9.5.4.3 Effect of High and Low-Temperature Performance on Starting
Characteristics
Usually, EHPU is required to work normally at high temperature ( þ 62
C) and low
temperature (À40
C). That is to say, the starting characteristics under high and low
temperature conditions should also meet the requirements. The influence of high
and low temperature on starting characteristics is mainly reflected in the gas generator and hydraulic oil. The ignition components and main grain of the gas generator are affected by temperature, and the burning rate changes greatly, which
makes the gas pressure change greatly. See the following:
a ¼ a 0 e
Àr p TÀT 0
ð
Þ
ð9:69Þ
where
a Burning rate;
a 0 Standard burning rate;
T 0 Standard temperature;
r p Temperature sensitivity coefficient.
At low temperature, the viscosity and resistance of hydraulic oil increase, which
aggravates the starting load and affects the starting characteristics. The starting
characteristics of EHPU under high and low temperatures are shown in Fig. 9.60. It
can be seen that the starting characteristics of EHPU under high and low temperatures are quite different. Curve 1 starts slowest at low temperature, so the system
design considerations must meet the severe operating conditions under low
temperature.
Fig. 9.59 Effect of different
pressure impulse on starting
characteristics
158
9 High-Temperature and High-Speed Gas Turbine Pump …