Supercooled liquid charging system and method of using the same to charge supercooled liquid into a propellant tank of a launch vehicle

Abstract

A supercooling liquid filling system for preventing stratification, comprising a propellant tank capable of storing a supercooling liquid inside, a supercooling liquid supplyer capable of supplying a supercooling liquid to the propellant tank, and a vacuum generator that discharges gas inside the propellant tank to the outside of the propellant tank to convert the pressure of the propellant tank to a pressure below a set pressure, wherein the supercooling liquid supplyer supplies a supercooling liquid to the propellant tank when the pressure of the propellant tank is below a set pressure.

Description

Technology Field

[0001] The following embodiments relate to a supercooled liquid filling system and a method for filling a projectile's propellant tank with a supercooled liquid using the same. Background Technology

[0002] Supercooling of liquid oxygen is utilized to improve the performance and efficiency of projectiles. By increasing the density of liquid oxygen through supercooling, more liquid oxygen can be supplied and stored within a tank of the same volume. When liquid oxygen is supercooled, the vapor pressure decreases, which can increase the Net Positive Suction Head (NPSH) at the pump inlet, thereby improving cavitation performance, and the increased propellant density can reduce the pump's rotational speed. A reduction in the pump's rotational speed can reduce the pressure exerted on the tank. A reduction in the pressure exerted on the tank can reduce the weight of the tank. Additionally, in the case of fuel supercooling, there is an effect of reducing the differential pressure of regenerative cooling. For example, Korean Patent Publication No. 10-2024-0001730 discloses a liquefied gas supercooling system and a liquefied carbon dioxide carrier equipped with the same. The problem to be solved

[0003] The objective according to one embodiment is to provide a supercooled liquid filling system that can mitigate or prevent thermal stratification.

[0004] The objective according to one embodiment is to provide a supercooled liquid filling system in which reverse stratification may occur.

[0005] The objective according to one embodiment is to provide a supercooled liquid filling system capable of storing more liquid per unit volume in a propellant tank.

[0006] The objective according to one embodiment is to provide a supercooled liquid filling system capable of operating an ejector while filling a propellant tank with a single supply tank. means of solving the problem

[0007] A supercooling liquid filling system according to one embodiment includes a propellant tank capable of storing a supercooling liquid inside, a supercooling liquid supply unit capable of supplying a supercooling liquid to the propellant tank, and a vacuum generator that discharges gas inside the propellant tank to the outside of the propellant tank to convert the pressure of the propellant tank to a pressure below a set pressure, and the supercooling liquid supply unit can supply a supercooling liquid to the propellant tank when the pressure of the propellant tank is below a set pressure.

[0008] In one embodiment, the set pressure may be determined according to the temperature of the supercooled liquid supplied to the propellant tank.

[0009] In one embodiment, the set pressure may be determined to be lower than the pressure at which the temperature of the supercooled liquid supplied to the propellant tank is the saturation temperature.

[0010] In one embodiment, the liquid filled in the propellant tank may have a higher temperature in the lower part than in the upper part of the liquid region of the propellant tank.

[0011] In one embodiment, the temperature of the propellant tank can gradually decrease as the height increases.

[0012] In one embodiment, the vacuum generator may be an ejector.

[0013] In one embodiment, the ejector may use nitrogen as the working fluid.

[0014] In one embodiment, the apparatus further includes a vaporizer that receives a supercooled liquid from the supercooled liquid supply unit and converts it into a gas, and the ejector can use the gas that has passed through the vaporizer as a working fluid.

[0015] In one embodiment, the supercooled liquid may be a supercooled oxygen liquid at atmospheric pressure.

[0016] In one embodiment, the vacuum generator may be a vacuum pump.

[0017] In one embodiment, a method for filling a propellant tank of a projectile with a supercooled liquid using the supercooled liquid filling system may include the steps of reducing the pressure of the propellant tank to below a set pressure using the vacuum generator, supplying the supercooled liquid to the propellant tank using the supercooled liquid supplyer, and maintaining the pressure of the propellant tank below a set pressure using the vacuum generator. Effects of the invention

[0018] A supercooled liquid filling system according to one embodiment can mitigate or prevent thermal stratification phenomena.

[0019] A supercooled liquid filling system according to one embodiment may exhibit reverse stratification.

[0020] A supercooled liquid filling system according to one embodiment can store more liquid per unit volume in a propellant tank.

[0021] A supercooled liquid filling system according to one embodiment can operate an ejector while filling a propellant tank with a single supply tank.

[0022] The effects of the supercooled liquid filling system according to one embodiment and the method of filling a propellant tank of a projectile with supercooled liquid using the same are not limited to those mentioned above, and other effects not mentioned will be clearly understood by a person skilled in the art from the description below. Brief explanation of the drawing

[0023] Figure 1a is a diagram showing a conventional supercooled liquid filling system. Figure 1b is a diagram showing a conventional supercooled liquid filling system. Figure 1c is a graph showing the temperature according to height of a propellant tank filled using a conventional supercooled liquid filling system. FIG. 2 illustrates a supercooled liquid filling system according to one embodiment of the present invention. FIG. 3 illustrates a supercooled liquid filling system according to another embodiment of the present invention. Figure 4 is a graph showing the temperature according to the height of the propellant tank of the embodiments of the present invention. Figure 5 is a graph showing pressure according to the saturation temperature of liquid oxygen. Specific details for implementing the invention

[0024] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the embodiments, and thus the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, and substitutions to the embodiments are included within the scope of the rights.

[0025] The terms used in the embodiments are for illustrative purposes only and should not be interpreted as intended to be limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0026] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments pertain. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0027] In addition, when describing with reference to the attached drawings, identical components are assigned the same reference numeral regardless of drawing symbols, and redundant descriptions thereof are omitted. In describing the embodiments, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the embodiments, such detailed description is omitted.

[0028] Additionally, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments. These terms are intended merely to distinguish the components from other components, and the nature, order, or sequence of the components is not limited by these terms. Where it is stated that a component is "connected," "combined," or "joined" to another component, it should be understood that the component may be directly connected or joined to the other component, but that another component may also be "connected," "combined," or "joined" between each component.

[0029] Components included in any one embodiment and components having common functions shall be described using the same names in other embodiments. Unless otherwise stated, the descriptions given in any one embodiment may also apply to other embodiments, and specific descriptions shall be omitted to the extent of overlap.

[0030] FIG. 1a is a diagram showing a conventional supercooled liquid filling system. FIG. 1b is a diagram showing a conventional supercooled liquid filling system. FIG. 1c is a graph showing the temperature according to the height of a propellant tank filled using a conventional supercooled liquid filling system. FIG. 2 illustrates a supercooled liquid filling system according to one embodiment of the present invention. FIG. 3 illustrates a supercooled liquid filling system according to another embodiment of the present invention. FIG. 4 is a graph showing the temperature according to the height of a propellant tank of embodiments of the present invention. FIG. 5 is a graph showing the pressure according to the saturation temperature of liquid oxygen.

[0031] A conventional supercooled liquid filling system is described with reference to FIGS. 1a, 1b, and 1c.

[0032] Referring to FIGS. 1a and 1b, a conventional supercooled liquid filling system includes a supply tank (10), a propellant tank (20), and a valve (30). The supply tank (10) supplies atmospheric pressure supercooled liquid to the propellant tank (20) through a supply line (11). When atmospheric pressure supercooled liquid is supplied to the propellant tank (20), the propellant tank (20) is divided into a gas region (21) and a liquid region (22) occupied by the supercooled liquid. The valve (30) discharges the gas in the gas region (21) of the propellant tank (20) to the outside of the propellant tank (20). The gas region (21) of the propellant tank (20) consists of atmospheric pressure gas, and as the supercooled liquid is supplied, the liquid region (22) increases and gradually decreases. The liquid region (22) is divided into an upper layer (23) and a lower layer (25).

[0033] While the propellant tank (20) is being filled with supercooled liquid, heat is introduced into the propellant tank (20) from the outside. The introduced heat is transferred to the supercooled liquid, raising the temperature of the supercooled liquid. The temperature of the upper part (23) of the liquid region (22) can be further increased through heat exchange between the gas region (21) and the liquid region (22), which are composed of gas at atmospheric pressure. The temperature of the liquid located in the lower part (25) is lower than that of the liquid located in the upper part (23) of the liquid region (22). Thermal stratification occurs in the liquid of the propellant tank (20).

[0034] Referring to FIG. 1c, conventionally, as the height of the propellant tank (20) increases, the temperature of the liquid rises. Thermal stratification occurs because the density of the liquid is high in the lower layer (25) and low in the upper layer (23). Due to the rise in the temperature of the liquid located in the upper layer (23), the density of the liquid in the upper layer (23) decreases, and the total amount of liquid filled into the propellant tank (20) decreases.

[0035] Referring to FIG. 2, a supercooled liquid filling system according to one embodiment of the present invention may include a supercooled liquid supply unit (100), a propellant tank (200), and a vacuum generator (300). The supercooled liquid supply unit (100) and the vacuum generator (300) may be ground facilities (1), and the propellant tank (200) may be part (2) of a projectile.

[0036] In one embodiment, the supercooling liquid supply unit (100) may be configured to supply supercooling liquid to the propellant tank (200). In particular, the supercooling liquid supply unit (100) may supply supercooling liquid at atmospheric pressure to the propellant tank (200). The supercooling liquid supply unit (100) may include a supply tank (110), a pump (120), and a relief valve (130).

[0037] In one embodiment, the supply tank (110) may store a supercooled liquid inside. The supercooled liquid stored inside the supply tank (110) may be at atmospheric pressure. The supercooled liquid may be any liquid that can be supplied to the propellant tank (200) of the projectile.

[0038] For example, supercooled liquid oxygen (LOX) at atmospheric pressure can be stored inside the supply tank (110). Referring to the saturation temperature (K)-pressure (Mpa) graph of liquid oxygen shown in FIG. 5, the saturation temperature of liquid oxygen at atmospheric pressure is 90.18K. The supercooled liquid oxygen stored inside the supply tank (110) can be cooled and stored to a lower temperature, such as 80K.

[0039] In one embodiment, the pump (120) may be configured to supply the supercooled liquid stored in the supply tank (110) into the propellant tank (200).

[0040] In one embodiment, the relief valve (130) may be installed in a supply line positioned between the supply tank (110) and the propellant tank (200).

[0041] In one embodiment, at least one of the plurality of valves (151, 152 and 153) is disposed between the supply tank (110) and the pump (120), between the pump (120) and the relief valve (130), and between the relief valve (130) and the propellant tank (200) to control the flow of the supercooled liquid.

[0042] In one embodiment, the propellant tank (200) may be configured to store a supercooled liquid inside. The propellant tank (200) may be divided into a gas region (201) and a liquid region (202) during the filling of the supercooled liquid. Before the liquid is filled into the propellant tank (200), the liquid region (202) does not exist, but as filling begins, the liquid region (202) is created, and as the amount of liquid being filled gradually increases, the gas region (201) decreases and the liquid region (203) increases.

[0043] In one embodiment, the pressure of the gas region (201) can be converted from atmospheric pressure to a set pressure or lower by a vacuum generator (300) to be described later before the filling of the supercooled liquid. When the pressure of the gas region (201) is below the set pressure, the supercooled liquid can be supplied from the supercooled liquid supplyer (100) to the propellant tank (200). The set pressure will be described later after explaining the liquid region (202) of the propellant tank (200).

[0044] In one embodiment, the liquid region (202) may be divided into an upper layer (203) and a lower layer (205) according to height. The upper layer (203) may be in contact with the gas region (201). For example, the upper layer (203) and the lower layer (205) may be divided into an upper part and a lower part, respectively, when the liquid region (202) is divided in a direction perpendicular to the height direction (e.g., + / -Z direction) of the propellant tank (200). As the liquid region (202) changes as the supercooled liquid is filled, the positions occupied by the upper layer (203) and the lower layer (205) within the propellant tank (200) may also change.

[0045] For example, if the liquid area (202) occupies half the height of the propellant tank (200), the lower part (205) of the liquid area (202) may be an area from the bottom of the propellant tank (200) to 1 / 4 of the total height, and the upper part (203) may be an area from 1 / 4 of the height of the propellant tank (200) to 1 / 2 of the height.

[0046] In one embodiment, the supercooling liquid supply unit (100) is connected to the lower side of the propellant tank (200) to fill the supercooling liquid. In this case, the supercooling liquid can be filled as the liquid level of the supercooling liquid rises from the lower side of the propellant tank (200).

[0047] In one embodiment, the set pressure may be determined according to the temperature of the supercooled liquid supplied from the supercooled liquid supplyer (100) to the propellant tank (200).

[0048] In one embodiment, the set pressure may be less than or equal to the vapor pressure when the temperature of the supercooled liquid supplied from the supercooled liquid supplyer (100) to the propellant tank (200) is the saturation temperature. That is, if the temperature of the supercooled liquid supplied from the supercooled liquid supplyer (100) to the propellant tank (200) is A, the set pressure may be less than or equal to the vapor pressure when the saturation temperature of the liquid is A.

[0049] For example, when the supercooled liquid is supercooled liquid oxygen (LOX) and is supplied from the supercooled liquid feeder (100) to the propellant tank (200) at a temperature of 80K, the set pressure may be 30kPa or less, which is the vapor pressure when the saturation temperature of oxygen is 80K (see FIG. 5).

[0050] In this case, since the temperature of the supercooled liquid being charged is equal to or higher than the saturation temperature at the set pressure, the temperature of the liquid in the upper part (203) of the liquid region (202) that meets the gas region (201) may rise relatively less, remain substantially unchanged, or even decrease.

[0051] In one embodiment, even if heat is introduced into the propellant tank (20) from the outside of the propellant tank (20) while the supercooled liquid is being filled, the temperature of the upper layer (203) may rise less compared to when the gas region (201) is at atmospheric pressure. If the temperature of the upper layer (203) rises less compared to when the gas region (201) is at atmospheric pressure, thermal stratification may be mitigated.

[0052] Alternatively, in one embodiment, even if heat is introduced into the propellant tank (20) from outside the propellant tank (20) while the supercooled liquid is being filled, the temperature of the upper layer (203) may be substantially the same as the temperature of the lower layer (205) into which the supercooled liquid is filled. If the temperature of the upper layer (203) is substantially the same as the temperature of the lower layer (205) into which the supercooled liquid is filled, thermal stratification may not occur.

[0053] Compared to the case where thermal stratification occurs, if thermal stratification occurs in a reduced or non-reduced manner, the amount of liquid filled per unit volume of the propellant tank (200) can be increased.

[0054] Alternatively, in one embodiment, the liquid in the upper part (203) of the liquid region (202) that meets the gas region (201) may be partially evaporated and cooled so that the temperature of the upper part (203) is lower than the temperature of the supercooled liquid in the lower part (205). If the temperature of the upper part (203) is lower than the temperature of the lower part (205) into which the supercooled liquid is filled, the density of the liquid in the upper part (203) may be higher than the density of the liquid in the lower part (205). This can be defined as the inverse stratification phenomenon described later.

[0055] When the temperature of the upper layer (203) is lower than the temperature of the lower layer (205), the temperature difference between the upper layer (203) and the lower layer (205) can gradually change along the height of the propellant tank (200). As the height increases from the lower layer (205) to the upper layer (203), the temperature decreases and the density can increase. The phenomenon in which the density of the liquid in the upper layer (203) is higher because the temperature of the upper layer (203) is lower than that of the lower layer (205) can be defined as inverse stratification. Referring to FIG. 4, a graph can be seen in which the temperature decreases as the height of the propellant tank (200) increases due to inverse stratification.

[0056] When reverse stratification occurs, compared to when thermal stratification occurs or when the temperature and density of the upper layer (203) and the lower layer (205) are substantially the same, the density of the upper layer (203) is greater, so the amount of liquid filled per unit volume of the propellant tank (200) can be greater.

[0057] In another embodiment, the set pressure may be between the pressure at which the temperature of the supercooled liquid supplied from the supercooled liquid supplyer (100) to the propellant tank (200) is the saturation temperature and the atmospheric pressure. That is, if the temperature of the supercooled liquid supplied from the supercooled liquid supplyer (100) to the propellant tank (200) is A, the set pressure may be between the vapor pressure of the liquid at which the saturation temperature of the liquid is A and the atmospheric pressure.

[0058] For example, when the supercooled liquid is supercooled liquid oxygen (LOX) and is supplied from the supercooled liquid feeder (100) to the propellant tank (200) at a temperature of 80K, the set pressure may be between 30kPa, which is the vapor pressure when the saturation temperature of oxygen is 80K, and atmospheric pressure (see FIG. 5).

[0059] In this case, the temperature of the supercooled liquid being charged is lower than the saturation temperature at the set pressure. However, compared to the case where the gas region (201) is at atmospheric pressure, the temperature of the upper layer (203) may rise relatively less. In other words, the temperature of the upper layer (203) when the gas region (201) is at atmospheric pressure may be lower than the temperature of the upper layer (203) when the gas region (201) is at atmospheric pressure, compared to the temperature of the upper layer (203) when the temperature of the supercooled liquid supplied to the propellant tank (200) is between the pressure at the saturation temperature and atmospheric pressure.

[0060] The temperature of the liquid in the upper part (203) of the liquid region (202) meeting the gas region (201) rises relatively less, so that thermal stratification can be mitigated, and thus the amount of liquid filled per unit volume of the propellant tank (200) can be increased.

[0061] In one embodiment, a check valve (211) may be installed in the pressurization line (220) between the propellant tank (200) and the vacuum generator (300).

[0062] In one embodiment, at least one of the plurality of valves (251, 252 and 253) is disposed between the supercooling liquid supply unit (100) and the propellant tank (200), between the vacuum generator (300) and the propellant tank (200), and between the propellant tank (200) and the outside thereof, respectively, to control the flow of gas in the supercooling liquid or gas region (201).

[0063] In one embodiment, the vacuum generator (300) can discharge the gas of the propellant tank (200) to the outside of the propellant tank (200) to convert the pressure of the gas region (201) to below a set pressure. The gas can be discharged to the outside of the propellant tank (200) at atmospheric pressure. The vacuum generator (300) can convert the pressure of the gas region (201) of the propellant tank (200) from atmospheric pressure to below a set pressure before filling with the supercooled liquid, and can maintain the pressure of the gas region (201) of the propellant tank (200) below a set pressure during filling with the supercooled liquid.

[0064] In one embodiment, the vacuum generator (300) may be an ejector (300). The ejector (300) may use nitrogen or oxygen as the working fluid, but the type of working fluid is not limited. The ejector (300) may use a high-pressure working fluid to draw in gas from the propellant tank (200) and discharge it to the outside of the propellant tank (200).

[0065] In another embodiment, the vacuum generator (300) may be a vacuum pump.

[0066] A plurality of valves (351 and 352) may each be positioned between the working fluid supply unit (400) and the vacuum generator (300), and between the vacuum generator (300) and the outside from which the working fluid is discharged.

[0067] In one embodiment, the working fluid supply unit (400) may be connected to the ejector (300). The working fluid supply unit (400) may include a working fluid supply tank (410) and a vaporizer (420). The working fluid supply unit (400) may supply high-pressure working fluid to the ejector (300) by vaporizing the liquid stored in the working fluid supply tank (410) through the vaporizer (420). The liquid stored in the working fluid supply tank (410) may be liquid oxygen or liquid nitrogen, but the type of liquid for generating the working fluid is not limited.

[0068] In one embodiment, at least one of the plurality of valves (451 and 452) may be disposed between the working fluid supply tank (410) and the vaporizer (420), and between the vaporizer (420) and the ejector (300).

[0069] With reference to FIG. 3, a supercooled liquid filling system according to another embodiment of the present invention will be described. To avoid repetition, redundant details will be omitted and the differences from the supercooled liquid filling system shown in FIG. 2 will be described, and common elements are indicated by the same reference numerals.

[0070] In one embodiment, the working fluid supply unit (500) may be connected to the ejector (300). The working fluid supply unit (500) may include a vaporizer (520). Unlike the working fluid supply unit (400) shown in FIG. 2, the working fluid supply unit (500) may omit the working fluid supply tank (410). Instead of the working fluid supply tank (410), the working fluid supply unit (500) may receive liquid to pass through the vaporizer (520) from the supply tank (110) of the supercooling liquid supply unit (100). The supercooling liquid filling system may supply working fluid to the ejector (300) by utilizing the supply tank (110) of the supercooling liquid supply unit (100) without having a separate working fluid supply tank (410).

[0071] In one embodiment, at least one valve (551) may be placed between the vaporizer (420) and between the vaporizer (520) and the supercooling liquid supply unit (100).

[0072] A method for filling a propellant tank (200) of a projectile with a supercooled liquid using the supercooled liquid filling system of the embodiments described above is described. The method for filling a propellant tank (200) of a projectile with a supercooled liquid may include the step of reducing the pressure of the propellant tank (200) to below a set pressure using a vacuum generator (300), the step of supplying the supercooled liquid to the propellant tank (200) using a supercooled liquid supplyer (100), and the step of maintaining the pressure of the propellant tank (200) below a set pressure using a vacuum generator (300).

[0073] Although the embodiments have been described above with reference to the limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, suitable results may be achieved even if the described techniques are performed in a different order than described, and / or if the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0074] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below.

Claims

Claim 1 A supercooling liquid filling system for preventing stratification comprising: a propellant tank capable of storing a supercooling liquid inside; a supercooling liquid supplyer capable of supplying a supercooling liquid to the propellant tank; and a vacuum generator that discharges gas inside the propellant tank to the outside of the propellant tank to convert the pressure of the propellant tank to a pressure below a set pressure; wherein the supercooling liquid supplyer supplies a supercooling liquid to the propellant tank when the pressure of the propellant tank is below a set pressure, and the set pressure is determined according to the temperature of the supercooling liquid supplied to the propellant tank, and is determined to be a pressure below the pressure when the temperature of the supercooling liquid supplied to the propellant tank is the saturation temperature. Claim 2 delete Claim 3 delete Claim 4 In claim 1, the liquid filled in the propellant tank is a supercooled liquid filling system in which the temperature is higher in the lower part than in the upper part of the liquid region of the propellant tank. Claim 5 In claim 4, the propellant tank is a supercooled liquid filling system in which the temperature gradually decreases as the height increases. Claim 6 A supercooling liquid filling system for preventing stratification, comprising: a propellant tank capable of storing a supercooling liquid inside; a supercooling liquid supplyer capable of supplying a supercooling liquid to the propellant tank; a vacuum generator that discharges gas inside the propellant tank to the outside of the propellant tank to convert the pressure of the propellant tank to a pressure below a set pressure; and a vaporizer that receives the supercooling liquid from the supercooling liquid supplyer and converts it into gas; wherein the supercooling liquid supplyer supplies the supercooling liquid to the propellant tank when the pressure of the propellant tank is below a set pressure, the vacuum generator is an ejector, and the ejector uses the gas that has passed through the vaporizer as a working fluid. Claim 7 In claim 6, the ejector is a supercooled liquid filling system that uses nitrogen as the working fluid. Claim 8 delete Claim 9 In claim 6, the supercooled liquid filling system, wherein the supercooled liquid is a supercooled oxygen liquid at atmospheric pressure. Claim 10 In claim 1, the vacuum generator is a vacuum pump, a supercooled liquid filling system. Claim 11 A method for filling a propellant tank of a projectile with a supercooled liquid using the system of claim 1, comprising: a step of reducing the pressure of the propellant tank to below a set pressure using the vacuum generator; a step of supplying the supercooled liquid to the propellant tank using the supercooled liquid supplyer; and a step of maintaining the pressure of the propellant tank below a set pressure using the vacuum generator.

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