Dimensional Analysis to Parameterise Ice Accretion on Mesh Strainers 2011-01-2795
Water is always present in jet fuel, usually in a mixture of forms. At very low temperatures this phenomenon can lead to the formation of ice crystals within the aircraft fuel system, which can then stay in suspension within the entire volume of fuel. Pumps within the fuel system transfer fuel around the system. Pumps such as boost pumps that are typically used in fuel systems are protected by a weave type filter mesh at the inlet. Ice accretion on the surface of this mesh has operational implications as it can cause non optimal fuel flow.
In this investigation, two fundamental tools are being used: 1) a high fidelity MATLAB model of a mesh strainer, pick-up line and pump, and 2) a test rig of the modelled system. The model is being used to investigate fuel system performance when exposed to fuel containing water/ice contaminants at cold temperatures. The test rig will be used to validate the model and to provide the necessary data to define a set of equations that may theoretically quantify ice accretion on the mesh.
The strategy of experimentation on the test rig is being optimized using dimensional analysis (DA) to reduce the number of key variables. Predicting the amount of ice accretion in the pump inlet mesh, is a complex task as the phenomenon depends on a number of factors. There is an extensive list of variables belonging to each of these factors, any of which may affect ice formation on the mesh. Through the use of dimensional analysis and careful design of experimentation (DOE), it is being possible to derive a set of non-dimensional combinations of variables without any direct or explicit knowledge of the laws of physics describing the phenomenon.
The development and refinement of the afore mentioned tools will allow the users to investigate ice accretion on the strainer, and predict the resulting system performance.