1. Single-stage impeller axial fan
In a single stage axial flow fan, only its impeller is characterized by low pressure and low efficiency. Since there is no rear flow guide, the kinetic energy of the rotating velocity at one and the outlet of the fan is not utilized. And lost in vain. The single stage fan has small total pressure coefficient but simple structure and convenient manufacture. It is mainly used in low pressure axial fan with low pressure and low power consumption. The range of specific rotation number is usually 205-490. The stage-blade hub is smaller than the general one.
2. Impeller and rear flow guide
The fan of a single stage axial flow fan is equipped with a rear flow guide at the back of the impeller, the main purpose of which is to be able to use the impeller outlet to rotate things partly or even entirely, so as to increase the pressure of the fan. And fan efficiency also has the corresponding improvement. Its characteristics are that the single-stage total pressure coefficient is larger, generally 0.15-0.72, and the efficiency is high, so this type of stage is widely used in axial fan. This type of axial fan usually has a specific speed of 90-305. The fan can be adjusted by changing the installation angle of impeller blade under the condition of stopping or running.
3. front guiedvane and Impeller stage
The fan has a blade mounting angle adjustable and a fixed front flow guide at the front of the impeller. In order to produce a negative speed of rotation before the inlet of the impeller and zero at the outlet of the impeller. The velocity field and pressure field at the inlet of the impeller are aggravated by the leading flow, and the average relative velocity of the impeller is increased, which results in the increase of the fan loss and the decrease of the efficiency. In addition, this type of axial fan noise is also increased.http://www.jnblower.com/