芳香烃对涡轴发动机排气冒烟影响的试验

为掌握涡轴发动机排气中的冒烟数及芳香烃体积分数对冒烟数的影响，设计了某涡轴发动机冒烟数测量试验方案，通过在RP-3航空煤油中添加甲苯(C6H5CH3)获得不同芳香烃体积分数，开展发动机排气冒烟试验；并根据实测冒烟数(SN)拟合得到了与计算冒烟质量浓度指数(CI)的关系式。试验结果表明:某型涡轴发动机采用基准燃油时各状态冒烟数均小于40，优于设计指标；最大起飞状态下芳香烃体积分数每增加3%可导致冒烟数升高6%。该试验为涡轴发动机排气冒烟数测量和预估提供了一种有效方法，并为通过减少燃油中芳香烃体积分数来抑制发动机冒烟数提供了依据。 

Test on influence of aromatic hydrocarbons on smoke emission characteristics in turboshaft engine

In order to obtain the test data and influence of aromatic volume fraction on smoke emission，the smoke number test scheme of a turboshaft engine was designed. Aromatic hydrocarbons volume fraction of kerosene from different production regions was compared and analyzed. By adding toluene(C6H5CH3) to RP-3 kerosene, different volume fractions of aromatic hydrocarbons could be gained.The influence of aromatic hydrocarbon volume fraction on smoke emission was studied in domestic aeroengine field. The correlation of smoke number (SN) with concentration index (CI) was fitted according to the measured smoke number. Test results showed that the smoke emission index increased with the power state of turboshaft engine, and the smoke number was less than 40, which was superior to design requirements when turboshaft engine adopted baseline fuel. The increase of 3 percent in aromatic hydrocarbon volume fraction can lead to increase of 6 percent in smoke number. The test has provided an effective method for measurement and prediction of exhaust smoke and also beneficial experience and alternative fuels for suppressing smoke of turboshaft engines.