A self-throttling mechanical seal

Abstract

A fluid sealing device may include a housing comprising an inner wall defining a cavity through which fluid may flow. The device may include a disk coupled to and extending radially inward from the inner wall, the disk defining a central opening. The disk includes a deformable surface. The device may include a shaft disposed within the cavity, the shaft comprising a first portion having a first diameter and a second portion coupled to the first portion to define a shoulder. The shoulder of the shaft is disposed adjacent and substantially parallel to the deformable surface of the disk to define a fluid flow area therebetween. The deformable surface of the disk is deformable to reduce the fluid flow area without contacting the shoulder to minimize a fluid flow through the fluid flow area.

Description

A SELF-THROTTLING MECHANICAL SEALCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to 63 / 549.669 filed February 5. 2024, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND

[0002] The present disclosure relates generally to systems, methods, and devices for fluid seals (e.g., for use in engines and / or turbomachinery). Existing fluid sealing devices and methods are overly complex, have high leakage, excessive wear, and limited application (e.g., only at lower pressures and temperatures). Therefore, a need exists for improved and efficient fluid seals.SUMMARY

[0003] One implementation of the present disclosure is a fluid sealing device including a housing, a disk, and a shaft. The housing includes an inner wall defining a cavity through which fluid may flow' from a first end to a second end of the cavity. The disk is coupled to and extends radially inward from the inner wall. The disk defines an outer perimeter secured to the inner wall of the housing and an inner perimeter defining a central opening. The disk further includes a deformable surface closer to the second end of the cavity and a stationary surface coupled to the deformable surface closer to the first end of the cavity. The shaft is disposed within the cavity. The shaft includes a first portion having a first diameter and a second portion coupled to the first portion to define a shoulder. The second portion of the shaft has a second diameter smaller than the first diameter. The second portion is disposed within the central opening and closer to the first end of the cavity than the first portion. The shoulder of the shaft is disposed adjacent and substantially parallel to the deformable surface of the disk to define a fluid flow area therebetween. The deformable surface of the disk is deformable to reduce the fluid flow area without contacting the shoulder to minimize a fluid flow through the fluid flow area.

[0004] In some implementations, the fluid sealing device further includes at least one hole defined in the stationary surface configured to allow' a fluid flow' into an inner chamber defined between the stationary surface and the deformable surface of the disk.

[0005] In some implementations, a pressure differential is formed across the fluid flow area from an inlet to an outlet of the fluid flow area such that a first pressure at the inlet of the fluid flow area is equal to a fluid inlet pressure in the first end of the cavity, and a second pressure at the outlet of the fluid flow area is less than the fluid inlet pressure and equal to a fluid outlet pressure in the second end of the cavity.

[0006] In some implementations, reduction in the fluid flow area is automatically adjusted by deformation of the deformable surface of the disk in response to fluid pressure differentials in the cavity.

[0007] In some implementations, the shaft is a shaft of a motor, a turbine, or a compressor.

[0008] In some implementations, the deformable surface is moveable between a first configuration wherein the deformable surface is spaced apart from the shoulder a first distance and a second configuration wherein the deformable surface is spaced apart from the shoulder a second distance that is smaller than the first distance, wherein the second configuration is an operating condition that reduces the fluid flow area.

[0009] According to another implementation of the present disclosure, a fluid sealing device is disclosed. The fluid sealing device includes a housing, a first disk member, a second disk member, a sealing surface, and a shaft. The housing includes an inner wall defining a cavity within which fluid may flow from a first end to a second end of the cavity a first direction parallel to a longitudinal axis of the housing. The first disk member is secured to and extends radially inward from the inner wall of the housing. The first disk member has a first inner edge defining a first inner perimeter. The second disk member is secured to and extends radially inward from the inner wall of the housing and is positioned further in the first direction with respect to the first disk member. The second disk member has a second inner edge defining a second inner perimeter. The sealing surface extends parallel to the longitudinal axis between the first inner edge of the first disk member and the second inner edge of the second disk member. The sealing surface and the first and second edges define a central opening coaxial with the longitudinal axis. The shaft is disposed within the cavity coaxial with the longitudinal axis. The shaft extends through the central opening to be spaced apart from the sealing surface by a first radial distance to define a fluid flow area.

[0010] In some implementations, the sealing surface is deformable to reduce the first radial distance and the corresponding the fluid flow area, without the sealing surface contacting the shaft, to minimize a fluid flow through the fluid flow area.

[0011] In some implementations, reduction in the fluid flow area is automatically adjusted by deformation of the sealing surface in response to fluid pressure differentials in the cavity.

[0012] In some implementations, the fluid sealing device further includes at least one hole defined in and extending through the first disk member, the at least one hole configured to allow a fluid flow into an inner chamber defined between (i) the first disk member, (ii) the second disk member, (iii) and the sealing surface.

[0013] In some implementations, a pressure differential is formed across the fluid flow area from an inlet to an outlet of the fluid flow area such that a first pressure at the inlet of the fluid flow area is equal to a fluid inlet pressure in the first end of the cavity, and a second pressure at the outlet of the fluid flow area is less than the fluid inlet pressure and equal to a fluid outlet pressure in the second end of the cavity.

[0014] In some implementations, the sealing surface is moveable between a first configuration wherein the sealing surface is spaced apart from the shaft a first distance and a second configuration wherein the sealing surface is spaced apart from the shaft a second distance that is smaller than the first distance, wherein the second configuration is an operating condition that reduces the fluid flow area.

[0015] In some implementations, the shaft is a shaft of a motor, a turbine, or a compressor.

[0016] According to another implementation of the present disclosure, a fluid sealing device is disclosed. The fluid sealing device includes a housing, a shaft, a first holder, and a disk seal. The housing includes an inner wall defining a cavity within which fluid may flow from a first end to a second end of the cavity a first direction parallel to a longitudinal axis of the housing. The shaft is disposed within the cavity coaxial with the longitudinal axis. The shaft includes a first portion having a first diameter, and a second portion coupled to the first portion to define a shoulder extending perpendicularly to the longitudinal axis. The second portion of the shaft has a second diameter smaller than the first diameter. The first holder is coupled to the inner wall and extends radially inwardly from the inner wall of the housing into the cavity. The first holder includes a blocking surface extending perpendicular to the longitudinal axis. The blocking surface defines at least one hole therethrough. A flange extends parallel to and about the longitudinal axis to define a central opening through which the second portion of the shaft extends. The disk seal is retained by the first holder between the flange and the inner wall of the housing. The disk seal includes a deformable surface in fluid communication with the first end of the cavity7via the at least one hole of the blockingsurface. The deformable surface is adjacent the shoulder of the shaft to define a fluid flow area therebetween. The deformable surface of the disk seal is deformable to reduce the fluid flow area without contacting the shoulder to minimize a fluid flow through the fluid flow area.

[0017] In some implementations, the deformable surface is moveable between a first configuration wherein the deformable surface is spaced apart from the shoulder a first distance and a second configuration wherein the deformable surface is spaced apart from the shoulder a second distance that is smaller than the first distance, wherein the second configuration is an operating condition that reduces the fluid flow area.

[0018] In some implementations, the first holder is coupled to the housing via at least one fastener.

[0019] In some implementations, the fluid sealing device further includes a second holder coupled between the inner wall and the first holder, wherein a radially outward portion of the disk seal adjacent to the housing is coupled to a portion of the second holder.

[0020] In some implementations, the fluid sealing device further includes at least one spring coupled between the radially outward portion of the disk seal and the second holder, the at least one spring configured to counteract vibrations and / or thermal expansion of the disk seal.

[0021] In some implementations, the deformable surface includes a pattern of etchings thereon facing the fluid flow area, the pattern of etchings configured to prevent contact between the shoulder and the deformable surface.

[0022] In some implementations, the pattern of etchings generates lift from the fluid flowing through the fluid flow area to maintain clearance between the deformable surface and the shoulder.

[0023] Additional advantages will be set forth in part in the description which follows or may be learned by practice. The advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive, as claimed.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIGS. 1A-1B shows a cross-sectional isometric view of a fluid sealing device in an initial condition, according to one implementation. FIG. IB shows the fluid sealing device of FIG. 1 A from a side view.

[0025] FIGS. 1C-1D shows a cross-sectional isometric view of a fluid sealing device in an operating condition, according to one implementation. FIG. ID shows the fluid sealing device of FIG. 1C from a side view.

[0026] FIGS. 2A-2B shows a cross-sectional isometric view of a fluid sealing device in an initial condition, according to another implementation. FIG. 2B shows the fluid sealing device of FIG. 2A from a side view.

[0027] FIGS. 2C-2D shows a cross-sectional isometric view of a fluid sealing device in an operating condition, according to one implementation. FIG. 2D shows the fluid sealing device of FIG. 2C from a side view.

[0028] FIGS. 3A-3B shows a cross-sectional view of a fluid sealing device in an initial condition, according to another implementation. FIG. 3B shows the fluid sealing device of FIG. 3A from a partial isometric view.

[0029] FIGS. 3C-3D shows a cross-sectional view of a fluid sealing device in an operating condition, according to one implementation. FIG. 3D shows the fluid sealing device of FIG. 3C from a partial isometric view.

[0030] FIG. 4 shows a side of a deformable sealing surface that faces the working fluid with exemplary potential etching patterns for the proposed seal, according to one implementation.

[0031] FIG. 5 shows a graph of leakage vs pressure illustrating experimental results for an exemplary sealing device, according to one implementation.

[0032] FIGS. 6A-6E show simulation results for a fluid sealing device, according to one implementation. FIGS. 6A and 6B show the magnitude of the seal deformation of the model fluid seal in millimeters. FIG. 6C shows a graph of seal deformation versus radial seal length for various inlet pressures. FIG. 6D shows a graph of radial seal length versus pressure on the bottom of the seal for various inlet pressures. FIG. 6E shows a graph of leakage rate versus pressure differential.

[0033] FIGS. 7A-7C shows simulation results for a fluid sealing device, according to another implementation. FIG. 7A shows the magnitude of the seal deformation of the model fluid seal in millimeters. FIG. 7B shows a graph of seal deformation versus radial seal length for various inlet pressures. FIG. 7C shows a graph of leakage rate versus pressure differential.

[0034] FIG. 8 shows an example experimental setup for the sealing systems and devices of this disclosure.

[0035] Various objects, aspects, features, and advantages of the disclosure will become more apparent and better understood by referring to the detailed description taken in conjunction with the accompanying drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements.DETAILED DESCRIPTION

[0036] Referring generally to the figures, a self-regulating fluid seal is shown, according to various implementations.

[0037] Disclosed herein is a novel fluid sealing device and / or system having a structure and function that improves upon existing sealing mechanisms. The proposed system may find applications in a variety of industries, devices, and situations. For example, the sealing systems and devices disclosed herein may be implemented into power generation systems, aircraft systems, or other mechanical systems comprising compressors, turbines, motors, and the like. For example, the disclosed sealing systems and devices may be implemented into power generation systems such as supercritical carbon dioxide (sCCh) power generation systems. Implementing the disclosed sealing systems and devices into such a power generally system may increase system efficiency by reducing leakage, improving cycle performance, and lowering CO2 emissions.

[0038] Existing seals have reached their technical limits. Some engine seals have low operational temperature (film riding seal), scalability (compliant foil seal), and complexity (finger and HALO seals). For example, existing seals in SCO2 power generation applications encounter issues such as high leakage rates and wear. Labyrinth seals, for instance, fail to respond effectively to shaft dynamics, leading to reduced thermodynamic efficiency. This loss could be as high as 0.65% of a cycle efficiency of 51.9%. Dry gas seals are complex, costly, and have high maintenance requirements. Compliant foil seals are unsuitable for SCO2applications because secondary flow systems increase leakage rates and are incompatible with lightweight, high-speed rotors. Both brush and finger seals suffer from short lifespans, as the seal's contact with rotating parts accelerates surface wear, and finger seals in particular, are hindered by complex designs.

[0039] Therefore, a need exists for an sCCh-compatible seal that is simple, cost-effective, high-pressure and high-temperature resistant, and wear-resistant. To this end. this disclosure provides a scalable, self-regulating shaft seal based on proven elastohydrodynamic (EHD) lubrication theory. The seal features a simple design, withstands high temperatures and pressures, and achieves lower leakage rates compared to existing sCCh turbomachinery sealing solutions. The elastohydrodynamic deformation phenomenon has not before been utilized in the manner proposed herein.

[0040] Improving on the existing systems, the fluid seal disclosed herein includes a selfregulating seal design that could be used to improve aircraft engine efficiency. This sealing design could be utilized in countless applications in practice, including power generation, the aerospace industry, ship propulsion, and the oil and gas industry'. The overall shape of the fluid sealing devices of this disclosure may have a variety of implementations depending on the geometry of the system and the use case. For example, the fluid sealing devices may have a cylindrical shape with a circular cross-section. In other implementations, the shape and cross-section of the fluid sealing device may be rectangular, square, ovular, or irregular.Example 1

[0041] In one implementation of the proposed design, shown in FIGS. 1A-1D, the fluid seal is a fluid sealing device 100 having an overall cylindrical shape. The fluid sealing device 100 is shown as a cross-section in FIGS. 1A-1D, having a circular cross-sectional shape representative of a fully cylindrical fluid seal. However, in other implementations, the fluid seal of this disclosure may have a different geometry and / or shape. For example, in some implementations, the cross-section of the fluid sealing device may be ovular, elliptical, rectangular, or an irregular shape. In some implementations, the fluid sealing device itself is an ocular prism, rectangular prism, or an irregular shape.

[0042] The fluid sealing device 100 includes a housing 102 comprising an inner wall 104. The inner wall 104 defines a cavity 106. A fluid may flow through the cavity 106 from a first end 108 to a second end 110. The housing 102 has a longitudinal axis 103 extending between the first end 108 and the second end 110. In the design shown, the first end includes apressurized fluid inlet (e.g., a high-temperature, high-pressure gas), and the second end includes a fluid outlet at or near atmospheric pressure.

[0043] The fluid sealing device 100 includes a disk 112 coupled to and extending radially inward from the inner wall 104. The disk 112 defines an outer perimeter secured to the inner wall 104 of the housing 102. The disk 112 defines an inner perimeter that defines a central opening 114. The disk 112 further includes a deformable surface 116 closer to the second end 110 of the cavity 106. The disk 112 further includes a stationary surface 118 coupled to the deformable surface 11 , the stationary' surface 118 being closer to the first end 108 of the cavity' 106. The disk 112 includes hard metal materials capable of high-temperature operation with a controllable deformation (e.g., Inconel 718). The deformable surface 116 of the disk 112 is 1mm thick but may be thinner or thicker in other implementations.

[0044] The disk 112, including the deformable surface 116 and the stationary’ surface 118. extends from the housing 102 perpendicular to the inner wall 104. However, in other implementations, the disk may extend at a slight angle w ith respect to the inner wall of the housing.

[0045] At least one hole 130 is defined in the stationary surface 118. An inner chamber 132 is defined between the stationary surface 118 and the deformable surface 116. The hole 130 is configured to allow a fluid flow into the inner chamber 132.

[0046] The fluid sealing device 100 further includes a shaft 120 disposed within the cavity 106. The shaft 120 includes a first portion 122 having a first diameter and a shoulder 124. The shaft includes a second portion 126 coupled to the first portion 122 at the shoulder 124. The second portion 126 has a second diameter smaller than the first diameter. The second portion 126 is disposed within the central opening 114 closer to the first end 108 of the cavity 106 than the first portion 122 of the shaft 120.

[0047] The shoulder 124 of the first portion 122 is disposed adjacent and substantially parallel to the deformable surface 116 of the disk 112 to define a fluid flow' area 128 therebetween. The deformable surface 116 of the disk 112 is deformable to reduce the fluid flow area 128 and minimize a fluid flow through the fluid flow area 128. However, the deformable surface 116 does not contact the shoulder 124.

[0048] In use, a pressure differential is formed across the fluid flow' area 128 from an inlet 134 to an outlet 136 of the fluid flow area 128. A first pressure at the inlet 134 of the fluid flow area 128 is equal to a fluid inlet pressure at the first end 108 of the cavity 106. A secondpressure at the outlet 136 of the fluid flow area 128 is less than the fluid inlet pressure and is equal to a fluid outlet pressure in the second end 110 of the cavity 106.

[0049] The pressure in the inner chamber 132 is also equal to the fluid inlet pressure due to the fluid flowing into the inner chamber 132 via the at least one hole 130 in the stationary surface 118. Therefore, the side of the deformable surface 116 facing the inner chamber 132 remains at the fluid inlet pressure.

[0050] As shown in FIGS. 1 A and IB, the fluid flow area 128 between the deformable surface 116 and the shoulder 124 has an initial gap (e.g., ho) in a first configuration (initial condition). In a second configuration (operating condition) shown in FIGS. 1C and ID, the fluid flow area 128 reduces to a smaller gap (e.g., hi) in response to the deformation of the deformable surface 116 of the disk 112.

[0051] The reduction in the fluid flow area 128 is automatically adjusted by the deformation of the deformable surface 116 of the disk 112 in response to fluid pressure differentials in the cavity’. During operation, the inlet pressure of the fluid on the first end 108 of the cavity 106 is much larger than the outlet pressure. For example, the inlet fluid may be at 15MPa while the outlet fluid is at 0.1 MP a. Therefore, the fluid flows from the first end 108 of the cavity 106 to the second end 110 of the cavity 106 through the central opening 114 of the disk 112.

[0052] When the fluid flow starts, a pressure distribution develops across the deformable surface 116 of the disk 112 and in the fluid flow area 128, as shown in FIG. IB. The pressure distribution decays from the inner perimeter of the disk 112 to the outer perimeter of the disk 112 (in other words, from the inlet 134 to the outlet 136 of the fluid flow area 128). At this time, the pressure across the side of the deformable surface 116 within the inner chamber 132, closer to the first end 108 of the cavity 106, is equal to the pressure at the inlet 134 of the fluid flow area 128. However, the pressures elsewhere in the fluid flow area 128 are less than the fluid inlet pressure.

[0053] The pressure difference on opposing sides of the deformable surface 116 of the disk 112 causes the deformable surface 116 to deform and / or change shape. The resulting shape of the deformable surface 116 is sho\\n in FIGS. 1C and ID, in the operating condition. The pressure difference causes a middle portion of the deformable surface 116 to deform towards the shoulder 124 of the first portion 122 of the shaft 120. The outer perimeter remains fixed to the inner wall 104 of the housing 102, and the inner perimeter remains fixed to the disk1 12. However, the middle portion of the deformable surface 116 between the inner and outer perimeters is moved to form a curved body.

[0054] This deformation reduces the gap between the deformable surface 116 and the shoulder 124 (e.g., reducing the gap of the fluid flow area 128 from ho to hi). The reduced flow area (or “throaf ’) of the fluid flow area 128 reduces the overall fluid flow rate through the fluid sealing device 100. Notably, the deformable surface 116 will not contact the shoulder 124 to completely seal the fluid flow area 128 because of the difference in pressures between the inlet 134 and the outlet 136 of the fluid flow area 128. The difference in pressures negotiates for the minimum clearance physically possibly in the fluid flow area 128, which throttles the leakage flow.

[0055] One advantage of this fluid sealing system having the fluid sealing device 100 is the non-contact between the disk 112 and the shoulder 124. The non-contact seal leads to low wear, low cost, simple design / geometry, simple manufacturing, low fatigue, and low maintenance.

[0056] Another advantage of the fluid sealing device 100 is the ability to increase the pressure of the fluid such that the overall fluid flow rate decreases. This inverse relationship allows for high temperature and pressure operation of a fluid without the risk of leaks or failure. The sealing system will always negotiate for the minimum possible clearance of the throat area, throttling the flow rate to the minimum leakage condition.Example 2

[0057] In another implementation of the proposed design, shown in FIGS. 2A-2D. a fluid sealing device 200 is disclosed. The fluid sealing device 200 is similar to the fluid sealing device 100 in that the overall shape is cylindrical and the cross-sectional is circular. However, the sealing component of the fluid sealing device 200 is oriented in the longitudinal direction. The longitudinal fluid sealing device 200 is similar to the fluid sealing device 100 in that a pressure differential across a fluid flow area causes a deformable surface to deform. In each of the fluid sealing device 200 and the fluid sealing device 100, the reduced gap between a deformable surface and a shaft reduces the overall fluid flow therethrough. However, the fluid sealing device 200 includes a deformable surface that is oriented along the flowdirection. rather than perpendicular to it (e.g.. parallel to a shaft and orthogonal to the deformable surface 116 of the fluid sealing device 100). Differences in structure will be understood with reference to FIGS. 2A-2D and the below description thereof.

[0058] The fluid sealing device 200 is shown as a cross-section in FIGS. 1 A-l D, representative of a fully cylindrical fluid seal. The fluid sealing device 200 includes a housing 202 comprising an inner wall 204. The inner wall 204 defines a cavity 206. A fluid may flow through the cavity 206 from a first end 208 to a second end 210 in a first direction parallel to a longitudinal axis 203 extending between the first end 208 and the second end 210. In the design shown, the first end includes a pressurized fluid inlet (e.g., a high-temperature, high- pressure gas), and the second end includes a fluid outlet at or near atmospheric pressure.

[0059] The fluid sealing device 200 includes a first disk member 212 secured to and extending radially inward from the inner wall 204 of the housing 202. The first disk member 212 has a first inner edge 214 defining a first inner perimeter. At least one hole 230 is defined in and extending through the first disk member 212.

[0060] The fluid sealing device 200 further includes a second disk member 250 secured to and extending radially inward from the inner wall 204 of the housing 202. The second disk member 250 is positioned further in the first direction, towards the second end 210 of the cavity 206, with respect to the first disk member 212. The second disk member 250 has a second inner edge 252 defining a second inner perimeter.

[0061] The fluid sealing device 200 further includes a sealing surface 216 (or a deformable surface) extending parallel to the longitudinal axis 203 between the first inner edge 214 and the second inner edge 252. The sealing surface 216, the first inner edge 214, and the second inner edge 252 define a central opening 218 that is coaxial with the longitudinal axis 203.

[0062] An inner chamber 224 is defined between (i) the first disk member 212, (ii) the second disk member 250, (iii) and the sealing surface 216. The at least one hole 230 of the first disk member 212 is configured to allow fluid to flow into the inner chamber 224 from the first end 208 of the cavity 206.

[0063] The fluid sealing device 200 further includes a shaft 220 disposed within the cavity 206. The shaft 220 is coaxial with the longitudinal axis 203. The shaft 220 extends through the central opening 218 such that the shaft 220 is spaced apart from the sealing surface 216 by a first radial distance to define a fluid flow area 222. The fluid flow area 222 extends in the same direction as the first direction - parallel to the longitudinal axis 203.

[0064] In use, the sealing surface 216 is deformable to reduce the first radial distance, and the corresponding fluid flow area 222. to the shaft 220. The reduction in the fluid flow area 222 is automatically adjusted by the deformation of the sealing surface 216 in response tofluid pressure differentials in the cavity 206. The sealing surface 21 does not contact the shaft 220. Instead, the sealing surface 216 negotiates for a minimum first radial distance to the shaft to minimize a flow of fluid through the fluid flow area 222 (similar to the operation of the deformable surface 116 of the fluid sealing device 100).

[0065] The fluid inlet pressure on the first end 208 of the cavity 206 is greater than the fluid outlet pressure on the second end 210 of the cavity 206. causing a fluid flow in the first direction. The at least one hole 230 in the first disk member 212 creates the same fluid inlet pressure in the inner chamber 224. Thus, the pressure on the side of the sealing surface 216 interior to the inner chamber 224 is the same as the fluid inlet pressure. However, the fluid flow through the fluid flow area 222 decays from the fluid inlet pressure to the lower fluid outlet pressure. Thus, the pressure on the side of the sealing surface 216 exterior to the inner chamber 224 and facing the shaft 220 changes in the longitudinal first direction along the fluid flow area 222.

[0066] Similar to Example 1 above, this deformation of sealing surface 216 reduces the gap between the sealing surface 216 and the shaft 220 (e.g., reducing the gap of the fluid flow area 222). The reduced flow area (or '’throat' ’) of the fluid flow area 222 reduces the overall fluid flow rate through the fluid sealing device 200. Notably, the sealing surface 216 will not contact the shaft 220 to completely seal the fluid flow area 222 because of the difference in pressures betw een the first end 208 and the second end 210 of the cavity 206 on either side of the fluid flow area 222. The difference in pressures negotiates for the minimum clearance physically possibly in the fluid flow area 222, which throttles the leakage flow.

[0067] One advantage of this fluid sealing system having the fluid sealing device 200 is the non-contact between the sealing surface 216 and the shaft 220. The non-contact seal leads to low wear, low cost, simple design / geometry, simple manufacturing, low fatigue, and low maintenance.

[0068] Another advantage of fluid sealing device 200 is the ability7to increase the pressure of the fluid such that the overall fluid flow rate decreases. This inverse relationship allows for high temperature and pressure operation of a fluid without the risk of leaks or failure. The sealing system will always negotiate for the minimum possible clearance of the throat area, throttling the flow rate to the minimum leakage condition.Example 3

[0069] In one implementation of the proposed design, shown in FIGS. 3A-3D, the fluid seal is a fluid sealing device 300 having an overall cylindrical shape. The fluid sealing device 300 includes a housing 302 comprising an inner wall 304. The inner wall 304 defines a cavity 306. A fluid (e.g., supercritical carbon dioxide (sCCh)) may flow through the cavity 306 from a first end 308 to a second end 310. The housing 302 has a longitudinal axis 303 extending between the first end 308 and the second end 310. In the design shown, the first end 308 includes a pressurized fluid inlet (e.g., high-pressure sCCh) and the second end 310 includes a fluid outlet at or near atmospheric pressure.

[0070] The fluid sealing device 300 further includes a shaft 320 disposed within the cavity 306. The shaft 320 extends along and is coaxial with the longitudinal axis 303. The shaft 320 includes a first portion 322 having a first diameter and a second portion 326 having a second diameter. The second diameter smaller than the first diameter. A shoulder 324 is defined at the interface betw een the first portion 322 and the second portion 326. The shoulder 324 extends substantially perpendicular to the longitudinal axis 303. The shaft 320 may be a shaft for a motor, turbine, compressor, or similar device configured to rotate and output power.

[0071] The fluid sealing device 300 further includes a first holder 330 coupled to the inner w all 304. The first holder 330 extends radially inwardly from the inner w all 304 of the housing 302 into the cavity 306. Specifically, the first holder 330 extends over a shoulder defined on the inner wall 304 and is secured to the inner wall 304 by at least one fastener 360 (e.g., a screw). However, in other implementations, the first holder may be coupled to the housing in a different manner (e.g., bolts, pressure fit, or integrally formed together).

[0072] The first holder 330 includes a blocking surface 332 extending perpendicular to the longitudinal axis 303. The blocking surface 332 extends across nearly the entire cross- sectional area of the cavity' 306. The blocking surface 332 defines at least one hole 334 therethrough. The at least one hole 334 allows fluid to pass through. The first holder 330 further includes a flange 336 extending parallel to and about the longitudinal axis 303. The flange 336 defines a central opening 338. The second portion 326 of the shaft 320 is disposed within the central opening 338 (e.g., closer to the first end 308 of the cavity’ 306 than the first portion 322 of the shaft 320).

[0073] The fluid sealing device 300 further includes a disk seal 340. The disk seal 340 includes a first member 342 (e.g., a radially inward member), a second member 344 (e g., a radially outward member), and a deformable surface 346 extending between the first member342 and the second member 344. The disk seal 340 is retained at least partially by the first holder 330. The first member 342 of the disk seal 340 is coupled to and / or abuts the flange 336 of the first holder 330. The second member 344 of the disk seal 340 is coupled to and / or abuts the inner wall 304 of the housing 302.

[0074] An inner cavity 349 of the disk seal 340 is defined by the first member 342. the second member 344. and the deformable surface 346. The inner cavity 349, and the deformable surface 346 therein, is in fluid communication with the first end 308 of the cavity 306 via the at least one hole 334 in the blocking surface 332 of the first holder 330. The deformable surface 346 extends substantially perpendicular to the longitudinal axis 303. The deformable surface 346 is adjacent to the shoulder 324 of the shaft 320 to define a fluid flow area 348 therebetween. The deformable surface 346 is deformable to reduce the fluid flow area 348 and minimize a flow of fluid therethrough. In some examples, the deformable surface 346 avoids contact with the shoulder 324. The deformable surface 346 may include a metal material or composite, such as Inconel or similar alternatives described herein.

[0075] In some implementations, the disk seal 340 is welded on a front and back ring (e.g., the first and second member 342, 344) in the radial direction. In some implementations, the disk seal is fabricated through a plunge electrical discharge machining (EDM) method. Plunge EDM can achieve high tolerances on complex geometries and patterns, and it is capable of high-quality surface finishes.

[0076] The deformable surface 346 further includes a pattern of etchings on a side facing the fluid flow area 348. For example, the etchings may be laser engraved or physically cut into the deformable surface 346. The pattern of etchings is configured to prevent contact between the deformable surface 346 and the shoulder 324. For example, the pattern of etchings generates lift from the fluid flowing through the fluid flow area 348 to maintain clearance between the deformable surface 346 and the shoulder 324. As shown in FIG. 4, a variety of different patterns of etching are contemplated by this disclosure. The examples shown in FIG. 4 are exemplary only, and the patterns, shapes, geometry, and practical effects of the etchings contemplated by this disclosure are not limited to those show in FIG. 4. The patterns of etching shown in FIG. 4, and variations thereof, may be implemented with any of the sealing devices disclosed herein.

[0077] The fluid sealing device 300 further includes a second holder 350 coupled between the inner wall 304 of the housing 302, the blocking surface 332 of the first holder 330, andthe second member 344 of the disk seal 340. The second holder 350 is coupled to the inner wall 304 and the first holder 330 by the at least one fastener 360, as shown in FIG. 3A. The second holder 350 at least partially couples to and / or abuts the second member 344 of the disk seal 340 to retain the disk seal 340 in place.

[0078] The second holder 350 defines a recess 352 on a downstream side of the second holder 350 facing the second member 344. A spring 354 is disposed within the recess 352. The spring 354 extends between the recess 352 of the second holder 350 and the second member 344 of the disk seal 340. The spring 354 may include a plurality of springs disposed within the second holder 350 around the periphery of the housing 302. The spring 354 is configured to counteract vibrations and / or thermal expansion of the disk seal 340 during use. Thus, the spring 354 makes the fluid sealing device 300 a floating sealing device movable in the axial direction, as shown in FIG. 3D.

[0079] In use, a pressure differential is formed across the fluid flow area 348 - similar to that of the fluid flow area 128 of FIGS. 1A-1D. The pressure differential is formed from an inlet 362 to an outlet 364 of the fluid flow area 348. A first pressure at the inlet 362 of the fluid flow area 348 is equal to a fluid inlet pressure at the first end 308 of the cavity 306. A second pressure at outlet 364 of the fluid flow area 348 is less than the fluid inlet pressure and is equal to a fluid outlet pressure in the second end 310 of the cavity 306.

[0080] The pressure in the inner cavity 349 of the disk seal 340 is also equal to the fluid inlet pressure due to the fluid flowing into the inner cavity 349 via the at least one hole 334 of the first holder 330. Therefore, the side of the deformable surface 346 facing the inner cavity 349 remains at the fluid inlet pressure.

[0081] As shown in FIGS. 3A and 3B, the fluid flow area 348 between the deformable surface 346 and the shoulder 324 has an initial gap (e.g., ho) in a first configuration (initial condition). In a second configuration (operating condition) shown in FIGS. 3C and 3D, the fluid flow area 348 reduces to a smaller gap (e.g., hi) in response to the deformation of the deformable surface 346.

[0082] The reduction in the fluid flow area 348 is automatically adjusted by the deformation of the deformable surface 346 of the disk seal 340 in response to fluid pressure differentials in the cavity. During operation, the inlet pressure of the fluid on the first end 308 of the cavity 306 is much larger than the outlet pressure. Therefore, the fluid flows from thefirst end 308 of the cavity 306 to the second end 310 of the cavity 306 through the central opening 338 of the first holder 330.

[0083] When the fluid flow starts, a pressure distribution develops across the deformable surface 346 and in the fluid flow area 348, as shown in FIG. 3A. The pressure distribution decays from the inner perimeter of the disk seal 340 to the outer perimeter of the disk seal 340 (in other words, from the inlet 362 to the outlet 364 of the fluid flow area 348). At this time, the pressure across the side of the deformable surface 346 within the inner cavity 349, closer to the first end 308 of the cavity 306, is equal to the pressure at the inlet 362 of the fluid flow area 348. However, the pressures elsewhere in the fluid flow area 348 are less than the fluid inlet pressure.

[0084] The pressure difference on opposing sides of the deformable surface 346 of the disk seal 340 causes the deformable surface 346 to deform and / or change shape. The resulting shape of the deformable surface 346 is shown in FIGS. 3C and 3D, in the operating condition. The pressure difference causes a middle portion of the deformable surface 346 to deform towards the shoulder 324 of the shaft 320 to form a curved body.

[0085] This deformation reduces the gap between the deformable surface 346 and the shoulder 324 (e.g., reducing the gap of the fluid flow area 348 from ho to hi). The reduced flow area (or “throat”) of the fluid flow area 348 reduces the overall fluid flow rate through the fluid sealing device 300. Notably, the deformable surface 346 will not contact the shoulder 324 to completely seal the fluid flow area 348 because of the difference in pressures between the inlet 362 and the outlet 364 of the fluid flow area 348. The difference in pressures negotiates for the minimum clearance physically possibly in the fluid flow area 348, which throttles the leakage flow.

[0086] One advantage of this fluid sealing system having the fluid sealing device 300 is the non-contact between the disk seal 340 and the shoulder 324. The non-contact seal leads to low wear, low cost, simple design / geometry, simple manufacturing, low fatigue, and low maintenance. Another advantage of the fluid sealing device 300 is the ability to increase the pressure of the fluid such that the overall fluid flow rate decreases. This inverse relationship allows for high temperature and pressure operation of a fluid without the risk of leaks or failure. The sealing system will always negotiate for the minimum possible clearance of the throat area, throttling the flow rate to the minimum leakage condition.

[0087] In some implementations of the disclosed sealing devices, including any one of the fluid sealing devices shown and described in FIGS. 1A-3D, various alternative configurations and optional features are contemplated by this disclosure. For example, in some implementations, cooling jackets are implemented to cool the working fluid before it enters the cavity. Cooling working fluid can help to stabilize the thermal profile around the sealing members. Such an approach can mitigate cyclic deformations, reduce wear and leakage, and provide enhanced seal reliability .

[0088] In some implementations, a surface coating is provided on the deformable surface of the sealing member and / or device. For example, a surface coating suitable for sCCh operating conditions may be applied to potential contact regions over the seal surface. Nickel-based coatings (NiCr, NiCrAl) and chromium-based coatings (CnC?. CrN) may be implemented due to their performance under similar harsh environments. Additionally, MCrAlY coatings could provide a reliable solution for both oxidation resistance and thermal cycling durabilityin sCCh turbomachinery.Testing Methodology and Results

[0089] FIG. 5 shows a leakage vs pressure curve displaying experimental results for an elastohydrodynamic (EHD) seal. The experimental seal was made of Bearing Grade PEEK with a sleeve thickness of 0.1-in. It maintained an overall clearance of 0.001-in with a 2-in shaft. Although PEEK material was used in the conducted experiment, in other implementations, other metal materials may be used. For example, ASME-approved Inconel and Haynes alloys may be selected as the seal materials as they meet the requirements for sCCh operating conditions. The reason for using PEEK in the demonstration was its lower elastic modulus, which allowed for the use of thicker seals in the radial direction.

[0090] In other implementations of the disclosed sealing device, Inconel and carbon graphite can be combined to create a composite seal structure, i.e., Inconel as the structural support and carbon graphite as the w ear surface, to produce a thicker sealing surface due to carbon graphite’s lower elastic modulus. This approach would also eliminate fabrication challenges associated with a potentially thin sealing face. Bonding these two materials could be accomplished with a mechanical fastening approach (like a clamping ring or bolting) to secure the carbon graphite to the Inconel structure. This method allows the materials to expand independently, minimizing thermal stress buildup while maintaining structural integrity.

[0091] As shown in FIG. 5, the maximum average leakage was measured to be 4.49 g / s at 6 MPa. The flow rate then began dropping to 0.43 g / s as the differential pressure increased up to 15 MPa, generating a bell-shaped curve. At a 95% confidence level, the estimated confidence intervals for the average data were ±0. 12 g / s and ±0.09 g / s, respectively, for pressures of 6 MPa and 15 MPa. This unique behavior of the EHD seal could become advantageous for sCCh turbomachinery considering that it, in fact, reduces the leakage on the higher end of the pressure spectrum. This is contrary to a typical clearance type seal, such as a dry gas seal, where the leakage increases linearly with increasing pressures.

[0092] Simulation Data

[0093] A computational study was performed to evaluate the performance of a radial fluidic seal of this disclosure. Specifically, a disk having two fixed ends, similar to FIGS. 1 A- 1D. was selected for the study. Fluid-structure-interaction simulations were carried out in COMSOL Multiphysics software. The simulations evaluated the deformation of the hollow disk structure only - not the flow of fluid around the entire seal system.

[0094] The results of this computational study are presented in FIGS. 6A-6E. Each of FIGS. 6A-6C shows the seal deformation (e g., the deformation of the deformable surface 116 of the fluid sealing device 100). As an example, FIG. 6C shows the seal deformation in millimeters across the radial seal length. In other words, FIG. 6C shows the curvature of the deformable portion of the hollow disk when subjected to varied pressures.

[0095] FIG. 6E shows the leakage rate versus pressure differential. Notably, FIG. 6E shows one of the advantages of the system disclosed. At the initial condition, the leakage rate is relatively low, reflecting the fluid seal in the initial configuration. As pressure increases, so does the flow rate of fluid through the seal, which is expected. However, after a critical pressure, the hollow disk deforms to reduce the throat area of the fluid flow, reducing the overall leakage rate. As a result, increasing pressures in the fluid result in decreasing leakage flow rates - an unexpected result of the disclosed structure.

[0096] Another computational study was performed to evaluate the performance of a radial fluid seal of this disclosure. Specifically, a disk having two fixed ends, similar to FIGS. 3A- 3D, was selected for the study. The properties and parameters for this study included the following: Seal Material - Carbon Graphite; Seal Length in radial direction - 25.4mm; Seal Thickness - 3mm; Seal Clearance - 33.75 pm; and Pressure Range - 0. 1 to 10 MPa. Fluidstructure-interaction simulations were carried out in COMSOL Multiphysics software. Thesimulations evaluated the deformation of the hollow disk structure only - not the flow of fluid around the entire seal system.

[0097] The results of this computational study are presented in FIGS. 7A-7C. FIG. 7A shows the seal deformation (e.g., the deformation of the deformable surface 346 of the fluid sealing device 300). As an example, FIG. 7B shows the seal deformation in millimeters across the radial seal length. In other words. FIG. 7B shows the curvature of the deformable portion of the disk seal when subjected to varied pressures.

[0098] FIG. 7C shows the leakage rate versus pressure differential. Notably, FIG. 7C shows one of the advantages of the system disclosed. At the initial condition, the leakage rate is relatively low, reflecting the fluid seal in the initial configuration. As pressure increases, so does the flow rate of fluid through the seal, which is expected. However, after a critical pressure, the hollow disk deforms to reduce the throat area of the fluid flow, reducing the overall leakage rate. As a result, increasing pressures in the fluid result in decreasing leakage flow rates - an unexpected result of the disclosed structure.

[0099] Experimental Methodology

[0100] FIG. 8 shows an example experimental setup for the sealing systems and devices of this disclosure. Experiments will be conducted on a 2-in static stepped shaft configuration. The tests will be conducted in a Thermo Fluidic Systems Laboratory. The tests will be carried out at room temperature with nitrogen as the working fluid for the sake of simplicity. A CGA-580 N2 tank, a cylindrical chamber, housing the static shaft and the test seal, steel tubing with compression-type fittings, a PX5500C0-2.5KA10E pressure sensor to measure the inlet pressure of the chamber after the pressure regulator from the tank, a PX409- 1.0KA10V pressure sensor and a TC-K-1 / 4NPT-U-72 temperature sensor to measure the outlet pressure and temperature, and lastly an FMA-1623AI mass flow meter to measure the volumetric and mass flow at the outlet will be used in the test rig (FIG. 4 below). The data will be collected using National Instruments DAQ - Modules NI- 9205, NI-9212, NI-9253, and Lab VIEW software to measure pressure, temperature, and mass flow rate. The trials will be run with an inlet pressure of up to 15.00 MPa and an initial clearance of 40 pm. It is expected that the leakage rate will increase with increasing inlet pressures, reaching a peak before starting to reduce to minimal values at the higher end of the pressure spectrum.Configuration of Certain Implementations

[0101] The construction and arrangement of the systems and methods as shown in the various implementations are illustrative only. Although only a few implementations have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative implementations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the implementations without departing from the scope of the present disclosure.

[0102] It is to be understood that the methods and systems are not limited to specific synthetic methods, specific components, or to particular compositions. It is also to be understood that the terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting.

[0103] As used in the specification and the appended claims, the singular forms “a,” “an7’ and “the’’ include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another implementation includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another implementation. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0104] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0105] Throughout the description and claims of this specification, the word “comprise” and variations of the w ord, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integersor steps. “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal implementation. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0106] Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific implementation or combination of implementations of the disclosed methods.

Claims

WHAT IS CLAIMED IS:

1. A fluid sealing device comprising: a housing comprising an inner wall defining a cavity through which fluid may flow from a first end to a second end of the cavity; a disk coupled to and extending radially inward from the inner wall, the disk defining an outer perimeter secured to the inner wall of the housing and an inner perimeter defining a central opening, the disk further comprising a deformable surface closer to the second end of the cavity and a stationary surface coupled to the deformable surface closer to the first end of the cavity; and a shaft disposed within the cavity, the shaft comprising a first portion having a first diameter, and a second portion coupled to the first portion to define a shoulder, the second portion of the shaft having a second diameter smaller than the first diameter, the second portion disposed within the central opening and closer to the first end of the cavity than the first portion, wherein the shoulder of the shaft is disposed adjacent and substantially parallel to the deformable surface of the disk to define a fluid flow area therebetween, and wherein the deformable surface of the disk is deformable to reduce the fluid flow area without contacting the shoulder to minimize a fluid flow through the fluid flow area.

2. The fluid sealing device of claim 1, further comprising at least one hole defined in the stationary surface configured to allow a fluid flow into an inner chamber defined between the stationary surface and the deformable surface of the disk.

3. The fluid sealing device of claim 1, wherein a pressure differential is formed across the fluid flow area from an inlet to an outlet of the fluid flow area such that a first pressure at the inlet of the fluid flow area is equal to a fluid inlet pressure in the first end of the cavity, and a second pressure at the outlet of the fluid flow area is less than the fluid inlet pressure and equal to a fluid outlet pressure in the second end of the cavity .

4. The fluid sealing device of claim 1, wherein reduction in the fluid flow area is automatically adjusted by deformation of the deformable surface of the disk in response to fluid pressure differentials in the cavity.

5. The fluid sealing device of claim 1, wherein the shaft is a shaft of a motor, a turbine, or a compressor.

6. The fluid sealing device of claim 1, wherein the deformable surface is moveable between a first configuration wherein the deformable surface is spaced apart from the shoulder a first distance and a second configuration wherein the deformable surface is spaced apart from the shoulder a second distance that is smaller than the first distance, wherein the second configuration is an operating condition that reduces the fluid flow area.

7. A fluid sealing device comprising: a housing comprising an inner wall defining a cavity within which fluid may flow from a first end to a second end of the cavity a first direction parallel to a longitudinal axis of the housing; a first disk member secured to and extending radially inward from the inner wall of the housing, the first disk member having a first inner edge defining a first inner perimeter; a second disk member secured to and extending radially inward from the inner wall of the housing and positioned further in the first direction with respect to the first disk member, the second disk member having a second inner edge defining a second inner perimeter; a sealing surface extending parallel to the longitudinal axis between the first inner edge of the first disk member and the second inner edge of the second disk member, the sealing surface and the first and second edges defining a central opening coaxial with the longitudinal axis; and a shaft disposed within the cavity coaxial with the longitudinal axis, the shaft extending through the central opening to be spaced apart from the sealing surface by a first radial distance to define a fluid flow area.

8. The fluid sealing device of claim 7, wherein the sealing surface is deformable to reduce the first radial distance and the corresponding the fluid flow area, without the sealing surface contacting the shaft, to minimize a fluid flow through the fluid flow area.

9. The fluid sealing device of claim 8, wherein reduction in the fluid flow area is automatically adjusted by deformation of the sealing surface in response to fluid pressure differentials in the cavity .

10. The fluid sealing device of claim 7, further comprising at least one hole defined in and extending through the first disk member, the at least one hole configured to allow a fluid flow into an inner chamber defined between (i) the first disk member, (ii) the second disk member, (iii) and the sealing surface.

11. The fluid sealing device of claim 7, wherein a pressure differential is formed across the fluid flow area from an inlet to an outlet of the fluid flow area such that a first pressure at the inlet of the fluid flow area is equal to a fluid inlet pressure in the first end of the cavity, and a second pressure at the outlet of the fluid flow area is less than the fluid inlet pressure and equal to a fluid outlet pressure in the second end of the cavity.

12. The fluid sealing device of claim 7, wherein the sealing surface is moveable between a first configuration wherein the sealing surface is spaced apart from the shaft a first distance and a second configuration wherein the sealing surface is spaced apart from the shaft a second distance that is smaller than the first distance, wherein the second configuration is an operating condition that reduces the fluid flow area.

13. The fluid sealing device of claim 7, wherein the shaft is a shaft of a motor, a turbine, or a compressor.

14. A fluid sealing device, comprising: a housing comprising an inner wall defining a cavity within which fluid may flow from a first end to a second end of the cavity a first direction parallel to a longitudinal axis of the housing; a shaft disposed within the cavity coaxial with the longitudinal axis, the shaft comprising a first portion having a first diameter, and a second portion coupled to the first portion to define a shoulder extending perpendicularly to the longitudinal axis, the second portion of the shaft having a second diameter smaller than the first diameter;a first holder coupled to the inner wall and extending radially inwardly from the inner wall of the housing into the cavity, the first holder comprising a blocking surface extending perpendicular to the longitudinal axis, the blocking surface defining at least one hole therethrough, and a flange extending parallel to and about the longitudinal axis to define a central opening through which the second portion of the shaft extends; and a disk seal retained by the first holder between the flange and the inner wall of the housing, the disk seal comprising a deformable surface in fluid communication with the first end of the cavity via the at least one hole of the blocking surface, the deformable surface being adjacent the shoulder of the shaft to define a fluid flow area therebetween, wherein the deformable surface of the disk seal is deformable to reduce the fluid flow area without contacting the shoulder to minimize a fluid flow through the fluid flow area.

15. The fluid sealing device of claim 14. wherein the deformable surface is moveable between a first configuration wherein the deformable surface is spaced apart from the shoulder a first distance and a second configuration wherein the deformable surface is spaced apart from the shoulder a second distance that is smaller than the first distance, wherein the second configuration is an operating condition that reduces the fluid flow area.

16. The fluid sealing device of claim 14, wherein the first holder is coupled to the housing via at least one fastener.

17. The fluid sealing device of claim 14. further comprising a second holder coupled between the inner wall and the first holder, wherein a radially outward portion of the disk seal adjacent to the housing is coupled to a portion of the second holder.

18. The fluid sealing device of claim 17. further comprising at least one spring coupled between the radially outward portion of the disk seal and the second holder, the at least one spring configured to counteract vibrations and / or thermal expansion of the disk seal.

19. The fluid sealing device of claim 14. wherein the deformable surface includes a pattern of etchings thereon facing the fluid flow area, the pattern of etchings configured to prevent contact between the shoulder and the deformable surface.

20. The fluid sealing device of claim 19, wherein the pattern of etchings generates lift from the fluid flowing through the fluid flow area to maintain clearance between the deformable surface and the shoulder.

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