A fuel system includes an external cool air source, and a fuel injector. The fuel injector includes a fuel circuit, an outer air circuit, an inner air circuit, and an outlet. The fuel circuit receives liquid fuel from a fuel inlet. The outer air circuit receives cool air from the cool air source and substantially surrounds the fuel circuit. The inner air circuit is in fluid communication with the outer air circuit and a portion of the fuel circuit substantially surrounds the inner air circuit. The outlet provides atomized fuel from the fuel circuit, outer air circuit and inner air circuit to a combustor.