Centrifugal fan in the design should pay attention to the following:
(1) leaf exit angle selection: leaf exit angle is the design of the first to be selected one of the main geometric parameters. In order to facilitate the application, the leaves are usually classified as: strong after bending the blade, after bending the circular blade, after bending straight blade, after bending machine wing blade; radial exit leaves, radial straight blade.
(2) reasonable choice of blade type: common fan at a certain speed, the impeller to the smaller pressure coefficient, the impeller diameter is larger, and its high efficiency; the opposite is the opposite of the impeller.
(3) the choice of volute size: volute size should be as small as possible. For the high than the number of wind turbines, can be used to shorten the scroll, the lower than the number of wind turbines generally use the standard scroll. Sometimes in order to narrow the volute size, optional volute export speed is greater than the fan inlet speed program, this time using the export diffuser to improve its static pressure value.
(4) the choice of the number of leaves: In the centrifugal fan, increasing the number of leaves of the impeller can increase the theoretical pressure of the impeller, because it can reduce the impact of relative vortex. However, the increase in the number of blades will increase the friction loss of the impeller channel, which will reduce the actual pressure of the fan and increase the energy consumption. Thus, for each impeller, there is an optimal number of blades. Determine the number of leaves, sometimes based on the experience of the designer.
(5) the choice of full pressure coefficient: the design of centrifugal fan, the actual pressure is always given in advance. At this time need to select the full pressure coefficient.
(6) the determination of the main geometric dimensions of the impeller inlet and outlet: the impeller is the only component of the fan's energy delivered to the gas, so its design has a great influence on the fan; can the correct structure of the impeller be determined correctly and the performance parameters of the centrifugal fan Key role. It contains the key technology of centrifugal fan design - the design of the blade. The key part of the design of the blade is how to determine the blade exit angle.