In: Mechanical Engineering
A centrifugal compressor works by imparting kinetic energy to the fluid flowing through it. This increases the velocity of the gas which is then converted to pressure head as the gas slows down in the diffuser.
This implies that, maximum discharge pressure is obtained at minimum flow and vice versa for any given speed. Therefore, surge is a point at which the compressor operates at maximum pressure and minimum flow. As such , it can be said that the compressor surges due to the decrease in flow rate of the fluid. This can happen due to a number of reasons viz.,
1. Suction Throttling
2. Discharge valve throttling
3. Change in operating speed of the compressor
4. Choking of the inlet filter due to dust particles
5. Change in properties of fluid