Provided are turbine engines and methods of operating thereof by heating and evaporating liquid fuels in a controlled manner prior to burning. Specifically, a fuel is heated and evaporated while avoiding coking. Coking is caused by pyrolysis when the fuel contacts a metal surface within a certain temperature range, which is referred herein to a coking temperature range. In the described methods, the fuel is transferred from one component, maintained below the coking temperature range, to another component, maintained above this range. The fuel is airborne and does not contact any metal surfaces during this transfer, and coking does not occur. In some examples, the fuel is also mixed with hot air during this transfer. The heated fuel, e.g., as an air-fuel mixture, is then supplied into a combustor, where more air is added to reach flammability conditions.