What causes a centrifugal compressor to surge?
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What causes a centrifugal compressor to surge?
Centrifugal compressor surge is a characteristic behavior of the compressor that occurs in situations when inlet flow is reduced and the compressor head developed is so low that it can not overcome the pressure at the compressor discharge.
Why is my compressor surging?
Surge is a condition that occurs in compressors when the amount of gas they are trying to compress is insufficient for the size of the compressor and the blades lose their ability to transfer energy from the shaft to the fluid, causing a reverse flow of the gas.
What is surging in centrifugal air compressor?
Compressor surge is a form of aerodynamic instability in axial compressors or centrifugal compressors. The term describes violent air flow oscillating in the axial direction of a compressor, which indicates the axial component of fluid velocity varies periodically and may even become negative.
How do you control the surge on a centrifugal compressor?
Anti-Surge Control Systems It is normally achieved by opening a control valve in a recycle line (Anti-Surge Control Valve or ASCV), returning the discharge gas to the inlet of the compressor via a suction cooler. The resulting increase in compressor inlet volume flow moves the operating point away from surge.
What is choking in centrifugal compressor?
Choking is the condition which occurs in the compressor in which it operates at a very high mass flow rate and flows through the compressor can’t be further increased as mach number at some part of the compressor reach to unity i.e. to sonic velocity and the flow is said to be choked.
How do centrifugal compressors avoid surges?
6 Ways to to Avoid Centrifugal Compressor Surge
- Larger Anti-surge Valve (ASV) Size with a Quick Opening Valve.
- Suction and Discharge Pipe Re-Routing.
- Re-Positioning Anti-surge Tap off- Point.
- Slowing Compressor Speed during Coast down.
- Discharge Side Gas Flaring.
- Hot Gas Recycle Valve Installation.
What is surging and choking?
Surge is a violent flow reversal that occurs when the process restricts the compressor flow below a certain minimum value. Choke occurs when the process does not create enough restriction to the compressor flow and the compressor operates at its maximum flow for a given performance level.
What is compressor surge margin?
The surge margin (SM) is defined as the distance between the surge line and the operating point on a vertical line for a constant corrected mass flow value. Several definitions are in use to define the SM. From the compressor map it is clear that the distance to the surge line can be defined using multiple definitions.
What is anti surge in compressor?
The basic function of anti-surge control is to maintain a minimum flow during extreme conditions. Using measurements from suction and discharge pressure, discharge pressure and temperature, and either suction or discharge flow, the anti-surge controller determines the flow at which the condition of surge will occur.
What is the difference between compressor stall and compressor surge?
A compressor stall is a local disruption of the airflow in the compressor of a gas turbine or turbocharger. A stall that results in the complete disruption of the airflow through the compressor is referred to as a compressor surge.
What is the difference between surge and stall?
In elementary terms, stall is a disturbance of the flow in the tangential direction, while surge is a disturbance in the axial direction. During stalled operation, the average flow rate through the compressor is steady, but during surge, the flow rate will pulse—sometimes so violently that reversed flow is induced.
What is the difference between a compressor stall and surge?
