Fuel State and Additive Analyzer

Fuels in high altitude and latitude aircraft (e.g., the U-2) must have freezing point temperatures well below -60 ¿C, and must maintain flow to similar temperatures (e.g., viscosity of ~ 6 cSt). JPTS, a high purity kerosene based fuel has the requiredproperties, but costs ~ 3 times more than standard jet fuels, such as JP-8 (military grade) or Jet A (commercial). The need for JPTS also presents a logistic problem, in that it is not readily available worldwide. A simple additive that can lower thefreezing point of the JP-8 (or Jet A) and maintain the flow at low temperatures is highly desirable. However, the cost of the enhancers being developed is also prohibitive, and their use is likely to be limited. Significant savings could be achieved byusing them only when needed at altitude. Two approaches to performing in-flight addition are being considered, enhancer tablets or capsules that will dissolve or break apart as a function of temperature or shear, or a more traditional approach employing asensor to control the addition of the enhancer from a separate compartment. We believe that a sensor based on Fourier transform (FT) -Raman spectroscopy could be designed to provide such a