Aircraft fuel jettison system performance analysis is presented in this paper. The system has been added to the actual basic Fuel System to improve the Aircraft performance with one engine inoperative condition as per specific requirement.
The fuel jettison system architecture for each half wing tank consists of:
- Two centrifugal pumps;
- One shut-off valve;
- One or more level sensors;
- A control unit.
The system is symmetric and is installed into the fuel tanks which are integral in the aircraft wings. The fuel tank volume is subdivided through the ribs of the wing main structure. Holes in the ribs assures the fuel flow between the tank sections. The flow rate of jettison system is twenty times the engine fuel supply system flow rate. This means that fuel tank empting during jettison operation occurs much more rapidily than during engine fuel tank supply.
The CFD analysis carried out with a commercial code has been performed to verify that, during fuel dump operation (jettison), the fuel flow between rib holes is regular with homogenous tank emptying. The optimal position of pumps inlet and “safe” residual quantity in the fuel tank have been studied. CAD parametric model of fuel tank has been built. It allows to consider the relevant wing deformation into the CFD model.
Two safety devices assure fuel dump stop: the Aircraft basic fuel quantity indicating system, and the level sensors. The next step in the performance analysis consists of finding the optimal position and the number of the level sensors to be installed in the fuel tanks. This activity will be carried out with modeFRONTIER tool. |
