Induced draft fan stall intelligent early warning method based on actual critical stall curve of fan

Abstract

The invention relates to an induced draft fan stall intelligent early warning method based on an actual critical stall curve of a fan. The method comprises the steps of 1, calculating specific pressure energy of an induced draft fan; step 2, cleaning historical operation condition sample data and removing faults, and determining a working condition point set of normal operation of the induced draft fan; and 3, fitting the boundary points above the working condition points of the induced draft fan in normal operation obtained in the step 2 through a polynomial fitting method. The method has theadvantages that compared with a single-parameter alarm method of a conventional DCS system, due to the fact that the distance between the actual operation working condition point and the critical stall curve serves as a judgment method, early warning can be conducted in advance according to distance changes; meanwhile, when the operation working condition point reaches or exceeds a critical stallcurve, an alarm can be given in time; the actual critical stall curve of the fan is obtained through fitting of long-term historical operation data and is closer to the actual operation condition than a stall curve given by a fan manufacturer, and accurate early warning of fan stall can be achieved.

Description

technical field [0001] The invention relates to the technical field of production safety in coal-fired power plants, and in particular includes an intelligent pre-warning method for induced draft fan stall based on the actual critical stall curve of the fan. Background technique [0002] Fan stall means that when the fan is in normal working condition, the angle of attack is very small (the angle between the airflow direction and the chord of the blade is the angle of attack), and the airflow bypasses the airfoil blades to maintain a streamline state. When the airflow and the blade inlet form The positive attack angle, that is, α>0, and when the positive attack angle exceeds a certain critical value, the flow condition on the back of the blade begins to deteriorate, the boundary layer is destroyed, and a vortex zone appears at the tail of the back of the blade. The more the angle of attack is greater than the critical value, the more serious the stall phenomenon is, and t...

AI Technical Summary

Problems solved by technology

However, when this method alarms, the fan is generally in a stall state, and in many cases it is difficult for operators to have enough time to operate in advance to avoid stalling

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