Evolution of temperature of a droplet of liquid composite fuel interacting with heated airflow
D.O. Glushkov, A.V. Zakharevich, P.A. Strizhak, and S.V. Syrodoy
National Research Tomsk Polytechnic University, Tomsk, Russia
E-mail: pavelspa@tpu.ru
Keywords: composite liquid fuel, coal-water fuel, droplet, airflow, heat transfer, ignition
Pages: 887–898
Abstract
The macroscopic patterns of a temperature change at the center of a droplet of three-component (coal, water, petroleum) composite liquid fuel (CLF) were studied using a low-inertia thermoelectric converter and system of high-speed (up to 105 frames per second) video recording during
the induction period at different heating intensity by the air flow
with variable parameters: temperature of 670-870 K and motion velocity of 1-4 m/s. The studies were carried out for two groups of CLF
compositions: fuel based on brown coal and coal cleaning rejects (filter cake).
To assess the effect of liquid combustible component of CLF on characteristics
of the ignition process, the corresponding composition of
two-component coal-water fuel (CWF) was studied. The stages of inert
heating of CLF and CWF droplets with characteristic size corresponding to
radius of 0.75-1.5 mm, evaporation of moisture and liquid oil (for CLF), thermal
decomposition of the organic part of coal, gas mixture ignition, and
carbon burnout were identified. Regularities of changes in the temperature
of CLF and CWF droplets at each of identified stages were identified for
the co-occurrence of phase transitions and chemical reactions. Comparative
analysis of the times of ignition delay and complete combustion of
the droplets of examined fuel compositions was performed with varying
droplet dimensions, temperatures, and oxidant flow velocity.
DOI: 10.1134/S0869864316060111
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