空调开式轴流风扇流固耦合振动分析

发布时间：2018-05-01 07:18

本文选题：空调开式轴流风扇 + 单向流固耦合　；参考：《华中科技大学》2015年硕士论文

【摘要】：开式轴流风机广泛应用于分体式空调室外机中,其无蜗壳的结构形式是造成风扇在工作时其内流场与常规轴流风机内流场之间存在较大差异的主要原因。因此改善开式轴流风扇性能、提高稳定性问题愈来愈受到科技人员的关注。开式轴流风扇在运转时,其叶片同时受到气动力、离心力和弹性力等多种力的耦合作用,而在实际工作中难以通过试验的方法来研究耦合场力对叶片振动的影响。为改善空调开式轴流风扇的振动性能,本文基于单向流固耦合理论,通过数值模拟和试验相结合,对一款开式轴流风扇的气动性能、结构强度以及共振进行研究,旨在为开式轴流风扇的气动性能和结构振动的预测提供指导。本文完成如下工作:(1)对一款空调开式轴流风扇开展了一系列性能试验,研究不同转速、不同流量工况对风扇性能的影响。基于Fluent软件对该开式轴流风扇模型进行流场建模,在参考性能试验条件的基础上对该风扇模型进行气动性能的预测,并将性能预测结果与试验结果进行对比,验证了流场数值模拟方法的可靠性。(2)以ANSYS Workbench为平台,采用单向流固耦合计算方法,将在流场中得到的开式轴流风扇叶片表面的气动力施加到结构模型上,并加载旋转约束,得到了风扇叶片在不同工况下的应力分布和结构变形,并与非流固耦合工况下叶片的应力分布和结构变形进行了对比。结果表明,叶片最大变形量位于叶尖部位,最大应力位于叶根前缘吸力面侧,并且叶片的安全系数远远大于材料的许用安全系数。(3)基于BruelKjaer-Pulse分析平台得到开式轴流风扇叶片自由状态下的模态频率,与基于Modal模块得到的计算模态频率进行对比,验证了该模态计算方法的可靠性;分别对空调开式轴流风扇进行非流固耦合模态和流固耦合模态的计算,并将上述三种模态下叶片的各阶固有频率和模态振型进行对比。结果表明离心力和流场气动力都不同程度的增加了风扇叶片的模态频率。对流固耦合状态下叶片的共振特性分析表明该开式轴流风扇的设计有效地避开了共振。该单向流固耦合研究为空调开式轴流风扇的气弹稳定性预测提供经验和指导。
[Abstract]:The open type axial fan is widely used in the outdoor air conditioners of the split type air conditioner. The main reason for the difference between the inner flow field of the fan and the flow field in the conventional axial flow fan is the main cause of the difference between the inner flow field of the fan and the flow field in the conventional axial flow fan. Therefore, the problem of improving the performance of the open axial fan and improving the stability is getting more and more attention of the scientific and technical personnel. During the operation of an axial fan, the blade is coupled with a variety of forces, such as aerodynamic force, centrifugal force and elastic force, and it is difficult to study the effect of coupling field force on blade vibration in practical work. In order to improve the vibration performance of an open axial flow fan, this paper is based on the unidirectional fluid solid coupling theory and through the numerical value. The aerodynamic performance, structural strength and resonance of an open axial fan are studied by the combination of simulation and experiment. The purpose is to provide guidance for the aerodynamic performance and structural vibration prediction of open axial fan. The following work is completed in this paper: (1) a series of performance tests are carried out on an open axial fan with air conditioning, and the different rotational speeds are studied. The effect of the same flow condition on the performance of the fan. Based on the Fluent software, the model of the open axial flow fan is modeled. On the basis of the reference performance test conditions, the aerodynamic performance of the fan model is predicted, and the performance prediction results are compared with the test results, and the reliability of the numerical simulation method is verified. (2) ANS On the platform of YS Workbench, the aerodynamic force of an open axial fan blade on the flow field is applied to the structure model, and the rotation constraint is loaded. The stress distribution and structural deformation of the fan blade under different working conditions are obtained, and the stress distribution and the junction of the blade under the non fluid solid coupling condition are obtained. The results show that the maximum deformation of the blade is located at the tip of the blade, and the maximum stress is located on the side of the suction surface of the front of the blade, and the safety factor of the blade is far greater than the allowable safety factor of the material. (3) based on the BruelKjaer-Pulse analysis platform, the modal frequency of the free state of the open axial fan blade is obtained, and it is based on the Moda. The calculated modal frequency of the L module is compared, and the reliability of the modal calculation method is verified. The non fluid solid coupling mode and the fluid solid coupling mode of the open axial flow fan are calculated respectively, and the natural frequencies of the blades are compared with the modal modes in the three modes. The results show that the centrifugal force and the flow field are aerodynamic. The modal frequency of the fan blade is increased in varying degrees. The analysis of the resonance characteristics of the blade in the convective solid coupling state shows that the design of the open axial fan effectively avoids the resonance. The unidirectional fluid solid coupling study provides experience and guidance for the aeroelastic stability prediction of the open axial flow fan in the air conditioning.

【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU83

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