Physical modelling is an investigative and diagnostic technique frequently used by RJM to re-create, as closely as possible, fuel fow dynamics prior to entry into the furnace. It has particular relevance for certain boiler and burner configurations such as T-fired units where the burners may not be circular, meaning that conventional air distribution analysis techniques cannot be used. In these situations, RJM will deploy physical modelling.
Typically, RJM will produce an accurate to-scale replica in Perspex of the air / fuel delivery system, often starting at the air heater outlet and running all the way through to the burner exit into the combustion chamber or furnace.
With Perspex pipework throughout, operatives can observe visually what is happening and also film the process. A DVD of the recording can be shared with the customer and reviewing the footage at reduced speed can provide further insights into precise fuel / air performance dynamics.
The above picture shows such a scale model produced for a 480MWe T-fired unit burning gas. In this type of model, airflows are verified at each burner for massflow distribution and by adjusting vanes attached to the ducts and the windbox, the system can be brought into balance, typically to within + / - 5% at each burner.
The laboratory will record the modelling process on DVD for training and for project records. The perspex model can also be purchased at the end of the study by the customer as an on-site training tool to improve understanding of dynamic air and fuel flow performance.