US-12623200-B2 - Lattice structure for sparging evaporator in catalytic inerting system

US12623200B2US 12623200 B2US12623200 B2US 12623200B2US-12623200-B2

Abstract

A sparging evaporator for an inerting system including an outer vessel, an inner vessel within the outer vessel, and a plenum formed between the inner and outer vessels. The outer vessel includes a gas inlet for receiving inlet gas into the plenum, and a liquid inlet for receiving liquid fuel into the plenum. The inlet gas in the plenum generates a gas pressure that is exerted against a free surface of the liquid fuel in the plenum thereby forcing the liquid fuel and the inlet gas through an inlet of the inner vessel. The inner vessel contains a lattice structure that promotes liberation of fuel vapor from the liquid fuel and enables the inlet gas in the liquid fuel to sparge the fuel vapor in the liquid fuel, thereby forming a fuel-enriched gas mixture that can be fed to a reactor of the inerting system.

Inventors

Daniel J. Henninger
Bryan D. Jensen
Daniel C. Massie
Scott P. Auld-Hill

Assignees

PARKER-HANNIFIN CORPORATION

Dates

Publication Date: 20260512
Application Date: 20240823

Claims (15)

1 . A sparging system comprising: a first sparging evaporator, comprising: a first outer vessel, a first inner vessel within the first outer vessel, and a plenum formed between the first inner and outer vessels, the first outer vessel having a gas inlet for receiving inlet gas, and a first liquid inlet for receiving liquid fuel, wherein both the gas inlet and the first liquid inlet are in fluid communication with the plenum; the first inner vessel having a first inner vessel inlet and a first gas outlet, wherein the first inner vessel inlet is in fluid communication with the plenum; and a first lattice structure at least partially contained within the first inner vessel, wherein the first lattice structure includes a network of lattice members and nodes with voids formed between the lattice members and nodes; and a second sparging evaporator, wherein the first outer vessel of the first sparging evaporator is integrated with a second outer vessel of the second sparging evaporator to form a single outer vessel of a combination of the first and second sparging evaporators, such that the plenum forms a single plenum between the first sparging evaporator and the second sparging evaporator; wherein the second sparging evaporator includes: a second inner vessel within the single outer vessel that is arranged within the single plenum, the second inner vessel having a second inner vessel inlet, a second liquid outlet, and a second gas outlet, wherein the second inner vessel inlet is in fluid communication with the single plenum; a second lattice structure at least partially contained within the second inner vessel; and a second liquid inlet for receiving the liquid fuel into the single plenum; wherein the gas inlet is a single gas inlet of the combination that is in fluid communication with the single plenum; wherein the first liquid inlet and the second liquid inlet are fluidly connected via a single fuel feed passage; wherein the first liquid outlet and the second liquid outlet are fluidly connected via a single fuel outlet passage that is fluidly connected to a single fuel discharge line; and wherein the first and second sparging evaporators are configured such that, when in use, the liquid fuel enters the plenum via the first and second liquid inlets, and the inlet gas enters the plenum via first gas inlet, the inlet gas in the plenum generating a gas pressure that is exerted against a free surface of the liquid fuel in the plenum thereby forcing the liquid fuel and the inlet gas through the first and second inner vessel inlets and through the first and second lattice structures, the first and second lattice structures being configured to promote liberation of fuel vapor from the liquid fuel and enable the inlet gas to interact with and sweep away the fuel vapor to thereby form a fuel-enriched gas mixture containing the inlet gas and the fuel vapor, wherein the fuel-enriched gas mixture is carried downstream and exits the first sparging evaporator via the first and second gas outlets.
2 . The sparging system according to claim 1 , wherein at least a portion of each of the first and second lattice structures includes a repeating pattern of unit cells, wherein each unit cell includes at least one of the respective lattice members and at least one of the respective nodes.
3 . The sparging evaporator according to claim 1 , wherein each of the first and second lattice structures comprises a first network and a second network of lattice members and nodes that form voids between the lattice members and nodes.
4 . The sparging evaporator according to claim 3 , wherein the first network of lattice members and nodes is independent of and disengaged from the second network of lattice members and nodes such that the first network of lattice members and nodes does not contact the second network of lattice members and nodes.
5 . The sparging evaporator according to claim 3 , wherein the first network of lattice members and nodes and the second network of lattice members and nodes together form an overall lattice structure; wherein spaces are formed between the first network of lattice members and nodes and the second network of lattice members and nodes, and wherein the spaces collectively form a porosity of the overall lattice structure, the porosity being in a range from 50% to 90% (open volume/total volume).
6 . The sparging evaporator according to claim 3 , wherein the first network of lattice members and nodes and the second network of lattice members and nodes together form an overall lattice structure; wherein spaces are formed between the first network of lattice members and nodes and the second network of lattice members and nodes, and wherein the spaces have a size in the range from about 0.01 inches to about 0.2 inches.
7 . The sparging evaporator according to claim 3 , wherein the first network of lattice members and nodes is made of a first material, and wherein the second network of lattice members and nodes is made of a second material that is different than the first material.
8 . The sparging evaporator according to claim 3 , wherein the first network of lattice members and nodes has a first thermal conductivity, and wherein the second network of lattice members and nodes has a thermal conductivity that is different than the first thermal conductivity.
9 . The sparging evaporator according to claim 8 , wherein the thermal conductivity of the first network of lattice members and nodes is in a range from 20 W/m-K to 200 W/m-K; and wherein the thermal conductivity of the second network of lattice members and nodes is in a range from 20 W/m-K to 200 W/m-K.
10 . The sparging evaporator according to claim 3 , wherein the first and second sparging evaporators include a substrate, and wherein the first lattice structure and the second lattice structure are connected to the substrate.
11 . The sparging evaporator according to claim 10 , wherein the first lattice structure and the second lattice structure are unitary with the substrate.
12 . The sparging evaporator according to claim 10 , wherein the substrate respectively is a wall of the single outer vessel.
13 . The sparging evaporator according to claim 12 , wherein the substrate is a surface outside of the single outer vessel.
14 . The sparging system according to claim 1 , further comprising: a heater in thermal communication with the liquid fuel, the heater being configured to heat and promote volatilization of at least a portion the liquid fuel to thereby form a volatilized fuel vapor; and wherein, when the first and second evaporators are in use, the first and second lattice structures are in thermal communication with the heater to promote liberation of the fuel vapor from the liquid fuel.
15 . An inerting system for a fuel tank, the inerting system comprising: a fluid circuit fluidly connectable to the fuel tank; a reactor connected in the fluid circuit; and the sparging system according to claim 1 that is connected in the fluid circuit upstream of the reactor; wherein the first and second sparging evaporator are configured to receive a flow of the liquid fuel from the fuel tank, and wherein the first and second evaporators are configured to receive at least a portion of flow of the inlet gas from ullage gas in the fuel tank; wherein the reactor is configured to convert at least a portion of the fuel-enriched gas mixture into an inert, non-flammable gas; and wherein the fluid circuit is configured to supply at least a portion of the inert, non-flammable gas to the fuel tank.

Description

RELATED APPLICATIONS This application is a divisional application of U.S. application Ser. No. 17/394,818 filed on Aug. 5, 2021, which claims the benefit of U.S. Provisional Application No. 63/062,067 filed Aug. 6, 2020, the contents of which are hereby incorporated by reference. TECHNICAL FIELD The present disclosure relates generally to inerting systems, more particularly to a catalytic inerting system (CIS) for an aircraft fuel tank, and even more particularly to a sparging evaporator for fuel enrichment in such catalytic inerting system. BACKGROUND The basic ullage-recirculating CIS architecture generally requires that ullage gas (the air and fuel vapor mixture that exists over the top of the liquid fuel in a fuel tank) be drawn from the fuel tank and reacted in a catalytic reactor. The catalytic process causes the reactive components present in the ullage gas (i.e., oxygen and fuel vapor) to chemically react and produce relatively inert, non-flammable chemical species, namely carbon dioxide (CO2) and water vapor. Nitrogen, which typically is the component present in the greatest amount in the ullage gas, is an inert species and does not participate in the fuel vapor and air reaction that occurs in the catalytic reactor. The byproducts of the catalytic reaction and the nitrogen are all inert (non-flammable) and can be returned to the fuel tank to create an inert environment in the ullage. Because water is undesirable in the fuel tank, the water typically is removed from the inert gas stream before the gas stream is returned to the fuel tank. Although the ullage space in the fuel tank will almost always contain fuel vapor in some concentration, this amount is typically below the so-called lower flammability limit (LFL) for tanks containing jet fuel or diesel fuel, and above the upper flammability limit (UFL) for fuel tanks containing gasoline. When the fuel vapor concentration in the ullage space is below the LFL, an insufficient quantity of fuel vapor exists in the ullage space to sustain a fire. When the fuel vapor concentration is above the UFL, the amount of fuel vapor present in the ullage is too great to sustain a fire. Fuels developed for automotive and aircraft applications are typically outside the so-called flammability window defined by the LFL and the UFL. SUMMARY The inerting performance of an inerting system is strongly related to the amount of fuel vapor introduced into the reactor for conversion to inert, non-flammable species (e.g., carbon dioxide and water). For example, if the fuel vapor composition is described by the hydrocarbon molecule C9H18, then the reaction equation is: C9H18+13.5 O2→9 CO2+9 H2O Assuming the reaction is limited by the quantity of fuel vapor molecules, then increasing the number of moles of fuel vapor introduced into the reactor will increase the number of moles of oxygen consumed, and thus increase the production of carbon dioxide and water. Ideally, the reactor would be provided with the maximum amount of fuel vapor while also staying just below the LFL during operation, thereby enabling the reactor to convert the maximum amount of available oxygen into the non-flammable inert byproducts. However, the fuel vapor content in the ullage gas (and therefore that which is introduced into the reactor) strongly depends on the temperature and pressure conditions, such as during flight, and may therefore vary significantly, thus degrading the inerting performance of the system. Accordingly, there is a need in the art to provide an inerting system that can supplement and/or control the fuel vapor content of the reactor's feed gas stream, such as when the ullage fuel vapor content decreases significantly, which may occur during low temperature conditions. An aspect of the present disclosure provides an inerting system that improves upon the inerting performance of conventional ullage-recirculating inerting systems by providing a sparging evaporator that enriches the fuel vapor content of the reaction gas that is fed to the inerting system reactor. More particularly, according to an aspect, the sparging evaporator disclosed herein receives a quantity of liquid fuel that is forced by an inlet gas through a sparging vessel in the evaporator, whereby fuel vapor liberated from the liquid fuel is swept away by the inlet gas to form a fuel-enriched gas mixture that is fed downstream to the reactor. More specifically, according to an aspect, the sparging evaporator disclosed herein includes a lattice structure that enhances interactions of the liquid fuel, fuel vapor liberated from the liquid fuel, and inlet gas in such a way to form the fuel-enriched gas mixture. The exemplary lattice structure may be configured to enhanced one or more of mass transfer, heat transfer, mixing, and flow field uniformity, such as while optimizing for low pressure drop and/or minimizing physical size and weight of the evaporator. According to a more specific aspect, the exemplary lattice structure