largest deformation occurs at the blade inducer tip. The tip clearance decreases from the inlet to the outlet of the blade because the deformed blade root and tip are close to the casing. When the tip clearance of the undeformed blade is O. 5mm, the tip clearance at the deformed blade outlet can decrease by up to 50%. In addition, the isoentropic efficiency of the centrifugal impeller at low flow rate decreases by 0. 9%-1.8%because of the variations of the tip clearance and the blade profile.

关 键 词：离心叶轮 叶片形变 流固耦合 气动性能 叶顶间隙 

分 类 号：TB302.3[一般工业技术—材料科学与工程] O346[理学—固体力学]