In the light of the phenomenon of oil leakage of bearing box in ACF axial mine ventilating fan,this paper analyzes the change condition of inside and outside air pressure of bearing box in the static and dynastic procedures of ventilating fan,points out the reasons of oil leakage of bearing box,and advances the modification scheme of bearing lubrication system.

According to the inlet and outlet velocity triangle of cascade,the paper approaches the reason that the bearing of two-grade fan for contra-rotating axial fan is more vulnerable than one-grade fan.

And a method is obtained in selection of an axial fan with minimum power from various type of axial fans.

By research of axial-flow fan characteristic distribution in high efficiency operating range,a distribution rule is discovered on the definite rotating speed and hub ratio condition,consequently condition of high efficiency operating point is easy to be found when axial-flow fan operating course is changed.

Numerical simulation of the tri-dimensional steady turbulent flow in bi-stage axial-flow fan is performed.

The N-S equation and Realizable κ-ε turbulent models are solved with SIMPLE method based on Fluent software for the axial-flow fan of OB-84 type.

Experimental study at the exit flow field of an axial flow fan with variable setting angle;

By means of fluent software numerical simulations about three-dimensional interior steady flow field of axial flow fan and the separately calculations to four flow states have be done.

This thesis aims at the saving energy problem for the axial flow fan with speed regulation,it begins with all air pressure equation of the axial flow fan,and derives the condition of the minimum energy consumption from the optimum control principle.