Revealing the Misfire Mechanism of Tri-propylene Glycol Monomethyl Ether Combining Experimental and Chemical Kinetic Modeling Methods

Tri-propylene glycol monomethyl ether (TPGME) is a renewable oxygenated biofuel that can alleviate the energy crisis and mitigate pollution issues. TPGME exhibits low-temperature exothermic performance compared with conventional fuels, and exploring its critical auto-ignition temperature can expand its application scope. In this study, TPGME spray auto-ignition experiments were carried out based on a constant volume combustor chamber. Moreover, the misfire mechanism at low temperatures was revealed via chemical kinetic modeling. The results show that the temperatures of TPGME spray auto-ignition are 713 K, 663 K, 653 K, and 643 K at ambient densities of 20.2 kg/m³, 15.7 kg/m³,11.2 kg/m³, and 6.7 kg/m³, respectively. There are two main reasons for the misfire. Firstly, 0D modeling indicates that the mass fraction of OH (Y-OH) decreases by orders of magnitude within the equivalence ratio (Φ) range of Φ < 0.5 or Φ > 1.75, which limits the high-temperature ignition (HTI). Results from 3D modeling show that the equivalence ratio of the first ignition site (Φ₀) decreases as the ambient temperature (T_a) decreases. At critical ignition conditions, Φ₀ drops below 0.5, Y-OH decreases dramatically, and no HTI occurs. Secondly, the heat release rate of key low-temperature exothermic reactions decreases as T_a decreases, which inhibits the HTI.