8.3 Aircraft Hydraulic Accumulator and Cylinder
in Extreme Temperature Environment
In the process of storage, transportation, and launch of aircraft, hydraulic components are often tested in extremely low-temperature and high-temperature environment. Storage conditions include extreme low temperature (À40
C) and
extreme high temperature ( þ 60
C). The characteristics of hydraulic accumulator
and gas storage cylinder in large temperature range, especially the gas pressure and
gas mass in the air chamber, and the working oil discharge and maximum oil filling
characteristics of accumulator are very important to the design of aircraft hydraulic
system.
8.3.1 Extreme Temperature Environment
Servo control originated from flying body attitude control of missile and rocket
before and after World War II. Gas generator, pneumatic servo valve, and gas motor
are used in gas servo system. Since 1950, in order to develop cosmic space, the
United States, the Soviet Union, and Europe have used cold or hot gas driven
pneumatic servo actuators or hydraulic actuators for servo control in thrust vector
control and attitude control of space rockets and spacecraft. The actuator of attitude
control system of China Long March series launch vehicle uses cylinder output gas
source to drive pneumatic vane to drive hydraulic pump or motor pump to generate
hydraulic energy. The storage and emission of gases, gas drive, and reliability of
gas cylinder system in the extreme environment of aircraft have not been completely solved, and have been listed as an important issue. Hydraulic accumulator
and gas booster tank are commonly used in aircraft hydraulic control system.
Hydraulic accumulator uses the compressibility principle of sealed gas to work and
realizes the function of oil absorption and drainage through the volume compression, expansion, and pressure change of the inflatable chamber. In order to ensure
the normal operation of the hydraulic control system and improve the high altitude
performance of the hydraulic system, the aircraft adopts a booster tank. The gas
booster tanks of missiles and rocket vehicles and the booster tanks used by airplanes
in high altitude flight are all under the action of pressurized gas to pressurize the
sealed oil stored in the tank so as to increase the pressure on the oil surface of the
tank in order to facilitate the oil suction of the hydraulic pump and prevent the oil
suction of the hydraulic pump from producing cavitation.
Hydraulic energy is often used in autopilot rudder control and seeker antenna
servo mechanism of air defense missile. For example, American Hooker missile
uses hydraulic steering engine to control rudder deflection. The Soviet S-300
missile initially used gas steering engine and then changed to hydraulic steering
engine. The American Patriot Air Defense Missile adopts the electric variable pump
40
8 Pneumatic Actuators, Driving Elements and Accessories
in Extreme Temperature Environment
In the process of storage, transportation, and launch of aircraft, hydraulic components are often tested in extremely low-temperature and high-temperature environment. Storage conditions include extreme low temperature (À40
C) and
extreme high temperature ( þ 60
C). The characteristics of hydraulic accumulator
and gas storage cylinder in large temperature range, especially the gas pressure and
gas mass in the air chamber, and the working oil discharge and maximum oil filling
characteristics of accumulator are very important to the design of aircraft hydraulic
system.
8.3.1 Extreme Temperature Environment
Servo control originated from flying body attitude control of missile and rocket
before and after World War II. Gas generator, pneumatic servo valve, and gas motor
are used in gas servo system. Since 1950, in order to develop cosmic space, the
United States, the Soviet Union, and Europe have used cold or hot gas driven
pneumatic servo actuators or hydraulic actuators for servo control in thrust vector
control and attitude control of space rockets and spacecraft. The actuator of attitude
control system of China Long March series launch vehicle uses cylinder output gas
source to drive pneumatic vane to drive hydraulic pump or motor pump to generate
hydraulic energy. The storage and emission of gases, gas drive, and reliability of
gas cylinder system in the extreme environment of aircraft have not been completely solved, and have been listed as an important issue. Hydraulic accumulator
and gas booster tank are commonly used in aircraft hydraulic control system.
Hydraulic accumulator uses the compressibility principle of sealed gas to work and
realizes the function of oil absorption and drainage through the volume compression, expansion, and pressure change of the inflatable chamber. In order to ensure
the normal operation of the hydraulic control system and improve the high altitude
performance of the hydraulic system, the aircraft adopts a booster tank. The gas
booster tanks of missiles and rocket vehicles and the booster tanks used by airplanes
in high altitude flight are all under the action of pressurized gas to pressurize the
sealed oil stored in the tank so as to increase the pressure on the oil surface of the
tank in order to facilitate the oil suction of the hydraulic pump and prevent the oil
suction of the hydraulic pump from producing cavitation.
Hydraulic energy is often used in autopilot rudder control and seeker antenna
servo mechanism of air defense missile. For example, American Hooker missile
uses hydraulic steering engine to control rudder deflection. The Soviet S-300
missile initially used gas steering engine and then changed to hydraulic steering
engine. The American Patriot Air Defense Missile adopts the electric variable pump
40
8 Pneumatic Actuators, Driving Elements and Accessories