As an important type of fluid machinery, explosion-proof centrifugal fans are widely used in various fields of the national economy. They are one of the main energy-consuming machinery and an important research field for energy conservation and emission reduction.
The design method of the impeller of explosion-proof centrifugal fan How to design an explosion-proof centrifugal fan with high efficiency and simple process has always been the main subject of scientific research, and the design of high-efficiency impeller blades is the main way to solve this problem.
The impeller is the core pneumatic component of the explosion-proof centrifugal fan, and its internal activities directly determine the function and efficiency of the whole machine. Therefore, scholars at home and abroad have done a lot of work in order to understand the real activities inside the impeller, improve the design of the impeller, and improve its function and efficiency.
In order to design a centrifugal impeller with high efficiency, researchers have studied the law of gas movement in the impeller from multiple angles and sought a better impeller design method. First use a one-dimensional design method. Through a large number of statistical data and theoretical analysis, the selection rules of aerodynamic and structural parameters of each hub section of the centrifugal breathable membrane machine are obtained. In the initial stage of using the element method, the hub parameters of the centrifugal impeller and volute can be simply determined by calculating the uniform speed of each hub section of the explosion-proof centrifugal fan. The general blade profile is formed by a simple single arc. This method is very rough, and the design of the fan function requires the designer to have a wealth of experience. Sometimes you can get a functional fan. However, in most cases, the designed ventilation equipment is inefficient.
In order to improve, the researchers designed the meridian surface of the impeller cover with the concept of the flow cross section. The centrifugal impeller wheel cover designed by Rusi has two or more arcs. Although the efficiency of the impeller designed by this method is slightly higher than the previous overall design method, the fan wheel cover designed by this method is difficult to process and costly, and it is difficult to use in the production of large fans and non-standard fans.
Another important aspect is to improve the blade design. For two-dimensional blades, the main improvement methods are equal deceleration method, equal expansion method and so on. And the method for the relative velocity in a given impeller to be distributed along a uniform streamline. From the perspective of loss, the method of waiting for deceleration can reduce the loss of activities and improve the efficiency of the impeller. The equal expansion method is a method to avoid the excessive expansion angle of the local area.
By controlling the change law of the relative uniform velocity along the streamline, the distribution of the relative uniform velocity along the uniform streamline in a given impeller (explosion-proof centrifugal fan accessory) can be obtained, and the distribution of the blade profile along the radius can be obtained through a simple geometric relationship. Although the above method is simple, it also requires complex numerical calculations.