A method and apparatus for vaporizing liquid fuel. The apparatus includes at least one capillary flow passage, the at least one capillary flow passage having an inlet end and an outlet end; a fluid control valve for placing the inlet end of the at least one capillary flow passage in fluid communication with the liquid fuel source and introducing the liquid fuel in a substantially liquid state; a heat source arranged along the at least one capillary flow passage, the heat source operable to heat the liquid fuel in the at least one capillary flow passage to a level sufficient to change at least a portion thereof from the liquid state to a vapor state and deliver a stream of substantially vaporized fuel from the outlet end of the at least one capillary flow passage; and means for cleaning deposits formed during operation of the apparatus. The flow passage can be a capillary tube heated by a resistance heater or a section of a tube heated by passing electrical energy therethrough. The liquid fuel can be supplied to the flow passage at any desired pressure depending on the required mass flow rate for the application. The vaporized fuel can be mixed with air to form an aerosol having a mean droplet size of 25 μm or less to minimize ignition energy of the fuel-air mixture, promote fuel flow in an air stream, and combust the liquid fuel efficiently and cleanly.