Valve assembly for an active clearance control system

#This application claims priority to European Patent Application No. 19461619.9 filed Dec. 23, 2019, the entire contents of which is incorporated herein by reference.

#This disclosure relates generally to a valve assembly for an active clearance control system. This disclosure also relates to an active clearance control system, a gas turbine engine, and a method of controlling flow rate in an active clearance control system for a gas turbine engine.

#During operation of a gas turbine engine, temperature and forces within the engine can cause parts of the engine to expand and contract. When designing engine turbines, it is desirable for the clearance between the turbine case and the turbine blades to be as low as possible without the blades contacting the case in order to optimise turbine efficiency. This efficiency gain can result in the reduction of engine fuel burn and consequently emissions. However, because the turbine case and turbine blades can expand and contract at different rates, optimum efficiency can be difficult to achieve using conventional design techniques.

#Some embodiments of the disclosure will now be described by way of example with reference to the accompanying drawings in which;

#FIG. 1 shows a perspective view of a valve assembly according to the present disclosure;

#FIG. 2 shows a partial cutaway view of the valve assembly of FIG. 1 showing detail of the valve discs;

#FIG. 1 shows a valve assembly 200 according to the present disclosure. The valve assembly 200 can be used in an active clearance control (ACC) system, such as an ACC system in a gas turbine engine.

#The valve assembly 200 has a housing 202 that defines an annular inlet duct 204, a first annular outlet duct 206, and a second annular outlet duct 208. The annular inlet duct 204 has a central inlet axis 210. The first annular outlet duct 206 has a first central outlet axis 212 and the second annular outlet duct 208 has a second central outlet axis 214.

#The inlet duct 204 is configured to direct a flow of fluid to the first outlet duct 206 and the second outlet duct 208. In this manner, fluid flow from the inlet duct 204 is split between the first and second outlet ducts 206, 208. The inlet duct 204 may be configured to direct any suitable fluid to the outlet ducts 206, 208. In exemplary embodiments, the fluid is cooling air coming from engine bleed sources. Example bleed sources include a compressor of a gas turbine engine or a bypass duct of a gas turbine engine. However, the fluid could be obtained from any other suitable source. The inlet duct 204 also features an annular flange 204a for connection to a suitable fluid supply or other upstream ACC system component.