Unusual Acoustic Vibration of a Shell and Tube Process Heat Exchanger

Acoustic vibration was experienced in a shell and tube process heat exchanger over a large range of operating conditions. Test and analysis results confirmed that the vibration was of an unusual type, characterized by a predominantly longitudinal acoustic wave rather than the usual diametral one. The typical approach of adding acoustic baffles or changing the baffle arrangement leads to relatively small frequency shifts which do not assure elimination of the problem. It is proposed to solve this problem by introducing sufficient acoustic damping to prevent the establishment of the longitudinal acoustic wave.