Few studies on the low-temperature combustion behavior of MIPK, being a promising fuel additive , have been conducted. In this work, ignition delay times (IDTs) of MIPK were measured in the temperatures ranging between 780–910 K and pressures of 20 and 25 bar using a rapid compression machine (RCM). Oxy-fuel combustion combined with biofuel could remove CO 2 from the atmosphere. The IDTs of MIPK were measured in the temperatures ranging between 1125–1600 K under the O 2 /CO 2 atmosphere at the pressures of 1 and 10 bar using a shock tube . A low to high-temperature MIPK kinetic model (HUST-MIPK model) was proposed, in which the low-temperature sub-model consists of 19 low-temperature reaction classes and was constructed by analogy-based method, the high-temperature sub-model was adapted from the works of Cheng et al.. The predictions of HUST-MIPK model are in good agreement with the present low-temperature IDTs, high-temperature O 2 /CO 2 atmosphere IDTs, and the literature experimental data. The negative temperature coefficient (NTC) behavior was not observed in the temperature range from 790 to 910 K in the present RCM experiments, but was observed for methyl propyl ketone (MPK) and diethyl ketone (DEK) under similar conditions. The low-temperature chemistry of three pentanone isomers (MIPK, MPK, and DEK) was compared using the flux and sensitivity analysis. The comparison of the experimental high-temperature IDTs between O 2 /CO 2 and O 2 /Ar atmospheres indicates the IDTs of MIPK under O 2 /CO 2 atmosphere are longer than those under O 2 /Ar atmosphere at 1 bar, and the effects of CO 2 are almost independent of the pressure. The physical and chemical effects of CO 2 on the ignition were studied in detail.
In response to issues such as poor accuracy and unstable delay times encountered in the practical use of tungsten-based delay compositions, an analysis of the combustion performance of tungsten-based delay compositions with the addition of copper oxide was conducted. This study selected five tungsten-based composite delay compositions prepared by blending tungsten-based delay compositions with copper oxide at different content, aiming to investigate the influence of varying copper oxide proportions on the combustion characteristics of tungsten-based delay compositions. Microscopic morphologies and thermal decomposition behaviors of the tungsten/copper oxide delay compositions were analyzed using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), while combustion products were examined by X-ray diffraction (XRD). The results indicate that copper oxide exerts a strong catalytic decomposition effect on tungsten-based delay compositions. Specifically, a low concentration of copper oxide enhances the combustion rate of tungsten-based delay compositions, while an increase in copper oxide content subsequently slows down the combustion rate. Notably, tungsten-based delay compositions with 9% copper oxide content demonstrate high precision, good stability, and a relatively slow combustion rate, offering a wider range of adjustability for controlling the combustion speed of delay compositions and providing a feasible method for managing the delay time range in practical applications.
Cellular instability of spherically expanding methanol/air flames was investigated in a constant-volume single-chamber cylindrical combustion vessel at initial temperatures of 373–423 K, initial pressures of 1–10 atm and equivalence ratios of 0.7–2.1. Flame morphology shows that the methanol/air flames suffer from cellular instability, especially at 5–10 atm. Stability analysis was performed to determine the logarithmic growth rate of disturbance, the critical Peclet number and the critical flame radius. The influences of initial temperature, initial pressure and equivalence ratio on cellular instability were analyzed to identify the influential factors. Both experimental results and stability analysis indicate cellular instability monotonically increases with increasing temperature or pressure and non-monotonically varies with increasing equivalence ratio. The reduced critical Peclet number and flame thickness slightly destabilize the flame surface as temperature increases. The almost unchanged critical Peclet number and the greatly reduced flame thickness with increasing pressure make the critical flame radius smaller and the flame surface more unstable at high pressures. The monotonically decreased critical Peclet number and the non-monotonically varied flame thickness result in the non-monotonic variation of cellular instability in methanol/air flames versus equivalence ratio. The critical flame radius consequently increases with increasing equivalence ratio under very rich conditions, while the corresponding flame surface becomes more smooth. The non-monotonic variation of cellular instability versus equivalence ratio is anticipated to exist widely in combustion of heavy fuels .
危险品化学品经营许可证（带存储）