Double shelf squealer tip with impingement cooling of serpentine cooled turbine blades

An impingement shelf of a turbine blade including a leading edge and a trailing edge disposed opposite to the leading edge, the impingement shelf extending between the leading and trailing edges and comprising:

• one or more walls arranged to form a serpentine cooling circuit within an airfoil of the turbine blade;
• and
• a plurality of impingement holes through which coolant is expelled to cool the turbine blade, the plurality of impingement holes communicating with the serpentine cooling circuit,
• wherein the serpentine cooling circuit communicates with a trailing edge cavity formed by a turnaround section configured to guide the coolant to the plurality of impingement holes and to force the coolant through the impingement holes by blocking a flow of the coolant through the trailing edge, and
• wherein the plurality of impingement holes are arranged along a length of an upper side of the turnaround section.

A turbine blade comprising:

• an airfoil having a leading edge and a trailing edge and including a cooling circuit formed by one or more serpentine walls;
• a squealer tip floor extending between the leading and trailing edges;
• and
• an impingement shelf facing a portion of the squealer tip floor and having a plurality of impingement holes through which coolant is expelled to cool the turbine blade,
• wherein the cooling circuit communicates with a trailing edge cavity formed by a turnaround section configured to guide the coolant to the plurality of impingement holes and to force the coolant through the impingement holes by blocking a flow of the coolant through the trailing edge, and
• wherein the plurality of impingement holes are arranged along a length of an upper side of the turnaround section.