Since the production of oil and gas is declining, the development and implementation of new, cost-efficient technology is an important focus area in order to enhance production and recovery from existing fields. The wet gas compressor represents a key element because it has been identified as one of the most relevant technologies to be developed.
In recent years, research on subsea installations has been carried out. A traditional centrifugal compressor may not be applicable to handle liquid during a standard process. A complete comprehension of the machine behaviour, in particular investigation with the presence of gas-liquid mixture is essential. Because of liquid impact, compressor performances and consequently the margin of stability might be modified. Delayed instability inception should also be pointed out.
The objective of this paper is to provide a consistent basis for the surge and rotating stall analysis of wet gas compressors and describe the mechanism leading to instabilities and their evolution. Visualisation of flow in the compressor stage is accomplished by means of fluorescent injection in correspondence with the impeller labyrinth seal and diffuser section. Simultaneously, a fast Fourier transform examination is realised in order to identify characteristic frequencies of unsteady events.