Controlling Acoustic Coupling

Acoustic coupling in industrial furnaces is an issue that appears to have become more prevalent as designs increase the volumetric heat density of furnaces, and burner technology is required to meet more-stringent emission requirements. The problems associated with acoustic coupling appear in the form of either large oscillations in the heater pressure or tonal and high-level emitted noise. Although the burner is often blamed for these occurrences, the coupling depends on both heater acoustic characteristics and burner dynamic characteristics. The acoustic coupling is a form of burner-heater interaction. This article shows that acoustic coupling in industrial heaters can be mitigated by enhancing the natural damping of the heater. An experimental study on how one can enhance heater damping is presented. The approach depends on restricting the flow of fluegases while they exit a smaller side stack using an inducing device to enhance natural damping and hence mitigate acoustic coupling in heaters. The use of this technique is proven to be independent of burner type, in other words, burner combustion dynamics. So, details of the burner combustion dynamics do not have to be known for configuring and designing the device. The approach sheds…