Fluid machines are a familiar part of everyday life in the home, the workplace and in transportation systems. Virtually all fluid machinery generates sound, and some examplessuch as motor cycle and aircraft jet enginesare notorious for their noise output. It is hard to identify any day to day human activity in which individuals are not exposed to fluid machinery noise. For instance in the BRITE EURAM project no. 5983 (EQUIP), fans, where flow is the main cause of noise generation, have been identified as one of the most important noise sources in machines. Another important aerodynamic source process is regenerated noise in flow ducts, which imposes a major limitation for the performance of compact flow systems. In improving the performance there is also a tendency to increase flow velocities in fluid machines, which increases the importance of flow generated noise. Increased flow velocities also change the sound transmission properties of flow ducts in machines.
Overall, the physics of sound generation and transmission in fluid machinery systems is not well understood. The state of the art in the acoustics of fluid machinery falls far short of the requirement for well developed and comprehensive predictive methods, that can be used for a better acoustical design of these devices. Even physical modeling of the passive components in the ductwork of fluid machines is limited mainly to relatively simple systems, and the understanding of source mechanisms and complex flow/acoustic interaction phenomena is only barely adequate in a limited number of cases.
The major innovative aspects of this project are new or improved prediction models with the following important applications:
* source descriptions for IC engines
* design of fans for minimum noise production in non ideal flow conditions
* minimization of sound transmission and regenerated noise in flow duct systems
* design of compact silencers based on periodic scatters or folded resonators
* design of dissipative silencers (effects of hot gas flow and vibrations).
The tools developed in this project will be used by the industry to develop less noisy systems and products in the following industrial sectors: power generation, transportation and domestic appliances. The industrial products directly linked to the project via the
participating industrial partners include: fans, air coolers, IC engines, ventilation systems, domestic appliances (e.g. vacuum cleaners, air cleaners and hair dryers) and exhaust mufflers for gas turbine power plants and automobiles.
Funding SchemeCSC - Cost-sharing contracts
721 83 Västeras
5600 MB Eindhoven
2628 CK Delft
9203 ZN Drachten
HU6 7RX Hull
405 08 Göteborg