## 3 Results and Discussion
### Initial Fuel Temperature
Compositions igniting under dispersion conditions at \(T_{0}=-60\)\({}^{\circ}\)C will disperse when droplets ignite with initial temperature of \(T_{0}=60\)\({}^{\circ}\)C. Therefore, it can be reasonably concluded that the patterns of physical and chemical transformations remain unchanged when varying in a wide range of initial temperatures of composite fuels, while only their duration and intensity change, which predictably affects the ignition delay times. It should be noted that \(T_{0}\) and \(t_{d}\) are inversely related in the considered temperature range (\(T_{0}=-60\)-60\({}^{\circ}\)C). The dependences of the ignition delay times of the compositions No. 1-No. 4 on their initial temperatures \(T_{0}\) that varied in the range between minus 60 \({}^{\circ}\)C and plus 60 \({}^{\circ}\)C are presented in Figure 6.  
The combustion process was initiated in a high-temperature air environment at \(T_{g}=900\)\({}^{\circ}\)C. The behavior of the dependences obtained experimentally (Figure 5) confirms that an increase in the initial fuel temperature can effectively intensify ignition of a composite liquid fuel in practice, for example, when it is used as the main fuel for widely used coal-fired boilers. A decrease in \(t_{d}\) for the considered compositions connected with an increase in the initial fuel temperature from minus 60 \({}^{\circ}\)C to plus 60 \({}^{\circ}\)C, under identical heating conditions, was about 55%. It is also worth noting that the component composition of fuel suspensions has a more significant effect on the ignition delay time at relatively low initial fuel temperatures (Figure 6). Increasing the fuel temperature to \(T_{0}=60\)\({}^{\circ}\)C not only reduces the duration of the induction period, but also reduces the effect of the component composition of fuel on the ignition delay time (compared to the conditions at \(T_{0}=-60\)\({}^{\circ}\)C). For example, the difference between \(t_{d}\) for fuel compositions No. 3 and  
Figure 6: Dependences of the ignition delay times of composite liquid fuels on their initial temperatures (\(T_{0}\)) at the heating source temperature of \(T_{g}=900\)\({}^{\circ}\)C.  
No. 4 (\(T_{g}\) = 900 \({}^{\circ}\)C) at \(T_{0}\) = \(-\)60 \({}^{\circ}\)C was about 30%, and the difference at \(T_{0}\) = 60 \({}^{\circ}\)C was about 25%. Figures S1-S4 in the Supplementary material present the dependences of the ignition delay times for fuel compositions No. 1-No. 4 on the heating source temperature in the range of 700-1000 \({}^{\circ}\)C, with initial fuel temperatures varying from minus 60 \({}^{\circ}\)C to plus 60 \({}^{\circ}\)C with 20 \({}^{\circ}\)C increments. An analysis of the results obtained (Figures 6 and S1-S4) allows us to conclude that it is typical that the ignition delay time decreases by 60-75% (depending on the composition) with an increase in the heating source \(T_{0}\) from 700 \({}^{\circ}\)C to 1000 \({}^{\circ}\)C for the considered compositions (No. 1-No. 4) of composite liquid fuel with varying initial temperatures from minus 60 \({}^{\circ}\)C to plus 60 \({}^{\circ}\)C.  
The experimental results illustrate (Figures S1-S4) that the compositions containing turbine oil (No. 2, No. 4) ignite earlier than the compositions with the addition of rapeseed oil with the same volume (No. 1, No. 3) over the entire range of temperature variations of \(T_{0}\) and \(T_{g}\). This is due to the physical properties of the oils. Turbine oil has a lower vaporization heat and lower boiling and autoignition temperatures. These characteristics together affect the ignition delay times of identical fuel compositions with the addition of different combustible liquids. The fuel composition No. 4 (Figure S4) demonstrates the minimum ignition delay times. This composition ignites under droplet dispersion conditions (Figure 5d) with the formation of many finely dispersed components flying apart in the radial direction.