Abstract: A hydrogen aircraft includes: an engine that uses hydrogen as a fuel; a fuel tank; and a fuel supply line from the fuel tank to the engine. The fuel tank or the fuel supply line includes a cooling medium supply port. The fuel supply line includes a cooling medium recovery port that is located downstream of the cooling medium supply port. A precooling system for the fuel supply line of the hydrogen aircraft includes: a cooling medium supply line to supply a cooling medium to the cooling medium supply port; and a cooling medium recovery line to recover the cooling medium from the cooling medium recovery port. The precooling system supplies the cooling medium from the cooling medium supply line to the fuel supply line through the cooling medium supply port and recovers the supplied cooling medium through the cooling medium recovery port to precool the fuel supply line.

Abstract: A burner device for supplying a mixture of a fuel gas and a combustion-supporting gas into a combustion region includes: a mixing path configured to inject the mixture from a downstream end portion of the mixing path into the combustion region; a fuel gas injection nozzle configured to inject the fuel gas into the mixing path toward the combustion region; and a combustion-supporting gas supply swirler configured to inject the combustion-supporting gas such that at least a part of the combustion-supporting gas collides directly with the fuel gas injected from the fuel gas injection nozzle, in a direction of a tangent line that is tangent to a fuel injection hole of the fuel gas injection nozzle on a cross-section.

Abstract: A burner device for supplying a mixture of a fuel gas and a combustion-supporting gas into a combustion region includes: a mixing path configured to inject the mixture from a downstream end portion of the mixing path into the combustion region; a fuel gas injection nozzle configured to inject the fuel gas into the mixing path toward the combustion region; and a combustion-supporting gas supply swirler configured to inject the combustion-supporting gas such that at least a part of the combustion-supporting gas collides directly with the fuel gas injected from the fuel gas injection nozzle, in a direction of a tangent line that is tangent to a fuel injection hole of the fuel gas injection nozzle on a cross-section.