Hypobaric Oxygen Chamber

The following describes the overall design analysis, system composition and functions, subsystem design and indicators, infrastructure requirements, etc. of the development of the integrated extreme environment simulation system. The technical specifications and standards to be referred to and the technical indicators of the overall technical demand indicators are as follows.
1. Basis documents

The integrated extreme environment simulation system is mainly composed of cabin structure system, temperature simulation system, pressure simulation system, atmosphere simulation system, noise simulation system, vibration simulation system, motion simulation system, control simulation system and equipment support system. Its function is to simulate the light, sound, smell, temperature, humidity, pressure, oxygen, motion and other factors of the extreme environment, and to carry out multi person cooperation, cooperation, game and other experimental tasks. The overall layout of the system is shown in the following figure:

Overall layout of integrated extreme environment simulation system

The cabin is designed in accordance with relevant standards and specifications such as GB/T27513-2011 “Hypobaric Oxygen Chamber”, GB150-2011 “Pressure Vessel”, vacuum design manual (Third Edition), and the finite element method is used for structural simulation analysis and optimization design to ensure the strength, stability and safety of the cabin.
The cabin is designed in accordance with relevant standards and specifications such as GB/T27513-2011 “Hypobaric Oxygen Chamber”, GB150-2011 “Pressure Vessel”, “Vacuum Design Manual” (Third Edition), and the finite element method is used for structural simulation analysis and optimization design to ensure the strength, stability and safety of the cabin.
The cabin structure is designed as a vertical box, and the main material is stainless steel, with an internal width of 5.8m, an internal length of 4.5m and an internal height of 2.6m. The cabin adopts duplex stiffening ring structure. The middle of the cabin is supported by columns. A door is set at one side of the cabin. The door is opened and closed by hinges. The door can be opened for personnel to enter and leave the cabin. The door of the cabin is stress relieved. The bottom of the cabin is connected with the moving platform as a whole by welding. The upper platform with six degrees of freedom is welded with section steel, and then welded with the stiffeners around the experimental cabin.

The temperature simulation system is mainly used for the temperature regulation of the test system. The temperature regulation range is: -20~60 ℃, the control accuracy is ± 1 ℃, the heating rate is 0~50 ℃ ≤ 1 hour, and the cooling rate is 0~-20 ℃ ≤ 2 hours.
The temperature simulation system is mainly used for the temperature regulation of the test system. The temperature regulation range is: -20~60 ℃, the control accuracy is ± 1 ℃, the heating rate is 0~50 ℃ ≤ 1 hour, and the cooling rate is 0~-20 ℃ ≤ 2 hours.The temperature regulation system is composed of a temperature regulation unit and a refrigeration unit. The temperature regulation unit is located inside the test system, the unit is located outside the test system, and the unit is connected with the test system body through a hose. In order to realize the circulation of flow field in the vessel, the equipment section is shown in the figure. The air is sucked in by the fan, passes through the evaporator and electric heater, the air temperature is adjusted, and then returns to the test space. The flow field design adopts parallel flow field design. The air flow flows evenly from the top to the bottom of the test cabin. The air flow is uniform and the wind speed is slow, which can meet the needs of the test temperature and ensure the comfort of the cabin personnel.

The interior of the cabin is required to be able to simulate the low-pressure environment, and the simulated pressure is atmospheric pressure ~ negative pressure 6000m above sea level. According to the height pressure conversion table, the pressure range in the cabin can be adjusted from 100kPa to 47kPa. The main equipment of the pressure simulation system includes screw dry pump unit, various vacuum valves and controllable valves, pressure measuring instruments and other equipment. The screw dry pump is used to extract air from each compartment, and the pump set is connected with each compartment through adjustable valves. Pressure measuring instruments are installed in each cabin section, which can complete the real-time measurement of cabin height pressure in real time. When the cabin pressure or the rate of pressure rise and fall needs to be maintained and controlled, the feedback control of the regulating valve through the pressure measuring instrument can realize the flow control of air extraction and air inlet, and then realize the constant maintenance and control of the final required pressure or the rate of pressure rise and fall.

The cabin is equipped with a fresh air system, which can be used for timely ventilation inside the cabin. According to the standard, the fresh air volume per person per hour shall not be less than 30 cubic meters. It shall be calculated according to the test of three people at the same time, and certain design allowance shall be considered. The fresh air system is mainly composed of filter, fan, dehumidifier, flow control unit and silencer, and its main function is to provide clean air. The main equipment of the whole system adopts brand products, and the main equipment has been widely used in the same industry in China. After a long time of practice and test, the technology is very mature, safe and reliable, and the performance is stable.

In order to ensure the smooth implementation of the later projects and the safety, reliability and ease of use of the later use links, the technical scheme and equipment selection shall be as mature as possible on the premise of ensuring the realization of functions, and have been tested and verified for many times.
Cabin noise simulation system mainly includes sound field simulation system and cabin sound insulation and noise reduction system. The sound field simulation system is used to simulate the sound field of different timbres and sound intensities in the cabin; The cabin sound insulation and noise reduction system is used to meet the requirements of cabin background noise and reverberation time.

The system is mainly used to simulate the vibration feeling transmitted to the test personnel through the seat. The overall design indicators are as follows:

1.Vibration frequency: 10~500Hz

2. Maximum acceleration amplitude: 0.5g

3. Seat load mass: 250kg

4. The seat vibration system has the function of moving

The system is mainly composed of mechanical platform, control cabinet, control software and special cables. The overall composition of the system is shown in the following figure:   The system is mainly composed of mechanical platform, control cabinet, control software and special cables. The overall composition of the system is shown in the following figure:

Schematic diagram of overall system composition

The technical indicators of the motion platform system in this scheme are as follows:

1) Load weight 25t, size 6.2m × 4.9M (Length × Width);

2) Pitch, roll and yaw: angle ±15°, angular acceleration ± 50°/s², angular velocity 10°/s

3) Lifting, lateral and longitudinal: maximum displacement ±0.25m, maximum acceleration    ± 2m/s²,Linear speed 300mm/s

4) Maximum motion frequency: 5HzFor the moving platform, due to heavy load, a separate room can be set in the test area of the platform cabin combination to reduce the impact of noise on the test control area.

The integrated extreme environment control and simulation system is composed of a master control server, a model simulation server and control units of each subsystem. The master control server is responsible for the overall scheduling, timing control and issuing control instructions to each subsystem; The model simulation server is used to calculate the model of simulation environment scenarios, provide specific input parameters for each execution system, and can also access existing simulation scenario models.

Circulating cooling water is required for vacuum pump, refrigerator and other equipment during system operation. The requirements for circulating cooling water are as follows:

a. Water supply pressure difference: 0.2MPa ～ 0.4MPa;

b. Inlet temperature: 15℃ ~ 25℃;c. The pH value of water quality shall be between 6.0 and 8.0, the concentration of calcium carbonate shall be lower than 77ppm, and the circulating water shall be clean and free of impurities.

According to the above requirements, the circulating cooling water is equipped with a cooling circulating water unit, and the water temperature control range is 5 ~ 50℃, meeting the equipment use requirements.

Statistics of main water equipment

Ambient temperature: 15℃ ~ 35℃;Relative humidity: 30 ~ 80%. 

The power consumption of the whole system mainly includes the power consumption of process equipment such as vacuum pump and refrigerator, as well as the power consumption of control systems such as computer, data acquisition instrument, lighting system, switch and controller. Main electrical equipment includes:

Statistics of main electric equipment.