炭棒燃烧传播速度对反应锥形状的影响

Effect of Combustion Propagation Velocity on Shape of Reaction Cone in a Char Rod

燃烧在固体燃料内稳定传播的机理目前尚不明确.在预实验发现炭棒稳定燃烧存在锥形反应面的基础上,以柏木和榆树皮粉制得的细炭棒(2~7 mm)为研究对象,对反应锥形状和燃烧传播速度间关系进行了理论和实验分析.结果表明:反应锥长度正比于燃烧传播速度和扩散及动力阻力总和的乘积(l∝u·(Rt_(ran)+R_(kin))).与圆管非预混气体贫燃燃烧的火焰长度与燃料体积流量间关系类似,细炭棒稳定燃烧的反应锥长度正比于燃料的质量流量.研究为进一步明确燃烧在固体燃料内的稳定传播提供了基础.

Theoretical knowledge about steady propagation of combustion inside solid fuels is still limited.In this paper,based on the conical-shaped reaction zone found in steady combustion of a char rod in our preexperiments,the relationship between shape of reaction cone and combustion propagation velocity was analyzed theoretically and experimentally using slim char rods(2—7 mm)prepared with cypress wood and elm bark powder.Results showed that the length of reaction cone is proportional to the product of the combustion propagation velocity and the sum of diffusion and kinetic resistance(l∝u·(R_(tran)+R_(kin))).Similar to the relationship between flame length and volumetric flowrate of fuel in overventilated coaxial nonpremixed combustion gas fuel,the length of reaction cone in steady combustion of a slim char rod is proportional to the mass flowrate of fuel.This study provides some basic information for investigation into steady propagation of combustion inside solid fuels.