Patent Application
20180231340
The subject matter disclosed herein relates to thermal management system for a directed energy weapon and, more specifically, a simplified two phase system for removing heat for a Directed Energy Weapon (DEW).
Next generation aircraft are being designed with advanced weapons like laser based direct energy weapons (DEWs). DEWs (e.g., laser weapons) may require substantial cooling at the lowest possible weight for sustained operation. DEWs typically operate at low efficiency and thus, generate a large amount of heat during lasing (weapon firing) operation. DEW operation typically consists of relatively brief operating intervals, wherein relatively large “bursts” of cooling are required, interspersed with relatively long intervals in which the weapon is quiescent, and therefore, requires little or no cooling. This large thermal transient may drive the size of the thermal management system (TMS) used to control the thermal loading of the DEW Such requirements may result in a TMS that is significantly oversized, in-efficient and heavy for normal operating (non-lasing) modes, particularly for airborne applications. Therefore, a fast and efficient TMS is required to address the thermal load of a DEW and to protect onboard components from thermal transients.
Various systems are utilized in attempt to remove this heat load created by a DEW. However, the current proposed solutions either are of very large size & weight or consume coolant requiring regular charging. Examples of existing DEW heating/cooling solutions include:
1) Conventional refrigeration systems (e.g., Freon compression/expansion systems) that cool the system using electricity as the power source;
2) Refrigerant evaporative approaches; which consume refrigerant after every weapon firing event resulting into limitation of weapon use per flight as well as constant maintenance;
3) “Phase change” approaches, which use solidified Phase Change Materials (PCMs). A PCM material, such as ice, that melts to provide cooling, and other systems in which the PCM is regenerated “offline. Some PCM-cooled DEW systems are very complex, employing multiple fluids in chemical reactions; and
4) Multiple Phase Change Heat Exchanger units that are used sequentially, which effect the discharging of one unit while one or more additional exhausted units are being charged for re-use.
To date, systems employing the foregoing approaches are all relatively heavy and/or do not provide optimal operational flexibility. For example, many existing PCM systems prevent the use of different fluids for removing heat from the DEW vs. dissipating heat to other systems. The latter drawback is a relatively important one for laser weapons, wherein the major coolant use is for laser diodes, in which water is commonly used as the cooling medium of choice, whereas, the formation of ice requires the use of a material (e.g., a glycol solution) for cooling of the PCM that will remain a liquid below the freezing point of water. Additionally, these devices operate in either a “charge” mode (i.e., freezing the PCM using an external refrigeration system) or a “discharge” mode (i.e., thawing the PCM to cool the circulating DEW coolant).
In one aspect described herein in an embodiment is a thermal management system for a directed energy weapon on an aircraft the thermal management system. The system includes an evaporator in thermal communication with the directed energy weapon and operatively configured to cool the directed energy weapon by evaporating a refrigerant therein, a refrigerant storage tank in fluid communication with the evaporator, the refrigerant storage tank configured to separate liquid refrigerant and vapor refrigerant, and a pump in fluid communication with the refrigerant storage tank and the evaporator and configured to pump substantially liquid refrigerant to the evaporator.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a check valve in fluid communication with the pump and the evaporator operable to ensure that the substantially liquid refrigerant flows to the evaporator.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a bypass valve operably connected in parallel to the evaporator.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the evaporator is a heat exchanger.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the refrigerant storage tank includes a separator section.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the separator section includes a coolant coil to condense vapor refrigerant.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the separator section includes a centrifugal separator.
In addition to one or more of the features described above, or as an alternative, further embodiments may include an air cycle machine in thermal communication with the refrigerant storage tank and wherein the refrigerant storage tank is configured to transfer heat to the air cycle machine.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the refrigerant is at least one of Ammonia, Freon, and CO2.
Also described herein on another embodiment is a method for removing heat from a directed energy weapon on an aircraft. The method including evaporating a refrigerant in an evaporator in thermal communication with the directed energy weapon and operatively configured to cool the directed energy weapon by evaporating a refrigerant therein, separating vapor refrigerant and liquid refrigerant in a refrigerant storage tank in fluid communication with the evaporator, condensing vapor refrigerant in the refrigerant storage tank, and pumping substantially liquid refrigerant from the refrigerant storage tank with a pump in fluid communication with the refrigerant storage tank and the evaporator.
In addition to one or more of the features described above, or as an alternative, further embodiments may include directing a flow of the substantially liquid refrigerant from the pump to the evaporator with a check valve in fluid communication with the pump and the evaporator operable
In addition to one or more of the features described above, or as an alternative, further embodiments may include a bypassing the evaporator via a valve operably connected in parallel to the evaporator.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the evaporating results in a phase change of the refrigerant in the heat exchanger.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the separating includes condensing the vapor refrigerant.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the separating includes centrifugally separating the vapor refrigerant and the liquid refrigerant.
In addition to one or more of the features described above, or as an alternative, further embodiments may include transferring heat from refrigerant in the refrigerant storage tank to an external system for subsequent dissipation.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the refrigerant is at least one of Ammonia, Freon, and CO2.
Technical effects of embodiments of the present disclosure include, but are not limited to a thermal management system and methodology for a directed energy weapon on an aircraft and more specifically, a simplified two phase system for removing heat for a Directed Energy Weapon (DEW).
The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.
The foregoing and other features, and advantages of embodiments are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The following description is merely illustrative in nature and is not intended to limit the present disclosure, its application or uses. As used herein, the term controller refers to processing circuitry that may include an application specific integrated circuit (ASIC), an electronic circuit, an electronic processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable interfaces and components that provide the described functionality.
Additionally, the term “exemplary” is used herein to mean “serving as an example, instance or illustration.” Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms “at least one” and “one or more” are understood to include any integer number greater than or equal to one, i.e. one, two, three, four, etc. The terms “a plurality” are understood to include any integer number greater than or equal to two, i.e. two, three, four, five, etc. The term “connection” can include an indirect “connection” and a direct “connection”.
As shown and described herein, various features of the disclosure will be presented. Various embodiments may have the same or similar features and thus the same or similar features may be labeled with the same reference numeral, but preceded by a different first number indicating the figure to which the feature is shown.
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The thermal management system 100 for a DEW 110 exhibits several advantages over existing thermal management systems. First, a two phase evaporative system provides for rapid heat removal. Likewise, such a system also facilitates rapid regeneration resulting into high weapon readiness/availability. Contrary to some refrigerant evaporative systems, the described embodiments present a regenerable system to reduce or avoid regular maintenance and “recharging”. Advantageously compared to other thermal management systems for DEWs, the described embodiments are relatively compact. For example, in one embodiment by reducing the peak loading by 30%, the thermal management system 100 may require only 50% of the volume of comparable systems. Moreover, the thermal management system of the described embodiments would be relatively light weight as it eliminates the need for heavy compressors and the like. Reductions in space and/or weight requirements are highly desired, particularly in airborne applications.
Turning now to
While the embodiments herein have been described with respect to a thermal management system for providing cooling to a directed energy weapon, most likely in an airborne application, it should be appreciated that the described embodiments are not limited as such. In fact, the described embodiments should be understood to cover any thermal management system application where a transient heat load with a short duration maximum load and a longer duration minimum load is encountered.
While the disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the disclosure is not limited to such disclosed embodiments. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the disclosure. Additionally, while various embodiments have been described, it is to be understood that aspects of the disclosure may include only some of the described embodiments. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
