A fuel injector for a gas turbine engine (20; 200) comprising: an inner housing having a center body installed within the inner housing; an intermediate housing arranged radially outward from the inner housing; and an outer housing arranged radially outward from the intermediate housing, wherein: the center body is a hollow body structure defining a center body airflow passage therethrough; a first fluid passage is partially defined between an outer surface of the inner housing and an inner surface of the intermediate housing; a second fluid passage is partially defined within the intermediate housing; and a third fluid passage comprises the center body airflow passage, an inner airflow passage defined between an exterior surface of the center body and an interior surface of the inner housing, and an outer airflow passage that is defined by the outer housing and radially outward from the intermediate housing, wherein the center body includes an open first end characterized in that the center body includes a partially obstructed, downstream second end; wherein the downstream second end includes a double-walled configuration, with an impingement plate and an effusion plate such that the second end includes an air cooled array of impingement holes in the impingement plate and effusion cooling holes in the effusion plate, wherein the impingement plate includes a plurality of apertures that are arranged to direct the airflow to impinge upon the effusion plate and provide impingement cooling thereto, and wherein the effusion plate includes a plurality of apertures, and directs an effusion flow of air out the second end of the center body. an inner housing having a center body installed within the inner housing; an intermediate housing arranged radially outward from the inner housing; and an outer housing arranged radially outward from the intermediate housing, wherein: the center body is a hollow body structure defining a center body airflow passage therethrough; a first fluid passage is partially defined between an outer surface of the inner housing and an inner surface of the intermediate housing; a second fluid passage is partially defined within the intermediate housing; and a third fluid passage comprises the center body airflow passage, an inner airflow passage defined between an exterior surface of the center body and an interior surface of the inner housing, and an outer airflow passage that is defined by the outer housing and radially outward from the intermediate housing, wherein the center body includes an open first end characterized in that the center body includes a partially obstructed, downstream second end; wherein the downstream second end includes a double-walled configuration, with an impingement plate and an effusion plate such that the second end includes an air cooled array of impingement holes in the impingement plate and effusion cooling holes in the effusion plate, wherein the impingement plate includes a plurality of apertures that are arranged to direct the airflow to impinge upon the effusion plate and provide impingement cooling thereto, and wherein the effusion plate includes a plurality of apertures, and directs an effusion flow of air out the second end of the center body. the center body is a hollow body structure defining a center body airflow passage therethrough; a first fluid passage is partially defined between an outer surface of the inner housing and an inner surface of the intermediate housing; a second fluid passage is partially defined within the intermediate housing; and a third fluid passage comprises the center body airflow passage, an inner airflow passage defined between an exterior surface of the center body and an interior surface of the inner housing, and an outer airflow passage that is defined by the outer housing and radially outward from the intermediate housing, wherein the center body includes an open first end characterized in that the center body includes a partially obstructed, downstream second end; wherein the downstream second end includes a double-walled configuration, with an impingement plate and an effusion plate such that the second end includes an air cooled array of impingement holes in the impingement plate and effusion cooling holes in the effusion plate, wherein the impingement plate includes a plurality of apertures that are arranged to direct the airflow to impinge upon the effusion plate and provide impingement cooling thereto, and wherein the effusion plate includes a plurality of apertures, and directs an effusion flow of air out the second end of the center body.