Catalyst chamber with a catalyst bed embedded therein for a monopropellant thruster of a rocket engine

Abstract

A catalyst chamber with a catalyst bed embedded therein for a monopropellant thruster of a rocket engine. The catalyst chamber comprises an inlet having a first cross-sectional area through which a propellant can be introduced into the catalyst chamber and an outlet having a second cross-sectional area through which the propellant and/or resulting reaction products can be introduced into a combustion chamber of the thruster. The outlet is connected to the inlet via a catalyst volume of the catalyst chamber. At least one helical wall member is arranged within the catalyst chamber and is dividing the catalyst volume into two or more segments such that an effective length of the catalyst bed of each segment passed through by the propellant and/or its reaction products is larger than a geometrical length of the catalyst chamber defined between the inlet and the outlet along a direction of extension of the catalyst chamber.

Claims

1. A monopropellant thruster embedded in a rocket engine, the monopropellant thruster comprising a catalyst chamber with a catalyst bed, the catalyst chamber comprising: an inlet having a first cross-sectional area through which a propellant can be introduced into the catalyst chamber; an outlet having a second cross-sectional area through which the propellant and/or resulting reaction products can be introduced into a combustion chamber of the monopropellant thruster, wherein the outlet is connected to the inlet via a catalyst volume of the catalyst chamber; an outer wall; an inner wall spaced apart from and arranged within the outer wall, such that the catalyst volume is subdivided by the inner wall to define an inner volume contained within the inner wall and an outer volume contained between the inner wall and the outer wall; and at least one helical wall member arranged within the catalyst chamber and extending between the inner wall and the outer wall to divide the outer volume into two or more segments, such that an effective length of a respective portion of the catalyst bed occupied by each segment of the two or more segments passed through by the propellant and/or the resulting reaction products is larger than a geometrical length of the catalyst chamber, which is defined between the inlet and the outlet along a direction of extension of the catalyst chamber; wherein the catalyst chamber has a cylindrical shape having a circular cross-section, such that bases of the catalyst chamber lie in parallel planes, with each of the parallel planes being orthogonal to the direction of extension of the catalyst chamber, a distance between the parallel planes corresponding to the geometrical length of the catalyst chamber; wherein a cross-section of the bases of the catalyst chamber corresponds to the inlet and the outlet of the catalyst chamber; wherein the first cross-sectional area of the inlet is circular and has a first cross-sectional area diameter that corresponds to a diameter of the catalyst chamber; and wherein the at least one helical wall member covers an entire extension of the inner wall in the direction of extension of the catalyst chamber.

2. The catalyst chamber according to claim 1, wherein the at least one helical wall member is an insertion element.

3. The catalyst chamber according to claim 1, wherein the at least one helical wall member is an integral element of the catalyst chamber.

4. The catalyst chamber according to claim 1, wherein the catalyst chamber comprises an inner wall being arranged concentrically to an outer wall.

5. The catalyst chamber according to claim 4, wherein the inner wall is adapted to receive a heating element for preheating the catalyst bed.

6. The catalyst chamber according to claim 4, wherein the inner wall comprises at least one further helical wall member arranged within the inner wall and dividing the catalyst volume of the inner wall into two or more further segments.

7. The catalyst chamber according to claim 6, wherein the segments and the further segments are arranged to be passed through by the propellant and/or its reaction products in parallel.

8. The catalyst chamber according to claim 1, wherein the segments and/or the further segments are separated from each other.

9. A rocket engine comprising a monopropellant thruster, the monopropellant thruster comprising a catalyst chamber with a catalyst bed embedded therein, the catalyst chamber comprising: an inlet having a first cross-sectional area through which a propellant can be introduced into the catalyst chamber; an outlet having a second cross-sectional area through which the propellant and/or resulting reaction products can be introduced into a combustion chamber of the monopropellant thruster, wherein the outlet is connected to the inlet via a catalyst volume of the catalyst chamber; an outer wall; an inner wall spaced apart from and arranged within the outer wall, such that the catalyst volume is subdivided by the inner wall to define an inner volume contained within the inner wall and an outer volume contained between the inner wall and the outer wall; and at least one helical wall member arranged within the catalyst chamber and extending between the inner wall and the outer wall to divide the outer volume into two or more segments, such that an effective length of a respective portion of the catalyst bed occupied by each segment of the two or more segments passed through by the propellant and/or the resulting reaction products is larger than a geometrical length of the catalyst chamber, which is defined between the inlet and the outlet along a direction of extension of the catalyst chamber; wherein the catalyst chamber has a cylindrical shape having a circular cross-section, such that bases of the catalyst chamber lie in parallel planes, with each of the parallel planes being orthogonal to the direction of extension of the catalyst chamber, a distance between the parallel planes corresponding to the geometrical length of the catalyst chamber; wherein a cross-section of the bases of the catalyst chamber corresponds to the inlet and the outlet of the catalyst chamber; wherein the first cross-sectional area of the inlet is circular and has a first cross-sectional area diameter that corresponds to a diameter of the catalyst chamber; and wherein the at least one helical wall member covers an entire extension of the inner wall in the direction of extension of the catalyst chamber.

10. The monopropellant thruster according to claim 9, wherein the at least one helical wall member is an insertion element.

11. The monopropellant thruster according to claim 9, wherein the at least one helical wall member is an integral element of the catalyst chamber.

12. The monopropellant thruster according to claim 9, wherein the catalyst chamber comprises an inner wall being arranged concentrically to an outer wall.

13. The monopropellant thruster according to claim 12, wherein the inner wall is adapted to receive a heating element for preheating the catalyst bed.

14. The rocket engine according to claim 9, comprising at least one further helical wall member arranged within the inner wall, such that the inner volume of the catalyst chamber is divided into two or more further segments.

15. The monopropellant thruster according to claim 14, wherein the segments and the further segments are arranged to be passed through by the propellant and/or its reaction products in parallel.

16. The monopropellant thruster according to claim 9, wherein the segments and/or the further segments are separated from each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure herein will be explained more detailed by reference to the accompanying figures.

(2) FIG. 1 shows a schematic view of a monopropellant thruster in a cross-section illustrating a catalyst chamber with a catalyst bed embedded therein.

(3) FIG. 2 shows a perspective view of a first embodiment of a catalyst chamber according to the disclosure herein.

(4) FIG. 3 shows a perspective view of a second embodiment of a catalyst chamber according to the disclosure herein.

(5) FIG. 4 shows a perspective view of a third embodiment of a catalyst chamber according to the disclosure herein.

DETAILED DESCRIPTION

(6) FIG. 1 is a schematic view illustrating a monopropellant thruster 1 of a rocket engine in a cross-section. The thruster 1 comprises a combustion chamber 2, a nozzle 3 and a propellant inlet 4. In the combustion chamber 2 which is arranged in between the propellant inlet 4 and the nozzle 3, a catalyst chamber 10 with a catalyst bed embedded therein is arranged. As indicated by the arrows 5 which illustrate the flow direction of the propellant, the propellant floods into the catalyst chamber 10 at an inlet 11 and passes through the catalyst chamber 10 and the catalyst bed, respectively, in a longitudinal direction of the monopropellant thruster 1. The propellant will be decomposed within the catalyst chamber 10. Resulting reaction products and/or propellant leave the catalyst chamber 10 at outlet 12 and will be introduced into the nozzle 3.

(7) The catalyst chamber 10 has a geometrical length l extending in the longitudinal direction, i.e. parallel to a longitudinal axis, of the thruster 1. In case of a conventional catalyst chamber 10 the catalyst bed of the catalyst chamber 10 is passed through by the propellant and/or resulting reaction products in a direction being parallel to the longitudinal direction of the thruster 1. This means the geometrical length l of the catalyst chamber 10 corresponds to the effective length of the catalyst bed passed through by the propellant and/or its reaction products.

(8) FIGS. 2 through 4 show different embodiments of a catalyst chamber 10 according to the disclosure herein in which the geometrical length l.sub.10 can be reduced while maintaining the effective length of the catalyst bed passed through by the propellant and/or its reaction products as compared to the embodiment in FIG. 1.

(9) According to the perspective views of the different embodiments of FIGS. 2 through 4, the catalyst chamber 10 has a substantially circular shape. It is to be noted that the axial direction of the catalyst chamber 10 and the direction of the propellant flow 5, in the figures, is seen from bottom to top. An outer wall 15 of the catalyst chamber 10 provides the already mentioned circular shape of the catalyst chamber 10. The inlet 11 has a circular cross-sectional area corresponding to the diameter of the catalyst chamber through which the propellant can be introduced into the catalyst chamber 10 and the catalyst bed, respectively. The outlet 12 has a circular cross-sectional area corresponding to the cross-sectional area of the inlet 11 and enables the introduction of the propellant and/or resulting reaction products into the combustion chamber of the thruster. A catalyst volume of the catalyst chamber 10 and the catalyst bed, respectively, is formed in between the inlet 11 and the outlet 12.

(10) The catalyst chamber 10 has a cylindrical shape having a circular cross-section. Its two bases correspond to the inlet 11 and the outlet 12 of the combustion chamber. The inlet 11 and the outlet 12 lie in parallel planes being orthogonal to the direction of extension of the catalyst chamber 10. The direction of extension corresponds to the longitudinal axis of the rocket engine. The distance of the two planes, i.e. the distance between the inlet 11 and the outlet 12, corresponds to the geometrical length l.sub.10 of the catalyst chamber 10. With reference to the embodiment illustrated in FIG. 2, within the catalyst chamber 10 a helical wall member 20 is arranged. The helical wall member 20 divides the catalyst volume into two segments. An inlet of a first segment is illustrated with 11-1, its outlet is denoted with 12-1. An inlet of the second segment is illustrated with 11-2 while its outlet is denoted with 12-2. Due to the helical shape of the wall member 20 the effective length of the catalyst bed of each of the two segments which is passed through by the propellant and/or its reaction products is larger than the geometrical length l.sub.10 of the catalyst chamber 10. In case that the geometrical length l.sub.10 of the catalyst chamber 10 according to the embodiment of FIG. 2 corresponds to the length l of FIG. 1, the effective length of the catalyst bed can be enlarged. On the other hand, if the effective length of the catalyst bed of the catalyst chamber 10 according to the disclosure herein corresponds to the length l of the catalyst chamber 10 of FIG. 1, the geometrical length l.sub.10 of the catalyst chamber 10 according to the disclosure herein can be reduced.

(11) By controlling the angle of the helical wall member 20 with respect to the direction of propellant flow 5, the effective length of the catalyst bed can be controlled. This angle may be dependent from the diameter D and the cross-sectional area of the inlet 11 and the outlet 12.

(12) FIG. 3 shows a second embodiment, in which the catalyst chamber 10 comprises an inner wall 30 being arranged concentrically to the outer wall 15 of the catalyst chamber 10. Between the inner and the outer walls 15, 30 by way of example four helical wall members are arranged dividing the catalyst volume into four segments. The inlets of the four segments are denoted with 11-1, 11-2, 11-3, 11-4, while the respective outlets are denoted with 12-1, 12-2, 12-3, 12-4. The inner wall 30 is adapted to receive a not shown heating element for preheating the catalyst bed in the four segments.

(13) In the third embodiment according to FIG. 4, the inner wall 30 comprises a further helical wall member 22 dividing the volume of the inner wall into two further segments instead of a heating element. An inlet of the first segment is denoted with 13-1, its outlet is denoted with 13-2. An inlet of the second further segment is denoted with 14-1, its outlet is denoted with 14-2. The four segments arranged between the inner and the outer wall 15, 30 and the two further segments arranged within the inner wall 30 are passed through by the propellant and/or its reaction products in parallel.

(14) In general, the helical wall member and the further helical wall member 22, respectively, may comprise or consist of one or more pieces. They can be provided as an insertion element or alternatively as an integral element of the catalyst chamber 10. In the latter, the helical wall member 20 may be provided by additive manufacturing methods together with the outer wall 15, for example. In case of the embodiments illustrated in FIGS. 3 and 4, they may be provided as an integral element of the inner wall 30.

(15) The helical wall member 20, 22 can be arranged in one or more catalyst beds which are arranged in the direction of flow of the propellant one behind the other.

(16) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

REFERENCE LIST

(17) 1 thruster

(18) 2 combustion chamber

(19) 3 nozzle

(20) 4 propellant inlet

(21) 5 direction of propellant flow

(22) 10 catalyst chamber

(23) 11 inlet

(24) 11-1 inlet of a first segment

(25) 11-2 inlet of a second segment

(26) 11-3 inlet of a third segment

(27) 11-4 inlet of a fourth segment

(28) 12 outlet

(29) 12-1 outlet of the first segment

(30) 12-2 outlet of the second segment

(31) 12-3 outlet of the third segment

(32) 12-4 outlet of the fourth segment

(33) 13-1 inlet of a first further segment

(34) 13-2 inlet of a second further segment

(35) 14-1 outlet of the first further segment

(36) 14-2 outlet of the second further segment

(37) 15 outer wall of the catalyst member

(38) 20 helical wall member

(39) 22 further helical wall member

(40) 30 inner (circular wall)

(41) l geometrical length of the catalyst chamber

(42) l.sub.10 geometrical length of the catalyst chamber

(43) D diameter of the catalyst chamber