DOC AIRBUS | AMM A320FHPT ACTIVE CLEARANCE CONTROL (ACC) SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The components of the High-Pressure Turbine Active Clearance Control (HPTACC) system are as follows:
** ON A/C NOT FOR ALL The components of the High-Pressure Turbine Active Clearance Control (HPTACC) system are as follows:
HPT Active Clearance Control- ACC inlet louver
- ACC inlet duct
- ACC forward wye duct HPTACC valve (consists of the actuator, valve and LVDT as a single component)
- ACC aft HPT valve elbow duct
- Four segment HPTACC air manifold.
2. System Description
The HPTACC system is installed on the left of the High Pressure Compressor (HPC) case at the 9 o'clock position. The system is routed aft and surrounds the High Pressure Turbine (HPT) case. The function of the HPTACC system is to control cooling-air flow to the exterior of the HPT case. This cooling-air is used to reduce the clearances between the HPT shrouds and the HPT rotor blades. The reduction in the clearances improve the specific fuel consumption and decrease the EGT overshoot during rapid acceleration. The Electronic Engine Control (EEC) uses sensor inputs and modulates the fuel actuated HPTACC valve during engine operation.
** ON A/C NOT FOR ALL The HPTACC system is installed on the left of the High Pressure Compressor (HPC) case at the 9 o'clock position. The system is routed aft and surrounds the High Pressure Turbine (HPT) case. The function of the HPTACC system is to control cooling-air flow to the exterior of the HPT case. This cooling-air is used to reduce the clearances between the HPT shrouds and the HPT rotor blades. The reduction in the clearances improve the specific fuel consumption and decrease the EGT overshoot during rapid acceleration. The Electronic Engine Control (EEC) uses sensor inputs and modulates the fuel actuated HPTACC valve during engine operation.
3. Component Description
A. HPTACC Valve
The HPTACC valve controls the quantity of fan discharge air delivered to the HPT air manifold. The operation of the HPTACC valve is performed by the EEC using servo fuel. The servo fuel drives an actuator which rotates the butterfly valve shaft. Dual LVDTs, attached to the actuator, gives the valve position feedback through separate cables to each EEC channel.
The HPTACC valve controls the quantity of fan discharge air delivered to the HPT air manifold. The operation of the HPTACC valve is performed by the EEC using servo fuel. The servo fuel drives an actuator which rotates the butterfly valve shaft. Dual LVDTs, attached to the actuator, gives the valve position feedback through separate cables to each EEC channel.
4. Operation
The fan discharge air enters the HPTACC system through the ACC inlet louver, the ACC inlet duct and through the ACC forward wye duct. The EEC schedules the HPTACC valve to modulate the fan discharge air through the HPTACC manifold.
The fan discharge air enters the HPTACC system through the ACC inlet louver, the ACC inlet duct and through the ACC forward wye duct. The EEC schedules the HPTACC valve to modulate the fan discharge air through the HPTACC manifold.