| CPC F02K 3/065 (2013.01) [F02C 3/06 (2013.01)] | 20 Claims | 

| 
               1. 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 (TPAR) between 3.5 and 100 and a core bypass ratio (CBR) between 0.1 and 10, wherein the TPAR 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 CBR is a ratio of the airflow through the fan duct to the airflow through the core duct; and 
                a booster located downstream of the secondary fan and comprising a booster rotor blade and a booster cowl, the booster cowl separating an upstream portion of the fan duct into an upper fan duct having an upper fan duct inlet and a lower fan duct having a lower fan duct inlet, the upper fan duct inlet and lower fan duct inlet collectively forming the fan duct inlet, the gas turbine engine defining a booster bleed ratio (BBR), wherein the BBR is a ratio of an airflow through the lower fan duct inlet to the airflow through the core duct, and 
                wherein BBR is less than or equal to an upper range of 0.005625×TPAR+0.2375, and greater than or equal to a lower range of 0.001125×TPAR+0.00977. 
               |