Experimental and Comparative RANS/URANS Investigations on the Effect of Radius of Volute Tongue on the Aerodynamics and Aeroacoustics of a Sirocco Fan
Experimental and Comparative RANS/URANS Investigations on the Effect of Radius of Volute Tongue on the Aerodynamics and Aeroacoustics of a Sirocco Fan
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DOI：
10.3390/pr8111442
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发表时间：
2020-11
期刊：
影响因子：
3.5
通讯作者：
X. Rui;Li-ming Lin;Junkui Wang;Xinxue Ye;Haijiang He;Wei Zhang;Zuchao Zhu
中科院分区：
文献类型：
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作者：
X. Rui;Li-ming Lin;Junkui Wang;Xinxue Ye;Haijiang He;Wei Zhang;Zuchao Zhu
蜗壳舌部的几何形状是西洛克通风机设计的关键。蜗舌的尺寸决定了蜗舌与叶轮的相对位置和距离，蜗舌的尺寸决定了蜗舌与叶轮的相对位置和距离，蜗舌与叶轮的相对位置和距离影响局部流动特性，从而影响风机的空气动力学和气动声学性能。在这项工作中，我们进行了实验和数值研究的影响，蜗壳舌半径的空气动力学和气动声学特性的西洛克风扇。从压力和流线的空间分布和时间变化、叶轮内和蜗壳表面（特别是蜗舌区）压力脉动特性、通道流动随叶轮旋转的变化以及风扇气动声学特性等方面对风扇内部流动特性进行了分析和讨论。采用带旋转效应修正的可实现k-ε湍流模型，采用定常雷诺平均纳维尔-斯托克斯（RANS）和非定常雷诺平均纳维尔-斯托克斯（URANS）方法进行了数值模拟，并将结果与实验数据进行比较，以定性和定量的方式评估预测能力和准确性。实验和数值计算结果表明：随着蜗舌半径的增大，静压增大，风机远场噪声增大，整个叶轮和蜗壳内的流动出现明显的波动;叶轮通道内的回流减少，高压区向蜗壳出口方向移动。半径的减小也扩大了蜗舌上的逆压梯度（APG）区域的大小，这有助于形成回流。RANS和URANS模拟的比较表明，这两种方法产生的时间平均流的结果基本一致，虽然URANS数据更接近那些实验的。然而，脉动流是不能被模拟的RANS仍然占主导地位的本配置，因此URANS是必要的准确预测的流动细节。
The geometry of volute tongue is crucial in the design of Sirocco fans. The size of the volute tongue determines its relative position and distance from the impeller which affects the local flow characteristics and thus the aerodynamic and aeroacoustic performances of the fan. In this work, we performed experimental and numerical investigations on the effect of volute tongue radius on the aerodynamic and aeroacoustic characteristics of a Sirocco fan. The internal flow characteristics are analyzed and discussed in terms of the spatial distribution and temporal variation of pressure and streamlines, the pulsating behaviors of pressure both in the impeller and on the volute surface with emphasis in the volute tongue region, the variation of passage flow with the rotation of impeller and the aeroacoustic features of the fan. We conducted numerical simulations using both steady Reynolds-Averaged Navier-Stokes (RANS) and unsteady Reynolds-Averaged Navier-Stokes (URANS) approaches with realizable k-ε turbulence model with rotation effect correction and the results are compared against the experimental data to assess the prediction capability and accuracy in qualitative and quantitative manners. Experimental and numerical results show that as the volute tongue radius increases, the static pressure rises as well as the far-field noise of the fan and pronounced fluctuation of flow is observed within the whole impeller and volute; the reversed flow in the passage of the impeller is reduced and the high-pressure region is found to be moving towards the outlet of the volute. The decreasing radius also enlarges the size of the adverse pressure gradient (APG) region on the volute tongue which contributes to the formation of recirculating flow. The comparative RANS and URANS simulations reveal that both approaches produce generally consistent results regarding the time-averaged flow although the URANS data are much closer to those of the experimental ones. However, the fluctuating flow which is not capable to be modeled by RANS still dominates for the present configuration and thus URANS is necessary for the accurate prediction of the flow details.