The output power of gas turbine is
N ¼ gG q L mg
ð9:61Þ
where
N
Turbine output power;
g
Turbine efficiency;
L mg Gas adiabatic work.
Steady output power of the turbine can be obtained by Eqs. (9.60) and (9.61),
which are proportional to the gas pressure. The output power of gas turbine is
consumed on generator and hydraulic pump. The output power of generator is
N n ¼
ffiffi ffi
3
p
I 1 V 1 þ I 2 V 2
ð
Þcos /
ð9:62Þ
where
I 1 ; I 2 Winding current (A);
V 1 ; V 2 Winding voltage (V).
The power consumed by the generator accounts for a small proportion of the
total output power of the EHPU.
The output power of the hydraulic pump is
N P ¼ PQ=612
ð9:63Þ
where
P Pump output pressure (kgf=cm
2 );
Q Pump output flow (L=min).
The output power of hydraulic pump is consumed in relief valve and steering
system, which accounts for the majority of the total output power of EHPU.
When the gas generator drives EHPU to run, it accelerates gradually from static
state to running state. In this process, inertia load of turbine disk, gear, generator,
and hydraulic pump should be overcome, and load moment should also be overcome. Therefore, in the process of starting, the starting power of gas generator must
be increased to produce peak power, that is, starting driving power.
N 0 ¼ N A þ N
ð9:64Þ
where
N 0 Start drive power;
N A Additional power;
N Steady-state power.
9.5 Starting Characteristics of Electronic and Hydraulic Power Unit
153