Mitigation of vibration in pipe systems
A liquid flow-induced vibration suppression device, system, and method are disclosed. In an embodiment, the device is a mounting ring or hoop to which fin-shaped strakes are secured. The hoop is affixable to an interior wall of a first pipe positioned upstream of, and connected by a flexible joint to, a second pipe. The strakes are angled inwardly from the interior wall, and are positioned adjacent to an interface of the first pipe and the flexible joint. In one fluid dynamics modeled example involving rocket motor thrust vectoring, liquid fuel is conveyed in 16-inch diameter pipes at cryogenic temperatures. The strakes are one inch long, spaced apart approximately 0.1 inch, and extend radially from the interior wall in a 10-to-30-degree angle range. The device is brazed to the interior wall of the first pipe, and can be formed of INCONEL® or titanium alloy to optimize fatigue life.
1 . A vibration suppression device for mitigating liquid flow-induced vibration within a first pipe connected to a second pipe by a flexible joint, the vibration suppression device comprising:
a circumferential hoop affixed to an interior wall of the first pipe, the first pipe positioned upstream of the second pipe,
wherein the circumferential hoop is affixed to the interior wall of the first pipe, at an interface of the first pipe and the second pipe, and
wherein the first pipe and the second pipe are separate pipes connected by the flexible joint; and
a plurality of strakes attached to the circumferential hoop, the plurality of strakes configured to extend axially downstream of the circumferential hoop, adjacent to the flexible joint, and angled radially inwardly from the interior wall of the first pipe.
2 . The vibration suppression device of claim 1 , wherein the circumferential hoop and the plurality of strakes are formed of titanium alloy or a nickel-chromium based alloy.
3 . The vibration suppression device claim 1 , wherein the plurality of strakes are bonded to the circumferential hoop by brazing.
4 . The vibration suppression device of claim 1 , wherein the plurality of strakes are configured to be oriented radially inwardly from the interior wall at an angle within a range of 10 to 30°.
5 . The vibration suppression device of claim 1 , wherein the circumferential hoop and the plurality of strakes are separately formed, and wherein the plurality of strakes are bonded to the circumferential hoop by brazing.
6 . The vibration suppression device of claim 1 , wherein the circumferential hoop comprises a first hoop and a second hoop to which the plurality of strakes are attached.
7 . The vibration suppression device of claim 6 , wherein both the first hoop and the second hoop are affixable to the interior wall.
8 . The vibration suppression device of claim 1 , wherein the circumferential spacing between the plurality of strakes is derived through an iterative modeling analysis.
9 . The vibration suppression device of claim 1 , wherein the plurality of strakes are fin-shaped, and are configured to be spaced about the circumferential hoop.
10 . The vibration suppression device of claim 1 , wherein the circumferential hoop and the plurality of strakes are formed by stamping.
11 . A vibration suppression system for reducing liquid flow-induced vibration, the vibration suppression system comprising:
a first pipe, a second pipe, and a flexible joint, the flexible joint connecting the first pipe and the second pipe for liquid flow from the first pipe through the flexible joint and into the second pipe, wherein the first pipe is positioned upstream of the flexible joint,
wherein the first pipe and the second pipe are separate pipes;
a circumferential hoop affixed to an interior wall of the first pipe adjacent to the flexible joint,
wherein the circumferential hoop is affixed to the interior wall of the first pipe, at an interface of the first pipe and the second pipe; and
a plurality of strakes attached to the circumferential hoop, the plurality of strakes extending downstream of the circumferential hoop, and oriented radially inwardly from the interior wall of the first pipe.
12 . The vibration suppression system of claim 11 , wherein each of the first pipe and the second pipe has a connection end, and wherein the flexible joint is a bellows secured to each connection end by a clamp.
13 . The vibration suppression system of claim 12 , wherein the bellows is formed of either a nickel-chromium based alloy or of a titanium alloy.
14 . The vibration suppression system of claim 12 , wherein the plurality of strakes are fin-shaped, and are oriented radially inwardly from the interior wall at an angle having a range of 10 to 30°.
15 . The vibration suppression system of claim 11 , wherein the circumferential hoop and the plurality of strakes are formed of a titanium alloy stamping.
16 . The vibration suppression system of claim 15 , wherein the circumferential hoop and the plurality of strakes are secured together by brazing.
17 . The vibration suppression system of claim 12 , wherein the bellows has a first pipe attachment end and a second pipe attachment end, and wherein each attachment end has an interior lip radially under convolutions of the bellows.
18 . The vibration suppression system of claim 17 , wherein the circumferential hoop is brazed to an outer surface of one interior lip that is part of the interior of the first pipe.
19 . A method, comprising:
mitigating, by a vibration suppression device, liquid flow-induced vibration within a first pipe connected to a second pipe by a flexible joint,
wherein the first pipe and the second pipe are separate pipes, and
wherein the vibration suppression device comprises:
a circumferential hoop affixed to an interior wall of the first pipe, the first pipe positioned upstream of the second pipe,
wherein the circumferential hoop is affixed to the interior wall of the first pipe, at an interface of the first pipe and the second pipe; and
a plurality of strakes attached to the circumferential hoop, the plurality of strakes configured to extend axially downstream of the circumferential hoop, adjacent to the flexible joint, and angled radially inwardly from the interior wall of the first pipe.
20 . The method of claim 19 , wherein the flexible joint connects the first pipe and the second pipe for liquid flow from the first pipe through the flexible joint and into the second pipe.
21 . A method of suppressing liquid flow-induced vibration within at least a first pipe, a second pipe, and a bellows connecting the first pipe to the second pipe; the method comprising:
conducting fluid dynamics modeling of the first pipe and second pipe, each having a predetermined diameter, the first pipe being configured to flow liquid through the bellows and into the second pipe,
wherein the bellows is flexible,
wherein modeling elements include a hoop and a plurality of strakes attached to the hoop for determining optimal hoop and strake criteria to mitigate liquid flow-induced vibrations within the first pipe, the second pipe, and the bellows,
wherein the first pipe and the second pipe are separate pipes;
forming a hoop in accordance with modeling-determined criteria, including hoop thickness;
forming and attaching a plurality of modeling-determined geometrically sized and angled strakes to the hoop,
wherein the strakes are configured to extend axially downstream of the hoop, adjacent to the flexible joint, and angled radially inwardly from an interior wall of the first pipe; and
securing the hoop to the interior wall of the first pipe in a location adjacent to and upstream of the bellows, in accordance with modeling-determined criteria,
wherein the hoop is secured at an interface of the first pipe and the second pipe, and
wherein the first pipe is positioned upstream of the second pipe.
22 . The method of claim 21 , wherein the hoop is secured to the interior wall by brazing.