Steam turbine bypass for increased water heat absorption capacity steam injected turbine engine

An aircraft propulsion system comprising:

• a core engine assembly including a compressor where an inlet airflow is compressed to generate a compressed core flow that is communicated to a combustor where the compressed core flow is mixed with fuel and ignited to generate an exhaust gas flow that is expanded through a turbine section to generate shaft power;
• a hydrogen based fuel system for supplying a hydrogen based fuel to the combustor;
• a condenser where water is extracted from the exhaust gas flow;
• a first evaporator where heat is input into the water extracted by the condenser to generate a first steam flow;
• a first steam turbine where the first steam flow is expanded and cooled to generate a first cooled flow;
• a superheater where at least one of the first steam flow and the first cooled flow is reheated to generate a second steam flow;
• a bypass passage defining a path for the first steam flow around the first steam turbine to the superheater;
• a second steam turbine where the second steam flow from the superheater is expanded and cooled;
• a valve regulating flow through the bypass passage;
• and
• a controller programmed to:
• open the valve to route the first steam flow around the first steam turbine in response to a steam quality of the first steam flow being below a predefined amount,
• use a temperature and pressure of the first steam flow at an inlet to the first steam turbine while the valve is open, to determine a predicted steam quality of what would be the first cooled flow at an exit of the first steam turbine if the valve were closed, and
• close the valve when the predicted steam quality reaches a predefined predicted steam quality.

A method of operating a steam injected turbine engine comprising:

• transforming a water flow into a first steam flow with a first heat input;
• determining a condition of the first steam flow;
• bypassing the first steam flow around a first steam turbine, through a bypass with a valve operated by a controller, to a second heat input in response to the determined condition of the first steam flow being indicative of condensation greater than a predefined amount;
• using a temperature and pressure of the first steam flow at an inlet to the first steam turbine while the first steam flow is bypassing the first steam turbine, to determine a predicted steam quality of what would be a first cooled flow at an exit of the first steam turbine if the first steam flow was expanded through the first steam turbine without being bypassed around the first steam turbine;
• operating the valve to stop bypassing the first steam flow around the first steam turbine when the predicted steam quality reaches a predefined predicted steam quality;
• generating a second steam flow with the second heat input;
• and
• injecting the second steam flow into a core flow path of a core engine.