Turbomachine blade trailing edge cooling circuit with turn passage having set of obstructions

A coupon for replacing a cutout of a predetermined area in an airfoil body of a turbomachine blade, the airfoil body having a pressure side and a suction side connected by a leading edge and a trailing edge, the cutout within the trailing edge of the airfoil body, the coupon comprising:

• a coupon body;
• a first cooling circuit defined in the coupon body, the first cooling circuit including:
• a first rearward passage extending toward the trailing edge from and fluidly coupled to a coolant feed passage defined in at least one of the coupon body and the airfoil body;
• a first radially spreading return passage extending away from the trailing edge toward and fluidly coupled to a first coolant reuse passage defined in at least one of the coupon body and the airfoil body;
• a first radially extending turn passage coupling the first rearward passage and the first radially spreading return passage;
• and
• a first set of obstructions positioned in the first radially extending turn passage.

A gas turbine system, comprising:

• a compressor;
• a combustor;
• and
• a gas turbine, the gas turbine including a turbomachine blade including a trailing edge cooling system, the turbomachine blade including:
• an airfoil body having a pressure side and a suction side connected by a leading edge and a trailing edge;
• a coolant feed passage defined in the airfoil body;
• a first coolant reuse passage defined in the airfoil body;
• a first cooling circuit defined in the airfoil body, the first cooling circuit including:
• a first rearward passage extending toward the trailing edge from and fluidly coupled to the coolant feed passage;
• a first radially spreading return passage extending away from the trailing edge toward and fluidly coupled to the first coolant reuse passage;
• and
• a first radially extending turn passage coupling the first rearward passage and the first radially spreading return passage;
• and
• a first set of obstructions positioned in the first radially extending turn passage.