The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

The present disclosure provides methods, assemblies, and systems for power production that can allow for increased efficiency and lower cost components arising from the control, reduction, or elimination of turbine blade mechanical erosion by particulates or chemical erosion by gases in a combustion product flow. The methods, assemblies, and systems can include the use of turbine blades that operate with a blade velocity that is significantly reduced in relation to conventional turbines used in typical power production systems. The methods and systems also can make use of a recycled circulating fluid for transpiration protection of the turbine and/or other components. Further, recycled circulating fluid may be employed to provide cleaning materials to the turbine.

The present disclosure provides methods, assemblies, and systems for power production that can allow for increased efficiency and lower cost components arising from the control, reduction, or elimination of turbine blade mechanical erosion by particulates or chemical erosion by gases in a combustion product flow. The methods, assemblies, and systems can include the use of turbine blades that operate with a blade velocity that is significantly reduced in relation to conventional turbines used in typical power production systems. The methods and systems also can make use of a recycled circulating fluid for transpiration protection of the turbine and/or other components. Further, recycled circulating fluid may be employed to provide cleaning materials to the turbine.

A gas turbine engine has a converging duct that has combustion products flow at low mach speeds through a first portion and a high mach speeds through a second portion. The converging duct has two types of cooling schemes formed. One type of cooling scheme is beneficial for the low mach speed combustion product flow and one type of cooling scheme is beneficial for the high mach speed combustion product flow. The two cooling schemes are blended together in order increase the efficiency of the cooling of the converging duct.

The present disclosure provides methods, assemblies, and systems for power production that can allow for increased efficiency and lower cost components arising from the control, reduction, or elimination of turbine blade mechanical erosion by particulates or chemical erosion by gases in a combustion product flow. The methods, assemblies, and systems can include the use of turbine blades that operate with a blade velocity that is significantly reduced in relation to conventional turbines used in typical power production systems. The methods and systems also can make use of a recycled circulating fluid for transpiration protection of the turbine and/or other components. Further, recycled circulating fluid may be employed to provide cleaning materials to the turbine.

A turbine blade has a blade tip, a cooling structure with cooling channels which are designed to have cooling fluid passed through them in order to cool the turbine blade during operation, an end section at a lower level than that of the blade tip, and an outer wall section extending up to the blade tip. The cooling structure is formed between the end section and the blade tip. A method produces a cooling structure of this type.

A turbine ventilation system includes a controller that is coupled to an actuator that is coupled to a vane that is disposed across an intake port between a gas turbine enclosure and the turbine ventilation system. The controller can cause the actuator to change a position of the vane to alter an air flow from the turbine ventilation system into the gas turbine enclosure based upon feedback from one or more sensors disposed within the gas turbine enclosure.

A gas turbine engine component includes a ceramic matrix composite (CMC) body that includes an interior surface that defines a blind cavity. A barrier coating is disposed on an exterior of the CMC body. A ceramic body in the blind cavity lines at least a portion of the interior surface of the CMC body. The ceramic body defines an open, interconnected network of pores.

An internally cooled component for a gas turbine engine includes a component having one or more exterior walls defining an internal component cavity configured for a cooling airflow to flow therethrough. An internal component rib extends into the internal component cavity from the one or more exterior walls. An insert is positioned in the internal component cavity, and a flow discourager is positioned at the insert and is configured to prevent the cooling airflow from flowing past the internal component rib.

A tip for a turbine component, turbine rotor blade or tip of a blade, is disclosed. The tip includes a tip plate configured to be coupled at a tip end of an airfoil chamber; and a tip rail extending radially from the tip plate, the tip rail disposed near or at a periphery of the tip plate. The trip rail includes a cooling structure constituting at least a portion of the tip rail. The cooling structure is in fluid communication with the airfoil chamber, and includes a plurality of repeating, three dimensional unit cells. Each unit cell defines a flow passage that is in fluid communication with the flow passage of at least one other unit cell. The flow passages of the 3D unit cells create a tortuous cooling passage in at least a portion of the tip rail.