Linear stability analysis of axisymmetric fuel jet issued into supercritical ambient

Linear stability analysis was carried out for a hydrocarbon liquid fuel jet (n-butane) that was issued into a stagnant gas (nitrogen) whose pressure a nd temperature exceeded the thermal critical values of the fuel. Within thi s high pressure/high temperature environment, the liquid fuel jet undergoes sub-to-supercritical transition due to heat addition, changes the method o f mass transfer at the gas-liquid interface, and loses surface tension. As a result, we obtained two types of flow instabilities : one is the Rayleigh type and the other is the Taylor type. We numerically calculated the maxim um amplification rate of the Rayleigh-type instability, which depends on th e square root of the Weber number and the thermodynamic phenomena, such as phase equilibrium and evaporation. Calculation results showed that fluid dy namic and thermal processes are highly coupled; therefore, the fuel jet ins tabilities in a Supercritical environment are strongly affected by thermody namic conditions and physical properties.