JP2015077825A - Cryogenic propellant storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cryogenic propellant storage adaptable to a propulsion system of a liquid-propellant rocket pursuing missions at intervals of months or intervals of years.SOLUTION: A cryogenic propellant storage includes: a fuel tank 2 for storing liquefied natural gas; a LOX tank 3 for storing LOX; a GNtank 4 filled with nitrogen gas; an LNtank 5 filled with liquid nitrogen; a gas pipe 6 in which the nitrogen gas flows; and a liquid pipe 7 in which the liquid nitrogen flows. A turbine 8 actuated by the nitrogen gas from the GNtank 4, and a JT valve 15 liquefying the nitrogen gas and pumping the liquefied nitrogen gas into the LNtank 5 are arranged halfway along the gas pipe 6. A pump 9 increasing a pressure of the liquid nitrogen by actuation of the turbine 8 is arranged halfway along the liquid pipe 7. Re-liquefaction heat exchangers 10 and 11 for heat exchange with the liquid nitrogen are arranged in the fuel tank 2 and the LOX tank 3, respectively. A gasification heat exchanger 12 for heat exchange with the nitrogen gas is arranged between the gas pipe 6 and the liquid pipe 7.

Description

  The present invention relates to a cryogenic propellant storage device used to store cryogenic propellants (cryogenic fuel and oxidizer LOX) in outer space or orbit in a liquid rocket propulsion system.

  Either the room temperature propellant or the cryogenic propellant is used for the propulsion system of the liquid rocket described above, and both of them are covered with a heat insulating material, for example, a foam heat insulating material or a multilayer insulator, so that heat from the outside is covered. It is stored in a blocked metal tank (see, for example, Non-Patent Document 1).

  In space and orbit, it is difficult to cut off heat almost completely because of weight restrictions, and in the case of a cryogenic propellant storage tank, it is heated by sunlight and evaporated. By releasing gas regularly into outer space, the pressure inside the tank is prevented from rising more than necessary.

Aerospace Engineering Handbook 3rd edition, Japan Aerospace Society, page 884

  As described above, in conventional propellant storage tanks, gas generated by evaporation of cryogenic propellant is periodically released into outer space to suppress pressure rise in the tank, so cryogenic propulsion Drugs will be gradually reduced, and therefore can only be used for missions of several hours or at most days, and cannot be used for monthly or yearly missions. It has been a conventional problem to solve this problem.

  The present invention has been made paying attention to the above-described conventional problems, and is adopted not only for a liquid rocket propulsion system that performs a mission for several hours but also for a liquid rocket propulsion system that performs a monthly or yearly mission. An object of the present invention is to provide a cryogenic propellant storage device.

  The invention according to claim 1 of the present invention is a cryogenic propellant storage device used for storing a cryogenic propellant in a propulsion system of a liquid rocket, and comprises a cryogenic fuel constituting the cryogenic propellant. A fuel tank to be stored, a LOX tank that stores LOX that constitutes the cryogenic propellant together with the cryogenic fuel, a gasification medium tank filled with a gasification medium, and a temperature higher than that of the cryogenic fuel and LOX A liquefied medium tank filled with a low liquefied medium; a gas pipe through which the gasified medium flows from the gasified medium tank toward the liquefied medium tank; and a liquefied medium from the liquefied medium tank toward the gasified medium tank. A liquid pipe that flows, and a turbine that is operated by the gasification medium from the gasification medium tank in the middle of the gas pipe; and the liquefaction medium by liquefying the gasification medium A JT valve that feeds into the tank, and a pump that raises the pressure of the low-temperature liquefied medium from the liquefied medium tank that flows through the liquid pipe by the operation of the turbine is disposed in the middle of the liquid pipe. And in each of the fuel tanks, heat exchange is performed with a liquefied medium having a low temperature and a high pressure flowing in the liquid pipe, and oxygen evaporated in the LOX tank and in the fuel tank Reliquefaction heat exchangers for returning the evaporated cryogenic fuel to the liquid are disposed, respectively, and a gas derived from the gas pipe is provided between the gas pipe and the liquid pipe in the vicinity of the gasification medium tank. A heat exchanger for gasification is provided that exchanges heat with the gasification medium, gasifies the liquefaction medium flowing in the liquid pipe, and introduces it into the gasification medium tank. And characterized by a was, and cryogenic propellant storage device of this configuration as a means for solving the conventional problems described above.

  In the cryogenic propellant storage device according to claim 2 of the present invention, a gasification medium is provided between the gasification medium tank and the LOX tank and between the gasification medium tank and the fuel tank. Pressurized gas supply pipes that supply tank pressurized gas to both the LOX tank and the fuel tank are arranged.

  The cryogenic propellant storage device according to claim 3 of the present invention is configured such that the gasification medium is nitrogen gas and the liquefaction medium is liquid nitrogen.

In the cryogenic propellant storage device according to the present invention, it is assumed that liquefied natural gas (LNG) mainly composed of methane is mainly used as the cryogenic fuel, but the liquid can be changed by changing the liquefaction medium. Hydrogen (LH ₂ ) can also be used. Moreover, although metals, such as aluminum and SUS, can be used for each tank of a fuel tank, a LOX tank, a gasification medium tank, and a liquefaction medium tank, all are not specifically limited.

  In the cryogenic propellant storage device according to the present invention, the turbine in the middle of the gas pipe is operated by the gasification medium from the high-pressure gasification medium tank, and the gasification medium that operates the turbine is JT in the middle of the gas pipe. It is liquefied by a valve and fed into a liquefied medium tank having a low internal pressure.

  At this time, due to the operation of the turbine in the middle of the gas piping, the pump in the middle of the liquid piping operates to increase the pressure of the liquefied medium having a low temperature from the liquefied medium tank flowing through the liquid piping.

  The liquefied medium flowing in the liquid pipe whose temperature is low and pressure is increased in this way passes through the reliquefaction heat exchangers arranged in the LOX tank and the fuel tank, and is thus evaporated in the LOX tank. The cryogenic fuel evaporated in the oxygen and fuel tanks is deprived of heat by the liquefied medium whose temperature is low and the pressure is increased, and returns to LOX and the cryogenic liquid fuel.

  The liquefied medium that has obtained heat through the re-liquefaction heat exchangers of the LOX tank and the fuel tank is the heat exchange for gasification located between the gas pipe and the liquid pipe in the vicinity of the gasification medium tank. Because it passes through the vessel, heat exchange is performed with the gasification medium led out from the gas pipe, and the liquefied medium that has obtained further heat through this heat exchange is gasified and introduced into the gasification medium tank. It becomes.

  As described above, in the cryogenic propellant storage device according to the present invention, the gas generated in the tank can be re-liquefied by evaporating the cryogenic fuel simply by circulating the gasification medium and the liquefaction medium. In other words, the gas generated by evaporating the cryogenic fuel is not released regularly into outer space, and the pressure rise in the tank can be suppressed. Therefore, not only the propulsion system of a liquid rocket that performs a mission for several hours. It can also be used in propulsion systems for liquid rockets that carry out monthly and yearly missions.

  Also, pressurized gas supply pipes are arranged between the gasification medium tank and the LOX tank and between the gasification medium tank and the fuel tank, respectively, so that the gasification medium is placed in both the LOX tank and the fuel tank. In contrast, if it is supplied as tank pressurization gas, pressurization that can quickly compensate for the drop in tank pressure when using cryogenic fuel (during rocket engine combustion) becomes possible, making it compact and efficient. A simple propellant supply system will be realized.

  Furthermore, by using nitrogen gas as the gasification medium and liquid nitrogen as the liquefaction medium, it is easier to handle than cryogenic helium, which can be used as a refrigerant in the same way as nitrogen, and also responds to this helium depletion problem. In addition, as described above, when supplying the gasification medium as tank pressurization gas to both the LOX tank and the fuel tank, a large amount of nitrogen gas as the gasification medium is required. Since it can be mounted on a liquid rocket as liquid nitrogen, the storage property is greatly improved.

  In the cryogenic propellant storage device according to claim 1 of the present invention, not only a liquid rocket propulsion system that performs a mission for several hours but also a liquid rocket propulsion system that performs a monthly or yearly mission. This is a very good effect that is possible.

  In the cryogenic propellant storage device according to claim 2 of the present invention, a compact and efficient propellant supply system can be realized. In the cryogenic propellant storage device according to claim 3 of the present invention, the refrigerant In addition, when nitrogen gas is supplied as tank pressurization gas to both the LOX tank and the fuel tank, the amount of nitrogen gas that can be mounted on a liquid rocket as liquid nitrogen A very excellent effect that it is possible to improve the storage property is also brought about.

It is a schematic system explanatory drawing of the cryogenic propellant storage apparatus by one Example of this invention.

Hereinafter, a cryogenic propellant storage device according to the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a cryogenic propellant storage device according to the present invention.

As shown in FIG. 1, a cryogenic propellant storage device 1 used to store a cryogenic propellant in a liquid rocket propulsion system is a liquefied natural gas (LNG) that is a cryogenic fuel constituting the cryogenic propellant. ), A LOX tank 3 that stores LOX as an oxidant that constitutes a cryogenic propellant together with liquefied natural gas, and a GN ₂ tank 4 that is filled with nitrogen gas as a gasification medium; LN ₂ tank 5 filled with liquid nitrogen as a liquefied medium having a temperature lower than that of liquefied natural gas and LOX, gas pipe 6 through which nitrogen gas flows from GN ₂ tank 4 toward LN ₂ tank 5, and LN ₂ A liquid pipe 7 through which liquid nitrogen flows from the tank 5 toward the GN ₂ tank 4 is provided.

In this case, in the middle of the gas pipe 6, a turbine 8 that is operated by nitrogen gas from the high-pressure GN ₂ tank 4 and a JT valve (Joule Thomson valve) 15 that liquefies the nitrogen gas and sends it to the low-pressure LN ₂ tank 5. On the other hand, a pump 9 is disposed in the middle of the liquid pipe 7 to increase the pressure of low temperature liquid nitrogen flowing through the liquid pipe 7 by the operation of the turbine 8.

  Further, in each of the LOX tank 3 and the fuel tank 2, heat exchange is performed with liquid nitrogen whose temperature flowing through the liquid pipe 7 is low and pressure is increased, and oxygen evaporated in the LOX tank 3 and Reliquefaction heat exchangers 10 and 11 for returning the liquefied natural gas evaporated in the fuel tank 2 to liquids are arranged.

Further, heat exchange is performed between the gas pipe 6 and the liquid pipe 7 in the vicinity of the GN ₂ tank 4 with nitrogen gas led out from the gas pipe 6 through an on-off valve (not shown), and the liquid A gasification heat exchanger 12 for gasifying the liquid nitrogen flowing through the pipe 7 and introducing it into the GN ₂ tank 4 is arranged.

Furthermore, between the GN ₂ tank 4 and the LOX tank 3, and between the GN ₂ tank 4 and the fuel tank 2, nitrogen gas is supplied to both the LOX tank 3 and the fuel tank 2 as tank pressurized gas. The pressurized gas supply pipes 13 and 14 are respectively provided to maintain the tank internal pressure at a predetermined pressure. In this embodiment, the internal pressures of the fuel tank 2 and the LOX tank 3 are both It is maintained at a certain pressure required for propellant retention.

  In FIG. 1, reference numeral 16 denotes a flow rate adjustment valve, reference numerals 17 and 18 denote pressure adjustment valves, and reference numeral 19 denotes a liquid nitrogen filling line, which is located at an appropriate position of each tank and each pipe of the cryogenic propellant storage device 1. A pressure sensor (not shown) is arranged.

In the cryogenic propellant storage device 1 according to this embodiment, the turbine 8 in the middle of the gas pipe 6 is operated by the nitrogen gas from the high-pressure GN ₂ tank 4, and the nitrogen gas that operates the turbine 8 is the gas pipe 6. It is liquefied by the JT valve 15 on the way and sent to the LN ₂ tank 5 having a low internal pressure.

At this time, due to the operation of the turbine 8 in the middle of the gas pipe 6, the pump 9 in the middle of the liquid pipe 7 is operated, and the pressure of the low temperature liquid nitrogen from the LN ₂ tank 5 flowing through the liquid pipe 7 increases.

  Since the liquid nitrogen flowing in the liquid pipe 7 having a low temperature and a high pressure passes through the reliquefaction heat exchangers 10 and 11 disposed in the LOX tank 3 and the fuel tank 2, respectively. Both the oxygen evaporated in the LOX tank 3 and the liquefied natural gas evaporated in the fuel tank 2 are deprived of heat by liquid nitrogen whose temperature is low and pressure is increased, as indicated by the white arrow. And return to liquefied natural gas.

The liquid nitrogen obtained through the reliquefaction heat exchangers 10 and 11 of the LOX tank 3 and the fuel tank 2 is between the gas pipe 6 and the liquid pipe 7 in the vicinity of the GN ₂ tank 4. Since it passes through the heat exchanger 12 for gasification, heat exchange is performed with the nitrogen gas led out from the gas pipe 6 as indicated by the white arrow, and further heat is obtained by this heat exchange. The liquid nitrogen is gasified and introduced into the GN ₂ tank 4.

  As described above, in the cryogenic propellant storage device 1 according to this embodiment, the gas generated in the propellant tank 2 is re-liquefied by the liquefied natural gas evaporating only by circulating nitrogen gas and liquid nitrogen. In other words, the liquid rocket which can suppress the pressure rise in the fuel tank 2 without periodically releasing the gas generated by the evaporation of the liquefied natural gas to the outer space, and thus performs a mission for several hours. It can be used not only for propulsion systems, but also for liquid rocket propulsion systems that perform monthly and yearly missions.

In the cryogenic propellant storage device 1 according to this embodiment, the pressurized gas supply pipe 13, between the GN ₂ tank 4 and the LOX tank 3, and between the GN ₂ tank 4 and the fuel tank 2, 14 is arranged so that nitrogen gas is supplied as tank pressurization gas to both the LOX tank 3 and the fuel tank 2, so that the inside of the tank when liquefied natural gas is used (during rocket engine combustion) A drop in pressure can be quickly compensated, and a compact and efficient propellant supply system can be constructed.

  Furthermore, in the cryogenic propellant storage device 1 according to this embodiment, since the gasification medium is nitrogen gas and the liquefaction medium is liquid nitrogen, it is handled in comparison with cryogenic helium used as a refrigerant in the same manner as nitrogen. When the nitrogen gas is supplied to both the LOX tank 3 and the fuel tank 2 as tank pressurization gas as described above, it is possible to cope with this helium depletion problem. Therefore, the storage capacity is greatly improved by the amount that can be mounted on the liquid rocket as the liquid nitrogen as a large amount of nitrogen gas.

  In the cryogenic propellant storage device 1 of the above-described embodiment, the gasification medium is nitrogen gas and the liquefaction medium is liquid nitrogen. However, the invention is not limited to this, and helium may be used as a refrigerant. In some cases, liquid hydrogen can be used as a cryogenic propellant.

1 Cryogenic propellant storage device 2 Fuel (liquefied natural gas) tank 3 LOX tank 4 GN ₂ tank (gasification medium tank)
5 LN ₂ tank (liquefaction medium tank)
6 Gas piping 7 Liquid piping 8 Turbine 9 Pumps 10, 11 Reliquefaction heat exchanger 12 Gasification heat exchanger 15 JT valve

Claims (3)

A cryogenic propellant storage device used to store cryogenic propellants in a liquid rocket propulsion system,
A fuel tank containing a cryogenic fuel constituting the cryogenic propellant;
A LOX tank containing LOX that constitutes a cryogenic propellant together with the cryogenic fuel;
A gasification medium tank filled with the gasification medium;
A liquefied medium tank filled with the cryogenic fuel and a liquefied medium having a temperature lower than that of LOX;
A gas pipe through which the gasification medium flows from the gasification medium tank toward the liquefaction medium tank;
A liquid pipe through which the liquefied medium flows from the liquefied medium tank toward the gasified medium tank;
In the middle of the gas pipe, a turbine that is operated by the gasification medium from the gasification medium tank, and a JT valve that liquefies the gasification medium and sends it to the liquefaction medium tank are disposed.
In the middle of the liquid pipe, a pump for increasing the pressure of the low-temperature liquefied medium from the liquefied medium tank flowing through the liquid pipe by the operation of the turbine is disposed,
In each of the LOX tank and the fuel tank, oxygen exchanged in the LOX tank and the fuel are performed by exchanging heat with a liquefied medium having a low temperature and a high pressure flowing in the liquid pipe. Re-liquefaction heat exchangers that return the cryogenic fuel evaporated in the tank to liquid respectively are arranged,
Between the gas pipe and the liquid pipe in the vicinity of the gasification medium tank, heat exchange is performed with the gasification medium derived from the gas pipe, and the liquefaction medium flowing through the liquid pipe is gasified. A cryogenic propellant storage device, wherein a heat exchanger for gasification that is converted into gas and introduced into the gasification medium tank is disposed.   Between the gasification medium tank and the LOX tank, and between the gasification medium tank and the fuel tank, the gasification medium is a tank pressurization gas with respect to both the LOX tank and the fuel tank. The cryogenic propellant storage device according to claim 1, wherein the pressurized gas supply pipes to be supplied as are respectively disposed.   The cryogenic propellant storage device according to claim 1 or 2, wherein the gasification medium is nitrogen gas and the liquefaction medium is liquid nitrogen.

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