# US 10,502,131 B2 · Wave rotor with piston assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,131 B2 - Document ID: US10502131B2 - Status: Granted - Kind: B2 - Application number: 15/044,674 - Filed: 2016-02-16 - Published: 2016-08-25 - Granted: 2019-12-10 - Earliest claimed: 2015-02-20 - Assignees: Rolls-Royce North American Technologies Inc. - Applicants: Rolls-Royce North American Technologies, Inc. - Inventors: Philip H. Snyder - Web page: https://patentgrep.com/patent/US10502131B2 ## CPC - F02C 5/02: characterised by the arrangement of the combustion chamber in the chamber in the plant (combustion chambers per se F23R) - F23R 3/56: Combustion chambers having rotary flame tubes - F23R 7/00: Intermittent or explosive combustion chambers - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16) ## Abstract A wave rotor includes an inlet plate, an outlet plate, and a rotor drum positioned therebetween. The inlet plate is formed to include an inlet port arranged to receive gasses. The outlet plate is formed to include an outlet port arranged to receive the gasses flowing out of the wave rotor. The rotor drum is arranged to rotate relative to the inlet and outlet plates. A piston assembly is used to counteract forces from pressure built up in the rotor drum. ## Claims ### Claim 1 A wave rotor assembly comprising a rotor drum having a forward end and an aft end, the rotor drum mounted for rotation about a central axis and including a plurality of rotor passages spaced apart from the central axis that extend along the central axis, an outlet plate offset from the aft end of the rotor drum by a clearance gap arranged to interact with gasses exiting the rotor passages at the aft end of the rotor drum, the outlet plate mounted for translation along the central axis relative to the rotor drum, and a piston assembly including a housing and a piston movable relative to the housing into engagement with the outlet plate to counteract pressure forces applied onto the outlet plate by gasses within the rotor passages at the aft end of the rotor drum to control translation of the outlet plate along the central axis, wherein the outlet plate is formed to include an outlet port spaced circumferentially apart from the piston assembly and a pressurizing passage aligned circumferentially with the piston assembly to allow gasses in the rotor passages to communicate with the piston assembly and wherein the piston is formed to include a piston passage aligned with the pressurizing passage formed in the outlet plate. ### Claim 2 (depends on 1) The wave rotor assembly of claim 1, wherein the piston includes a front face that faces the outlet plate and a back face spaced apart from and opposite the front face and the piston passage extends through the piston between the front face and the back face. ### Claim 3 (depends on 1) The wave rotor assembly of claim 1, wherein the outlet port extends circumferentially around a portion of the outlet plate to conduct gasses exiting out of the rotor passages at the aft end of the rotor drum. ### Claim 4 (depends on 1) The wave rotor assembly of claim 1, wherein the pressure forces of the gasses within the rotor passages are applied onto the outlet plate in a predetermined region and the piston is aligned with the predetermined region. ### Claim 5 (depends on 1) The wave rotor assembly of claim 1, wherein the piston is mounted in the housing for movement along a piston axis that is spaced apart from and parallel to the central axis. ### Claim 6 (depends on 1) The wave rotor assembly of claim 1, further comprising an inlet plate arranged adjacent to the forward end of the rotor drum wherein the inlet plate is formed to include an inlet port aligned with at least some of the rotor passages at the forward end of the rotor drum. ### Claim 7 (depends on 6) The wave rotor assembly of claim 6, wherein the rotor drum is mounted for rotation about the central axis relative to the inlet plate. ### Claim 8 (depends on 1) The wave rotor assembly of claim 1, wherein the rotor drum includes an inner tube, an outer tube, and a plurality of webs extending radially between the inner tube and the outer tube to define the rotor passages. ### Claim 9 A wave rotor assembly comprising a rotor drum having a forward end and an aft end, the rotor drum mounted for rotation about a central axis and including a plurality of rotor passages spaced apart from the central axis that extend along the central axis, an inlet plate arranged to block gasses from exiting the rotor passages at the forward end of the rotor drum, and a piston assembly arranged to engage with the inlet plate to counteract pressure forces applied onto the inlet plate by gasses within the rotor passages at the forward end of the rotor drum, wherein the inlet plate is formed to include an inlet port spaced circumferentially apart from the piston assembly and a pressurizing passage aligned circumferentially with the piston assembly to allow gasses in the rotor passages to communicate with the piston assembly and wherein the piston assembly includes a housing engaged with the inlet plate and a piston that is formed to include a piston passage aligned with the pressurizing passage formed in the inlet plate. ### Claim 10 (depends on 9) The wave rotor assembly of claim 9, wherein the pressure forces of the gasses within the rotor passages are applied onto the inlet plate in a predetermined region, and the housing is aligned with the predetermined region. ### Claim 11 (depends on 9) The wave rotor assembly of claim 9, further comprising an outlet plate arranged adjacent to the aft end of the rotor drum wherein the outlet plate is formed to include an outlet port aligned with at least some of the rotor passages at the aft end of the rotor drum. ### Claim 12 (depends on 11) The wave rotor assembly of claim 11, wherein the rotor drum is mounted for rotation about the central axis relative to the outlet plate. ### Claim 13 A method of operating a wave rotor assembly, the method comprising providing a rotor drum having a forward end and an aft end, an outlet plate offset from the aft end of the rotor drum by a clearance gap, and a piston assembly arranged to engage the outlet plate, introducing gasses into the rotor drum to cause a first force to be applied onto the outlet plate at the aft end of the rotor drum, and applying a pressure from the gasses in the rotor drum to the piston assembly to cause the piston assembly to apply a second force onto the outlet plate to counteract the first force, wherein the outlet plate is formed to include an outlet port spaced apart circumferentially from the piston assembly and a pressurizing passage aligned circumferentially with the piston assembly to allow a portion of the gasses to communicate with the piston assembly and wherein a piston included in the piston assembly is formed to include a piston passage that is aligned with the pressurizing passage formed in the outlet plate.