【作者】 王企鲲； 戴韧； 陈康民；

【Author】 Wang Qikun Dai ren Chen kangmin (University of Shanghai for Science and Technology, College of Power Engineering, Shanghai, 200093)

【机构】 上海理工大学动力工程学院；

【摘要】 采用先进的CFD技术,对一多级离心压缩机整级流场进行了数值模拟,着重研究了无叶扩压器、弯道等静止部件内的气动特性及其对整个机组性能的影响。研究结果表明,多级离心压缩机的性能不仅决定于各级动叶本身的气动性能,而且受级间静止部件的气动性能影响较大。各静止部件内气动性能与能量损失各具特点:级间与级后无叶扩压器内的能量损失均很大,并以摩擦损失为主。但级间扩压器中由于其下游弯道对流体的扰动作用,形成了边界层分离,其内的损失是摩擦与分离共同作用的结果;不同位置的弯道对流动不均匀性的影响程度是不同的:连接级间无叶扩压器与回流器的弯道由于其内的流速较低,气流流经弯道后在“自掺混”的作用下,流动显得比较均匀。但连接回流器与次级动叶间的弯道内,随着流速的增加,经弯道后流动表现出强烈的不均匀性,改变了后级动叶的进气条件,从而影响其工作性能。因此,多级离心压缩机静止部件的设计应充分考虑其各自的气动特点及其间的匹配关系;对级间动叶轮的设计,应充分考虑其进口来流的不均匀性。更多还原

【Abstract】 The flow field inside the whole stages of a multistage centrifugal compressor is numerically investigated by commercially available CFD software. The emphasis of this paper is attached on the aerodynamic performance of the stationary components such as vaneless diffusers and crossovers and their influence on the total aerodynamic performance of the whole machine. Results indicate, the aerodynamic performance of the whole machine is not just determined by the rotating impellers but the stationary components may have an intensive influence on the whole machine’s performance. There are different characteristics for the aerodynamic performance and energy loss in different stationary components. Large amount of energy loss occurs in both vaneless diffusers, which is mainly caused by viscous friction. But inside the vaneless diffuser between stages, flow separation occurs resulted from the disturbance of the crossover. So separation loss is another main part of the loss source, resulting in much more energy loss there. The crossovers at different positions maybe have different effects on the flow distortion. The centrifugal force is small inside the crossover between the vaneless diffuser and deswirl cascade because of the low velocity, which results in a uniform flow at the exit of crossover. But the flow is intensively distorted at the exit of the crossover between the deswirl cascade and the next impeller because of the high flow velocity. The distorted flow deteriorates the inlet flow for the next impeller, resulting in the decrease of the impeller’s performance. In summary, the aerodynamic performance and the match among different stationary components should be fully taken into account for the design of multistage centrifugal compressor. The distortion of the upstream flow should be also taken into consideration for the design of impellers between stages.更多还原