<p>Conventional
rocket propellants such as monomethyl hydrazine (MMH) and hydrazine have been
used for decades due to their high specific impulse and performance. However,
interest in greener alternatives, including HAN or HAN-based propellants, has
grown due to high levels of toxicity and difficulties in the handling and
storage of conventional fuels. Included among potential propellants are
monopropellants nitromethane (NM) and isopropyl nitrate (IPN) and their blends.
Though large-scale investigations on the ignition and combustion of these fuels
have been done, the ignition and combustion processes of these monopropellant
fuels are still not well understood. Droplet studies have been traditionally
and extensively employed to decipher the influence of ambient conditions and
fuel properties on ignition and combustion of different fuels. These
fundamental studies allow for the isolation of different factors such as
ambient temperature and initial droplet size among others, to provide a deeper
understanding of their effects in overall spray combustion.</p>
<p> </p>
<p>The
research described here seeks to add to the knowledge on the ignition and
combustion processes of NM and IPN through single droplet ignition and
combustion studies. To this end, the first effort has been to establish a
suitable method of studying the ignition and combustion of droplets in
conditions similar to those in practical systems. Droplet ignition delay
measurements for NM and IPN droplets have also been conducted, and the
influence of ambient temperature and droplet size has been studied. The double
flame structures of NM and IPN, representative of hybrid combustion, have also
been observed. In addition, the applicability of the hybrid combustion model,
developed to predict mass burning rates for hypergolic fuels exhibiting hybrid
burning including MMH, UDMH and hydrazine,
has been assessed. Lastly, the ability of the quasi-steady droplet ignition
model to predict ignition delays of IPN and NM monopropellant droplets is also
discussed.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/8039993 |
| Date | 11 June 2019 |
| Creators | Angela W. Mbugua (5930036) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Characterization_of_Ignition_and_Combustion_of_Nitromethane_and_Isopropyl_Nitrate_Monopropellant_Droplets/8039993 |
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