CIESC Journal ›› 2020, Vol. 71 ›› Issue (S1): 194-203.DOI: 10.11949/0438-1157.20191145

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Numerical analysis on aerodynamically generated sound dipole source characteristics of shunt T-elbow

Yalin LIU1,2(),Ke WANG1,Lei ZHAO1()   

  1. 1. School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi, China
    2. State Key Laboratory of Green Building in Western China, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi, China
  • Received:2019-10-09 Revised:2019-12-26 Online:2020-04-25 Published:2020-04-25
  • Contact: Lei ZHAO

分流三通气动噪声偶极子声源特性的数值分析

刘雅琳1,2(),王珂1,赵蕾1()   

  1. 1. 西安建筑科技大学建筑设备科学与工程学院,陕西 西安 710055
    2. 西安建筑科技大学西部绿色建筑国家重点实验室,陕西 西安 710055
  • 通讯作者: 赵蕾
  • 作者简介:刘雅琳(1983—),女,博士,讲师,liuyalin@xauat.edu.cn
  • 基金资助:
    国家自然科学基金项目(51505362);中国博士后科学基金项目(2018M643810XB)

Abstract:

To explore the generation mechanism of airflow regenerative noise caused by the presence of local components such as T-elbow in duct systems and suppress it from the source, the distribution of aerodynamically generated sound on the inner surface of the local component pipe segment represented by the T-elbow pipe were obtained by using finite element method (FEM) and computational fluid dynamics (CFD) method jointly. The strengths and distributions of the aerodynamic sources on inner surface of T-elbows with different inclination angle of branch pipe and different airflow rate ratio of the branch pipe were investigated. Results show that the dipole source caused by the turbulent motion dominates the noise within the pipeline when the airflow through the T-elbow,and the main noise sources are located along the branch pipe. An inclination angle of 30° at the branch inlet can weaken the sound source intensity to the greatest extent and reduce the sound energy transmitted by the sound wave. A change in the flow rate ratio of the branch pipe can not cause the main positions of the aerodynamic sound source to change, but may bring about the change in intensity of sound source accordingly. The changes in the inclination angle and in flow rate ratio may lead to the change of unsteady vortex motion of the flow in the pipeline, thereby affecting the surface dipole source intensity and noise propagation.

Key words: air conditioning system, T-elbow aerodynamic noise, computational fluid dynamics, turbulence, dipole source characteristics

摘要:

为研究空调通风系统中因存在三通等局部构件而引起的气流再生噪声产生机理,从声源处对其进行控制,采用声学有限元与计算流体动力学相结合的方法,对分流三通局部管段内气动噪声进行分析,获得了管道内表面气动噪声源的强度及其分布规律。探讨了支管前过渡倾角和支管流量分配比对声源强度与噪声传播特性的影响。研究结果表明:当气流流经分流三通管道时,由湍流运动引起的偶极子声源占主导地位,且主要噪声源位于支管处;在支管入口前增加倾角,可削弱声源强度,减少声波向声场传递的声能量,存在某个最优倾角角度使最大声源强度最低;若仅改变支管流量分配比例,声源强度改变,气动噪声主要声源位置不发生变化。倾角与流量分配比变化会导致管道内流体的非定常涡旋运动改变,从而影响到表面偶极子声源强度与噪声传播。

关键词: 空调系统, 三通气动噪声, 计算流体力学, 湍动, 偶极子声源特性

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