The inlet particle separator removes particles from the inlet air flow. The inlet air is drawn into the swirl frame and the swirl vanes direct the air into a swirling pattern. Centrifugal action then removes dust, sand, and foreign objects. The foreign objects are carried to the outer section of the main frame and collected in the scroll case. The inlet particle separator blower draws the objects from the scroll case and discharges them overboard.
(d) Compressor Section-The compressor section is a 6 stage air pump that continuously pressurizes the combustion chamber, supporting combustion, and cooling the hot section components. The compressor is arranged in a 5 and 1 combination. This means, it is a 5 stage axial compressor and a 1 stage centrifugal impeller. P 2.5 air is also used for: seal pressurization, engine and engine inlet anti-ice, pressurization of the pneumatic manifold for crossbleed engine start, pressurization of the Auxiliary Fuel Management System (AFMS), and cockpit heat.
1.
Compressor Stator-The burning of the unpressurized fuel/air mixture yields very little power, a continuous supply of compressed air is needed so the engine can produce large amounts of power. A large amount of energy is required to drive the compressor. Approximately 75% of the combustion energy is consumed by the GG rotors as they self sustain the engine by driving the compressor and AGB components. The remaining 25% of the combustion energy passes beyond the GG rotors, and acts upon the power turbine. The 25% combustion pressure acting upon the power turbine rotors equates to a potential of 1,546 SHP.
2.
Diffuser Section-The axial compressor raises the air pressure approximately 7 times above atmosphere, with the air slowing as it reaches the 5th stage. A dual entry centrifugal impeller raises the speed of the compressed air and becomes supersonic as it leaves the centrifugal impeller entering the diffuser. The diffuser reduces velocity and increases pressure, and then directs the air into and around the combustion chamber. At the combustion chamber, about 33% of the P3 air supports combustion, with the remaining 66% used for cooling and other purposes.
3.
Compressor Rotor-The combined 6 stages of the compressor yield a total compression ratio of about 17:1. The product of the compressor is referred to as Pressure at 3rd Engineering Stage (P3), or CDP. Compressor speed varies depending on the PCL and collective positions, increasing as the collective is raised and decreasing as the collective is lowered. Speed ranges of the compressor are between 29,000 rpm (minimum idle 63% Ng) and 44,700 rpm (maximum continuous 99% Ng).
4.
Compressor Variable Geometry Actuation System-The variable geometry actuation system of the T700 high performance compressor permits optimum performance over a wide range of operating conditions. Use of variable stator vane angles facilitates rapid stall-free accelerations and optimizes fuel consumption at partial power conditions. The variable geometry components include the stage 1 and stage 2 variable vanes of the compressor casing, Inlet Guide Vanes (IGV's) in the main frame, lever arms attached to the individual vanes, and three actuating rings (one for each stage). The three actuating rings, levers, and vanes are actuated and synchronized by the crankshaft assembly, which is positioned by an actuator within the Hydromechanical Unit (HMU). This actuator is in turn, positioned by a servo system with feedback, which responds to compressor or gas generator speed (Ng), compressor inlet temperature (T2), and physical position of the variable geometry actuator.
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