A fluid mixing apparatus includes mixing conduits that extend through a fluid plenum and that define injection holes therethrough. The fluid plenum, which surrounds a first wall defining a main passage fluidly coupled to a low-pressure fluid source, is surrounded itself by a second wall defining a high-pressure plenum fluidly coupled to a high-pressure fluid source. The mixing conduits fluidly couple the high-pressure plenum to the main passage, and the fluid from the fluid plenum is delivered with the high-pressure fluid to the main passage, where the fluids mix before being discharged from an outlet of the main passage. The fluid mixing apparatus may be used to mix one or more fuels with high- and low-pressure air in a gas turbine combustor. Alternately, the fluid mixing apparatus may mix a fluid with high- and low-pressure water streams.

Methods and devices are disclosed for introducing a fresh airflow, crankcase ventilation gases, fuel, and charge bypass flow upstream of a pressure source of an internal combustion engine.

Methods and devices are disclosed for introducing a fresh airflow, crankcase ventilation gases, fuel, and charge bypass flow upstream of a pressure source of an internal combustion engine.

An exhaust gas system for an internal combustion engine includes an exhaust gas treatment unit, an exhaust gas guide conducting exhaust gas to the exhaust gas treatment unit and a reactant discharge unit for the discharge of reactant into the exhaust gas guide. The exhaust gas guide includes an outer pipe and an inner pipe in a longitudinal region between the reactant discharge unit and the exhaust gas treatment unit. An external volume through which exhaust gas can flow and an internal volume through which exhaust gas can flow in the inner pipe are provided.