Views: 0 Author: Site Editor Publish Time: 2022-08-12 Origin: Site
The structure of the aircraft is precise, and the aircraft air-conditioning system is an important system module that supports the safe and stable flight of the aircraft, and plays a role in tracking and adjusting the environmental parameters of the aircraft cabin and equipment cabin. Aircraft air conditioning systems are used in aircraft pipeline components, aircraft operating systems, passenger and cargo compartments, electronic equipment cabins, and cockpits, with high probability of operating failures and high maintenance requirements.
1. Aircraft area temperature control system
The high-pressure hot bleed air generated in the aircraft air source system can be used by independent air conditioning components after the flow control is obtained. Aircraft Mixing Header. In the actual operation process, the cold air in the mixing header can be circulated and mixed with the air in the aircraft cabin. The cold air in the mixing header is mainly distributed to the cockpit, front and rear passenger cabin pipes through the air conditioning system. In addition, emergency ram air can enter through the entry door in the event of any failure of the air conditioning components, ensuring that the aircraft remains ventilated. In terms of air flow and aircraft area temperature adjustment, it is mainly realized by the air conditioning panel knob and temperature knob. The two-component controller responds to the air signal and air flow command, and adjusts the flow and temperature with the cooperation of the trim air valve.
2. Aircraft passenger and cargo compartment pressurization system
The aircraft passenger and cargo cabin pressurization system mainly adjusts and pressurizes the pressure in the cabin, so as to ensure that the passengers and crew on the plane can always be in a safe and comfortable cabin environment. CPC, namely the cabin pressure controller, controls the opening and closing of the outflow valve, and automatically adjusts the amount of air that needs to be discharged from the passenger and cargo compartment of the aircraft. In addition, there is a mode selection knob on the cabin pressure panel of the aircraft. If the automatic booster adjustment system fails to work properly, the manual mode can be turned on, and the manual vertical speed control switch can be used to open and close the outflow valve.
3. Aircraft electronic equipment ventilation system
During the flight of the aircraft, the long-term operation of the electronic equipment and the cockpit instrument panel is likely to generate accumulated heat. The electronic equipment ventilation system mainly plays the role of ventilation of the electronic equipment rack and the instrument panel with the help of the exhaust fan and the blower fan. AEVC—electronic equipment ventilation computer realizes automatic ventilation control. When the aircraft is in different configuration states, the electronic equipment ventilation system can have three working modes: open state, closed state and intermediate configuration state.
4. Aircraft cargo compartment ventilation system and heating system
The ventilation air of the aircraft cargo compartment is mainly provided by the cargo compartment ventilation system, and the air in the passenger cabin area enters the cargo compartment through the opening of the aircraft side wall panel. The system mainly uses an exhaust fan for air suction, the air is ventilated, flows through the outflow valve, and finally is discharged outside the machine. The cargo compartment heating system is mainly realized by the selected level of cargo compartment temperature. The hot bleed air flows in from the APU bleed air pipe, and is mixed with the aircraft cabin air, and then introduced into the cargo compartment ventilation system.
Aircraft air conditioning systems are prone to hidden faults during operation. These faults are often repetitive and need to be carefully checked and maintained before and after the flight. The following is an analysis of troubleshooting and maintenance measures for aircraft air conditioning system components.
1. Aircraft cockpit and cabin temperature balance maintenance
The temperature of the cockpit and cabin of the aircraft should reach a balanced state, and key maintenance should be done on the aircraft hot air mixing system. In actual flight, there are many temperature imbalances caused by overheating of air-conditioning components, such as the outlet temperature of the compressor is higher than 230°C, and the outlet temperature of the components is higher than 90°C. In terms of maintenance, check and check the temperature knob range of the air conditioner panel. The temperature range should be kept between 18°C and 30°C, and the temperature in the middle of the knob should be kept at 24°C. In the maintenance of air-conditioning components, in order to improve maintenance efficiency and quickly identify fault distribution, one component can be turned off and the other component can be observed. The maintenance of the hot air mixing system should be carried out in combination with single-zone temperature measurement and multi-zone temperature measurement.
2. Maintenance of flow control valve of aircraft air conditioning system
Electric control closing and air control closing will cause the flow control valve to close. In the maintenance of this component, analyze the air supply sufficiency of the aircraft and the temperature of the compressor. If it is insufficient or too high, operate and deal with it in time according to the technical manual. During maintenance, first remove the pressure line from the flow valve, check whether there is still air pressure upstream of the valve, and check the compressor line for leakage to find out the cause of the overheating of the line. In order to avoid air leakage due to poor installation during the valve removal operation, which will affect the difficulty of opening the valve, the entire sensor can be removed [4]. If the valve is still difficult to open after the above operations are completed, the cause of the failure is considered to be the venting circuit of the stepping motor, and the flow control valve needs to be replaced.
3. Aircraft air conditioning system sensor and relay maintenance
For the maintenance of the components of the ventilation system of the sensor and electronic equipment, the importance of the signal output should be considered, the parameters should be retrieved, the deviation value should be checked, and the investigation should be carried out one by one. In terms of relay maintenance, the air conditioning components are mainly closed by the left and right start relays. When maintaining them, strictly refer to the aircraft maintenance circuit manual, and use the method of measuring the line to identify potential failures, and follow the TSM manual during maintenance. In addition, for the air leakage detection loop in the air conditioning system, great attention should be paid to the maintenance. The maintenance method is mainly to disconnect the measurement at the nearest location, test the joint part, check the connection quality, and avoid leakage problems.
The composition of the aircraft air-conditioning system is complex, and each component may have potential failures during operation. When maintaining the aircraft air-conditioning system, the maintenance personnel should fully grasp the component types and working principles of the aircraft air-conditioning system, and be proficient in the flight manual and TSM manual. , carry out daily inspection and maintenance of components, and use logical reasoning methods to check according to the appearance of components to ensure that the aircraft air-conditioning system is in a safe and reliable state and create a comfortable cabin environment.
