Rocket engine thrust chamber, injector, and turbopump
Disclosed herein are various technologies pertinent to rocket engines, including injector, thrust chamber, and electrical turbopump devices that may be combined to provide a highly efficient rocket engine and methods of manufacturing such devices, such as additive manufacturing. The use of additive manufacturing techniques allows for injectors and thrust chambers with complex geometries that provide for more efficient engine operation, including, for example, thrust chambers with varying surface roughness within cooling passages thereof and injectors with multiple annular plenums.
1. An apparatus comprising:
a thrust chamber, the thrust chamber including:
an exterior skin,
an interior skin offset from the exterior skin so as to form a first gap between the exterior skin and the interior skin, and
a plurality of walls bridging between the exterior skin and the interior skin and located within the first gap, wherein the walls define a plurality of coolant flow passages that extend from a first end of the thrust chamber to a second end of the thrust chamber; and
an injector for a rocket engine, the injector comprising:
a plate with a plurality of first propellant ports fluidically connecting one side of the plate with an opposing side of the plate;
a propellant distribution plenum;
a plurality of annular plenums including a first annular plenum and a second annular plenum;
a plurality of radial passages; and
a plurality of support columns, wherein:
the propellant distribution plenum is annular and has an outer diameter and an inner diameter,
each annular plenum of the plurality of annular plenums has an outer diameter and an inner diameter,
the inner diameter of the first annular plenum is larger than the outer diameter of the second annular plenum,
the plurality of radial passages includes first radial passages and second radial passages, wherein the first radial passages fluidically connect the propellant distribution plenum with the first annular plenum and are equidistantly spaced about the outer diameter of the first annular plenum and the second radial passages fluidically connect the first annular plenum with the second annular plenum and are equidistantly spaced about the outer diameter of the second annular plenum,
the first annular plenum and the second annular plenum are both offset from the plate to form a gap,
the injector is connected to the first end of the thrust chamber,
the thrust chamber and the injector are configured so that fluid flowed through the first end of the thrust chamber via the coolant flow passages enters the propellant distribution plenum of the injector via the plurality of first propellant ports, and
each support column of the plurality of support columns:
spans the gap between the plate and one of the annular plenums,
includes a column base adjacent to the plate, a base plenum within the column base, a riser passage that fluidically connects the base plenum with the respective annular plenum of the plurality of annular plenums to which the support column spans, and at least one second propellant port, and
the at least one second propellant port of that support column is not collocated with the first propellant ports of the plurality of first propellant ports.
2. The apparatus of claim 1 , wherein:
the thrust chamber includes one or more sections, and
the exterior skin, the interior skin, and the plurality of walls, with respect to at least each section, are a contiguous sintered metal structure.
3. The apparatus of claim 2 , wherein:
the one or more sections are manufactured using direct metal laser sintering.
4. The apparatus of claim 2 , wherein the sections are made from an alloy selected from the group consisting of: titanium alloys, steel alloys, unified numbering system (UNS) N06625, UNS N07718, Ti 6 Al 4 V, stainless steel alloys, maraging steel alloys, and copper alloys.
5. The apparatus of claim 2 , wherein:
the thrust chamber includes a barrel section, a throat section, and an expansion section,
the throat section is between the barrel section and the expansion section and has an average inner diameter that is smaller than the average inner diameter of the barrel section and that is smaller than the average inner diameter of the expansion section,
at least some portions of one or more of the coolant flow passages in the throat section have a surface roughness that is greater than the surface roughness of at least some portions of one or more of the coolant flow passages in one or more sections selected from the group consisting of: the barrel section, the expansion section, and the barrel section and the expansion section.
6. The apparatus of claim 5 , wherein:
the at least some portions of the one or more of the coolant flow passages in the throat section have a surface finish that is 1.25 to 3.5 times rougher than the surface finish of the at least some portions of the one or more of the coolant flow passages in the barrel section.
7. The apparatus of claim 5 , wherein:
the at least some portions of the one or more of the coolant flow passages in the throat section have a surface finish that is 1.5 to 5.6 times rougher than the surface finish of the at least some portions of the one or more of the coolant flow passages in the expansion section.
8. The apparatus of claim 2 , wherein:
the thrust chamber includes a barrel section, a throat section, and an expansion section, and
the average particle diameter of metal particles used in making the sintered metal structure of the throat section is between 1.8 and 2.2 times larger than the average particle diameter of metal particles used in making the sintered metal structure of the barrel section, thereby resulting in a different surface roughness between at least some portions of one or more of the coolant flow passages.
9. The apparatus of claim 2 , wherein:
the thrust chamber includes a barrel section, a throat section, and an expansion section, and
the average particle diameter of metal particles used in making the sintered metal structure of the throat section is between 3.6 and 4.4 times larger than the average particle diameter of metal particles used in making the sintered metal structure of the expansion section, thereby resulting in a different surface roughness between at least some portions of one or more of the coolant flow passages.
10. The apparatus of claim 2 , wherein:
the thrust chamber includes a barrel section, a throat section, and an expansion section, and
at least some portions of the sintered metal structure of the throat section are made in a DMLS process that uses a lower laser beam intensity than the laser beam intensity used to make at least some portions of the sintered metal structure of the barrel section in a DMLS process, thereby resulting in a different surface roughness between at least some portions of one or more of the coolant flow passages.
11. The apparatus of claim 2 , wherein:
the thrust chamber includes a barrel section, a throat section, and an expansion section, and
at least some portions of the sintered metal structure of the throat section are made in a DMLS process that uses a lower laser beam intensity than the laser beam intensity used to make at least some portions of the sintered metal structure of the expansion section in a DMLS process, thereby resulting in a different surface roughness between at least some portions of one or more of the coolant flow passages.
12. The apparatus of claim 2 , wherein there are at least two sections and at least two of the sections are formed as a single, contiguous part.
13. The apparatus of claim 2 , wherein:
there are a plurality of sections,
each section is formed as a discrete component, and
the sections are welded together to form the thrust chamber.
14. The apparatus of claim 13 , further comprising:
a lap joint adapter, wherein:
the interior skin of a first section of the sections has a first edge,
the interior skin of a second section of the sections has a second edge,
the first edge is welded to the second edge at a first weld,
the exterior skin of the first section has a third edge that is offset from the first edge in a direction parallel to the interior skin of the first section at one or more locations along the first edge and perpendicular to the first edge at one or more locations along the first edge,
a second gap exists between the third edge and a fourth edge of the exterior skin of the second section,
the lap joint adapter is welded to the exterior skin of the first section at a second weld and is welded to the exterior skin of the second section at a third weld, and
the lap joint adapter spans the second gap.
15. The apparatus of claim 14 , wherein the fourth edge is offset from the second edge in a direction parallel to the interior skin of the second section at one or more locations along the second edge and perpendicular to the second edge at one or more locations along the second edge.
16. The apparatus of claim 14 , wherein the walls of the first section do not extend to the first edge.
17. The apparatus of claim 14 , wherein the walls of the first section do not extend past the second edge.
18. The apparatus of claim 1 , wherein at least some portions of one or more of the coolant flow passages have a different surface roughness than at least some other portions of the one or more coolant flow passages.
19. The apparatus of claim 18 , wherein the at least some portions of the one or more of the coolant flow passages have a surface roughness that is at least two times greater than the surface roughness of the at least some other portions of the one or more coolant flow passages.
20. A method comprising:
using one or more additive manufacturing processes to form a thrust chamber and an injector for a rocket engine, wherein:
the thrust chamber includes:
an exterior skin,
an interior skin offset from the exterior skin so as to form a first gap between the exterior skin and the interior skin,
a plurality of walls bridging between the exterior skin and the interior skin and located within the first gap, wherein the walls define a plurality of coolant flow passages within the first gap and extend from a first end of the thrust chamber to a second end of the thrust chamber; and
the injector includes:
a plate with a plurality of first propellant ports fluidically connecting one side of the plate with an opposing side of the plate,
a propellant distribution plenum,
a plurality of annular plenums including a first annular plenum and a second annular plenum,
a plurality of radial passages, and
a plurality of support columns, wherein:
the propellant distribution plenum is annular and has an outer diameter and an inner diameter,
each annular plenum of the plurality of annular plenums has an outer diameter and an inner diameter,
the inner diameter of the first annular plenum is larger than the outer diameter of the second annular plenum,
the plurality of radial passages includes first radial passages and second radial passages, wherein the first radial passages fluidically connect the propellant distribution plenum with the first annular plenum and are equidistantly spaced about the outer diameter of the first annular plenum and the second radial passages fluidically connect the first annular plenum with the second annular plenum and are equidistantly spaced about the outer diameter of the second annular plenum,
the first annular plenum and the second annular plenum are both offset from the plate to form a gap,
the injector is connected to the first end of the thrust chamber,
the thrust chamber and the injector are configured so that fluid flowed through the first end of the thrust chamber via the coolant flow passages enters the propellant distribution plenum of the injector via the first propellant ports, and
each support column of the plurality of support columns:
spans the gap between the plate and one of the annular plenums, and
includes a column base adjacent to the plate, a base plenum within the column base, a riser passage that fluidically connects the base plenum with the respective annular plenum of the plurality of annular plenums to which the support column spans, and at least one second propellant port, and
the at least one second propellant port of that support column is not collocated with the first propellant ports of the plurality of first propellant ports.
21. The method of claim 20 , wherein the one or more additive manufacturing processes includes a direct metal laser sintering process.
22. The method of claim 20 , wherein the at least one of the one or more additive manufacture processes varies the surface finish of at least some portions of the one or more of the coolant flow passages such that the surface roughness of the at least some portions of the one or more of the coolant flow passages is different than the surface roughness of at least some other portions of the one or more coolant flow passages.
23. The method of claim 22 , wherein teh one or more additive manufacturing processes includes a direct laser metal sintering process and the method further comprises:
causing at least one of the one or more additive manufacturing processes to vary the surface finish of the at least some portions of the one or more of the coolant flow passages such that the surface roughness of the at least some portions of the one or more of the coolant flow passages is different than the surface roughness of the at least some other portions of the one or more coolant flow passages by varying an average particle diameter of metal particles used in the direct metal laser sintering process between formation of the at least some portions of the one or more of the coolant flow passages and formation of the at least some other portions of the one or more coolant flow passages.
24. The method of claim 23 , wherein:
the thrust chamber includes a plurality of sections,
each section is formed as a discrete part using the additive manufacturing process, and
the metal particles used to create at least one of the sections have a larger average diameter than the metal particles used to create at least one of the other sections, the method further comprising:
welding the sections together after the sections are formed in order to create the thrust chamber.
25. The method of claim 23 , wherein:
the thrust chamber includes a barrel section, a throat section, and an expansion section,
the throat section is between the barrel section and the expansion section,
the throat section has an average inner diameter that is smaller than the average inner diameter of the barrel section and that is smaller than the average inner diameter of the expansion section, and
the metal particles used in the direct metal laser sintering process to create at least a portion of the throat section have an average particle diameter that is larger than the average particle diameter of the metal particles used in the direct metal laser sintering process to create at least one section selected from the group consisting of: the barrel section, the expansion section, and the barrel section and the expansion section.
26. The method of claim 22 , further comprising:
causing the at least one of the one or more additive manufacturing processes to vary the surface finish of the at least some portions of the one or more of the coolant flow passages such that the surface roughness of the at least some portions of the one or more of the coolant flow passages is different than the surface roughness of the at least some other portions of the one or more coolant flow passages by using a lower laser beam intensity than the laser beam intensity used to make the at least some other portions of the one or more coolant flow passages.