Analysis and mitigation of pressure fluctuations in compressors

Compressors are used worldwide in various applications: from compressing air that is used to power pneumatic tools, to compressing a refrigerant in a cooling installation. Inside a compressor, gas is aspirated at a low pressure, compressed and then discharged at a higher pressure. During the suction and discharge process, the unsteady mass flow creates pressure fluctuations in intake and exhaust systems. These pressure fluctuations can be severe and lead to strong vibrations in connected pipes and auxiliary equipment. They can also lead to significant torque fluctuations, subsequent vibrations and noise emission of the compressor itself through various transmission paths, e.g. through bearings and the housing. In addition pressure fluctuations often have a negative impact on the energy efficiency of the compressor, either directly because of bad timing between the discontinuous discharge process and the pressure fluctuations or indirectly because of energy losses generated in pulsation dampers needed to reduce the pressure fluctuations up- and/or downstream of the compressor. It is therefore necessary to take pressure fluctuations into account in the design of compressors in order to obtain a highly efficient, durable and low-noise product. Current design approaches often neglect the high level amplitudes of the pressure fluctuations and possible non-linear acoustic behavior, as well as the presence of lubricants and their possible impact on for example the speed of sound and the density of the acoustic medium. This research proposal focuses on gaining a deeper insight and thorough understanding of the behavior of these pressure fluctuations in compressors and the development of novel mitigation approaches to reduce their impact on the energy efficiency and noise emissions.