Case study: use of inlet manifold design techniques for combustion applications

Forced-draught fired heaters are commonly employed in offshore oil and gas production facilities. Manifolds supplying air to the heater often have to compete for space with other essential equipment resulting in complicated, asymmetric designs. A typical manifold design is analysed, for a range of flow-rates and exit pressure drops, using computational fluid dynamics and an empirical technique. High flow-rates and exit pressure drops produce even flow distributions in the manifold branches, as expected. Lower flow-rates and exit pressure drops produce less even distributions and indicate quantitative disparity between analysis techniques. This case study illustrates the use of calculation techniques to predict upstream airflow behaviour for combustion equipment nominally relying on even flow distributions.