Coolant passages for gas turbine components

A gas turbine engine component comprising a wall with a first surface which is adapted to be supplied with a flow of cooling air, and a second surface which is adapted to be exposed to a hot gas stream, the wall further having passage walls which define therein a plurality of passages, which interconnect passage inlets in said first surface of the component to passage outlets in said second surface, the passages, passage walls defining the passages, cooling air and the hot gas stream being arranged such that in operation a flow of cooling air is directed from the passage inlets to the passage outlets through said passages to provide a flow of cooling air over at least a portion of the second surface;

• wherein a cross sectional area of each of the passages in a direction of cooling air flow through a passage progressively decreases overall from the passage inlets to the passage outlets such that in use the flow of cooling air from the passage inlets to the passage outlets through each passage is accelerated, each passage having a centerline, the passage walls, which define the passages through the walls of the component, being profiled such that in a first direction substantially perpendicular to a flow direction through the passage, they converge towards said respective centerline through the passage, and in a second direction also perpendicular to a cooling flow direction through the passage they diverge from the centerline of the passage.