Experimental Study of Fuel Gas Leak in a Real Scale GT Enclosure

Abstract As part of NovaLT16 100% H2 product release, a new ventilation system was designed to achieve hydrogen dilution within the gas turbine (GT) package according to safety criteria. In this context, an experimental study of fuel gas leak in a real GT enclosure was performed to have valuable reference, due to a lack of literature experience with this kind of application. This paper describes test bench setup and requirements to validate the ventilation design as part of NovaLT16 100% H2 test campaign. The test is representative of a typical gas leak from the fuel gas line inside the GT package leading to a target %LFL (Lower Flammability Limit) at the ventilation outlet defined according to gas detection control. During the test, the ventilation is kept in operation while the GT is turned off to avoid any potential source of ignition. The gas leak is generated releasing natural gas into the GT package via a set of orifices with sonic flow. For safety reasons, natural gas is chosen instead of pure hydrogen, being equally indicative of a gas release phenomenon. The simulated flow rates are representative of real possible leakages that may occur due to damage to connections or flanges along the fuel supply line. Multiple gas detectors both within the package and in the ventilation outlet duct provide a visualization of the dynamic evolution of the gas cloud both in terms of concentration and location. The test confirms the gas detection system capability to identify presence of local gas leaks preventing the occurrence of hazardous scenarios. Moreover, acquired data are employed to tune numerical models that are used to design ventilation and gas detection systems with a higher level of confidence.