As part of the second development of the Cargo Apron, ejet carried out a complete hydraulic analysis of the Aviation Fuel hydrant system serving the Cargo Aprons (and by necessity including all other apron areas) in order to prove the design for a hydrant system extension project and to assess the capacity of the entire system for future expansions. As part of this, a full surge analysis was carried out in-house using computerised modelling, and calculated results were compared against fuelling performance in the field.
This was a complicated project, and depended upon our expertise and knowledge in how aircraft are fuelled, and the impact that many aircraft fuelling at once has on the hydrant system. Whilst the hydrant system must unfailingly deliver fuel to all aircraft that need it when they need it, it is not a simple case of aggregating the theoretical demands of those aircraft. If this is done, there is the major risk that the hydrant system will be over-sized, too many pumps will be specified at the fuel farm, and a large amount of money will be wasted.
Using flight schedules, we calculated the fuel uplift of each aircraft which might fuel simultaneously, (using data on aircraft cruise fuel consumption, statutory fuel for diversions etc.) and built a model for fuel demand for the 24 hours of each of a series of typical days in the design year. From this we calculated flow rates in the hydrant system, and were then able to model flow, pressure loss, and then carried out a surge analysis. Surge is a critical aspect of hydrant fuelling and needs to be modelled accurately using credible scenario analysis – if it is not taken properly into account there are considerable risks of pipe damage and leaks, and on the other hand, over-sizing of pipelines and excessive cost.
We are happy to report that our modelling checked out well against actual aircraft fuelling (and we spent a lot of time observing fuelling underneath the wings of aircraft being fuelled). Whilst we have considerable experience in hydraulic analysis, gained over many years, this gave confidence that the hydraulic analysis was correct in this case, and cemented a valuable service in our portfolio.
