What is surge curve?

What is surge curve?

if a curve is drawn through the point of zero slope for each characteristic curve, the region to the left of this line is where the instabilities of surge and stall occur. in the litera- ture, this line is called either the stall line or the surge curve. in this text it will be always called the surge curve.

What is a surge line on a compressor curve?

Surge line is the line which connects the surge points (S) on each characteristic curve corresponding to different constant speeds. The stable range of operation for the compressor is on the right hand side of the surge line.

What is the surge line?

Surge is defined as the operating point at which centrifugal compressor peak head capability and minimum flow limits are reached. A collection of surge points during varying compressor speed or varying inlet gas angle is fitted as surge line.

What is surging cycle?

Surging occurs when flow through the compressor falls to a critical value so that a momentary reversal of flow occurs. This reversal of flow tends to lower the discharge pressure and normal flow resumes. The surge cycle is then repeated.

What causes pump surging?

Surges are caused by sudden changes in flow velocity that result from common causes such as rapid valve closure, pump starts and stops, and improper filling practices.

What is Chiller surging?

Chiller surge is a condition in which refrigerant flows in reverse from the condenser back to the compressor, which can lead to severe damage. Surge is identifiable by its loud, distinctive sound, sometimes likened to an elephant’s squeal or a surging jet engine, as well as a fluctuation in compressor amperage.

What is the difference between stalling and surging in rotary compressors?

Compressor surge During stalled operation, the average air flow through the compressor is steady, but during surge, the flow rate will rapidly (milliseconds, msec) pulse—sometimes so violently that reverse flow is induced, often accompanied by a loud “bang.”

Why does my water pressure pulsate?

Usually, well water pulsates when there isn’t enough air pressure in the tank. The two parts that regulate this pressure are the electric pressure switch and the internal air bladder inside the water tank. If either of them is malfunctioning, this can cause the water from your taps to pulsate rather than flow steadily.

What is VGD in chiller?

The VGD mechanism may be used to minimize compressor backspin and associated transient loads during compressor shut down by preventing a reverse flow of refrigerant gas through the diffuser gap during compressor shutdown, which is prevented because the diffuser gap is substantially blocked by the full extension of the …

Why does point B Fall in the surge line?

The point “B” fall in the surge line. Due to this surge phenomena will occur in the compressor. Due to the presence of dirty particles in the inlet filter will decrease the flow rate and reduce the suction pressure. Due to the reduced flow rate, the operating point will move toward the surge line.

What causes a surge line in an engine?

Surge lines are effected by phenomena such as engine structural loads creating asymmetric tip clearances, inlet distortion, or heat soakage within the HP compressor which lowers the surge line after a decel.

Which is the surge point on the characteristic curve?

Surge point. Surge points are the peak points on the characteristic curves (as in Figure 5.) left of which the pressure generated by the compressor is less than the pipe pressure and these points initiates the surge cycle.

When does a compressor have a surge line?

When a compressor is operated on the left of the surge line in Fig. 15.28, the compressor will experience a global unstable condition, called surge, throughout the entire compressor. Compressor surge is associated with a sudden drop in delivery pressure and with violent aerodynamic pulsation, which is transmitted throughout the whole machine.