RU2734172C1 - Helicopter type aircraft engine liquid cooling system - Google Patents

Abstract

FIELD: aviation; engine cooling systems.SUBSTANCE: invention relates to cooling systems of helicopter type aircraft engines. System includes engine cooling jacket (1), radiators communicated by supply and discharge pipelines with cooling jacket. System is equipped with individual thermostats installed at the radiator inlet or outlet. Radiators are made in the form of a row of hollow deflectors (5) of air flow located under bearing screws (14) and connected to supply and discharge pipelines in parallel.EFFECT: higher uniformity of engine cooling at changes of its operation mode and environmental conditions, as well as reduced material consumption and power consumption for cooling.3 cl, 4 dwg

Description

The invention relates to aeronautical engineering and, in particular, to cooling systems for engines of helicopter-type aircraft, for example, internal combustion engines for unmanned aerial vehicles.

Special requirements are imposed on internal combustion engines of helicopter-type unmanned aerial vehicles due to the need to increase the engine tension in order to increase the specific power and reduce weight. This leads to the need to ensure effective and uniform cooling of the engine for the rotor drive, which constantly operates at high speeds in conditions of changing ambient temperature due to frequent movement from the lower atmosphere to the upper and back. Conventional, classical schemes for organizing the cooling system are not very suitable for this, due to the use of rather heavy and dimensional radiators with forced airflow from a special fan. Therefore, the development of highly specialized cooling systems for engines of unmanned aerial vehicles of a helicopter type remains relevant.

Known engine cooling system for an unmanned vehicle with a direct drive from the main engine of two fans, forcibly cooling the liquid in two radiators (CN 106741977).

However, such a system, in addition to an increase in weight due to the use of an additional radiator and fan, and the use of a double kinematic scheme, takes up a significant part of the engine's power, reducing its efficiency.

Known is a water cooling system for an unmanned aerial vehicle engine, which includes a cylinder block cooling jacket and a cooling circuit (CN 109592027).

This system has the known drawbacks of the classical cooling scheme and does not have the necessary flexibility of reconfiguring the cooling depending on the changing environmental conditions and operating conditions of the aircraft.

The closest technical solution to the proposed one is the engine cooling system of a helicopter-type aircraft, including an engine cooling jacket, radiators located near the rotor propellers, connected by supply and exhaust pipelines with a cooling jacket (CN 107697309).

The disadvantages of this design are insufficient cooling efficiency at heavy engine operating conditions - when lifting the apparatus and hovering, since the radiators are located in the upper part of the fuselage on the side of the propellers and are not additionally blown with air from the rotors. In addition, this system has all the other disadvantages of the classical cooling system - high material consumption and energy consumption for cooling.

The technical result of the claimed invention is an increase in the uniformity of engine cooling when changing its operating mode and environmental conditions, as well as a decrease in material consumption and energy consumption for cooling.

The technical result is achieved by the fact that the system includes an engine cooling jacket, radiators connected by supply and outlet pipelines with a cooling jacket, while it is equipped with individual thermostats installed at the inlet or outlet of the radiators, and the radiators are made in the form of a row of hollow air flow deflectors located under the carriers screws and connected to the inlet and outlet pipelines in parallel. The technical result is also achieved by the fact that the deflectors are installed with the ability to change the distance between them and move in a plane parallel to the plane of the screws.

These features of the invention are essential.

Combining the functions of a radiator and an air flow deflector located under the rotor reduces the material and energy consumption of the structure, since there is no need for a separate radiator and cooling fan, and the heat transfer in the deflector increases. At the same time, the deflectors are heated, which reduces the air density at their surface and, thus, the aerodynamic resistance of the deflectors when they perform the functions of controlling the air flow from the rotor is reduced.

FIG. 1 shows a simplified schematic diagram of the cooling system.

FIG. 2 shows an aircraft with deflectors, top view.

FIG. 3 shows an aircraft with an alternative arrangement of deflectors.

FIG. 4 shows a sectional view of the deflector.

The engine 1 has a cooling jacket 2 connected by a supply pipe 3 through the main thermostat 4 with radiators made in the form of air flow deflectors 5. Individual thermostats 6 are installed at the inlet of the deflectors 6. Outlets 7 of the deflectors 5 are connected through the outlet nozzles 12 with the outlet pipe 8 communicated through the pump 9 with the cooling jacket 2. The deflectors 5 are shaped as profiled plates with cavities 10, which are connected by the inlet 11 with the inlet 3 and outlet nozzles 12 with outlet 8 pipelines parallel to each other. The thermostat 4 is also connected through a pressure reducing valve 13 with a discharge line 8 parallel to the deflectors. Deflectors 5 are installed under the screws 14 with the ability to move in a plane parallel to the plane of the screws, and also with the ability to change the distance between them. Deflectors 5 can be made with an additional cavity 15, separated from the cavity 10 by a flexible partition 16 and filled with gas.

The cooling system works as follows.

In the initial state, when the engine 1 is not running, thermostats 4 and 6 are closed, and the pressure reducing valve 13 is open and the cooling jacket is communicated directly with the pump 9 through valve 13. In the initial state, thermostat 4 closes the fluid supply channel to the thermostats 6, and the coolant access channel to the reducing valve 13 is constantly open. After starting the engine, the coolant heats up and flows along a small circuit through the pressure reducing valve 13 and pump 9. As the engine warms up, the pressure in the cooling system increases and the pressure reducing valve reduces the flow of liquid in the small circle, maintaining a constant initial pressure before pump 9, which accelerates the heating of the coolant. When the temperature in the cooling jacket reaches a predetermined minimum value, for example, 60 ° C, the main thermostat 4 adjusted to this temperature opens access to the heated liquid to the individual thermostats 6 of the deflectors 5. Thermostats 6 are individually adjusted to different opening temperatures, for example, to 60 ° C, 90 ° C and 110 ° C. Accordingly, the radiator deflectors 5 come into operation to cool the engine sequentially, as the temperature rises. Upon reaching the maximum allowable pressure in the system, the pressure reducing valve 12 completely blocks the flow in a small circle, and all the liquid goes only through the deflectors 5, increasing heat transfer. The efficiency of heat removal through the deflectors can be adjusted by moving them under the rotor and / or changing the distance between them, depending on the operating conditions of the aircraft and the priority of the deflectors performing cooling functions or the direction of air flow from the rotor. Deflectors 5 with an additional cavity 15 also serve as a receiver - an expansion tank to compensate for pressure fluctuations in the system.

Simultaneously with the function of cooling radiators, the deflectors 5 perform the functions of directing the air flow from the rotors. By changing the angle of inclination of the deflectors, a multidirectional deflection of the rotor flow is created. Tests have shown that the thrust loss during yaw control due to the "shading of the propeller" by the plates and the retaining structure on cold deflectors is less than 1.5%, and on heated ones - no more than 0.8%. The air currents propelled by the rotors are not strictly perpendicular to the plane of the propellers, but are slightly chamfered. The flow slope depends on the design and operation of the screw. The deflectors 5 used are set parallel to the flow and thus increase the efficiency of the yaw control. Also, such a control system compensates for the skew of the flow that occurs when the aircraft moves quickly horizontally. When moving at high speed, the flow of the rotor 14 deviates from its initial position significantly (by tens of degrees) and the efficiency of the deflectors in the propeller flow increases markedly when they are positioned along the flow, both due to their rotation along the flow, and due to the possibility move them under the screw to the desired position. This possibility, in addition to increasing the efficiency of the device control, also increases the heat transfer of the cooling system, since the deflectors are always located in the main air flow.

The proposed design of the combination of the engine cooling system and the system for regulating the direction of the air flow from the rotor propellers provides a decrease in material consumption and energy consumption for cooling and air flow control by reducing the aerodynamic resistance of the deflectors.

Claims (3)

1. A liquid cooling system for a helicopter-type aircraft engine, including an engine cooling jacket, radiators connected by supply and outlet pipelines with a cooling jacket, characterized in that it is equipped with individual thermostats installed at the inlet or outlet of the radiators, and the radiators are made in the form of a series of hollow deflectors air flow located under the rotors and connected to the supply and return pipelines in parallel. 2. The system of claim. 1, characterized in that the deflectors are installed with the ability to move in a plane parallel to the plane of the screws. 3. The system of claim. 1, characterized in that the deflectors are installed with the ability to change the distance between them.

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