Impeller opposed arrangement (the high-pressure side and low-pressure side of the impeller are arranged back-to-back)
The axial force generated by a single-stage impeller points towards the impeller inlet, that is, from the high-pressure side to the low-pressure side. If multi-stage impellers are arranged in sequence, the total axial force of the rotor is the sum of the axial forces of each stage of impellers. Obviously, such an arrangement will result in a large axial force on the rotor. If multi-stage impellers are arranged in an opposed manner, impellers with opposite inlets will generate an axial force in the opposite direction, which can be balanced with each other. Therefore, the opposed arrangement is the most commonly used axial force balancing method for multi-stage centrifugal compressors.
Setting a balance disk
A balance disk is a commonly used axial force balancing device for multi-stage centrifugal compressors. The balance disk is generally installed on the high-pressure side, and a labyrinth seal is provided between the outer edge and the cylinder. This allows a certain pressure difference to be maintained between the high-pressure side and the low-pressure side connected to the compressor inlet. The axial force generated by this pressure difference is in the opposite direction to the axial force generated by the impeller, thereby balancing the axial force generated by the impeller.
