Department of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Taian, Shandong, China.
College of Geomatics,Shandong University of Science and Technology, Qingdao, Shandong, China.
PLoS One. 2018 Jul 19;13(7):e0200510. doi: 10.1371/journal.pone.0200510. eCollection 2018.
This paper describes the investigations performed to better understand unsteady effect that develop in a contra-rotating axial fan. More specifically, this study focuses on rotor-rotor interactions effects on unsteady characteristic and blade aerodynamic force. The investigation method is based on three-dimensional URANS simulations, in conjunction with SST turbulence model. At first, the experimental measurements are compared to evaluate ability of the numerical method in estimation of unsteady flows. The results show that rotor-rotor interaction in the contra-rotating fan played an important role in aerodynamic efficiency. Unsteady effect increased flow losses of rotor 1, but effectively inhibited flow losses of rotor 2. The inhibition effect was mainly caused by wake recovery effect of upstream wakes in the flow passage of rotor 2. Meanwhile, negative jet flow enhanced boundary layer energy of the blade of rotor 2, so that flow separation was postponed. Different configurations consider five sets of axial spacing dimensions. Specific survey of flows under the same operation conditions indicates that axial spacing is responsible for the unsteady interaction effect. The blade aerodynamics analysis shows that the influence of the downstream potential flow disturbance on rotor 1 is greater than the effect of the upstream wake on rotor 2.
本文描述了为更好地理解对转轴向风扇中出现的非定常效应而进行的研究。更具体地说，本研究侧重于转子-转子相互作用对非定常特性和叶片空气动力的影响。研究方法基于三维 URANS 模拟，并结合 SST 湍流模型。首先，将实验测量值与数值方法的评估能力进行比较，以评估非定常流的评估能力。结果表明，对转风扇中的转子-转子相互作用对空气动力效率起着重要作用。非定常效应对转子 1 的流动损失有增加作用，但有效地抑制了转子 2 的流动损失。抑制效应主要是由于上游尾流在转子 2 的流道中的尾流恢复效应引起的。同时，负射流增强了转子 2 叶片的边界层能量，从而推迟了流动分离。不同的配置考虑了五组轴向间距尺寸。在相同操作条件下对流动的具体调查表明，轴向间距是导致非定常相互作用的原因。叶片空气动力学分析表明，下游势流干扰对转子 1 的影响大于上游尾流对转子 2 的影响。
