An evaporative cooling pack formed from first and second corrugated media sheets is provided. The evaporative cooling pack cools a flow of air using a cooling fluid. The first and second corrugated media sheets have flutes that extend at different angles relative to a reference line and at such relative angles and have flute pitches that inhibit nesting of the adjacent sheets.

An evaporative cooling pack formed from first and second corrugated media sheets is provided. The evaporative cooling pack cools a flow of air using a cooling fluid. The first and second corrugated media sheets have flutes that extend at different angles relative to a reference line and at such relative angles and have flute pitches that inhibit nesting of the adjacent sheets.

An aerofoil component (32) defining an in use leading edge (38) and a trailing edge (40). At least one of the leading edge and the trailing edge (38, 40) comprises a plurality of first and second recesses (52, 56) projecting in a direction corresponding with an in use flow direction, the first and second recesses being spaced apart normal to the in use flow direction and having a different chordal extent.

An aerofoil component (32) defining an in use leading edge (38) and a trailing edge (40). At least one of the leading edge and the trailing edge (38, 40) comprises a plurality of first and second recesses (52, 56) projecting in a direction corresponding with an in use flow direction, the first and second recesses being spaced apart normal to the in use flow direction and having a different chordal extent.

A variable displacement exhaust turbocharger according to at least one embodiment comprises: a plurality of nozzle vanes; an annular drive ring; and a lever plate fitted at one end in a groove portion disposed in the drive ring via a connecting pin portion and connected at another end to each nozzle vane. The value of dimensionless slippage S between the groove portion and the connecting pin portion is equal to or less than 0.0016. The dimensionless slippage S is represented by a certain equation.

A gas turbine engine comprises a fan, a core turbine engine coupled to the fan, a fan case housing the fan and the core turbine engine, a plurality of outlet guide vanes extending between the core turbine engine and the fan case, and an acoustic spacing. Relationships between acoustic spacing and a high-speed shaft rating allow for a gas turbine engine that reduces noise emissions while maintaining high performance.

A gas turbine engine includes a fan, an engine core, a fan case housing the fan and the engine core, a plurality of outlet guide vanes extending between the engine core and the fan case, and an acoustic spacing. Relationships between acoustic spacing and a high-speed shaft rating allow for a gas turbine engine that reduces noise emissions while maintaining high performance.

A gas turbine engine comprises a fan, a core turbine engine coupled to the fan, a fan case housing the fan and the core turbine engine, a plurality of outlet guide vanes extending between the core turbine engine and the fan case, and an acoustic spacing. The acoustic spacing parameter, in combination with composite fan blades that include one or both of a fan leading edge to trailing edge compression factor (FLTCF) and a fan leading edge to trailing edge opening ratio (FLTOR), provide improved performance and reduced acoustic noise.

A gas turbine engine comprises a fan, a core turbine engine coupled to the fan, a fan case housing the fan and the core turbine engine, a plurality of outlet guide vanes extending between the core turbine engine and the fan case, and an acoustic spacing. The acoustic spacing parameter, in combination with composite fan blades that include one or both of a fan leading edge to trailing edge compression factor (FLTCF) and a fan leading edge to trailing edge opening ratio (FLTOR), provide improved performance and reduced acoustic noise.