VRD16旋片真空泵气动噪声和结构振动噪声的数值计算及降噪分析

发布时间：2018-04-21 06:28

本文选题：旋片泵 + 多体动力学　；参考：《东北大学》2014年硕士论文

【摘要】：由于旋片泵的工作原理及结构特性,振动和噪声是不可避免的。国外厂家很早就注意对其进行减振降噪,其产品的噪声一般比国产泵低10dB(A)左右,国内用户近年来对减小振动和噪声的要求强烈,所以很有必要对其振动噪声进行研究和控制。本论文对VRD16旋片泵由于转子慢偏心引起的振动及腔体辐射噪声、排气噪声、挡油罩和限位板的辐射噪声进行了数值化仿真分析研究和优化设计。运用多体动力学和油膜动力润滑方法,对RD16旋片泵转子系统进行耦合数值化计算,其中油膜压力数学模型采用Capone短轴承理论得到的解析解,并将得到的轴心运动参数与只进行多体动力学分析得到的数据进行对比,可知将油膜动力润滑引入到多体动力学分析中更符合实际情况。对比两种转子系统,可知两轴垂直放置油膜压力较大,将计算得到的油膜压力进行傅里叶变换,并将其施加到腔体上,以MPC节点耦合的方法模拟螺栓连接,运用有限元方法,在频域内求得了腔体的振动响应。用最小二乘法对油膜压力进行拟合,滤掉其高频振动,经傅里叶变换后,其200Hz-400Hz处与实验不符,所以本论文对腔体的振动响应的计算考虑了油膜压力的高频部分。将400Hz以内腔体的振动响应与实验进行对比,其理论计算结果与实验数据基本符合,可间接证明整个频带内的计算符合实际情况。由于油膜压力频带较宽,激起了腔体的前14阶共振模态,所以腔体的振动较大。以计算得到的腔体的振动响应为边界条件,运用边界元方法,计算得到了腔体的辐射噪声。通过改变油膜间隙的大小,对油膜压力进行调整改进,减小其幅值并稳定其波动量,从而减小腔体的振动。根据VRD16旋片泵的结构,计算了压缩腔面积、入口压力、排气速度等参数,并以此作为流场分析的边界条件。运用大涡模拟方法对VRD16旋片泵排气腔流场进行计算,得到排气腔内流场的压力、速度等参数。将排气腔内的壁面压力进行傅立叶变换,生成偶极子噪声源,运用声学有限元方法和LMS Virtual.Lab软件中AML技术计算排气腔远场噪声。经对比,在2500Hz以下高真空腔内的气动噪声明显高于低真空腔内的气动噪声,而在2500Hz以上,两腔内气动噪声值相差不是很大。通过对挡油罩内的流场进行分析,得出其由于壁面波动而引起较多漩涡,所以将挡油罩内流道进行了优化改进,改进后部分监测点的压力波动明显降低,经计算得到,高真空区域场点声功率级平均降低7.70dB,低真空区域场点声功率级平均降低6.92dB,高真空区域监测点Field_Point声压级平均降低8.72dB,低真空区域监测点Field_Point声压级平均降低7.83dB。通过增加排气口的方法,对高真空腔流道进行改进,经计算高真空腔内气动噪声有明显的降低,场点声功率级平均降低31.62dB,监测点Field Point声压级平均降低31.33dB。运用流固耦合技术,对挡油罩和限位板的振动响应和辐射噪声进行了计算,得到了挡油罩和限位板的振动响应,其振动位移和速度在某一恒定值附近振荡,所以挡油罩和限位板的振动呈收敛状态,即最终挡油罩和限位板在气流的作用下发生静变形,所以由气体压力引起的固体振动和辐射噪声并不大。
[Abstract]:Vibration and noise are unavoidable due to the working principle and structural characteristics of the rotary pump. The noise and noise reduction of the foreign manufacturers are very early. The noise of the products is generally lower than 10dB (A) of the domestic pump. The domestic users have a strong demand for reducing the vibration and noise in recent years. So it is necessary to study the vibration and noise of the products. Control.
In this paper, the vibration and radiation noise of the cavity caused by the slow eccentricity of the rotor, the exhaust noise, the radiation noise of the oil shield and the limit plate are numerically simulated and optimized in this paper, which is caused by the slow eccentricity of the rotor VRD16.
Using the multi-body dynamics and the oil film dynamic lubrication method, the rotor system of the RD16 rotary blade pump is coupled numerically, in which the mathematical model of the oil film pressure is solved by the analytical solution of the Capone short bearing theory, and the obtained axis motion parameters are compared with the data obtained only by the multi-body dynamic analysis. Sliding into multi body dynamic analysis is more in line with the actual situation. Comparing the two rotor systems, it is known that the pressure of the oil film on the two axes is larger and the oil film pressure is calculated by Fourier transform, and it is applied to the cavity, and the bolt connection is simulated by the coupling of MPC nodes. The finite element method is used to obtain the cavity in the frequency domain. The vibration response of the body is used to fit the oil film pressure by the least square method and filter out its high frequency vibration. After Fu Liye transformation, the 200Hz-400Hz is not consistent with the experiment. So the vibration response of the cavity is calculated in this paper. The high-frequency part of the oil film pressure is taken into account. The theoretical calculation of the vibration response of the inner cavity of the 400Hz is compared with the experiment. The results are basically consistent with the experimental data, which can indirectly prove that the calculation in the whole frequency band is in accordance with the actual situation. Because the pressure band of the oil film pressure is wide, the first 14 modes of the cavity are aroused, so the vibration of the cavity is larger. The vibration response of the cavity is calculated as the boundary condition, and the cavity radiation is calculated by the boundary element method. Noise. By changing the size of the oil film gap, the oil film pressure is adjusted to improve, reduce its amplitude and stabilize its wave momentum, thereby reducing the vibration of the cavity.
According to the structure of the VRD16 rotating disk pump, the parameters of the area of the compressed cavity, the inlet pressure and the exhaust velocity are calculated and used as the boundary condition of the flow field analysis. The flow field of the exhaust cavity of the VRD16 rotary pump pump is calculated by the large eddy simulation method, and the pressure and velocity parameters of the flow field in the exhaust cavity are obtained. The wall pressure in the exhaust cavity is carried out by Fu Liye. Transform, generate the dipole noise source, use the acoustic finite element method and the AML technology in the LMS Virtual.Lab software to calculate the far field noise of the exhaust cavity. By contrast, the aerodynamic noise in the high true cavity below 2500Hz is obviously higher than that in the low true cavity, and the difference of the aerodynamic noise value in the two cavity is not very much above 2500Hz. The flow field in the hood is analyzed, and it is concluded that it causes more whirlpools due to the wall fluctuation. Therefore, the inner flow path of the oil shield is improved, and the pressure fluctuation of some monitoring points is obviously reduced. The sound power level of the high vacuum area field is reduced by 7.70dB, and the sound power level of the low vacuum area field is reduced by 6.92dB, as a result. The Field_Point sound pressure level of the high vacuum area monitoring point is reduced by 8.72dB, and the Field_Point acoustic pressure level of the low vacuum area monitoring point is reduced by the average 7.83dB.. Through the method of increasing the vent, the high true cavity flow channel is improved. The aerodynamic noise in the high true cavity is obviously reduced, the sound power level of the field point decreases 31.62dB, and the monitoring point Field The average reduction of Point sound pressure level by 31.33dB.
The vibration response and radiation noise of the oil shield and the limit plate are calculated by the fluid solid coupling technique. The vibration response of the oil shield and the limit plate is obtained. The vibration displacement and velocity oscillate near a constant value, so the vibration of the oil shield and the limit plate is convergent, that is, the final oil shield and the limit plate are under the action of the air flow. Static deformation occurs, so the solid vibration and radiation noise caused by gas pressure are not large.

【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535;TB752

【参考文献】