Hydrazine propellant standard gas generator for launch vehicle and generation method

Abstract

The application belongs to the technical field of analytical measurement, and particularly relates to a standard gas generating device and method for hydrazine propellant of a carrier rocket. The standard gas generating device comprises an inert gas source, the inert gas source is connected with an inert gas outlet pipe, the inert gas outlet pipe is divided into two paths, one path is sequentially connected with a constant temperature module and a mixer through a first pipeline, and the other path is connected with the mixer through a second pipeline; the constant temperature module comprises a constant temperature cavity, and a gasification chamber is arranged in the constant temperature cavity; the gasification chamber comprises a liquid storage tank and a capillary tube arranged on the liquid storage tank, and the liquid storage tank is used for placing liquid hydrazine propellant of the carrier rocket. Through the standard gas generating device and method, the standard gas of the uniform and stable hydrazine propellant can be obtained, and the concentration of the gas can be adjusted and set according to requirements.

Description

Technical Field

[0001] This invention belongs to the field of analytical measurement technology, specifically relating to a standard gas generator and method for generating hydrazine-based propellants for launch vehicles. Background Technology

[0002] Hydrazine fuels are commonly used propellants in launch vehicles, including hydrazine, methylhydrazine, and unsymmetrical dimethylhydrazine. Hydrazine fuels are highly toxic; leaks can seriously endanger the health of on-site personnel, and high concentrations pose a risk of combustion and explosion. Therefore, hydrazine fuel gas detectors are widely used in launch vehicles, test ranges, and underground storage facilities for detecting hydrazine fuel leaks. Hydrazine fuel gas detectors require periodic calibration with standard gases to ensure the accuracy of detection results.

[0003] Hydrazines have low boiling points and condense under low temperature and high pressure conditions. Furthermore, hydrazine molecules are easily adsorbed. Adsorption and condensation affect the accuracy and stability of the standard gas, therefore, conventional bottled forms cannot be used to prepare and store hydrazine standard gases. Summary of the Invention

[0004] The purpose of this invention is to provide a standard gas generator and method for generating hydrazine propellant standard gas for launch vehicles, which can generate accurate and stable hydrazine propellant standard gas in a continuous and dynamic manner. When used for calibration of hydrazine fuel gas detectors, it can ensure the accuracy of the test results.

[0005] Specifically, the present invention provides the following technical solutions: A standard gas generator for hydrazine-based propellant in a launch vehicle includes an inert gas source connected to an inert gas outlet pipe. The inert gas outlet pipe is divided into two paths: one path is connected to a temperature control module and a mixer via a first pipeline, and the other path is connected to the mixer via a second pipeline. The constant temperature module includes a constant temperature cavity, in which a vaporization chamber is provided; the vaporization chamber includes a liquid storage tank and a capillary tube disposed on the liquid storage tank, the liquid storage tank being used to hold liquid hydrazine propellant for launch vehicles.

[0006] Hydrazine propellants for launch vehicles are liquid at room temperature, and the saturated vapor pressure of their liquid components increases with increasing temperature, showing a direct correlation. Liquid hydrazine propellant is added to a vaporization chamber equipped with a capillary tube, which is then placed in a thermostatic chamber. The hydrazine components in the vaporization chamber generate saturated vapor, which, under the influence of a pressure gradient, is transported out of the vaporization chamber through the capillary tube. At a constant temperature and with the capillary tube, the hydrazine components in the vaporization chamber exhibit a constant diffusion rate, forming a stable source of hydrazine gas. Different diffusion rates can be obtained by changing the set temperature of the thermostatic chamber and the diameter and length of the capillary tube.

[0007] Using a constant flow of inert gas in the first pipeline as a carrier gas, the hydrazine component gas generated in the vaporization chamber is transported out of the isothermal chamber, resulting in a stable and continuous carrier gas containing hydrazine components. A flow controller is used to control the inert gas in the second pipeline, obtaining a constant flow of dilution gas. Both the carrier gas containing hydrazine components and the dilution gas are then introduced into a mixer, where they are thoroughly mixed and uniformly distributed to obtain a hydrazine propellant standard gas. By controlling the flow rates of the carrier gas and the dilution gas, the desired concentration of hydrazine propellant standard gas can be obtained. This generated hydrazine propellant standard gas is further introduced into a hydrazine propellant concentration detector for testing and calibration.

[0008] In a preferred embodiment, the liquid storage tank of the vaporization chamber is made of materials such as stainless steel or quartz glass, which has good chemical compatibility with hydrazine propellants; the liquid storage tank is usually cylindrical, with a capillary tube vertically installed above the liquid storage pool; the liquid storage pool is also provided with a liquid filling port for easy liquid filling and replenishment, while having good sealing performance to prevent gas and liquid leakage.

[0009] In a preferred embodiment, the mixer is made of corrosion-resistant and anti-adsorption materials, and its interior features a spiral or zigzag flow channel design to increase gas turbulence and allow different gases to mix thoroughly within it.

[0010] Preferably, the constant temperature module further includes a constant temperature bath, a preheating pipe, a heating layer, an insulation layer, a carrier gas inlet, and a carrier gas outlet; The preheating pipe and the constant temperature chamber are arranged in the constant temperature bath; the heating layer and the insulation layer are arranged sequentially outside the constant temperature bath; the carrier gas inlet is connected to the bottom of the constant temperature chamber through the preheating pipe; the carrier gas outlet is located at the top of the constant temperature chamber. The carrier gas enters the constant temperature chamber through the carrier gas inlet and the preheating pipe, carrying the hydrazine gas generated in the vaporization chamber out of the constant temperature chamber; the preheating pipe can prevent temperature fluctuations in the constant temperature chamber; the constant temperature bath can be a water bath, oil bath, metal bath, etc., to maintain a constant and uniform temperature; the insulation layer can be made of inorganic or organic insulation materials, such as rock wool, polyurethane, etc.; the heating layer can be heated by metal heating wires, semiconductor heating plates, etc., and the heating element and temperature sensor, together with the temperature controller, form a temperature control circuit to achieve constant temperature control; the constant temperature chamber can be made of corrosion-resistant and anti-adsorption materials, such as quartz glass, silicon passivated stainless steel, etc.

[0011] Preferably, a first flow controller and a first check valve are sequentially installed on the first pipeline; The second pipeline is sequentially equipped with a second flow controller and a second check valve. The first flow controller controls the flow rate of the inert gas used as the carrier gas; the second flow controller controls the flow rate of the inert gas used as the dilution gas. The flow controllers can be float flow meters, thermal mass flow controllers, differential pressure mass flow controllers, etc. To prevent uneven temperature and concentration fields, the flow rate of the inert gas introduced into the constant temperature chamber should be as small as possible, for example, controlled at (50~200) mL / min.

[0012] Preferably, the inert gas source is at least one of nitrogen, argon, and helium. Since hydrazine components have strong reducing properties, inert gases such as nitrogen should be used for the carrier gas and dilution gas to avoid reaction with hydrazine components, which could affect the accuracy of the standard gas determination.

[0013] Preferably, a purifier is installed on the inert gas outlet pipe. Hydrazine components have strong hygroscopic properties; therefore, this invention adds a purifier at the inlet of the gas path to remove moisture and impurities. The purity of the inert gas exiting the purifier should typically be greater than 99.99999%.

[0014] The present invention also provides a method for generating standard gas for hydrazine propellants in launch vehicles, applied to the aforementioned standard gas generating apparatus, comprising the following steps: Liquid hydrazine propellant is added to the vaporization chamber until it becomes saturated vapor and diffuses into the thermostatic chamber; the diffusion rate of the hydrazine propellant is adjusted by controlling the diameter and length of the capillary tube and the temperature inside the thermostatic chamber. An inert gas, used as a carrier gas, is introduced into the constant temperature chamber to obtain a carrier gas containing hydrazine propellant, which is then further introduced into the mixer; at the same time, an inert gas, used as a dilution gas, is introduced into the mixer. The concentration of the hydrazine propellant standard gas obtained in the mixer is adjusted by controlling the flow rates of the inert gas used as the carrier gas and the inert gas used as the dilution gas.

[0015] Preferably, the diffusion rate of the hydrazine propellant is calculated using the following formula:

[0016] In the formula: F is the diffusion rate, m 3 / s; r is the radius of the capillary tube, m; L is the length of the capillary tube, m; D is the diffusion coefficient of the hydrazine propellant gas, m. 2 / s; P is the pressure inside the storage tank, Pa; P v The saturated vapor pressure of hydrazine propellant is given in Pa. Among them, the diffusion coefficient D and the saturated vapor pressure P VAll of these are related to the temperature of hydrazine propellants.

[0017]

[0018]

[0019] T represents the temperature of the hydrazine propellant, expressed in K.

[0020] Based on the aforementioned standard gas generator for hydrazine propellants in launch vehicles, this invention creatively proposes the aforementioned diffusion rate calculation formula. When the pressure inside the storage tank is atmospheric pressure, the propellant diffusion rate is only related to the temperature T, capillary diameter r, and capillary length L. By changing some or all of the three parameters T, r, and L, the desired diffusion rate can be adjusted. Alternatively, based on the diffusion rate, the optimal values ​​of K, r, and L can be calculated, and the capillary can be designed accordingly.

[0021] The beneficial effects of this invention are at least as follows: (1) The present invention provides a standard gas generator and method for generating hydrazine propellants for launch vehicles, which can obtain uniform and stable standard gases of hydrazine propellants such as unsymmetrical dimethylhydrazine, methylhydrazine, and anhydrous hydrazine; (2) The present invention provides a standard gas generator and method for generating hydrazine propellant for launch vehicles. The gas concentration can be adjusted and set as needed, and the preparation of ppm and ppb level standard gases can be realized. It can be used for testing, calibration and calibration of hydrazine propellant concentration detection equipment. (3) The present invention provides a standard gas generator and method for generating hydrazine propellant standard gas for launch vehicles. The device has a simple structure and is easy to use. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a standard gas generator for hydrazine propellant in a launch vehicle, provided in Example 1. Figure 2 This is a schematic diagram of the isothermal module in a standard gas generator for hydrazine propellant in a launch vehicle, as provided in Example 1. Figure 3 This is a schematic diagram of the vaporization chamber in a standard gas generator for hydrazine propellant in a launch vehicle, as provided in Example 1. Among them, 1-Inert gas source; 2-Constant temperature module; 3-Mixer; 4-Constant temperature chamber; 5-Vaporization chamber; 6-Storage tank; 7-Capillary tube; 8-Liquid inlet; 9-Constant temperature bath; 10-Preheating tube; 11-Heating layer; 12-Insulation layer; 13-Carrier gas inlet; 14-Carrier gas outlet; 15-First flow controller; 16-First check valve; 17-Second flow controller; 18-Second check valve; 19-Purifier; 20-Temperature sensor. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art, or in accordance with the product manual.

[0024] Example 1 Example 1 provides a standard gas generator for hydrazine propellants in launch vehicles, such as... Figures 1-3 As shown, it includes an inert gas source 1, which is connected to an inert gas outlet pipe. The inert gas outlet pipe is divided into two paths: one path is connected to the constant temperature module 2 and the mixer 3 in sequence through a first pipe, and the other path is connected to the mixer 3 through a second pipe. The constant temperature module 2 includes a constant temperature cavity 4, and a vaporization chamber 5 is provided in the constant temperature cavity 4; the vaporization chamber 5 includes a liquid storage tank 6, a capillary tube 7 and a liquid inlet 8 provided on the liquid storage tank 6, and the liquid storage tank 6 is used to hold liquid hydrazine propellant for launch vehicles.

[0025] The constant temperature module also includes a constant temperature bath 9, a preheating pipe 10, a heating layer 11, a heat insulation layer 12, a carrier gas inlet 13, and a carrier gas outlet 14. The preheating pipe 10, the constant temperature chamber 4, and the temperature sensor 20 are disposed in the constant temperature bath 9; the heating layer 11 and the heat preservation layer 12 are disposed sequentially outside the constant temperature bath 9; the carrier gas inlet 13 is connected to the bottom of the constant temperature chamber 4 through the preheating pipe 10; and the carrier gas outlet 14 is disposed at the top of the constant temperature chamber 9.

[0026] The first pipeline is provided with a first flow controller 15 and a first check valve 16 in sequence; the second pipeline is provided with a second flow controller 17 and a second check valve 18 in sequence; the first flow controller 15 and the second flow controller 17 control the flow rate of the inert gas used as carrier gas and dilution gas, respectively.

[0027] The inert gas source is nitrogen.

[0028] The inert gas outlet pipe is equipped with a purifier 19, which removes moisture and impurities from the inert gas. The purity of the inert gas after the purifier is greater than 99.99999%.

[0029] Example 2 Example 2 provides a method for generating standard gas for hydrazine-based propellants in launch vehicles, applied to the standard gas generating apparatus of Example 1, comprising the following steps: Liquid hydrazine propellant is added to the vaporization chamber until it becomes saturated vapor and diffuses into the thermostatic chamber; the diffusion rate of the hydrazine propellant is adjusted by controlling the diameter and length of the capillary tube and the temperature inside the thermostatic chamber. An inert gas, used as a carrier gas, is introduced into the constant temperature chamber to obtain a carrier gas containing hydrazine propellant, which is then further introduced into the mixer; at the same time, an inert gas, used as a dilution gas, is introduced into the mixer. The concentration of the hydrazine propellant standard gas obtained in the mixer is adjusted by controlling the flow rates of the inert gas used as the carrier gas and the inert gas used as the dilution gas.

[0030] The diffusion rate of the hydrazine propellant is calculated using the following formula:

[0031] In the formula: F is the diffusion rate, m 3 / s; r is the radius of the capillary tube, m; L is the length of the capillary tube, m; D is the diffusion coefficient of the hydrazine propellant gas, m. 2 / s; P is the pressure inside the storage tank, Pa; P v The saturated vapor pressure of hydrazine propellant is given in Pa. Among them, the diffusion coefficient D and the saturated vapor pressure P V All of these are related to the temperature of hydrazine propellants.

[0032]

[0033]

[0034] T represents the temperature of the hydrazine propellant, expressed in K.

[0035] Specifically, taking anhydrous hydrazine as an example, at a temperature of 323 K, a capillary radius of 2 mm, and a capillary length of 10 cm, the diffusion rate is 0.00913 mL / min. If the capillary radius is changed to 3 mm, while the T and L parameters remain unchanged, the diffusion rate changes to 0.0206 mL / min.

[0036] When the diffusion rate is 0.00913 mL / min, the flow rate of the inert gas used as the carrier gas is controlled at 100 mL / min, and the flow rate of the inert gas used as the dilution gas is controlled at 900 mL / min, a standard gas for hydrazine propellant with a concentration of 9.13 μmol / mol is obtained.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A standard gas generator for hydrazine-based propellant in launch vehicles, characterized in that, It includes an inert gas source, which is connected to an inert gas outlet pipe. The inert gas outlet pipe is divided into two paths: one path is connected to the constant temperature module and the mixer in sequence through a first pipeline, and the other path is connected to the mixer through a second pipeline. The constant temperature module includes a constant temperature cavity, in which a vaporization chamber is provided; the vaporization chamber includes a liquid storage tank and a capillary tube disposed on the liquid storage tank, the liquid storage tank being used to hold liquid hydrazine propellant for launch vehicles.

2. The standard gas generator for hydrazine propellant in a launch vehicle according to claim 1, characterized in that, The constant temperature module also includes a constant temperature bath, a preheating pipe, a heating layer, an insulation layer, a carrier gas inlet, and a carrier gas outlet; The preheating pipe and the constant temperature chamber are arranged in the constant temperature bath; the heating layer and the insulation layer are arranged sequentially outside the constant temperature bath; the carrier gas inlet is connected to the bottom of the constant temperature chamber through the preheating pipe; and the carrier gas outlet is arranged at the top of the constant temperature chamber.

3. A standard gas generator for hydrazine propellant in a launch vehicle according to claim 1 or 2, characterized in that, A first flow controller and a first check valve are sequentially installed on the first pipeline; The second pipeline is equipped with a second flow controller and a second check valve in sequence.

4. A standard gas generator for hydrazine propellant in a launch vehicle according to claim 1 or 2, characterized in that, The inert gas source is at least one of nitrogen, argon, and helium.

5. A standard gas generator for hydrazine propellant in a launch vehicle according to claim 1 or 2, characterized in that, A purifier is installed on the inert gas outlet pipe.

6. A method for generating standard gas for hydrazine-based propellant in a launch vehicle, characterized in that, The standard gas generator for hydrazine propellant in launch vehicles, as described in any one of claims 1-5, comprises the following steps: Liquid hydrazine propellant is added to the vaporization chamber until it becomes saturated vapor and diffuses into the thermostatic chamber; the diffusion rate of the hydrazine propellant is adjusted by controlling the diameter and length of the capillary tube and the temperature inside the thermostatic chamber. An inert gas, used as a carrier gas, is introduced into the constant temperature chamber to obtain a carrier gas containing hydrazine propellant, which is then further introduced into the mixer; at the same time, an inert gas, used as a dilution gas, is introduced into the mixer. The concentration of the hydrazine propellant standard gas obtained in the mixer is adjusted by controlling the flow rates of the inert gas used as the carrier gas and the inert gas used as the dilution gas.

7. A method for generating standard gas for hydrazine-based propellant in a launch vehicle according to claim 6, characterized in that, The formula for calculating the diffusion rate of the hydrazine propellant is as follows: In the formula: F is the diffusion rate, m 3 / s; r is the radius of the capillary tube, m; L is the length of the capillary tube, m; D is the diffusion coefficient of the hydrazine propellant gas, m. 2 / s; P is the pressure inside the storage tank, Pa; P v The saturated vapor pressure of hydrazine propellant is given in Pa. Among them, the diffusion coefficient D and the saturated vapor pressure P V All of these are related to the temperature of hydrazine propellants. T represents the temperature of the hydrazine propellant, expressed in K.

Images