Compressor rotates stall and asthma Zhen Jian upright: The commonnest not stable phenomenon

QiAir Compressor

2 years ago

Rotate stall and asthma brace up it is high speed a kind of oscillatory breakdown with centrifugal peculiar compressor, also be a the commonnest kind of not stable phenomenon. Depart causes this kind of trouble, equipment does not have apparent structural blemish commonly, do not need shutdown overhaul consequently, come through moving section discharge to be able to make vibration is decreased allow a value.

Should rotate break away from further progress to be asthma brace up when, can cause efficiency of WECS to drop not only, and still can cause serious harm to the machine. Asthma brace up can cause the damage such as machine interior weather strip, bearing, serious can bring about rotor to bend even, shaft coupling attaint. Breathe heavily brace up it is the fluid machinery such as centrifugal compressor runs one of the the most abominable, most dangerous operating mode, very big to machine harm. Great to sex of this kind of harm but do not need to stop again machine the trouble that can handle, can show condition to monitor the action that diagnoses the job with breakdown and beneficial result most.

Compressor existence rotates the undee spectrum graph when stall

One, rotate the mechanism of stall

Rotate the pressure wave motion that stall produces inside impeller is incentive the incentive force with rotor unusually oscillatory happening, the opposite element quality of the size of incentive force and gas is concerned, if opposite element quality of gas is greater, incentive power is greater also, bigger also to the moving influence of the machine.

The whirl of fluid machinery breakdown of speed per hour always exists generally speaking, but it is not certain can incentive rotor makes aircrew produces intense vibration, should rotate only when the coupling of some natural frequency of the frequency region aircrew of stall, the machine just produces resonance likely, occurrence danger is oscillatory.

When compressor discharge decreases, because develop horn to increase, foliaceous bar the reverse side will produce depart of attrib border layer, part of flow path general or be jammed entirely. Such stall areas meet what move to foliaceous bar with some speed turn over directional transmission. The experiment makes clear, the turns under foliaceous bar relative to speed absolute velocity of stall area. Accordingly, we can observe the rotational direction of rotor of stall area edge moves with the speed under labour frequency, friend says separate division, the whirligig of bar of this kind of opposite leaf is rotate stall. Rotate the condition of going from place to place that stall makes compressor medium is exasperate, discharge and pressure follow time to fluctuate. Below certain rotate speed, when entrance discharge reduces some to be worth, unit can emerge intense whirl stall. Intense whirl stall can be caused further, whole compressor the not stable pneumatic phenomenon with a kind of dangerous bigger sex of group system, breathe heavily namely brace up. In addition, rotate lamina of the compressor when stall gets a kind stimulate periodicly brace up force, if rotate the be identical of natural frequency photograph of the frequency of stall and lamina, will cause intense vibration, make blade exhaustion attaint causes an accident.

Rotate the identifying of stall feature:

Vibration happening decreases Xiaoshi in discharge, and reduce and increase as discharge;

Of oscillatory frequency and labour frequency be less than the constant value of 1 than be;

The axial vibration of rotor is very sensitive to rotate speed and discharge;

Exhaust pressure has fluctuant appearance;

Discharge directive has fluctuant appearance;

The pressure ratio of aircrew drops somewhat, serious when pressure ratio may light;

The element measures the aircrew with bigger or higher compression ratio more incidental.

2, breathe heavily brace up mechanism

Rotate asthma can be brought about when stall is serious brace up, but both is not one and the same. Asthma brace up besides as in-house as compressor gas condition of going from place to place is concerned besides, the working character of the pipeline network system that still is linked together to it together has close connection.

Compressor always is mixed of teamwork work tubal a network, manage a network to make sure constant flow is passed, must keep constant pressure, with the obstruction that will overcome tubal net. The outlet pressure when aircrew works normally is balanced with photograph of obstruction tubal a network. But when the discharge when compressor reduces some to be worth, outlet pressure can drop very quickly, however the size as a result of tubal net is larger, the pressure in tubal net is not reduced immediately, then, the aeriform pressure in managing a network is more than the outlet pressure of compressor instead, accordingly, the gas in managing a network pours regurgitate compressor, drop to the pressure in managing a network all the time under compressor outlet pressure till. At this moment, compressor begins again to air feed tubal a network, the discharge of compressor increases, regain normal working position. But when the pressure in should managing a network returns original pressure again, the discharge of compressor decreases again, the fluid in the system flows backwards again. Such go round and round produced the low frequency with intense gas pulsatile phenomenon —— breathes heavily brace up.

By asthma brace up closely related the machine vibration frequency that cause, amplitude and size of cubage tubal a network, volume tubal a network is larger, rate of asthma Zhen Pin is lower, amplitude is bigger. The vent-pipe net size of a few machines is very large, right now rate of asthma Zhen Pin is less than 1Hz even.

Breathe heavily brace up the identifying of breakdown feature:

Generation breathes heavily brace up the aeriform motive force that the object of breakdown reduces aircrew or conduit of other belt length, container for gas is mechanical;

Breathe heavily brace up when happening, the entrance discharge of aircrew is less than the least flow below corresponding rotate speed;

Breathe heavily brace up when, oscillatory amplitude can fluctuate substantially;

Breathe heavily brace up when, oscillatory diagnostic frequency is commonly in 1~15Hz;

With the provides net and recipient dimension that connects at the back of compressor size becomes inverse ratio;

Attachment and the ground such as aircrew and the conduit that are linked together to it produce intense vibration;

Outlet pressure is shown substantially fluctuant;

The discharge of compressor is shown substantially fluctuant;

The electric machinery electric current of the compressor group of electric machinery drive shows periodic change;

Asthma brace up when companion has periodic blare, the size of blare and the molecular amount that reduce gas and compression ratio become direct ratio.

3, rotate stall and asthma brace up oscillatory feature

4, rotate stall and asthma brace up oscillatory and sensitive parameter

5, discriminate rotate the main method of stall and oily film oscillation

6, rotate stall and asthma brace up breakdown reason and processing measure

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