Patent Application
20240066435
This application relates to a fiber membrane type fuel deoxygenation system wherein the fiber membrane system has enhanced durability.
Gas turbine engines are known and typically include a fuel supply for supplying fuel to a combustor. The fuel is mixed with air and ignited.
It is known that if oxygen is dissolved in the fuel when heated carbonaceous deposits will form. This is undesirable.
Thus, it is known to provide oxygen removal systems in a fuel supply system, such as for a gas turbine engine. While various types of oxygen removal systems are known, one that has proven successful is a bundle of hollow membrane tubes. The fuel is passed into the bundle and the oxygen passes through the tubes.
The dissolved gasses are then removed from the system, such as through a vacuum.
In practice, leakage of the fuel into the membranes has sometimes occurred. This is undesirable.
A method of forming a system for degassing a fluid includes the steps of a) forming a bundle of hollow tube membrane members by wrapping hollow tube membrane members to form the bundle. The hollow membrane tube member is wrapped at an angle with respect to an axial direction of the bundle. In step b) the bundle is inserted into an outer canister. Step a) is performed in an enclosure maintained at a temperature above 100° F. (38° C.).
A method of forming a system for degassing a fluid includes the steps of a) forming a bundle of hollow tube membrane members by wrapping hollow tube membrane members to form the bundle. The hollow membrane tube member is wrapped at an angle with respect to an axial direction of the bundle. In step b) the bundle is inserted into an outer canister. Step b) is performed in an enclosure maintained at a temperature above 100° F. (38° C.).
A fuel supply system for a gas turbine engine includes a pump, an oxygen removal system and a combustor. The pump is configured to move fuel through the oxygen removal system to the combustor. The oxygen removal system has a bundle of hollow tube membrane members forming a bundle. The hollow tube membrane members are wrapped at an angle relative to each other, and received within an outer canister. A wrapping step for wrapping the hollow tube members occurs at a temperature equal to or above 100° F. (38° C.), and insertion of the bundle into the outer canister also occurs at a temperature above 100° F. (38° C.).
These and other features will be best understood from the following drawings and specification, the following is a brief description.
The fuel is then delivered into a combustor 26 of a gas turbine engine 127, shown schematically.
One type of oxygen removal system 24 is illustrated in
Fuel is passed within the bundle 28, and oxygen or other gasses are removed from the fuel by passing through the wall over the tubes. It should be understood that coatings such as a Teflon AF is highly permeable to oxygen and, therefore, this coating is applied on an outer surface of the membranes.
As shown in
An axial direction is defined from an inlet end 100 to an outlet end 102.
The tube bundle 28 is positioned around an interior baffle 36. The fuel passes into an inlet port 21 from the fuel pump 22, and the baffles 36 cause the fuel to move radially inwardly and outwardly, and encounter the tube bundle 28.
The fuel eventually reaches a location downstream of the baffle 36 and exits to the engine 127 through an outlet port 19. Oxygen passes into an outer periphery of the tube members in the bundle 28 into chambers 31 which is inwardly of the outer canister 29. Ports 32 may be connected to a vacuum pump 25 to remove the oxygen. There is an area 38 inward of the inner periphery 34 of the bundle 28 that allows the fuel to flow along the inner periphery 34 as guided by the baffles 36. The system as described above is generally as known.
As mentioned above, there has sometimes been challenges with fuel leaking into the bundle, which is undesirable. Applicant has recognized that some of the leakage occurs due to localized damage in the fiber bundle 28 at least partially due to thermal strains and stresses. Applicant has recognized that this local damage is due to both loads and thermal deformation and thermal stresses. Applicant has recognized that the thermal stresses are a result of differences in coefficients of thermal expansion between different components in the system 24, and also a temperature range between the temperature at which the bundle 28 and system 24 were formed and assembled, and the temperature that they might see in practice.
Essentially, Applicant has recognized that one reason for the leakage is initiation and growth of micro-damages during service conditions, and that the micro-damages are primarily influenced i) by stresses due to local load transfer and also ii) by thermal stresses due to differences in thermal expansion properties of key constituents of the fiber membrane system and temperature variation from conditions of fabrication to temperature actual service. Thus, the proposed solution is aimed to reduce the thermal stresses to improve durability of fuel deoxygenation systems, i.e., reduce risks of their fuel leakage.
Thermal strain is defined by a formula as follows:
Δε=ΔT*α,
where ΔT=temperature range between formation or assembly temperature and operating temperature, and α=coefficient of thermal expansion (CTE).
The above formula of thermal strains in shown on example of constant CTE, i.e., independent of temperature. However, even in a case of thermal dependence of CTE, higher temperature range ΔT will still be associated with higher thermal strains Δε. In other words, reduction of ΔT is an efficient way to reduce thermal strains and stresses. For simplicity, the description below is given for a case where CTE a is independent of temperature.
In the past, the tube bundle 28 has typically been wrapped at ambient temperatures. Moreover, the system 24 has generally been assembled at ambient temperatures. Of course, ambient temperatures are the easiest to utilize.
However, as shown schematically in
As is known, the membrane fibers 27 are wrapped at an angle relative to each other and around each other. The angle of each wrap need not be equal to angles of other wraps.
Any number of methods may be used for the wrapping step.
A control 40 controls a temperature with an interior 44 of an enclosure 42 in which the wrapping occurs. The interior 44 is maintained at an elevated temperature. This allows the ΔT component to be dramatically reduced. Since the wrap of the fibers 27 occurs at elevated temperature, the ΔT compared to the operating temperatures typically seen in a gas turbine engine will be significantly smaller.
It is typical that an oxygen removal system in an aircraft fuel supply may see temperatures in operation between 170° F. (77° C.) and 270° F. (132° C.). As mentioned above, in the past, the wrapping of the bundle 28 has typically occurred at ambient temperatures, or approximately 70° F. (21° C.). Thus, ΔT was routinely as high as 200° F. (93° C.).
However, in a disclosed method, the temperature within the chamber 44 is maintained above 100° F. In embodiments, it is also below 400° F. In further embodiments, it is above 120° F. and less than 300° F. In some embodiments, it is between 150° F. (66° C.) and 190° F. (88° C.). In alternative embodiments, it is between 200° F. (93° C.) and 240° F. (116° C.).
Gas turbine engines are being developed which will operate at increasing temperatures. Thus, the ΔT for the prior art oxygen removal systems wrapped at ambient temperatures will become even larger. The disclosed method dramatically reduces those differences, and will provide a more efficient operation.
However, as shown schematically at
This assembly occurs within an enclosure 50 and in a space 52 within the enclosure 50. Here again, the control 40 controls the temperature within the chamber 52 during this assembly.
It is typical that an oxygen removal system in an aircraft fuel supply may see temperatures between 170° F. (77° C.) and 270° F. (132° C.). As mentioned above, in the past, the assembly has typically occurred at ambient temperatures, or approximately 70° F. (21° C.). Thus, ΔT was routinely as high as 200° F. (93° C.).
However, in a disclosed method, the temperature within the space 52 is maintained above 100° F. (38° C.). In embodiments, it is also below 400° F. (204° C.). In further embodiments, it is above 120° F. (49° C.) and less than 300° F. (149° C.). In some embodiments, it is between 150° F. (66° C.) and 190° F. (88° C.). In alternative embodiments, it is between 200° F. (93° C.) and 240° F. (116° C.).
A method of forming a system for degassing a fluid under this disclosure could be said to include the steps of a) forming a bundle of hollow tube membrane members by wrapping hollow membrane tubes to form the bundle. The hollow tube membrane members are wrapped at an angle with respect to an axial direction of the bundle. In step b) the bundle is inserted into an outer canister. Step a) is performed in an enclosure maintained at a temperature above 100° F. (38° C.).
A method of forming a system for a hydrocarbon fluid under this disclosure could also be said to include the steps of a) forming a bundle of hollow tube membrane members by wrapping hollow membrane tubes to form the bundle. The hollow membrane tubes are wrapped at an angle with respect to an axial direction of the bundle. In step b) the bundle is inserted into an outer canister. Step b) is performed in an enclosure maintained at a temperature above 100° F. (38° C.).
A fuel supply system for a gas turbine engine under this disclosure could be said to include a pump, an oxygen removal system and a combustor. The pump is configured to move fuel through the oxygen removal system to the combustor. The oxygen removal system has a bundle of hollow tube membrane members. The hollow tube membrane members are wrapped at an angle relative to each other with respect to an axial direction of the bundle, and received within an outer canister. A wrapping step for wrapping the hollow tube membrane members occurs at a temperature equal to or above 100° F. (38° C.), and insertion of the bundle into the outer canister also occur at a temperature above 100° F. (38° C.).
While the apparatus mentioned above differentiates from the prior art only by the method step, a worker of skill in this art would recognize that as disclosed above that method step does result in a distinct structure for the oxygen removal system as to the ΔT quantities.
Although embodiments have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content.
