A design method of volute profile of multi-blade centrifugal fan based on DRBF model

Abstract

The forward-curved multi-blade centrifugal fan is widely used in the ventilation and household appliance industries with limited space due to its small size factor, high pressure coefficient, and large outlet flow coefficient. Conventional centrifugal fan structural designs rely on empirical data, resulting in drawbacks during usage such as low airflow velocity, high noise levels, and high energy consumption. In order to optimize fan structure, enhance aerodynamic performance, and seek new, effective approaches for energy efficiency and emissions reduction, this paper focuses on a combined design method that integrates scroll line design with aerodynamic performance and noise control. The goal is to propose a noise prediction and analysis method for multi-blade centrifugal fans, addressing the design contradiction between optimal fan functionality and minimal noise within limited design dimensions. The dynamic radial basis function method is introduced to investigate the geometric parameters of the scroll line, utilizing coherence analysis to identify the reasons for insufficient aerodynamic performance and noise reduction measures. Through the research, it is found that unreasonable design leads to a large turbulent vortex region within the blade passage and internal flow field, particularly involving circulation and backflow, which significantly reduces the fan's aerodynamic performance and operational efficiency. The design incorporates a composite scroll with a logarithmic spiral and circular arc integrated into one, and algorithm-based optimization of the scroll tongue, facilitating the transition of turbulence at the scroll outlet and the gap between the scroll tongue and impeller. Numerical results show an increase in airflow of 3.04 m3/min and a noise reduction of 3.79%. This indicates that the composite scroll design with a logarithmic spiral plays a dominant role in accelerating the aerodynamic performance of the scroll and reducing noise radiation.