Vibroacoustic Optimization Study for the Volute Casing of a Centrifugal Fan

Abstract

A numerical optimization is presented to reduce the vibrational noise of a centrifugal fan volute. Minimal vibrational radiated sound power was considered as the aim of the optimization. Three separate parts of volute panel thickness (ST: the side panel thickness; BT: the back panel thickness; FT: the front panel thickness) were taken as the design variables. Then, a vibrational noise optimization control method for the volute casing was proposed that considered the influence of vibroacoustic coupling. The optimization method was mainly divided into three main parts. The first was based on the simulation of unsteady flow to the fan to obtain the vibrational noise source. The second used the design of experiments (DoE) method and a weighted-average surrogate model (radial basis function, or RBF) with three design variables related to the geometries of the three-part volute panel thickness, which was used to provide the basic mathematical model for the optimization of the next part. The third part, implementing the low vibrational noise optimization for the fan volute, applied single-objective (taking volute radiated acoustical power as the objective function) and multi-objective (taking the volute radiated acoustical power and volute total mass as the objective function) methods. In addition, the fan aerodynamic performance, volute casing surface fluctuations, and vibration response were validated by experiments, showing good agreement. The optimization results showed that the vibrational noise optimization method proposed in this study can effectively reduce the vibration noise of the fan, obtaining a maximum value of noise reduction of 7.3 dB. The optimization in this study provides an important technical reference for the design of low vibroacoustic volute centrifugal compressors and fans whose fluids should be strictly kept in the system without any leakage.

Tonal noise of voluteless centrifugal fan generated by turbulence stemming from upstream inlet gap

“…It has been found in Ref. 7 that the interaction between the blades and the volute generates tonal noise at the blade passing frequency (denoted by BPF 0 ).…”

Flow and Noise Characteristics of Centrifugal Fan in Low Pressure Environment

“…At the same time, two noise monitoring points (as shown in Figure 10) are set along the fan radial direction and axis central direction respectively for real-time monitoring of the sound pressure change of the fan. The location of Point 1 and Point 2 are shown in Figure 10, and all dimensions are in millimetres [21,22]. The noise spectrogram of the prototype fan is shown in Figure 11 when the rotational speed of the fan is 5500 r/min and the flow rate is 8.5 m 3 /s at atmospheric pressure.…”

Optimal Design of a Plenum Fan with Three-Dimensional Blades

“…The effects of the inclined blade are demonstrated by the variations in static pressure, efficiency, and pressure and velocity distributions at various inclination angles. Additionally, there have been numerical analyses and experimental studies on the method of reducing noise by changing the structure of the volute or the material of the volute tongue of the centrifugal blower [10][11][12][13][14]. However, there has been little research on improving the efficiency of scroll-less plenum blowers.…”