碳氢燃料热裂解与引发裂解换热对比实验

通过流动管反应器对碳氢燃料RP-3在超临界条件下的热裂解及引发裂解进行了实验，对两种条件下的燃料吸热能力及传热特性进行了对比分析，并对裂解产物进行了采样分析。结果表明，引发裂解降低了燃料的裂解起始温度，在一定温度区间内提高了燃料的裂解率，从而有效提高了燃料热沉，在相同热通量条件下，降低了燃料温度，并降低了加热段壁面温度。对流换热受化学反应及物性变化的影响，燃料裂解吸热可增强换热，而大量气态产物的生成会降低换热，因此，裂解反应的增强不一定增强换热。

Heat transfer of thermal cracking and initiated cracking of aviation kerosene

Nitro-propane (NP) was employed as the initiator to investigate the effect of initiated cracking on heat transfer of aviation fuel RP-3 with a one-stage and cracking system operating under supercritical pressure. The pyrolysis products are analyzed using a chromatograph/mass spectrometry (GC-MS). The heat sink, conversion rate and heat transfer coefficient were calculated based on the experimental results. Experimental results indicate that the heat transfer characteristics are influenced by the pyrolysis rate and physical property change caused by products distribution. NP accelerates the pyrolysis and increases the heat sink of fuel in temperature range of 800 K to 900 K. Under the same heat flux conditions, the effects of NP are reflected in the reduction of fuel and wall temperature. The reductions of fuel and wall temperature increase first and decrease along the flow direction, and the maximum decrease is more than 10 K. However, the Reynolds numbers decrease because of large amount gaseous products generated by pyrolysis reaction, which has negative effect on the convective heat transfer. So the influence of initiated cracking on the heat transfer of RP-3 is not a simple effect of promotion or inhibition, the regularity is different in different temperature ranges.