# US 11,028,802 B2 · Liquid rocket engine assemblies and related methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,028,802 B2 - Document ID: US11028802B2 - Status: Granted - Kind: B2 - Application number: 15/351,239 - Filed: 2016-11-14 - Published: 2018-05-17 - Granted: 2021-06-08 - Earliest claimed: 2016-11-14 - Assignees: Northrop Grumman Systems Corporation - Applicants: Northrop Grumman Systems Corporation - Inventors: John K. Shigley; Russell J. George; Martin Neunzert; Martin McCulley; Marc Hernandez; Robert K. Roberts; Lauren F. Breitenbach; Klaron Cramer - Web page: https://patentgrep.com/patent/US11028802B2 ## CPC - F02K 9/97: Rocket nozzles (thrust or thrust vector control F02K9/80) - F02K 9/34: Casings; Combustion chambers; Liners thereof - F02K 9/343: {Joints, connections, seals therefor} - F02K 9/60: Constructional parts; Details not otherwise provided for - F02K 9/62: Combustion or thrust chambers - F02K 9/978: {Closures for nozzles; Nozzles comprising ejectable or discardable elements} - F05D 2230/60: Assembly methods - F05D 2240/55: Seals - F05D 2260/31: Retaining bolts or nuts - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A liquid rocket engine assembly comprising a thrust chamber, a nozzle, and a joint structure. The joint structure attaches the thrust chamber and the nozzle and comprises at least one seal element and an attachment ring interposed between the thrust chamber and the nozzle. Fasteners extend between the nozzle and the thrust chamber through the at least one seal element and the attachment ring. Materials of the thrust chamber and of the nozzle comprise different coefficients of thermal expansion. A method of forming a liquid rocket engine assembly is also disclosed. ## Claims ### Claim 1 A liquid rocket engine assembly, comprising: a thrust chamber having a first annular recess extending into the thrust chamber and radially inward from an outer surface of the thrust chamber and toward a center longitudinal axis of the liquid rocket engine assembly; a nozzle having a first annular protrusion extending radially outward from an outer surface of the nozzle and the center longitudinal axis; and a joint structure separate and discrete from the thrust chamber and the nozzle, the joint structure attaching the thrust chamber and the nozzle, the joint structure comprising: an attachment ring comprising a second annular recess extending into the joint structure and radially outward from the center longitudinal axis, the second annular recess being sized and shaped to receive the first annular protrusion; a flange member comprising a second annular protrusion extending radially inward from an inner surface of the joint structure and sized and shaped to be received in the first annular recess of the thrust chamber; at least one seal element interposed between the thrust chamber and the nozzle and between the attachment ring and the flange member; and fasteners extending completely through the attachment ring and the at least one seal element and into the flange member, wherein materials of the thrust chamber and of the nozzle comprise different coefficients of thermal expansion. ### Claim 2 (depends on 1) The liquid rocket engine assembly of claim 1, wherein each of the at least one seal element and the attachment ring comprises an annular shape. ### Claim 3 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the at least one seal element comprises a flexible graphite material. ### Claim 4 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the at least one seal element is sized and configured to seal at least one gap between the thrust chamber and the nozzle. ### Claim 5 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the attachment ring comprises a metal material, a carbon phenolic material, a yttria-stabilized zirconia (YSZ) material, a carbon-carbon material, or a carbon-carbon plus silicon carbide material. ### Claim 6 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the joint structure comprises a first surface of the at least one seal element adjacent the thrust chamber and a second, opposing surface of the at least one seal element proximal to the nozzle, the attachment ring in contact with the second, opposing surface of the at least one seal element, and the fasteners extending through holes in the at least one seal element and the attachment ring. ### Claim 7 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the at least one seal element comprises two seal elements, and further comprising an insulation ring disposed between the two seal elements, and the attachment ring aft of the insulation ring. ### Claim 8 (depends on 7) The liquid rocket engine assembly of claim 7, wherein the insulation ring comprises a carbon phenolic material. ### Claim 9 (depends on 1) The liquid rocket engine assembly of claim 1, further comprising an insulation ring laterally adjacent the nozzle and the attachment ring. ### Claim 10 (depends on 1) The liquid rocket engine assembly of claim 1, further comprising an insulation ring axial to the nozzle and forward of the attachment ring. ### Claim 11 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the at least one seal element comprises two seal elements, and further comprising a support ring laterally adjacent to the insulation ring and between a portion of the two seal elements. ### Claim 12 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the fasteners are recessed relative to an aft surface of the attachment ring. ### Claim 13 (depends on 1) The liquid rocket engine assembly of claim 1, wherein a side surface of the attachment ring proximal to the nozzle is longer than a side surface of the attachment ring distal to the nozzle. ### Claim 14 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the fasteners are flush relative to an aft surface of the attachment ring. ### Claim 15 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the thrust chamber is configured to contain at least one of a liquid fuel or a liquid oxidizer. ### Claim 16 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the joint structure comprises two seal elements comprising a flexible graphite material, an insulation ring comprising a carbon phenolic material between the two seal elements, and the attachment ring comprising a carbon phenolic material aft of the insulation ring. ### Claim 17 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the joint structure comprises one seal element comprising a flexible graphite material and the attachment ring comprises a carbon cloth phenolic material aft of the one seal element, a side surface of the attachment ring proximal to the nozzle being longer than a side surface of the attachment ring distal to the nozzle. ### Claim 18 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the joint structure comprises one seal element comprising a flexible graphite material, the attachment ring comprises a carbon-carbon material aft of the one seal element, and further comprising an insulation ring comprising a yttria-stabilized zirconia (YSZ) material positioned between the one seal element and the attachment ring. ### Claim 19 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the at least one seal element comprising a flexible graphite material and wherein the attachment ring comprising a silica phenolic material aft of the one seal element. ### Claim 20 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the joint structure comprises two seal elements comprising a flexible graphite material and the attachment ring comprises a carbon-carbon material aft of the insulation ring, the joint structure further comprises an insulation ring comprising a yttria-stabilized zirconia (YSZ) material between a portion of the two seal elements and a support ring comprising a carbon cloth phenolic material between the two seal elements. ### Claim 21 (depends on 1) The liquid rocket engine assembly of claim 1, further comprising an oxidation coating on an inner surface of the nozzle. ### Claim 22 (depends on 21) The liquid rocket engine assembly of claim 21, wherein the oxidation coating comprises a material selected from the group consisting of silicon carbide, silicon-silicon carbide (Si+SiC), tantalum carbide, titanium carbide, hafnium carbide, zirconium silicate, zirconium boride, hafnium diboride, a tungsten alloy, an alloy of tungsten and rhenium, and combinations thereof. ### Claim 23 (depends on 21) The liquid rocket engine assembly of claim 21, wherein the oxidation coating further comprises hafnium oxide or molybdenum disilicide. ### Claim 24 (depends on 1) The liquid rocket engine assembly of claim 1, wherein the nozzle lacks a cooling system. ### Claim 25 A method of forming a liquid rocket engine assembly, the method comprising: placing a joint structure comprising an attachment ring, a flange member, and at least one seal element at least partially between a nozzle and a thrust chamber, comprising: causing a first annular protrusion extending radially outward from an outer surface of the nozzle and a center longitudinal axis of the liquid rocket engine assembly to be received into a first annular recess extending into the attachment ring of the joint structure and radially outward from the center longitudinal axis; and causing a second annular protrusion extending radially inward from an inner surface of the flange member of the joint structure to be received into a second annular recess extending into the thrust chamber and radially inward from an outer surface of the thrust chamber and toward the center longitudinal axis; inserting fasteners through mutually aligned holes in the attachment ring, the at least one seal element, and the flange member, the fasteners, upon insertion, extending completely through the attachment ring and the at least one seal element, wherein materials of the thrust chamber and of the nozzle comprising different coefficients of thermal expansion; and tightening the fasteners. ### Claim 26 (depends on 25) The method of claim 25, wherein inserting the fasteners through mutually aligned holes in the joint structure, the nozzle, and the thrust chamber comprises inserting the fasteners through holes in the joint structure, the nozzle and holes in a flange of the thrust chamber.