Gas turbine engine with third stream

A gas turbine engine comprising:

• a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct;
• a primary fan driven by the turbomachine;
• a secondary fan located downstream of the primary fan within the inlet duct, the gas turbine engine defining a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct;
• and
• an electric machine embedded in the gas turbine engine, wherein the gas turbine engine and the electric machine define a secondary fan radius to electric machine radius ratio equal to or greater than 1.33 and less than or equal to 3.8.

A gas turbine engine comprising:

• a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct;
• a primary fan driven by the turbomachine;
• a secondary fan located downstream of the primary fan within the inlet duct, the gas turbine engine defining a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct;
• and
• an electric machine embedded in the gas turbine engine, wherein the gas turbine engine defines a primary fan radius to secondary fan radius ratio equal to or greater than 2.0 and less than or equal to 6.5.

A gas turbine engine comprising:

• a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbine section comprising a low pressure turbine, the turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct;
• a primary fan driven by the turbomachine;
• a secondary fan located downstream of the primary fan within the inlet duct, the gas turbine engine defining a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct;
• and
• an electric machine embedded in the gas turbine engine, wherein the gas turbine engine defines an electric machine length to low pressure turbine length ratio equal to or greater than 0.01 and less than or equal to 3.0.

A gas turbine engine comprising:

• a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbine section comprising a low pressure turbine, the turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct;
• a primary fan driven by the turbomachine;
• a secondary fan located downstream of the primary fan within the inlet duct, the gas turbine engine defining a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct;
• and
• an electric machine embedded in the gas turbine engine, wherein the gas turbine engine defines an electric machine tip radius to low pressure turbine last stage hub radius ratio as being equal to or greater than 0.1 and less than or equal to 1.0.

A gas turbine engine comprising:

• a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbine section comprising a high pressure turbine, the turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct;
• a primary fan driven by the turbomachine;
• a secondary fan located downstream of the primary fan within the inlet duct, the gas turbine engine defining a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct;
• and
• an electric machine embedded in the gas turbine engine, wherein during operation of the gas turbine engine, the gas turbine engine defines a secondary fan tip speed to high pressure turbine tip speed ratio equal to or greater than 0.7 and less than or equal to 1.5.

A gas turbine engine comprising:

• a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct;
• a primary fan driven by the turbomachine;
• a secondary fan located downstream of the primary fan within the inlet duct, the secondary fan comprising a secondary fan blade having a hub, the gas turbine engine defining a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct;
• and
• an electric machine embedded in the gas turbine engine, wherein the gas turbine engine defines a secondary fan hub radius to electric machine radius ratio equal to or greater than 0.1 and less than or equal to 1.0.