正庚烷液滴在惰性多孔介质内的燃烧

Combustion of n-heptane in porous inert medium

多孔介质内燃机具有高效、低污染而且实用的潜在优点.我们用零维模型加详细化学反应机理来模拟正庚烷(C7H16)液滴在惰性多孔介质内的定容点火过程.气固、气液之间的对流换热系数,气液之间的对流传质系数均由经验公式给出;液滴表面的化学平衡服从Raoult定律;假定多孔介质内为均匀各向同性黑体辐射场.研究表明,正常工况下多孔介质(PIM)可看作恒温热源,PIM能大大缩短点火延迟期,有利于内燃机的点火控制;同时能大大降低点火阶段的压升速率,减轻噪音.总体上污染物浓度较低.

Application of porous inert medium （PIM） to internal combustion engines（ICE） promises high efficiency, low emissions and general practicability. The constant volume ignition of n heptane droplets in PIM was simulated by a zero dimensional model using detailed chemical kinetics. Empirical relations for heat and mass transfer coefficients were used in the model, and Raoult＇s law was employed to account for chemical equilibrium at the droplet surface. A homogeneous isotropic black-body radiation was assumed within PIM. Under normal conditions, PIM remained at a nearly constant temperature. Results show that PIM can drastically reduce the ignition delay time. This is of great benefit to ignition control of ICEs.Rate-of-pressure-rise can also be reduced, leading to a relatively low noise level. Emissions are, in general, relatively low.