Ⅱ级生物安全柜气流模拟和降噪研究

发布时间：2019-04-10 14:58

【摘要】：随着卫生、生物、医疗事业的快速发展,越来越多的生物安全柜在微生物学、动物实验、生物制品、基因重组等领域投入使用,它是实验室生物安全一级防护屏障中主要的安全防护设备。近年来人们对工作环境要求的提高,安全柜的噪声问题正逐渐成为企业和消费者关注的焦点。本文针对安全柜的噪声问题,对生物安全柜的流场和噪声进行数值模拟和研究,提出可行性降噪措施。在研究气动声学流场和噪声关系的基础上,建立了比较完善的生物安全柜气流流场模拟的三维模型以及噪声预测模型。安全柜模型的建立过程中做了适当处理:离心风机的动静区域采用多重参考系(MRF)模型,把高效过滤膜处理为固定孔隙率的多孔介质结构。然后把模型导入FLUENT软件中进行数值模拟计算得到气流流动的流场图,再通过FLUENT中的噪音模}DAcoustic:FW-H,经过傅里叶快速变换(FFT)求得流动声场的频谱图。根据数值模拟结果得出,生物安全柜噪声是离散噪声和宽带噪声叠加的结果,且偶极子声源是安全柜的主要流动噪声源。叶轮旋转流动区域和蜗舌附近流道流动复杂紊乱,对安全柜噪声的作用较大属于噪音源。导流板前后壁附近区域的流场不均匀不稳定且有涡旋产生,导致噪声场与流场发生耦合,对安全柜整体噪声的作用较大,导流板是安全柜的重要构件也是一个重要的噪音源。因此,通过改变叶轮、蜗舌、导流板的结构形式以及调节导流板离风机出口适当距离达到降低噪声的目的。安全柜的噪声较高部分主要分布在离心风机区域以及高效过滤膜以上流速较大的气流部分,通过调节风机适当的转速来减少气流速度以及流场的不均匀性进而降低安全柜整体噪音。对生物安全柜进行气流流场与噪声声场的实验测试,实验数据与模拟结果基本吻合,进而验证了安全柜模型的有效性。本文通过对生物安全柜气流流场及噪声的数值模拟和实验研究,对安全柜等相关设备优化分析和降噪提供了理论参考。
[Abstract]:With the rapid development of health, biology and medicine, more and more biosafety cabinets have been put into use in the fields of microbiology, animal experiments, biological products, gene recombination and so on. It is the main safety protection equipment in the primary protection barrier of laboratory biosafety. In recent years, with the improvement of the requirement of work environment, the noise problem of safety cabinet has gradually become the focus of enterprises and consumers. In this paper, the numerical simulation and research on the flow field and noise of biosafety cabinet are carried out to solve the noise problem of the safe cabinet, and the feasible measures to reduce the noise are put forward. Based on the study of the relationship between aeroacoustic flow field and noise, a perfect three-dimensional model and noise prediction model for the simulation of air flow field in biosafety cabinets are established. In the process of establishing the safety cabinet model, proper treatment has been made: the dynamic and dynamic region of centrifugal fan adopts multiple reference system (MRF) model, and the high efficiency filter membrane is treated as porous medium structure with fixed porosity. Then the model is imported into the FLUENT software and the flow field diagram is obtained by numerical simulation. Then the frequency spectrum of the flow sound field is obtained by Fourier transform (FFT) through the noise mode} DAcoustic:FW-H, in FLUENT. According to the numerical simulation results, it is found that the biosafety cabinet noise is the superposition of discrete noise and wide band noise, and the dipole source is the main flow noise source of the safe cabinet. The rotating flow area of impeller and the flow around the worm tongue are complicated, and the noise effect on the safe cabinet belongs to the noise source. The flow field near the front and back wall of the diversion plate is not uniform, unstable and vortex, which leads to the coupling of the noise field and the flow field, which has a great effect on the overall noise of the safety cabinet. The diversion plate is also an important component of the safety cabinet and an important noise source. Therefore, the noise reduction can be achieved by changing the structure of the impeller, worm tongue and guide plate and adjusting the distance between the draft plate and the outlet of the fan. The high noise part of the safety cabinet is mainly distributed in the area of centrifugal fan and the air flow part above the high efficiency filtration membrane. By adjusting the appropriate speed of the fan to reduce the airflow velocity and the non-uniformity of the flow field, the overall noise of the safety cabinet can be reduced. The experimental results of air flow field and noise field in biosafety cabinet are in good agreement with the simulation results, and the validity of the safety cabinet model is verified. Through numerical simulation and experimental study of air flow field and noise in biosafety cabinets, this paper provides a theoretical reference for optimization analysis and noise reduction of safety cabinets and other related equipment.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH79

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