# Construction of a Chemical Kinetic Mechanism of Five-Component Surrogate Fuel for RP-3 Kerosene
## 5 Conclusions  
Based on the physicochemical properties of RP-3 fuel, this study constructed a surrogate fuel composed of five components: n-dodecane, n-tetradecane, isododecane, decalin, and 1,3,5-trimethylbenzene. The accuracy of the mechanism in predicting the combustion process of the RP-3 series of fuels was verified by comparing the ignition delay time, laminar flame speed, and partial component product data with the experimental results:  
1. The reaction pathways of 1,3,5-trimethylbenzene were analyzed using the generation rate analysis method, and three main low-temperature reaction pathways of 1,3,5  
Figure 24: Verification of partial concentration variations in 1,3,5-trimethylbenzene. Figure 23: Verification of laminar flame speeds for 1,3,5-trimethylbenzene [32, 57, 58]. trimethylbenzene were determined. A simplified mechanism consisting of 22 species and 69 elementary reactions was obtained. 2. Based on six selection criteria, including MW, H/C, CN, LHV, TSI and density, five-component surrogate fuels consisting of n-dodecane, n-tetradecane, isododecane, decalin, and 1,3,5-trimethylbenzene (12.1%, 13.5%, 31.8%, 32.6%, and 10% by mole) were constructed. The single-component mechanisms of each fuel and the simplified mechanism of 1,3,5-trimethylbenzene were coupled with the transitional C2-C3 mechanism and the detailed C0-C1 mechanism using the decoupling method, resulting in a five-component surrogate fuel mechanism containing 142 species and 502 elementary reactions. 3. The mechanism of the surrogate fuel mixture was analyzed using the temperature sensitivity analysis method. Based on the comparison between the predicted values and the experimental values of the mechanism, the kinetic parameters of the key reactions involving small molecules such as R1, R36, and R37 containing H radicals and OH radicals, as well as the reactions generating small-molecule radicals through the endothermic reaction of HCO radicals, were corrected. The reliability of the corrected mechanism was verified by comparing the ignition delay time, laminar flame speed, and combustion products of some components with the experimental data. The comparison between the simulation results and the experimental data shows that in the high-temperature region at 1 MPa and above 1000 K, the mechanism can well predict the ignition delay time of the fuel, especially at 1.0 and 1.5, where the NTC phenomenon of the simulation values is more obvious. The mechanism constructed in this research is of a relatively small size and can represent the ignition, oxidation, and flame propagation characteristics of RP-3 aviation kerosene. It offers a reference for the investigation of surrogate fuel mixture mechanisms, facilitating an in-depth understanding of the combustion characteristics of RP-3 aviation kerosene and being applicable to the high-precision numerical simulation of the combustion reaction flow. However, the PAH sub-mechanism employed in this research fails to consider the pathways for the formation of polycyclic aromatic hydrocarbons through the interaction among large-molecule fuels. Meanwhile, the incorporation of the sub-mechanism, to some extent, weakened the predictive performance of the surrogate fuel mixture. In subsequent studies, corresponding research should be carried out to address these issues. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app15094971/s1](https://www.mdpi.com/article/10.3390/app15094971/s1)]([https://www.mdpi.com/article/10.3390/app15094971/s1](https://www.mdpi.com/article/10.3390/app15094971/s1)), Table S1: The mechanism involves species; Table S2: Kinetic parameters for primitive reactions. Conceptualization, Z.Z. ; data curation, C.D. ; formal analysis, C.D. and Q.C. ; methodology, C.D. and Q.C. ; software, C.D. and Q.C. ; supervision, Z.Z. ; validation, C.D. and Q.C. ; writing--original draft, C.D. ; writing--review and editing, Z.Z. All authors have read and agreed to the published version of the manuscript.