Performance NVD

Performance NVD must provide the required fuel consumption as the engine start mode, at low speed, and at the highest pump speed according to the selection of the units to fuel systems.

Centrifugal pumps of high pressure, the fuel feed to the FCC, working at high speeds: 25 LLC. .30 Ltd. min-1. Their maximum capacity is determined by the need to maximize fuel in the FCC and up to 60 000 kg / h.

The maximum fuel pressure at the outlet FN determined maximum output of the engine fuel consumption at maximum temperature. Its value must be less than the pressure in the FCC on the value of the differential pressure at the injectors for high-quality spray of fuel and the loss of pressure in the pipes and units located between the FN and FCC nozzles.

High-pressure plunger pump for driving the nozzle flaps provide a fuel supply pressure to 21 3000 MPa at speed. .3800 min-1 and fuel consumption, allowing to obtain the necessary speed of the sashes.

One of the most important in the design of STP is the problem of achieving an acceptable thermal regime of the fuel supply system due to necessity of special events:

- the use of fuel-oil heat exchangers for cooling the oil in the engine lubrication system and cooling the drive of constant revolutions of the electric generator;

- the presence of fuel by-passes from the outputs to the inputs of the pumping units;

- significant heating of fuel in the aircraft tanks (for engines with FCC);

- using fuel for cooling the power hydraulic cylinders of the nozzle (for engines with FCC).

In this connection, in the fuel supply system, in order to reduce the temperature of the fuel, its bypass can be introduced due to the DHS into the aircraft tank when the engine is running on a heat-stressed mode. The bypass valve is activated when the temperature of the fuel at the pump outlet reaches a certain value. The amount of By-pass fuel depends on the maximum fuel temperature at the entrance to the fuel system of the engine and at the design stage can be determined by performing a thermal calculation of the operating conditions of the engine's fuel system in conjunction with the fuel system of the aircraft. It is necessary to take into account the temperature

round of fuel during refueling, the temperature of the fuel in the tanks during takeoff and heat transfer between the fuel tank and the ambient air.

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