Flow Induced Vibration of Shell & Tube Type Heat Exchanger (1st Report, Understanding of Phenomena)

Abstract

This paper describes the phenomenon of flow-induced vibration in a shell & tube type heat exchanger. This type heat exchanger has often been used in the LPG gas carrier ship and has sometimes caused a fretting and finally comes to a fatigue failure. In flow-induced vibration, there are vortex-induced vibrations, fluid elastic instability and buffeting. Experiments are carried out by use of an actual heat exchanger in order to clarify the cause of tube vibration. The vibration of a lot of tubes is measured for various flow rates and the natural frequency and its damping ratio are also measured. As a result, the cause of the vibration of tubes is not the fluid elastic instability and the vortex-induced vibration but the buffeting due to the turbulence of upstream flow. The main reason is that these tubes are supported by many baffle plates with clearance and then the vibration system becomes the nonlinear.

Study on Behavior of the Heat Exchanger with Conically-Corrugated Tubes and HDD Baffles

“…The experimental results of St and tube natural frequency are verified numerically. Ishihara et al [13] tested the actual heat exchanger to investigate the causes of tube vibration. The results showed that the tube chattering is caused by the turbulence caused by the gap between the heat exchange tube and the baffle.…”

Cause analysis of vibration in shell-and-tube heat exchanger

“…De Paula et al [19] discussed some characteristics of turbulent flow in triangular arranged tubes through hot wire measurement in aerodynamic channels and flow visualization in waterways. Ishihara [20] conducted experiments with actual heat exchangers, measured the vibration of a large number of tubes under different flow rates, and measured natural frequencies and the damping ratio of the tubes. The results show that the cause of tube vibration is the buffeting caused by upstream turbulence.…”