AUTOIGNITION STUDY OF 'GAS-TO-LIQUID' FISCHER-TROPSCH JET FUELS

摘要

In recent years, there has been an interest in finding a jet fuel alternative to the crude oil-based kerosene. Gas-to-liquid (GtL) fuel is being derived via Fischer-Tropsch synthesis processes by converting natural gas to longer-chain hydrocarbons which form the basis for jet fuel. In this study, new experimental ignition delay time measurements of GtL jet fuels have been determined at elevated pressures and temperatures. The measurements were conducted in a heated, high-pressure shock-tube facility capable of initial temperatures up to 200°C. Two GtL jet fuels were investigated, Shell GTL and Syntrol-eum S-8, which can be used in aviation applications at concentrations up to 50% blended with conventional oil-based kerosene. The ignition delay time measurements were conducted behind reflected shock waves for gaseous-phase fuel in air at a pressure around 10 atm and over a temperature range of 966 to 1266 K for two equivalence ratios, fuel lean (Φ=0.5) and stoichiometric (Φ=1.0). Ignition delay time was determined by observing the pressure and electronically excited OH chemi-luminescence around 307 nm at the endwall location. Similar ignition delay times were observed for the two fuels at the fuel lean condition, while Syntroleum S-8 showed shorter ignition delay times at the stoichiometric condition. Comparisons are made with ignition delay time measurements for Jet-A previously conducted in the same facility and showed reasonable agreement over the tested conditions. The predictions from the available literature for GtL fuel surrogate kinetics models were obtained and compared with the experimental measurements.