9.1.3.3 High Speed
When the output flow of the hydraulic pump is constant per minute, increasing the
rotational speed can reduce the displacement per revolution, thus reducing the
geometric size of the hydraulic pump and achieving the purpose of reducing weight.
On the other hand, the development of prime mover to high speed also puts forward
high-speed requirements for hydraulic pumps. The typical power transmission form
of rocket electro-hydraulic servo system is the output shaft reducer hydraulic pump
of turbopump (propellant transport in power system). In order to reduce the volume,
weight, and efficiency, it is necessary to remove the reducer, so as to improve the
speed of the hydraulic pump to match it. While increasing the speed of the
hydraulic pump, it is necessary to keep the working life of the pump unchanged. It
is necessary to solve the problem of overheating and wear resistance of the parts,
such as developing heat-resistant, wear-resistant sealing materials, and metal
coatings, and adopting high-speed precision bearings. In order to ensure that the
hydraulic pump sucks oil adequately at high speed, it is necessary to increase the
suction pressure of the pump. And it is necessary to pressurize the tank or increase
the pre-pressurization of the first-stage pre-pump, which can work at a lower speed.
Table 9.7 lists the application examples of hydraulic pumps with different rotational
speeds, from which the advantages of using high rotational speeds to reduce weight
can be seen.
9.1.3.4 High Reliability
In extreme environments, electro-hydraulic servo systems may have various failure
modes, such as servo valve (nozzle, throttle hole) blocking, slide valve clamping,
input circuit breaking, and feedback disconnection. First of all, measures must be
taken to improve reliability in design to ensure absolute safety.
Table 9.7 Weight and application examples of hydraulic pumps with different rotational speeds
for aircraft
Turbine speed/
(r/min)
Hydraulic pump
Speed/(r/min) Pressure/MPa Flow/(L/min) Weight/kg
Missile hydraulic
system
90,000
13,000
24
12.5
0.75
Rocket hydraulic
system
10,000
5,000
20.7
38
9.5
Aircraft hydraulic
system
-
11,200
20.7
14.4
1.5
Aircraft hydraulic
system
-
10,000
20.7
36.1
2.17
70
9 High-Temperature and High-Speed Gas Turbine Pump …
When the output flow of the hydraulic pump is constant per minute, increasing the
rotational speed can reduce the displacement per revolution, thus reducing the
geometric size of the hydraulic pump and achieving the purpose of reducing weight.
On the other hand, the development of prime mover to high speed also puts forward
high-speed requirements for hydraulic pumps. The typical power transmission form
of rocket electro-hydraulic servo system is the output shaft reducer hydraulic pump
of turbopump (propellant transport in power system). In order to reduce the volume,
weight, and efficiency, it is necessary to remove the reducer, so as to improve the
speed of the hydraulic pump to match it. While increasing the speed of the
hydraulic pump, it is necessary to keep the working life of the pump unchanged. It
is necessary to solve the problem of overheating and wear resistance of the parts,
such as developing heat-resistant, wear-resistant sealing materials, and metal
coatings, and adopting high-speed precision bearings. In order to ensure that the
hydraulic pump sucks oil adequately at high speed, it is necessary to increase the
suction pressure of the pump. And it is necessary to pressurize the tank or increase
the pre-pressurization of the first-stage pre-pump, which can work at a lower speed.
Table 9.7 lists the application examples of hydraulic pumps with different rotational
speeds, from which the advantages of using high rotational speeds to reduce weight
can be seen.
9.1.3.4 High Reliability
In extreme environments, electro-hydraulic servo systems may have various failure
modes, such as servo valve (nozzle, throttle hole) blocking, slide valve clamping,
input circuit breaking, and feedback disconnection. First of all, measures must be
taken to improve reliability in design to ensure absolute safety.
Table 9.7 Weight and application examples of hydraulic pumps with different rotational speeds
for aircraft
Turbine speed/
(r/min)
Hydraulic pump
Speed/(r/min) Pressure/MPa Flow/(L/min) Weight/kg
Missile hydraulic
system
90,000
13,000
24
12.5
0.75
Rocket hydraulic
system
10,000
5,000
20.7
38
9.5
Aircraft hydraulic
system
-
11,200
20.7
14.4
1.5
Aircraft hydraulic
system
-
10,000
20.7
36.1
2.17
70
9 High-Temperature and High-Speed Gas Turbine Pump …