Fuel consumption spiked rapidly which caused subsequent increase of pump capacities, diameter of pipelines and unit weight. Fuel temperature, at which fuel system units should operate, rose too.
Those factors in some cases limited and in specific cases rendered impossible the use of electric driven pumps in fuel systems of modern and promising aircraft.
In order to reduce the weight of fuel systems and the pump units proper, as well as to increase their reliability and service life, the GTN-6, GTN-7, GTN-10 and some other hydraulic turbine driven pumps were developed, with delivery rates ranging from 500 to 100,000 l/h to pump over fuel between tanks and for fuel pumping from the feeder tank to the engine driven pump.
Fuel hydraulic turbine driven pumps have some advantages, the main of which are: low weight, small overall dimensions, simple design, operational reliability, operational capability at high temperatures, explosion and fire safety. The last-mentioned at one time spurred the use of hydraulic turbine driven pumps in chemical industry when dealing with explosive working fluids.
Hydraulic turbines enable to achieve wide range of pump speed. The fuel being supplied by an aircraft engine-driven centrifugal pump is the working medium for hydraulic turbines of aircraft pumps.
The choice of optimum power supply circuits of aircraft pump hydraulic turbines and fuel discharge from them to a certain aircraft fuel system depends on particular requirements being imposed upon it and a power unit fuel system in terms of power aspects, weight, reliability, design and operation.
|HYDRAULIC TURBINE DRIVEN PUMPS|
|Dessignation||Рт||Qт||Output flow||Differential pressure||Mass, max||Working fluid||Dimensions|
|HYDRAULIC MOTOR DRIVEN CENTRIFUGAL PUMPS|
|Designation||Hydraulic motor drive||Output flow||Differential pressure||Mass, max||Working fluid||Dimensions|