| Fan aerodynamic performance test is an indispensable part in the process of fan development.Therefore,in this paper,the influence of the structure of the fan aerodynamic performance test system on the fan aerodynamic performance test is studied.The fan aerodynamic performance test system to be studied in this paper is based on GB / T 1236-2000 performance test of standard air duct for industrial fans,and C-type(pipe inlet and free outlet)fan aerodynamic performance test device is adopted.Due to the lack of verification of the theoretical basis of this standard in China,this paper confirms and studies the theory in the standard.In order to study the influence of the structure of the fan aerodynamic performance test system on the fan aerodynamic performance test,this paper adopts the method of combining CFD simulation and experimental research,and mainly analyzes the following factors :1.Due to the need of motor drive in the test of this kind of on-board fan,a motor needs to be installed and connected with the impeller through the connecting shaft,so bearing support needs to be installed,but the bearing support will hinder the air flow at the fan outlet,so it is necessary to find a suitable bearing support structure,The results show that when the distance between the main body of bearing support and the front end is too close,the static pressure at the fan outlet will increase,which will cause the measured value of fan efficiency to be lower than the actual value,and have an impact on the fan aerodynamic performance test.2.The influence of the diameter of the test air duct on the aerodynamic performance test of the fan is discussed.The variation of the performance curve of the fan with different diameters of the air duct is calculated,and the pressure variation of the conical tube with different diameters of the air duct is analyzed.The results show that the closer the diameter of the air duct is to the diameter of the impeller inlet,the higher the efficiency of the fan.3.When the impeller is installed on the fan aerodynamic performance test-bed,the influence of the tip clearance and impeller eccentricity on the fan aerodynamic performance test is discussed.The variation of the fan performance curve with different tip clearance and impeller eccentricity is calculated.The results show that the tip clearance has an important influence on the fan performance,too much clearance leads to the decrease of fan efficiency,and the impeller installation eccentricity leads to the decrease of fan performance The higher the heart rate,the lower the efficiency of the fan.4.In the fan aerodynamic performance test system,the pressure measurement needs to arrange measuring holes.This paper explores the influence of the structure and size of the measuring hole on the pressure measurement,and analyzes the influence of different diameter,inclination and protrusion of the measuring hole on the pressure measurement in the test.5.Finally,based on the analysis of the results of the above factors,the actual fan aerodynamic performance test is carried out on the existing test bench,and the fan aerodynamic performance test is carried out on the influence of blade tip clearance and impeller eccentricity,and compared with the simulation results.Due to the model simplification and measurement errors,the results show that the efficiency of the experimental results is low compared with the simulation results,and the trend is consistent.The feasibility of CFD simulation on the optimization and improvement of the fan aerodynamic performance test device is verified. |
