CN104197189B - A kind of liquid oxygen gasifier device - Google Patents

Abstract

The invention discloses an oxidant heat exchange gasification device for a direct-connected supersonic combustion ground experiment platform, which is characterized in that the gasifier is in the shape of a long cylinder, and a plurality of thin circular tubes are arranged for liquid oxygen transportation. , the rest of the internal space in the housing is for air flow, and there are multiple round holes in the outlet section for gaseous air to pass through; the gasifier is installed after the main air pipeline, before the air-oxygen mixing chamber and the butane combustion heater, so that The air to be mixed is heat-exchanged with liquid oxygen and causes the latter to vaporize. This gasification device can meet the oxidant gasification requirements of simulating high, medium and low flight Mach numbers, different proportions and pressure flow rates under different total temperature conditions. The invention directly uses the air that needs to be mixed to exchange heat with the liquid oxygen and makes the latter gasify without any additional external working medium or energy input for assistance, which is simple, easy and efficient.

Description

A liquid oxygen vaporizer device

technical field

The invention relates to a design device of a liquefied oxygen evaporator, in particular to a liquefied oxygen evaporator device and method for a butane and oxygen combustion heating system of a direct-connected supersonic combustion ground experiment platform.

Background technique

In order to carry out research on supersonic combustion ramjet better, it is necessary to establish a long-term direct-coupled supersonic combustion ground test platform. As an important part of this ground test platform, the butane and oxygen combustion heating system plays a key role in simulating the high-altitude incoming air on the ground through the product high-temperature mixed gas formed after the violent chemical reaction inside it. In order to simulate incoming air under different flight conditions in the same butane combustion heating system, it is necessary to fully mix pure oxygen and air in advance according to a certain ratio to form oxygen-enriched air, and then ignite and burn with butane. Because liquid oxygen has a higher density than high-pressure gas oxygen, it is more convenient to store and transport, and the operation is safer, so the use of liquid oxygen is a good choice. However, before liquid oxygen and air are mixed, they need to go through a series of complex processes such as droplet breaking, atomization and evaporation. There is no particularly mature theory for the design of atomizing nozzles, and the effect of mixing liquid oxygen and air is difficult to accurately predict and grasp. And then certainly will influence the effect that the mixed oxygen-enriched air and butane carry out combustion. If the requirements of different working conditions are considered, the situation will be more complicated, and it will be more difficult to achieve a good air-oxygen mixing effect and subsequent full combustion of butane with oxygen.

Contents of the invention

Aiming at the current challenge of fully mixing liquid oxygen and air, the purpose of the present invention is to provide a design method and device for a liquid oxygen evaporator used in a butane and oxygen combustion heating system. Using this design method and gasification device, it can It is fully guaranteed that liquid oxygen changes from an overpressure liquid state to a gaseous state in the transportation pipeline before it is premixed with air, so as to avoid the liquid droplets brought by the transcritical atomizing nozzle that must be used if this gasification device is not used The uncertainty of a series of complex processes such as broken atomization and evaporation can more effectively realize the full mixing of oxygen and air, which provides a solid foundation for the efficient and sufficient chemical reaction between oxygen-enriched air and butane in the combustion heating system.

Specifically, the present invention proposes a liquid oxygen gasifier device for a butane and oxygen combustion heating system, which is characterized in that the gasifier is in the shape of a long cylinder, and a plurality of thin circular tubes are arranged for liquid oxygen transportation In use, the rest of the internal space in the shell is for air flow, and there are multiple round holes in the outlet section for gaseous air to pass through; Make the air to be mixed and liquid oxygen carry out effective heat exchange and make the latter completely vaporize before mixing.

Further, the gasifier is made of stainless steel, the outer casing has a diameter of 90 mm and a thickness of 5 mm.

Further, there are 84 thin circular tubes with an outer diameter of 4 mm and a thickness of 1 mm.

Further, the multiple circular holes in the outlet section are 85 circular holes with a diameter of 4mm.

The invention directly uses the air that needs to be mixed to exchange heat with the liquid oxygen and makes the latter gasify without any additional external working medium or energy input for assistance, which is simple, easy and efficient. The effective heat exchange length of the vaporizer in the present invention is 1.2m, and 84 thin tubes are evenly placed in the outer cavity of the gasifier, liquid oxygen is passed into the slender tubes, air is passed into the cavity, and the heat transfer is achieved by convective heat exchange. Heating with liquid oxygen; it can quickly gasify liquid oxygen corresponding to different flight conditions with a flow rate of 0.5-1.5Kg/s from -100°C, so that oxygen and air can be fully mixed to form oxygen-enriched air, which can fully react with butane and burn efficiently A high enthalpy gas is formed for experimental use.

Description of drawings

Fig. 1 is a schematic diagram of the gasifier structure;

Figure 2 is a schematic diagram of the installation position of the gasifier.

Fig. 3 is the calculation result of gasification length when the number of liquid oxygen pipelines in the gasifier is different.

Figure 4 shows the calculation results of the temperature distribution of air and oxygen when the number of liquid oxygen pipelines in the vaporizer is different.

detailed description

The specific implementation of a liquefied oxygen evaporator device for a butane and oxygen combustion heating system provided by the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the shape of the gasifier is long cylinder, the material is stainless steel, the diameter of the outer shell is 90mm, the thickness is 5mm, and the diameter of the actual air supply chamber is 80mm. A total of 84 thin round tubes with an outer diameter of 4mm and a thickness of 1mm are arranged for liquid oxygen transportation, and the rest of the internal space in the shell is used for air flow, providing a large enough heat exchange area between liquid oxygen and air to ensure the heat exchange process Successfully completed, the liquid oxygen is completely vaporized before the outlet; the outlet section has 85 round holes with a diameter of 4mm for gaseous air to pass through, so that the passage area ratio of oxygen and air here is about 1:4. Both oxygen and air flow in the same direction along the flow direction for heat exchange. The effective length capable of heat exchange needs to be 1.2m (to meet the heat exchange requirements of large flow conditions), and it is supported in sections.

As shown in Figure 2, in order to directly use the air that needs to be mixed to exchange heat with liquid oxygen and make the latter gasify, the gasifier is installed after the main air pipeline ①, and before the air-oxygen mixing chamber ② and the butane combustion heater ; Its main function is to use a large flow rate of normal temperature air to heat the low-temperature liquid oxygen, so that the liquid oxygen can be vaporized before the outlet of the gasifier.

The gasification process of liquid oxygen is mainly affected by temperature and pressure. The liquid oxygen temperature in the upstream liquid oxygen storage tank is -90°C, and the temperature rises to about -100°C when it enters the gasifier inlet after passing through the transportation pipeline. What is difficult to determine is the working pressure in the liquid oxygen pipeline, which will change correspondingly with different working conditions, and its variation range is lower than the actual working pressure of the upstream liquid oxygen pump, higher than the working pressure of the downstream butane combustion heating system, And it is mainly affected by the downstream pressure. At high Mach number and high total temperature (2100K), the total pressure of the downstream butane heating system can reach 2.8MPa; at medium Mach number and medium total temperature (1650K), the total pressure of the heating system can reach 1.0MPa; At low Mach number and low total temperature (1200K), the total pressure of the heater system is only 0.68MPa. Therefore, correspondingly, the liquid oxygen inlet pressure of the heat exchanger is 4.0MPa at the high Mach number, the liquid oxygen inlet pressure of the heat exchanger is 2.5MPa at the middle Mach number, and 2.0MPa at the low Mach number. The design should be more appropriate. The safe vaporization temperatures corresponding to liquid oxygen under these pressures are 150K, 138K and 133K respectively. If the gasifier of the same size can meet the working requirements of these three working conditions at the same time, the most demanding gasification is obviously the high Mach number working condition of 4.0MPa and 150K. Therefore, it is necessary to carry out specific parametric design for this working condition.

Due to the large variety of parameters, here are a few parameter ranges temporarily determined according to the common size of the pipe: the optional range of the size of the slender heat exchange tube: Φ4-1, Φ5-1 (the corresponding inner diameter Dp is 2 and 3mm respectively), and the number is 60-120 ; Vaporizer outer diameter Φ80-Φ100. It is necessary to ensure that a certain number of slender cooling pipes of a certain size can be evenly arranged on a mounting plate with a certain outer diameter and leave enough space for air to pass, escape and install. In the legend, 0.5, 1.0, 1.5 represent liquid oxygen flow rate, unit Kg/s.

From Figure 3 and Figure 4, it can be found that the gasification length becomes shorter with the decrease of the liquid oxygen flow rate, and the oxygen temperature at the outlet of the vaporizer increases with the decrease of the liquid oxygen flow rate. When the effective outer diameter is 80 mm, the More than 75 gasifiers with liquid oxygen channels with an outer diameter of 4mm and a thickness of 1mm can make the gasification length less than 1.1m under all working conditions, so the length of the gasifier is set at 1.2m (slightly greater than 1.1m as an engineering surplus) amount) is appropriate. At the same time, the oxygen temperature at the outlet of the gasifier can be guaranteed to be higher than 160K (meeting the design requirement higher than 150K). On the whole, the gasifier design with a length of 1.2m, an effective outer diameter of 80mm, and more than 75 liquid oxygen channels with an outer diameter of 4mm and a thickness of 1mm can meet the requirements of various working conditions. Based on this basic requirement, the specific design of the gasifier device as shown in Figure 1 is finally given.

The above description is only a preferred embodiment of the present invention, and the values and numerical ranges mentioned in the description of the above specification are not used to limit the present invention, but to provide preferred implementation modes for the present invention, and are not used to limit the present invention. Various modifications and variations of the present invention will occur to those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. A liquid oxygen vaporizer device for butane and oxygen combustion heating system, characterized in that, the vaporizer is in the shape of a long cylinder, and a plurality of thin round tubes are arranged for the transportation of liquid oxygen, and the rest in the shell The internal space is for air flow, and the outlet section has multiple round holes for gaseous air to pass through; the gasifier is installed after the main air pipeline, before the air-oxygen mixing chamber and the butane combustion heater, so that the air that needs to be mixed Effective heat exchange with liquid oxygen before mixing to make the latter completely vaporized; among them, the effective heat exchange length of the gasifier is 1.2m, and 84 thin round tubes are evenly placed in the outer cavity of the gasifier, and the thin round tubes Liquid oxygen is fed into the cavity, and air is fed into the cavity to heat the liquid oxygen through convective heat exchange; it can quickly gasify liquid oxygen corresponding to different flight conditions with a flow rate of 0.5-1.5Kg/s from -100°C, which is convenient Oxygen and air are fully mixed to form oxygen-enriched air, and then fully react with butane and burn efficiently to form high-enthalpy gas for experimental use. 2. The device according to claim 1, characterized in that, the gasifier is made of stainless steel, the outer shell has a diameter of 90 mm and a thickness of 5 mm. 3. The device according to claim 1, wherein the plurality of thin round tubes is 84, with an outer diameter of 4 mm and a thickness of 1 mm. 4. The device according to claim 1, characterized in that the plurality of circular holes in the outlet section are 85 circular holes with a diameter of 4mm.