Aluminised Gelled Fuels for Ramjets. Introductory Experimental Studies.

摘要

In theory, consideral higher performance can be obtained with aluminium as filler in ramjet fuels. For example, in a test calculation, the density specific impulse was increased 25% when 30% of aluminium was added to a jet fuel. Regular aluminium, however, gives serious problems for e.g. combustion and suspension stability. In this work a type of coated nano-sized aluminium powder, L-Alex, has been studied with respect to chemical stability and hazardous properties. The stability of gelled suspensions of L-Alex in jet fuels was tested by rheology methods. A simple test-firing rig has been set up for small samples of liquid fuels. Results from flame tests, drop weight tests, DSC (differential scanning calorimetry) and microcalorimetry indicate that the L-Alex powder can be handled safely, both with respect to impact and moderate heating. The results show that it has a good stability in dry air but reacts quickly, though not vigorously in humid air at a moderately elevated temperature. Rheology studies of gelled suspensions of L-Alex (15% and 30% L-Alex) in the jet fuels FF 75 and JP-10 indicate good separation stability. Preliminary combustion experiments of gelled suspensions of L-Alex has been carried out. The test firing rig needs, however, more development before any useful results can be achieved.