Vapor jet system enabling jetting for many seconds using multiple kinds of mutually insoluble liquid gases as fuel

Abstract

A vapor jet system to continuously jet vapors while suppressing cavitation. One vapor jet system includes a liquid storage part for separately storing two or more kinds of mutually insoluble liquids; a jet orifice; and a jet control part. Jetting the vapors is from a state where pressure in the space storing the vapors in the liquid storage part is higher than the saturated vapor pressure in any of the two or more kinds of liquids. Alternatively, a vapor jet system can include a fluid storage part storing one kind of liquid and at least one kind of inactive gas having a composition different from the liquid; a similar jet orifice; and a similar jet control part. Jetting the vapors and inactive gas(es) is (are) from a state where pressure in a vapor storing space in the fluid storage part is higher than the saturated vapor pressure in the liquid.

Claims

1. A vapor jet system comprising: a first storage container including an inner wall to which a first foam metal is attached; a first liquid held by the first foam metal; a first vapor generated by vaporization of the first liquid in the first storage container; a second storage container including an inner wall to which a second foam metal is attached; a second liquid held by the second foam metal; a second vapor generated by vaporization of the second liquid in the second storage container; a first filter that prevents the passage of liquids; a second filter that prevents the passage of liquids; a jet orifice connected to a vapor passage connected to each of the first storage container and the second storage container; a jet control part; a first heater positioned at the first storage container; and a second heater positioned at the second storage container, wherein the first liquid and the second liquid are mutually insoluble.

2. The vapor jet system according to claim 1, wherein the first liquid is liquid ammonia or ammonia water, and the second liquid is liquid butane.

3. The vapor jet system according to claim 1, wherein at least one storage container of the first storage container and the second storage container further comprises a flat plate.

4. The vapor jet system according to claim 2, wherein at least one storage container of the first storage container and the second storage container further comprises a flat plate.

5. A vapor jet system comprising: a single storage container; a separation wall positioned inside the single storage container; a first foam metal attached to an inner wall of the single storage container; a second foam metal attached to an inner wall of the single storage container, the second foam metal being separated from the first foam metal by the separation wall; a first liquid held by the first foam metal; a first vapor generated by vaporization of the first liquid in the single storage container; a second liquid held by the second foam metal; a second vapor generated by vaporization of the second liquid in the single storage container; a filter that prevents the passage of liquids; a jet orifice connected to a vapor passage connected to the single storage container; a jet control part; and a heater positioned at the single storage container, wherein the first liquid and the second liquid are mutually insoluble.

6. The vapor jet system according to claim 5, wherein the first liquid is liquid ammonia or ammonia water; and the second liquid is liquid butane.

7. A vapor jet system comprising: a first storage container including an inner wall to which a foam metal is attached; a liquid held by the foam metal; a vapor generated by vaporization of the liquid in the first storage container; a second storage container; an inactive gas in the second storage container; a first filter that prevents the passage of liquids; a second filter that prevents the passage of liquids; a jet orifice connected to a vapor passage connecting to the first storage container and the second storage container; a jet control part; and a heater positioned at the first storage container, wherein the inactive gas has a composition different from the liquid.

8. A vapor jet system comprising: a single storage container; a separation wall positioned inside the single storage container; a foam metal attached to an inner wall of the single storage container; a liquid held by the foam metal; a vapor generated by vaporization of the liquid in the single storage container; an inactive gas in the single storage container; a filter that prevents the passage of liquids; a jet orifice connected to a vapor passage connecting to the single storage container; a jet control part; and a heater positioned at the single storage container, wherein the inactive gas has a composition different from the liquid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 A system diagram of the vapor jet system (thruster) according to the first embodiment of the present invention.

(2) FIG. 2 A system diagram of the vapor jet system (thruster) according to the second embodiment of the present invention.

(3) FIG. 3 A system diagram of the vapor jet system (thruster) according to the third embodiment of the present invention.

(4) FIG. 4 A system diagram of the vapor jet system (spray) according to the fourth embodiment of the present invention.

(5) FIG. 5 A system diagram of the vapor jet system (for experiment) according to the fifth embodiment of the present invention.

(6) FIG. 6 A graph showing the change of the pressure in the container when a vapor jet experiment was conducted using the vapor jet system of comparative examples.

(7) FIG. 7 A graph showing the change of the pressure in the container when a vapor jet experiment was conducted using the vapor jet system of FIG. 5.

(8) FIG. 8 A system diagram of the vapor jet system (for experiment) according to the sixth embodiment of the present invention.

(9) FIG. 9 Photographs showing behaviors of the liquid propellant when a vapor jet experiment was conducted using the vapor jet system of comparative examples (from the upper side, nozzle diameter of 0.4 mm, 0.6 mm, 0.8 mm).

(10) FIG. 10 Photographs showing behaviors of the liquid propellant when a vapor jet experiment was conducted using the vapor jet system of FIG. 8 (from the upper side, nozzle diameter of 0.6 mm, 0.8 mm, 1.0 mm).

DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

(11) In the following, embodiments of the vapor jet system according to the present invention will be explained with figures. In this regard, it should be noted that the vapor jet system of the present invention is not limited to the specific particular configurations shown in the respective figures and related explanations, and the vapor jet system can be appropriately modified within the scope of the present invention. For example, the vapor jet system can be configured using three or more kinds of mutually insoluble liquids (In the configuration of FIG. 1, liquid fuel storage containers should be provided so that the number of the containers is equal to the numbers of the kinds of the liquids, as liquid fuel storage container 2A, 2B, 2C . . . , and they should join together at the pipe similarly to the configuration of FIG. 1), and two or more kinds of inactive gases can be used when using a vapor jet system using one kind of liquid and inactive gases. Furthermore, even in a case where two or more kinds of mutually insoluble liquids are used, it is possible to configure the vapor jet system of the present invention by further injecting one or more kind of inactive gas into the liquid fuel storage container(s).

(12) Configuration of Vapor Jet System

(13) FIG. 1 shows an example of a system diagram of the vapor jet system 1 (thruster) usable for a thruster system for a small spacecraft according to the first embodiment of the present invention. The vapor jet system 1 comprises: liquid fuel storage containers 2A, 2B made of aluminum, SUS (stainless steel), or the like, each of which stores each of mutually insoluble liquid gases A, B; inject and eject valves 5A, 5B for injecting and ejecting liquid gases A, B into or from the liquid fuel storage containers 2A, 2B; filters 6A, 6B for preventing impurities and fuels in liquid state from passing through; latch type electromagnetic valves 7A, 7B for controlling moving, to the side of propellant valves 7C, of vapors of the liquid gases A, B which passed through the filters 6A, 6B; the electromagnetic valves (propellant valves) 7C for controlling jetting out of the vapors of the liquid gases A, B from jet orifices 8; and the jet orifices 8 for jetting out vapors of the liquid gases A, B. Foam metals 3A, 3B made of, for example, copper, SUS, or the like with about 95% of airspace rate are attached to the inner walls of the liquid fuel storage containers 2A, 2B using adhesive agents, respectively. And, heaters 4A, 4B are attached to the outer walls of the liquid fuel storage containers 2A, 2B around their whole circumferences, respectively. Line segments connecting respective components in FIG. 1 indicate pipes. In addition, a pressure sensor 9 for detecting pressure in the pipes, and inject and eject valve 5C for using in a ground test etc. for checking existence of a leak by injecting helium gas etc. while closing the propellant valve 7C, are provided in the vapor jet system 1.

(14) Operation of the Vapor Jet System

(15) In the following, the operation of the vapor jet system 1 will be explained. It is assumed here that opening and closing of the respective electromagnetic valves (jet control part) and operational control of the heaters, respective sensors etc. are performed by remote control etc. via arbitrary control circuits (not shown in figures), and that injecting of liquid (gas) and ejecting of liquid (gas) from the respective inject and eject valves are performed typically by an operator. However, specific means for performing those controls/operations can be appropriately changed according to embodiments (The same holds true for the subsequent embodiments).

(16) When using the vapor jet system 1, different kinds of liquid gases A, B are firstly injected from the inject and eject valves 5A, 5B into the liquid fuel storage containers 2A, 2B, respectively, and the liquid gases A, B in liquid state are held in the airspace parts in the foam metals 3A, 3B by surface tension. Respective vapors generated by vaporizing the liquid gases A, B in the liquid fuel storage containers 2A, 2B are released from the liquid fuel storage containers 2A, 2B via the pipes. After the vapors pass through the filters 6A, 6B, the latch type electromagnetic valves 7A, 7B are opened and those vapors join together in the pipe. At this time, the pressure in the space storing the vapors in the liquid fuel storage containers 2A, 2B is higher than the saturated vapor pressures of the liquid gases A, B. This gas pressure is monitored by the pressure sensor 9. When the propellant valves 7C of the thruster are opened in a state where the latch type electromagnetic valves 7A, 7B are opened, the vapors which joined together are jetted out from the jet orifices 8 outward and a thrust force is generated. Since the above pressure at the beginning of the jetting out is higher than the saturated vapor pressures of the liquid gases A, B, it becomes possible to continuously jet out for a long time without occurrence of cavitation.

(17) Explanations were presented above about the vapor jet system 1 of FIG. 1 operated using two kinds of liquid gases (or they can be liquids in the broad sense of the term), but it is also possible to configure the vapor jet system 1 of FIG. 1 as a vapor jet system operated using one kind of liquid gas (or liquid in the broad sense of the term) and at least one kind of inactive gas. In this case, one of the liquid fuel storage containers 2A, 2B is filled with, not the liquid gas, but at least one kind of inactive gas (GN2, GHe etc. with high pressure). It is not necessary to attach a foam metal to the storage container (inactive gas storage container) filled with the inactive gas. Similarly to the case where two kinds of liquid gases are used, vapors of the liquid gas and the inactive gas join together in the pipe by opening the latch type electromagnetic valves 7A, 7B, and the pressure in the space storing the vapors becomes higher than the saturated vapor pressure of the liquid gas. When the propellant valves 7C of the thruster are opened in a state where the latch type electromagnetic valves 7A, 7B are opened, the vapors and the inactive gas which joined together are jetted out from the jet orifices 8 outward and a thrust force is generated. Since the above pressure at the beginning of the jetting out is higher than the saturated vapor pressures of the liquid gas, it becomes possible to continuously jet out for a long time without occurrence of cavitation. In intervals between a jetting out operation and a jetting out operation, temperatures of those liquid gases are recovered by heating the liquid gases A, B with the heaters 4A, 4B.

(18) In the vapor jet system 1 of FIG. 1, the liquid fuel storage containers 2A, 2B storing the liquid gases A, B (or, a liquid fuel storage container and an inactive gas storage container) are provided as distinct containers, but they can be substituted with a single tank having a cross wall (a fluid storage container). FIG. 2 shows an example of a system diagram of the vapor jet system 1 (thruster) according to the second embodiment of the present invention configured using a single fluid storage container.

(19) Configuration of Vapor Jet System

(20) The vapor jet system 1 comprises: a fluid storage container 2 which stores mutually insoluble liquid gases A, B, or a liquid gas A and at least one kind of inactive gas respectively in spaces separated by a cross wall (made of aluminum, SUS, or the like); inject and eject valves 5A, 5B for injecting and ejecting liquid (gas) of the liquid gas and inactive gas into or from the fluid storage container 2; a filter 6 for preventing impurities and fuels in liquid state from passing through; a latch type electromagnetic valve 7AB for controlling moving, to the side of propellant valves 7C, of vapors of the liquid gas which passed through the filter or the inactive gas; the electromagnetic valves (propellant valves) 7C for controlling jetting out of the vapors of the liquid gas and the inactive gas from jet orifices 8; and the jet orifices 8 for jetting out vapors of the liquid gas and the inactive gas. Foam metals 3A, 3B are attached to the inner walls of the respective spaces separated by the cross wall 10 in the fluid storage container 2 (they are not needed on the inner wall of the space storing an inactive gas), and, a heater 4 is attached to the outer wall around the whole circumference. Line segments connecting respective components in FIG. 2 indicate pipes. In addition, a pressure sensor 9 for detecting pressure in the pipes, and inject and eject valve 5C for using in a ground test etc. are provided in the vapor jet system 1, similarly to the configuration of FIG. 1.

(21) Operation of the Vapor Jet System

(22) When using the vapor jet system 1, different kinds of liquid gases A, B, or a liquid gas and at least one kind of inactive gas, are firstly injected from the inject and eject valves 5A, 5B into the spaces separated by the cross wall 10 in the fluid storage container 2, respectively, and the liquid gas(es) is (are) held in the airspace parts in the foam metal(s) and the inactive gas is held in the corresponding space, respectively (the inactive gas may flow into the space on the side storing the liquid gas). Vapors of the liquid gases A, B, or vapors of the liquid gas and the inactive gas join together in the fluid storage container 2, and are released from the fluid storage container 2 via the pipes. The pressure in the space storing the vapors in the fluid storage container 2 is higher than the saturated vapor pressure of the liquid gas. This gas pressure is monitored by the pressure sensor 9. When the latch type electromagnetic valve 7AB is opened, and the propellant valves 7C of the thruster are further opened, vapors released from the fluid storage container 2, or the vapors and the inactive gas are jetted out from the jet orifices 8 outward and a thrust force is generated. Since the above pressure at the beginning of the jetting out is higher than the saturated vapor pressure(s) of the liquid gas(es), it becomes possible to continuously jet out for a long time without occurrence of cavitation. In intervals between a jetting out operation and a jetting out operation, the temperature of the liquid gas(es) is (are) recovered by heating the liquid gas(es) with the heater 4.

(23) As another embodiment, a net type object, a foam metal, a flat plate can be placed in the liquid storage containers as described in the Patent Document 3. FIG. 3 shows an example of a system diagram of the vapor jet system 1 (thruster) according to the third embodiment of the present invention configured using them.

(24) Configuration of Vapor Jet System

(25) The vapor jet system 1 comprises: liquid fuel storage containers 2A, 2B each of which stores each of mutually insoluble liquid gases A, B; inject and eject valves 5A, 5B for injecting and ejecting liquid gases A, B into or from the liquid fuel storage containers 2A, 2B; filters 6A, 6B for preventing impurities and fuels in liquid state from passing through; latch type electromagnetic valves 7A, 7B for controlling moving, to the side of propellant valves 7C, of vapors of the liquid gases A, B which passed through the filters; the electromagnetic valves (propellant valves) 7C for controlling jetting out of the vapors of the liquid gases A, B from jet orifices 8; and the jet orifices 8 for jetting out vapors of the liquid gases A, B.

(26) Differently from the configuration of FIG. 1, net type objects 11A, 11B made of SUS or the like are attached to the inner walls of the liquid fuel storage containers 2A, 2B using adhesive agents, respectively. By forming liquid films by surface tensions of liquid gases A, B in reticulations of those net type objects 11A, 11B, inner spaces of the liquid fuel storage containers 2A, 2B are separated into spaces storing vapors (upper side from the net type objects 11A, 11B in FIG. 3) and spaces storing liquids (lower side from the net type objects 11A, 11B in FIG. 3) (see FIG. 1, [0032] of the Patent Document 3). In addition, foam metals 3A, 3B storing each of liquid gasses A, B in liquid state in their airspaces, respectively, are attached to the inner walls of the liquid fuel storage containers 2A, 2B adjacent to the net type objects 11A, 11B. In this regard, the spaces storing liquids can be fully occupied by the foam metals 3A, 3B, but it is also possible that the foam metals 3A, 3B are placed only partially in the spaces storing the liquids as shown in FIG. 3 and that the remaining spaces are occupied by the liquid gases 13A, 13B in liquid state since gas-liquid separation is conducted by the net type objects 11A, 11B in this embodiment.

(27) Further, heaters 4A-1, 4A-2 and 4B-1, 4B-2 are attached to the outer walls of the liquid fuel storage containers 2A, 2B, respectively. By heating with the heaters 4A-1 and 4B-1, the temperatures of the inner spaces of the liquid fuel storage containers 2A, 2B are controlled so that the temperatures in the spaces storing vapors are higher than the temperatures in the spaces storing liquids. In this way, inversion of spaces storing vapors and spaces storing liquids is prevented (see [0014] in the Patent Document 3). And, by heating with the heaters 4A-2 and 4B-2 in intervals of jetting out, the temperatures of the respective liquid gases are recovered as described above. In this regard, although not shown in figures, it is preferable to appropriately provide heaters to pipes from the liquid fuel storage containers 2A, 2B to the jet orifices 8 to keep the temperature in the pipes higher than the temperatures in the liquid fuel storage containers 2A, 2B to prevent vapors from returning to liquids (The same holds true for other embodiments). In this way, a temperature gradient is realized which moves upward from the spaces storing the liquids to the spaces storing the vapors of the liquid fuel storing containers 2A, 2B, and toward the pipes outside of the containers. In addition, a plurality of flat plates 12A, 12B made of SUS or the like are attached to the inner walls of the liquid fuel storage containers 2A, 2B by adhesive agents, and it is possible to capture floating droplets by the flat plates 12A, 12B by rotating the liquid fuel storage containers 2A, 2B around the rotation axes AX-A, AX-B (using arbitrary driving circuits etc. not shown in figures), respectively while operating the vapor jet system 1 (see [0043] in the Patent Document 3).

(28) Operation of the Vapor Jet System

(29) When using the vapor jet system 1, different kinds of liquid gases A, B are firstly injected from the inject and eject valves 5A, 5B into the liquid fuel storage containers 2A, 2B, respectively, and the liquid gases A, B in liquid state are held in the airspace parts in the foam metals 3A, 3B, and liquid films are formed in the reticulations of the net type objects 11A, 11B. Respective vapors generated by vaporizing the liquid gases A, B in the liquid fuel storage containers 2A, 2B are released from the liquid fuel storage containers 2A, 2B via the pipes. After the vapors pass through the filters 6A, 6B, the latch type electromagnetic valves 7A, 7B are opened and those vapors join together in the pipe. At this time, the pressure in the space storing the vapors in the liquid fuel storage containers 2A, 2B is higher than the saturated vapor pressures of the liquid gases A, B. This gas pressure is monitored by the pressure sensor 9. When the propellant valves 7C of the thruster are opened in a state where the latch type electromagnetic valves 7A, 7B are opened, the vapors which joined together are jetted out from the jet orifices 8 outward and a thrust force is generated. Since the above pressure at the beginning of the jetting out is higher than the saturated vapor pressures of the liquid gases A, B, it becomes possible to continuously jet out for a long time without occurrence of cavitation.

(30) The vapor jet system 1 of FIG. 3 operated using two kinds of liquid gases is described above, but this vapor jet system 1 can also be operated similarly with similar configurations in an embodiment where the vapor jet system 1 is operated using one kind of liquid gas and at least one kind of inactive gas except the difference in that a net type object, a foam metal, a flat plate, or a heater is not required to be provided in the container storing an inactive gas (gas storage container) in the liquid storage containers 2A, 2B.

(31) The vapor jet system according to the present invention can be used for other objects than a thruster. As an example, a system diagram of the vapor jet system 1 according to the fourth embodiment of the present invention configured as a vapor jet spray is shown in FIG. 4 as an example.

(32) Configuration of Vapor Jet System

(33) The vapor jet system 1 comprises: a liquid storage container 2 (aluminum can or the like) in which a cross wall 10 made of aluminum is provided and which stores mutually insoluble liquid gases A, B respectively; a filter 6 for preventing impurities and the liquid gases in liquid state from passing through; a nozzle control part 7 which controls jetting out of vapors of the liquid gases A, B from a jet orifice 8; and the jet orifice 8 for jetting out vapors of the liquid gases A, B. The respective liquid gases A, B in liquid state (13A, 13B) are stored respectively in the spaces separated by the cross wall 10.

(34) Operation of the Vapor Jet System

(35) When using the vapor jet system 1, it is assumed that different kinds of liquid gases A, B were injected into the spaces separated by the cross wall 10 in the liquid storage container 2 in advance (when manufacturing the spray). At this time, the pressure in the space storing vapors in the liquid storage container 2 is higher than the saturated vapor pressures of the liquid gases A, B. Respective vapors generated by vaporization of the liquid gases A, B in the liquid storage container 2 pass through the pipe and are released from the liquid storage container 2. After passing through the filter 6, they are jetted out from the jet orifice 8 by operating the nozzle (air nozzle) control part 7. Since the above pressure at the beginning of the jetting out is higher than the saturated vapor pressures of the liquid gases A, B, it becomes possible to continuously jet out for a long time without occurrence of cavitation.

(36) The vapor jet system 1 of FIG. 4 operated using two kinds of liquid gases is described above, but this vapor jet system 1 can also be operated in an embodiment where the vapor jet system 1 is operated using one kind of liquid gas and at least one kind of inactive gas. Specifically, by enclosing a liquid gas and at least one kind of inactive gas in advance in a liquid (fluid) storage container 2 (a cross wall 10 is not required), the pressure in the space storing the vapors in the liquid storage container 2 is higher than the saturated vapor pressure of the liquid gas and thus it becomes possible to continuously jet out for a long time without occurrence of cavitation.

(37) The vapor jet system 1 with the configuration shown in FIG. 5 was made and an experiment of jetting out was conducted.

(38) In the vapor jet system 1 of FIG. 5, a liquid fuel storage container 2A of 0.1 L (acrylic) is connected to the inside of a liquid fuel storage container 2B of 1.0 L (acrylic) via a spacer 15 (aluminum). The liquid fuel storage container 2A is filled with 28% (concentration by percent by mass) ammonia water 13A, and the liquid fuel storage container 2B is filled with liquid butane 13B (The liquid fuel storage container 2A is filled with ammonia water 13A first, and stored in the liquid fuel storage container 2B, and then liquid butane 13B is injected from a inject and eject valve 5B connected to the bottom of the liquid fuel storage container 2B. Foam metals 3A, 3B made of nickel are inserted into the respective containers. The inject and eject valve 5C is for ground tests such as checking of a leak.). The mixture vapor pressure of the ammonia water and the liquid butane is monitored by a temperature sensor 14 and a pressure sensor 9 connected to the liquid fuel storage container 2B. Jetting out of gases outward is conducted by opening an electromagnetic valve 7C connected shortly before a jet orifice (nozzle) 8. The performance of the vapor jet system was evaluated in the following viewpoints:

(39) (1) Pressure of the mixed vapors of ammonia water and liquid butane measured by the temperature sensor 14 and the pressure sensor 9 connected to the liquid fuel storage container 2B.

(40) (2) Measurement value by the pressure sensor 9 at the time of occurrence of cavitation confirmed from images of a high-speed camera (imaging speed: 120 fps) (Since acrylic plastic is used as materials of the liquid fuel storage container 2A, 2B, existence or non-existence of occurrence of cavitation from inside of the liquid fuels stored in the containers could be captured.).

Experiment with a Comparative Example

(41) First, vapor jets were conducted without filling the liquid fuel storage container 2A with ammonia water and with filling the liquid fuel storage container 2B with liquid butane in the configuration of FIG. 5. The vapor jets were conducted with three types of nozzle throat diameter of 0.4 mm, 0.6 mm, 0.8 mm, respectively, and pressure in the container at the time of occurrence of cavitation was measured in the respective throat diameters. FIG. 6 shows the change of the pressure in the liquid fuel storage container 2B in the vapor jet experiments. In FIG. 6, the solid line corresponds to the nozzle throat diameter of 0.4 mm (No. 1-1), the dashed line corresponds to 0.6 mm (No. 1-2), and the dot-and-dash line corresponds to 0.8 mm (No. 1-3), respectively. In addition, initial temperature (before decompression by jetting out) and initial pressure in the liquid fuel storage container 2B, pressure in the liquid fuel storage container 2B at the time of occurrence of cavitation (bubbles), vapor pressure of butane at the initial temperature, and jetting duration from the beginning of the vapor jet to the occurrence of cavitation, in the experiments with the respective nozzle throat diameters, are shown in Table 1 below.

(42) TABLE-US-00001 TABLE 1 pressure at throat initial initial the time of vapor diameter temperature pressure generation of pressure of jet duration No. [mm] [ C.] [MPa] bubble [MPa] butane [MPa] [sec] 1-1 0.4 26.9 0.258 0.255 0.257 2.2 1-2 0.6 27.1 0.258 0.255 0.259 0.2 1-3 0.8 27.1 0.259 0.253 0.259 0.2 2-1 0.4 27.2 0.296 0.260 0.260 42.4 2-2 0.6 27.4 0.288 0.261 0.261 1.9 2-3 0.8 27.1 0.296 0.258 0.259 1.4

(43) Here, vapor pressure of butane is the pressure P calculated using the following Antoine equation (1) from the initial temperature (T is absolute temperature):

(44) $\begin{array}{cc}\left[\mathrm{Numeral}1\right]& \\ \log P\left[\mathrm{kPa}\right]=A-\frac{B}{T\left[K\right]+C}A=5.93266,B=935.773,C=-34.361& \left(1\right)\end{array}$

(45) As a result of the experiments, it was confirmed that, in the conventional vapor jet system with a single liquid gas as single butane, the initial pressure in the liquid fuel storage container 2B was the saturated vapor pressure of liquid butane, and that cavitation occurred shortly after jetting out of vapors regardless of the nozzle throat diameter, namely regardless of decompression speed.

(46) (Experiment with a System According to the Present Invention)

(47) Next, ammonia water was stored in the liquid fuel storage container 2A, liquid butane was stored in the liquid fuel storage container 2B, and vapor jets were conducted with three types of nozzle throat diameter of 0.4 mm, 0.6 mm, 0.8 mm. FIG. 7 shows the change of the pressure in the liquid fuel storage container 2B when the vapor jet experiments were conducted. In FIG. 7, the solid line corresponds to the nozzle throat diameter of 0.4 mm (No. 2-1), the dashed line corresponds to 0.6 mm (No. 2-2), and the dot-and-dash line corresponds to 0.8 mm (No. 2-3), respectively. In addition, initial temperature and initial pressure in the liquid fuel storage container 2B, pressure in the liquid fuel storage container 2B at the time of occurrence of cavitation, vapor pressure of butane at the initial temperature, and jetting duration from the beginning of the vapor jet to the occurrence of cavitation, in the experiments with the respective nozzle throat diameters, are shown in Table 1 above.

(48) As a result of the experiments, the pressure in the container before the above jet was higher than the saturated vapor pressure of liquid butane by about 30-40 kPa. It was confirmed that, after vapor jets, cavitation occurred from the bottom of the liquid fuel storage container 2B after the pressure fell below the saturated vapor pressure of single butane calculated from the temperature sensor 14 regardless of decompression speed. Therefore, it was confirmed that occurrence of cavitation can be delayed by the vapor pressure of ammonia water relative to the case of vapor jet with single butane.

(49) A vapor jet system for experiment with configurations shown in FIG. 8 was made. Experiments with microgravity which utilize a drop tower were conducted in order to confirm that performance of jetting out for many seconds is improved by suppressing cavitation. In the present experiments, jetting experiments were conducted in the same environment for one liquid type and 1 liquid+(plus) 1 gas type thruster system and the gas-liquid separation performance was compared. The present experiments were conducted at the drop tower of 50 m in Akabira City, Hokkaido. The gravity level is 10.sup.3 G, and the falling duration is about 2.5 sec.

(50) (Experiment Device)

(51) A foam metal 3 (Duocel 40PPI6 by ERG) was constructed in a fluid storage container 2 made of 0.3 L polycarbonate, and it was filled with liquid HFC 134a to the same height as the foam metal 3. Behaviors of liquid propellant in the fluid storage container 2 while jetting out were recorded by four pressure sensors 9A9D, one temperature sensor 14, a high speed camera 16 (imaging speed: 120 fps). The pressure sensors measured the ullage part (PG) storing vapors of HFC 134a, liquid part (PL1, PL2), and nozzle chamber part (PC) of jet orifice 8, respectively. The temperature sensor measured temperature of the ullage (gas). In addition, the flow rate was adjusted by changing the nozzle throat diameter.

(52) (Experimental Items)

(53) Differences in behaviors of the liquid propellant between a case where single HFC 134a is jetted out (corresponding to one liquid type) and a case where Ar is added to HFC134a (corresponding to 1 liquid+(plus) 1 gas type) were observed with changing the nozzle throat diameter. By controlling the electromagnetic valve 7C by a microcomputer (not shown in figures), jetting outs were conducted for 1.6 seconds duration from 0.2 second after to 1.8 seconds after the dropping of a capsule.

(54) (Experimental Result)

(55) Experimental results are shown in Table 2 below.

(56) TABLE-US-00002 TABLE 2 nozzle diameter No. sample fluid [mm] judgment 1-1 HFC134a 0.4 1-2 HFC134a 0.6 1-3 HFC134a 0.8 x 2-1 HFC134a Ar 0.6 2-2 HFC134a Ar 0.8 2-3 HFC134a Ar 1.0 x

(57) In Table 2, judgment is defined as O (circle mark) when the liquid propellant is still held by the foam metal when jetting out, and it is defined as X (cross mark) when the liquid propellant is not held, in that ascension of the gas-liquid interface was observed, from images taken by the high-speed camera 16.

(58) When using single HFC134a (No. 1-11-3), the liquid propellant was held in the foam metal in jetting out with (phai, nozzle diameter) of 0.4 mm, 0.6 mm, but the liquid propellant was not held with (phai) of 0.8 mm. FIG. 9 shows photographs of the liquid propellant when a jetting experiment was conducted (2.0 seconds after start of fall) using single HFC 134a (from the upper side, nozzle diameter of 0.4 mm, 0.6 mm, 0.8 mm). From FIG. 9, it is confirmed that the liquid propellant flowed out from the foam metal in the test case of (phai) 0.8 mm. In addition, according to pressure histories measured by the pressure sensors 9A9D, the pressure is monotonically decreasing during jetting out in the pressure history of the case where the liquid propellant is held by the foam metal, but the pressure recovered in a later stage of the jetting out in the case No. 1-3 where the liquid propellant flowed out. It is considered that, in that case, the pressure rose since vaporization by cavitation was added to vaporization by evaporation.

(59) On the other hand, the liquid propellant was held in the foam metal in a case where Ar is added to HFC 134a at (phai) 0.6 mm, 0.8 mm, but flowing out of the liquid propellant was observed at (phai) 1.0 mm. FIG. 10 shows photographs showing inside of the fluid storage container 2 after 2.0 seconds from start of falling of the respective test cases (from the upper side, nozzle diameter of 0.6 mm, 0.8 mm, 1.0 mm). According to the pressure histories measured by pressure sensors 9A9D, it is observed that, in No. 2-2 and No. 2-3, the ullage pressure (PG) was below the partial pressure of HFC 134a (it was calculated using Antoine equation from the temperature value before the jetting out measured by the temperature sensor, and it corresponds to the pressure from which bubbles start to be generated from the liquid) at the later stage of the jetting out. Also from images of the high-speed camera 16 (FIG. 10), occurrence of bubbles with nozzle diameter (phi) 0.8 mm and 1.0 mm was measured. However, in the case of (phi) 0.8 mm with small flow rate, it was not enough to rise the gas-liquid interface. On the other hand, in the case of (phi) 1.0 mm, it is considered that the gas-liquid interface rose by bubbles accompanying cavitation in HFC 134a.

(60) From the above test results, it was found that, for a same flow rate (nozzle throat diameter), flowing out of liquid propellant from the foam metal can be better suppressed in a test case where pressure is applied by Ar gas. Therefore, it was confirmed that suppressing of cavitation is effective for improving the continuous jet performance.

INDUSTRIAL APPLICABILITY OF THE INVENTION

(61) The vapor jet system according to the present invention can be applied to, from a thruster for a small thrust system for planet, a spray, to arbitrary devices, methods, systems etc. for stably jetting out vapors.

EXPLANATION OF SYMBOLS

(62) 1 vapor jet system (thruster, spray) 2 liquid (fluid) storage container 2A, 2B liquid fuel (inactive gas) storage container 3, 3A, 3B foam metal 4, 4A(-1, 2), 4B(-1, 2) heater 5, 5A, 5B, 5C inject and eject valve 6, 6A, 6B filter 7, 7A, 7B, 7AB, 7C electromagnetic valve, nozzle control part 8 jet orifice 9, 9A, 9B, 9C, 9D pressure sensor 10 cross wall 11A, 11B net type object 12A, 12B flat plate 13A, 13B liquid 14 temperature sensor 15 spacer 16 high speed camera