METHOD FOR PROTECTION OF COMPRESSOR FROM SURGE Russian patent published in 2011 - IPC F04D27/02 

FIELD: machine building.

SUBSTANCE: method for protection of compressor from surge consists in measurement at its inlet, in raising temperature and pressure, and in measurement of rotation velocity of compressor rotor. There is additionally measured humidity of gas and barometric pressure of atmospheric air. There is determined absolute temperature and gas pressure at inlet and outlet, volume composition of gas at inlet to the compressor, and current compression ratio of the compressor. Functional dependence of compression ratio from flow rate is determined by a known graphic or chart gas-dynamic characteristic of the compressor in such way, that mean-square evaluation of relative error in the range of a specified ratio of compression should not exceed ±1 %. Ratio of compression in a point of specified stability factor is determined by found dependence and non-dimensional assignment for stability factor to surge, and is used as assignment to PID-control of compression ratio actuating an opposite valve. Further, there is determined a current value of gas constant, compressibility factor at inlet, indices of isentropy of gas and poly-tropic coefficient of efficiency. On base of these and also on base of values of these parametres and rotation velocity of the rotor, determined at obtaining gas-dynamic characteristic of the compressor, current compression factor for conditions of suction, at which the gas-dynamic characteristic has been obtained, is re-calculated considering measured rotation velocity of the rotor. Thus found compression ratio is used as regulated variable in the PID-control of compression ratio.

EFFECT: increased reliability of protection of compressor from surge.

5 cl, 2 dwg