DOC AIRBUS | AMM A320FROTOR ACTIVE CLEARANCE CONTROL SYSTEM (RACC) - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The Rotor Active Clearance Control system (RACC) is controlled by the FADEC system which maintains HPC rotor blade clearance relative to HPC stator compressor case.
** ON A/C NOT FOR ALL The Rotor Active Clearance Control system (RACC) is controlled by the FADEC system which maintains HPC rotor blade clearance relative to HPC stator compressor case.
Rotor Active-Clearance-Control System2. Description
The RACC system modulates the fifth stage High Pressure (HP) compressor bleed air into the compressor rotor bore to vary and control the clearances. The air flow to the rotor is mixed with the booster discharge air. By heating the compressor rotor with fifth stage bleed air, the compressor clearances are reduced. This improves the efficiency of the compressor and the overall Specific Fuel Consumption (SFC) of the engine.
When the RACC valve is closed, the total air flow through the rotor is from the booster discharge air and the clearances are maximized. As the RACC valve opens, the amount and temperature of the air through the rotor is increased due to the introduction of fifth stage bleed air: then the clearances are closed to optimize performance.
** ON A/C NOT FOR ALL The RACC system modulates the fifth stage High Pressure (HP) compressor bleed air into the compressor rotor bore to vary and control the clearances. The air flow to the rotor is mixed with the booster discharge air. By heating the compressor rotor with fifth stage bleed air, the compressor clearances are reduced. This improves the efficiency of the compressor and the overall Specific Fuel Consumption (SFC) of the engine.
When the RACC valve is closed, the total air flow through the rotor is from the booster discharge air and the clearances are maximized. As the RACC valve opens, the amount and temperature of the air through the rotor is increased due to the introduction of fifth stage bleed air: then the clearances are closed to optimize performance.
3. Rotor Active Clearance Control Valve
The Rotor Active Clearance Control (RACC) valve is a butterfly valve with one inlet port and one outlet port. The valve has a RACC port and a PCR port. It consists of an outer housing, a rotating plate, and an integral fuel powered actuator with dual independent transducers for position feedback. The inlet port receives 5th stage compressor bleed air which is modulated by rotating the plate. The RACC valve outlet port supplies modulated bleed air. The RACC valve is located on the HPC compressor case at 12:00 o'clock.
The Rotor Active Clearance Control (RACC) valve is a butterfly valve with one inlet port and one outlet port. The valve has a RACC port and a PCR port. It consists of an outer housing, a rotating plate, and an integral fuel powered actuator with dual independent transducers for position feedback. The inlet port receives 5th stage compressor bleed air which is modulated by rotating the plate. The RACC valve outlet port supplies modulated bleed air. The RACC valve is located on the HPC compressor case at 12:00 o'clock.