What is stalling phenomenon in centrifugal compressor?

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.

Can a centrifugal compressor stall?

The operating range of a compression system is limited by the onset of the well-known phenomena, rotating stall and surge [3]. A wide variety of stall and surge behavior in centrifugal compressors is reported in the literature, a consequence of the broad range of geometries in operation.

What causes stall in centrifugal compressor?

As for stall in compressors, a single blade or a small number of blades, may stall due to many reasons – mainly micro disturbance of flow going into the compressor. This is normally local phenomena. A surge is a “rotor” phenomena. Or it is a “global” occurrence, of which all the blades in a rotor stall.

How do stalling and surging take place in centrifugal compressor stages?

An unstable flow originates at the impeller middle-rear region and a high-frequency stall wave occurs firstly in the impeller during mild surge. Then the flow disturbance propagates downstream, and a high-frequency stall occurs in the diffuser prior to a deep surge.

What is stalling phenomenon?

Stall is a common flow phenomenon in the rotating machinery under partial load conditions. When the flow rate decreases to 0.5, the vortexes become strong, but not occupy the whole passage, which is defined as the preliminary stall.

What is choking and stalling in centrifugal compressor?

Choking or stonewall The choking occurs in the compressor which operates at a low discharge pressure and maximum flow rate. It is the limit of the performance curve, at this point velocity of the impeller reaches a velocity of sound of the gas at that condition within the compressor (Mach number reaches Unity).

What happens in a stall?

Stall is an undesirable phenomenon in which aircraft wings experience increased air resistance and decreased lift. It can cause an airplane to crash. Stall occurs when a plane is under too great an angle of attack (the angle of attack is the angle between the plane and the direction of flight).

What is stall point?

A stall is a condition in aerodynamics and aviation such that if the angle of attack increases beyond a certain point, then lift begins to decrease. The angle at which this occurs is called the critical angle of attack.

What is stalling in axial flow compressor?

Explanation: The phenomena in which air stream fails to follow the blade contour is called stalling. Stalling and surging both are unstable operation condition in an axial compressor, a stall occurs normally when airflow separates from the convex sides of the compressor blades.

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 causes a compressor stall?

A compressor stall occurs when there is an imbalance between the air flow supply and the airflow demand; in other words, a pressure ratio that is incompatible with the engine RPM. Compressor stalls cause the air flowing through the compressor to slow down or stagnate and sometimes result in reverse flow.

What is the mechanism of stall and surge in a centrifugal compressor?

In this paper, the mechanism of stall and surge in a centrifugal compressor with a variable vaned diffuser is experimentally investigated, where the diffuser blade setting angle can be adjusted. Many dynamic pressure transducers are mounted on the casing surface of the compressor.

Is the compressor rotor blade a rotating stall?

Although rotating stall may occur in any turbomachinery component, this phenomenon is most frequently studied in compressor rotor-blade passages. In centrifugal pumps, experimental studies([2]- [4]) indicate the existence of rotating stall in the impeller and in the diffuser/volute and in both for some geometries.

What causes choking and stalling in a compressor?

In a stalling, flow rate oscillates at the localized region around the rotor. A rotating stall may develop into a surge. The choking occurs in the compressor which operates at a low discharge pressure and maximum flow rate.

Is there a rotating stall in a centrifugal pump?

In centrifugal pumps, experimental studies([2]- [4]) indicate the existence of rotating stall in the impeller and in the diffuser/volute and in both for some geometries. Computational studies of stall prediction in industrial centrifugal pumps are limited