The aerodynamic design principle of the industrial double-width airfoil double width fan is based on the flow characteristics of air on the airfoil surface. The unique curvature difference between the upper and lower surfaces of the airfoil causes a velocity difference when the air flows through. According to the Bernoulli principle, the pressure in the area with fast flow velocity is low, thus forming a pressure difference between the upper and lower surfaces of the airfoil, providing lift for the fan and driving the airflow. At the same time, when the fan rotates, the airfoil shape of the blade accelerates the air flow along the axial direction, generates thrust, and realizes the directional delivery of gas.
The blade geometric parameters of the airfoil double width fan are the key elements of aerodynamic design. Parameters such as the chord length, installation angle, twist angle, and number of blades of the blade directly affect the interaction between the airflow and the blade. The chord length determines the area of contact between the blade and the air, affecting the size of the aerodynamic force; the installation angle controls the angle at which the airflow enters the blade, and a reasonable installation angle can reduce the separation of the airflow; the twist angle allows the blade to adapt to the change of airflow velocity at different radii and optimize the aerodynamic performance; the number of blades affects the stability and flow of the airflow, and too many or too few may lead to reduced efficiency or increased noise.
The Reynolds number and the Mach number are important indicators for measuring the aerodynamic performance of the fan. The Reynolds number reflects the ratio of inertial force to viscous force, and its size affects the flow state of the airflow. When the Reynolds number is low, the airflow is laminar, and when it is high, it turns into turbulent flow. The aerodynamic characteristics of the blades are different under different flow states. The Mach number reflects the relationship between the airflow velocity and the speed of sound. When running at high speed, if the Mach number is too high, it may cause shock waves, resulting in energy loss and increased noise. Therefore, the influence of the Reynolds number and the Mach number must be fully considered during the design to ensure that the fan operates under appropriate working conditions.
One of the aerodynamic optimization paths is to use advanced numerical simulation methods. Through computational fluid dynamics (CFD) software, a three-dimensional model of the fan is established to simulate the airflow under different working conditions, analyze parameters such as pressure distribution, velocity field, and turbulence intensity, and intuitively discover undesirable phenomena such as airflow separation and vortex, providing data support for optimized design. CFD simulation can also quickly compare the advantages and disadvantages of different design schemes, greatly shorten the R&D cycle, and reduce test costs.
Based on the simulation results, the geometric shape of the blade is optimized. By adjusting the airfoil curve of the blade to make it more in line with aerodynamic characteristics, the airflow resistance and separation can be reduced; the torsion angle distribution of the blade can be optimized to make the airflow flow evenly on the blade surface and improve the energy conversion efficiency; the tip shape of the blade can be reasonably designed to reduce the tip vortex intensity, reduce energy loss and noise. In addition, the surface roughness of the blade can be optimized to reduce viscous resistance.
In addition to the blade design, the overall structural layout of the airfoil double width fan can also be optimized. Reasonable design of the fan's hub ratio can not only ensure the installation strength of the blade, but also improve the airflow passing capacity; optimize the coordination of the fan with the shroud, diffuser and other components to reduce the local resistance and backflow of the airflow, so that the airflow can pass through the fan system more smoothly. At the same time, considering the operating conditions of the fan, a variable installation angle or adjustable speed control system is designed so that the fan can maintain efficient operation under different working conditions.
Experimental verification is an important part of aerodynamic optimization. Through wind tunnel tests, the performance parameters of the fan such as flow, pressure, efficiency, and noise are measured, and compared with the numerical simulation results to verify the effectiveness of the optimized design. Based on the test results, the design plan was further adjusted and continuously optimized, ultimately achieving a comprehensive improvement in the aerodynamic performance of the industrial double-width airfoil double width fan to meet the needs of industrial applications for high efficiency, energy saving and low noise.
