Effects of Water Content on the Combustion Characteristics of Hydrous Ethanol/RP-3 Mixed Fuel

Constant volume chamber (CVC) was adopted to measure the laminar burning velocity (LBV) and Markstein length <i>L</i> _b of hydrous ethanol/RP-3 mixed fuel at initial temperature <i>T</i> = 450 K, initial pressure <i>P</i> = 0.1 MPa, and equivalence ratio ϕ = 0.8-1.4 with hydrous ethanol blending ratio <i>R</i> _{hydrous ethanol} of 0.2, and the effects of the water content in hydrous ethanol on the LBV and <i>L</i> _b were studied. It is found that with the increased water ratio, the LBV of hydrous ethanol/RP-3 decreases. Kinetic analysis of chemical reactions shows that with the increased water ratio the generations of CH₃ and CH₂ decreased because of more OH radicals participating in the key reactions. Meanwhile, the concentrations of H, O, and OH radicals decreased too, which inhibits the LBV of hydrous ethanol/RP-3. The results also show that with the increased water ratio, the <i>L</i> _b of hydrous ethanol/RP-3 increased, which means that the water content in hydrous ethanol would be beneficial to improve combustion stability. The experimental data obtained in our study will bring theoretical basis and technical support for the use of bioethanol in thermodynamic machinery.