Technical Challenges and Scientific Approach for a Sustainable Energy Efficient Future - Novel Combustion Concepts for Sustainable Energy Development - page 11

with a smaller system. The high carbon-to-hydrogen ratio of these fuels makes
higher soot emission in issue. In particular, the increased soot can increase the
possibility of the source (platform) of the weapon being detected more easily.
Research studies have shown that sequential timed fuel injection with respect to the
incipient vortex can reduce the soot by orders of magnitude (Fig. 3 ). Also reactant
stream velocity studies indicate that the soot production can be controlled by the
relative velocity of fuel and oxidant streams (Fig. 4 ).
When the density of the fuels is increased, the gravimetric energy density usually
decreases. But with this family of strained hydrocarbon fuels, energy density
increases providing a double advantage (fuel density + energy density), thereby
making it very advantageous for volume-limited propulsion systems.
However, there are several technical challenges. Fuels have been synthesized in
small quantities only, and the number of steps involved in the synthesis should be
reduced. Pilot plant to full-size production facility requires substantial investment.
Development and facility buildup andmaintenance could cost more than conventional
plants. However, the advantages could justify the added cost for military applications.
Fig. 3 Effect of sequential
fuel injection
Fig. 4 Soot control by
changing onsoot formation
reactant stream velocity