[Objective

]

In many fields such as aerospace and energy engineering

aerodynamic testing equipment is a fundamental platform for key technology development and product performance testing. The uniformity of the flow field plays a decisive role in the accuracy and reliability of the test results. To construct a 1:1 aerodynamic testing device within a limited space

this study addresses the challenge of flow uniformization in the highly unstable flow field at the centrifugal fan outlet

aiming to achieve accurate airflow measurement in multi-ring spaces

complex structures

and unstable flow fields of boiler combustion systems. [Methods

]

This paper uses CFD numerical simulation to systematically compare the internal flow characteristics

flow field uniformity

and resistance characteristics of three sche

mes: a cavity structure

a flow uniformity structure containing a double-layer honeycomb structure

and a novel composite flow uniformity structure. Simultaneously

a physical test platform is built

and the numerical calculation and experimental measurement results are compared and verified using the velocity standard deviation(S

v

) as the core evaluation index. [Results

]

The results show that the cavity structure

relying solely on pipe expansion for natural rectification

cannot eliminate vortices

backflow

and large velocity gradients at the fan outlet

and the flow field uniformity continuously deteriorates with increasing wind speed. The double-layer honeycomb structure can break up large-scale vortices and straighten the airflow

but its ability to suppress velocity gradients and attenuate turbulent fluctuations is limited

resulting in poor flow uniformity at low wind speeds. The novel composite flow uniformity structure proposed in this paper achieves uniform velocity redistribution through multi-stage resistance control of the double-layer perforated plate. Combined with the flow stabilization and guidance of the honeycomb structure and the dissipation of small-scale vortices

it achieves a high degree of flow field uniformity across a wide wind speed range. When the wind speeds at the standard measurement section are 10

30

and 50 m/s

the standard deviations of velocity S

v

at the measurement sections are 0.281%

0.909%

and 1.401%

respectively. Comparison of experimental and numerical simulation results shows that the deviations of the standard deviation S

v

of the velocity of the novel composite flow uniformity structure are 3.45%

4.21%

and 7.28%

respectively

and the structural resistance is within the allowable head range of the system

indicating its outstanding flow uniformity performance and engineering applicability. [Conclusion

]

This study reveals the working mechanism of the synergistic rectification of the double-layer flow equalization plate and the hone

ycomb device

and verifies the technical superiority of the novel composite flow equalization structure under conditions of limited space

wide wind speed range

and unstable incoming flow. It provides theoretical support and an engineering technical approach for the design and performance optimization of flow equalization structure in aerodynamic test devices.