Lift-adjustable helicopter rotor blade with anti-icing function and working method

Abstract

A lift-adjustable helicopter rotor blade with anti-icing function and its working method belong to the fields of energy and power engineering and airfoil anti-icing and de-icing. The blade includes an airfoil housing, a heating cavity, a jet oscillator, a connecting pipe, an air outlet, a hot gas pipeline, a cold air inlet pipe, an ejector, a nozzle, and a diversion port. In the present invention, the jet oscillator simultaneously utilizes the characteristics of both enhanced heat transfer and fluid control. By using the characteristic that the jet oscillator can generate a large range of high-frequency sweeping without moving parts, fluid control on the upper surface of the blade is achieved, thereby achieving the effect of increasing lift. At the same time, high-temperature gas from the compressor of the turboshaft engine is used to efficiently heat the leading edge of the helicopter blade over a large area to achieve the effect of anti-icing and de-icing. Meanwhile, the high-temperature gas after heat exchange will leave the blade from the air outlet of the second jet oscillator located at the upper part of the blade.

Description

[0001] Technical Field

[0002] The present invention relates to a lift - adjustable helicopter rotor blade with anti - icing function and its working method, belonging to the fields of energy and power engineering and airfoil anti - icing and de - icing. Background Art

[0003] With the enhancement of China's economic strength and the improvement of scientific and technological level, the application fields of helicopters have been continuously expanding. This requires helicopters to adapt to more severe flight conditions such as Arctic scientific research, mountain rescue, and flight in low - temperature environments. When the flight environment temperature is too low, icing is likely to occur at the leading edge of the rotor blade, changing the shape and mass distribution of the airfoil, resulting in uncontrollable lift changes and accidents. Therefore, anti - icing of the blade is an important factor in improving the safety performance of helicopters. For the leading edge part of the blade, by utilizing the characteristic that the jet oscillator can generate high - frequency oscillating jets, the leading edge of the airfoil can be uniformly heated and the heat transfer effect can be enhanced; at the same time, the jet oscillator can be used for boundary - layer control on the wing surface to achieve the effect of increasing the lift of the airfoil. Summary of the Invention

[0004] The purpose of the present invention is to provide a lift - adjustable helicopter rotor blade with anti - icing function and its working method.

[0005] A lift - adjustable helicopter rotor blade with anti - icing function, the airfoil shell is divided into a main body section and a root connection section. The main body section is the part that provides lift for the helicopter airfoil. It is characterized in that:

[0006] Several control areas are arranged along the main beam direction of the rotor blade at the leading edge of the airfoil shell of the main body section;

[0007] A heating cavity is arranged at the front end of each control area. The cross - section of the heating cavity along the direction perpendicular to the main beam of the rotor blade is crescent - shaped; An air delivery pipe is installed inside the airfoil shell. The inlet of the air delivery pipe is connected to the outlets of the high - pressure, medium - pressure, and low - pressure stages of the engine compressor, and it sequentially passes through the root connection section and all control areas of the main body section of the airfoil shell until the closed end of the last control area;

[0008] A first connecting pipe, a second connecting pipe, a first jet oscillator, and a second jet oscillator are installed at each heating cavity; The first connecting pipe and the second connecting pipe are respectively located on both sides of the control area, and they connect the ends of the upper and lower parts of the crescent of the heating cavity; The first jet oscillator is located in the middle part of the leading edge of the control area. The outlet of the first jet oscillator is connected to the heating cavity, and the inlet is connected to the air delivery pipe; An air outlet communicating with the external environment is arranged near the middle of the upper surface in the control area; The second jet oscillator is arranged near the upper surface at the leading edge of the control area. The outlet of the second jet oscillator is connected to the air outlet, and the inlet is connected to the upper part of the heating cavity;

[0009] An ejector is installed on the gas pipeline part at the root connection section. The primary fluid inlet and the mixed fluid outlet of the ejector are both connected to the gas pipeline, and a nozzle is arranged inside the ejector; a diversion port communicating with the external environment is arranged at the leading edge of the root connection section, and the secondary fluid inlet of the ejector is connected to the diversion port through a cold air inlet pipe.

[0010] The working method of a lift-adjustable helicopter rotor blade with anti-icing function includes the following processes:

[0011] The ejector is used to mix the external air, and by switching the outlet channels of the high, medium, and low-pressure compressors, the gas flow rate entering the ejector from the gas pipeline can be controlled. According to the requirements of heating and increasing lift, the following multiple modes can be switched, which are specifically divided into the following working modes:

[0012] Mode 1: Non-air extraction mode

[0013] When there is no heating requirement for the blade, the compressor air extraction is closed, and only the pressure difference generated by the rotation of the blade is used to naturally suck the external air to drive the second jet oscillator to achieve the auxiliary effect of increasing lift, ensuring the full power operation of the engine. The gas flow pattern is as follows:

[0014] At the root connection section, the outlets of the high, medium, and low-pressure stages of the helicopter turboshaft engine compressor are closed, so there is no gas from the compressor in the gas pipeline. Utilizing the pressure difference generated when the blade rotates, the external air is sucked into the ejector from the diversion port and the cold air inlet pipe. The air is accelerated in the contraction channel of the ejector and enters the gas pipeline towards the control area;

[0015] In the main body section, the air sequentially passes through all control areas. The air in the gas pipeline in the control area enters the first jet oscillator, then enters the heating cavity. Subsequently, the air flow is divided into two streams. One stream enters the upper part of the heating cavity, and the other stream enters the lower part of the heating cavity. Then, it enters the upper part through the first connecting pipe and the second connecting pipe; the two fluids are remixed at the end of the upper part of the heating cavity and enter the second jet oscillator, forming a high-frequency oscillating jet at the air outlet to control the separation of the boundary layer on the upper surface of the airfoil to achieve the effect of increasing lift.

[0016] Mode 2: Air extraction mode

[0017] When there is no heating requirement and the blade speed is too slow to suck in the external air, the low-pressure gas of the compressor is introduced to provide the primary fluid for the ejector to suck the external air from the cold air inlet pipe to achieve the auxiliary effect of increasing lift; when there is a heating requirement, the medium-temperature and medium-pressure or high-temperature and high-pressure gas of the compressor is introduced according to the demand intensity to achieve the auxiliary effects of heating and increasing lift at the same time. The gas flow pattern is as follows:

[0018] In the root connection section, high-temperature and high-pressure gases are led out from the high, medium, and low-pressure stages of the compressor of a helicopter turboshaft engine and enter the gas pipeline. After the gases enter the nozzle and are accelerated, a negative pressure area is generated inside the ejector, and atmospheric air in the external environment enters the ejector through the diversion port and the cold air inlet pipe and mixes with the high-temperature gases from the gas pipeline;

[0019] In the main body section, it passes through all control areas in sequence. After the mixed gases in the gas pipeline in the control area enter the first jet oscillator, an oscillating jet is formed in the heating cavity and sweeps and heats the front wall surface of the heating cavity; Subsequently, the air flow is divided into two streams, one of which enters the upper part of the heating cavity and heats it, and the other air flow enters the lower part of the heating cavity, heats it and then enters the upper part through the first connecting pipe and the second connecting pipe; The two fluids are remixed at the end of the upper part of the heating cavity and enter the second jet oscillator, and a high-frequency oscillating jet is formed at the air outlet, controlling the separation of the boundary layer on the upper surface of the airfoil to achieve the effect of increasing lift.

[0020] In the present invention, there are no moving parts on the airfoil blade, and the volume of the components is very small, ensuring the structural strength of the blade;

[0021] The present invention can meet the requirements of anti-icing and de-icing and lift increase for various airfoils such as helicopter rotor blades. Description of the Drawings

[0022] Figure 1 is a schematic diagram of the root connection section and the individual control area of a lift-adjustable helicopter rotor blade with anti-icing function;

[0023] Figure 2 is a complete schematic diagram of the airfoil shell of a lift-adjustable helicopter rotor blade with anti-icing function;

[0024] Figure 3 is Figure 1 the top view of;

[0025] Figure 4 is Figure 2 the sectional view taken along the A-A direction of;

[0026] Figure 5 is a schematic diagram of the structure of the second jet oscillator and the first jet oscillator.

[0027] The reference numerals in the figures: 1, airfoil shell; 2, heating cavity; 3-1, first connecting pipe; 3-2, second connecting pipe; 4, first jet oscillator; 5, second jet oscillator; 6, air outlet; 7, gas pipeline; 8, ejector; 9, nozzle; 10, cold air inlet pipe; 11, diversion port. Detailed Embodiment

[0028] The following refers to Figure 1Describe the movement process of the gas in the lift-adjustable helicopter rotor blade with anti-icing function.

[0029] High-temperature and high-pressure gas is led out from the high, medium, and low-pressure stages of the compressor of the helicopter turboshaft engine and enters the gas transmission pipe. After the gas enters the nozzle and is accelerated, a negative pressure area is generated inside the ejector, and the ambient air at normal pressure enters the ejector through the diversion port and the cold air inlet pipe and mixes with the high-temperature gas in the gas transmission pipe. After the mixed gas in the gas transmission pipe enters the first jet oscillator, an oscillating jet is formed in the heating cavity, sweeping and heating the front wall surface of the heating cavity. Subsequently, the air flow is divided into two streams, one of which enters the upper part of the heating cavity and heats it, and the other air flow enters the lower part of the heating cavity and heats it, and then enters the upper part through the connecting pipes on both sides of the heating cavity. The two fluid streams are remixed at the end of the upper part of the heating cavity and enter the second jet oscillator, forming a high-frequency oscillating jet at the air outlet and leaving the airfoil housing.

Claims

1. A lift-adjustable helicopter rotor blade with anti-icing function, the airfoil housing (1) is divided into a main body section and a root connection section, and the main body section is the part that provides lift for the helicopter airfoil; characterized in that: In the leading edge of the airfoil shell (1) of the main body section, several control areas are arranged along the direction of the main beam of the rotor blade; At the front end of each control area, a heating cavity (2) is arranged. The cross-section of the heating cavity (2) perpendicular to the direction of the main beam of the rotor blade is crescent-shaped; An air delivery pipe (7) is installed in the airfoil shell (1). The inlet of the air delivery pipe (7) is connected to the outlets of the high, medium, and low pressure stages of the engine compressor. It sequentially passes through the root connection section of the airfoil shell (1) and all control areas of the main body section until the closed end of the last control area; Each heating cavity (2) is equipped with a first connecting pipe (3-1), a second connecting pipe (3-2), a first jet oscillator (4), and a second jet oscillator (5); The first connecting pipe (3-1) and the second connecting pipe (3-1) are respectively located on both sides of the control area, and they connect the ends of the upper and lower parts of the crescent of the heating cavity (2); The first jet oscillator (4) is located in the middle part of the leading edge of the control area. The outlet of the first jet oscillator (4) is connected to the heating cavity (2), and the inlet is connected to the air delivery pipe (7); An air outlet (6) communicating with the external environment is arranged near the middle of the upper surface of the control area; The second jet oscillator (5) is arranged near the middle of the upper surface of the control area. The outlet of the second jet oscillator (5) is connected to the air outlet (6), and the inlet is connected to the upper part of the heating cavity (2); An ejector (8) is installed in a part of the air delivery pipe (7) at the root connection section. The primary fluid inlet and the mixed fluid outlet of the ejector (8) are both connected to the air delivery pipe (7). A nozzle (9) is arranged in the ejector (8); A diversion port (11) communicating with the external environment is arranged at the leading edge of the root connection section. The secondary fluid inlet of the ejector (8) is connected to the diversion port (11) through a cold air inlet pipe (10).

2. The working method of the lift-adjustable helicopter rotor blade with anti-icing function according to claim 1 is as follows: Use an ejector (8) to mix external air, and control the gas flow entering the ejector (8) from the gas transmission pipe (7) by switching the high, medium, and low-pressure compressor outlet channels. According to the needs of heating and increasing lift, the following multiple modes can be converted, specifically divided into the following working modes: Mode 1, non-air extraction mode When there is no heating requirement for the blade, close the compressor air extraction, and only use the pressure difference generated by the blade rotation to naturally suck in external air to drive the second jet oscillator (5) to achieve the auxiliary effect of increasing lift, and ensure the full power operation of the engine; the gas flow mode is as follows: In the root connection section, close the high, medium, and low-pressure outlets of the helicopter turboshaft engine compressor, then there is no gas from the compressor in the gas transmission pipe (7); using the pressure difference generated when the blade rotates, external air is sucked into the ejector (8) from the diversion port (11) and the cold air inlet pipe (10), and the air is accelerated in the contraction channel of the ejector (8) and enters the gas transmission pipe (7) in the direction of the control area; In the main body section, the air passes through all control areas in turn. The air in the gas transmission pipe (7) in the control area enters the first jet oscillator (4), then enters the heating cavity (2), and then the air flow is divided into two streams. One stream enters the upper cavity of the heating cavity (2), and the other stream enters the lower cavity of the heating cavity (2), and then enters the upper part through the first connecting pipe (3-1) and the second connecting pipe (3-2); the two fluid streams are remixed at the end of the upper part of the heating cavity (2) and enter the second jet oscillator (5), and a high-frequency oscillating jet is formed at the air outlet (6) to control the separation of the boundary layer on the upper surface of the airfoil to achieve the effect of increasing lift; Mode 2, air extraction mode When there is no heating requirement and the blade speed is too slow to suck in external air, introduce low-pressure gas from the compressor to provide the primary fluid for the ejector (8) to suck in external air from the cold air inlet pipe (10) to achieve the auxiliary effect of increasing lift; when there is a heating requirement, introduce medium-temperature medium-pressure or high-temperature high-pressure gas from the compressor according to the demand intensity, and achieve the auxiliary effects of heating and increasing lift at the same time; the gas flow mode is as follows: At the root connection section, high-temperature and high-pressure gas is led out from the high, medium, and low pressure stages of the compressor of the helicopter turboshaft engine and enters the gas pipeline (7). After the gas enters the nozzle (9) and is accelerated, a negative pressure area is generated inside the ejector (8), and atmospheric air in the external environment enters the ejector (8) through the diversion port (11) and the cold gas pipeline (10) to be mixed with the high-temperature gas from the gas pipeline (7). At the main body section, passing through all control areas in sequence, after the mixed gas in the gas pipeline (7) in the control area enters the first jet oscillator (4), an oscillating jet is formed in the heating cavity (2) to sweep and heat the front wall surface of the heating cavity (2). Subsequently, the air flow is divided into two streams. One stream enters the upper part of the heating cavity (2) and heats it, and the other stream enters the lower part of the heating cavity (2), is heated, and then enters the upper part through the first connecting pipe (3-1) and the second connecting pipe (3-2). The two fluid streams are remixed at the end of the upper part of the heating cavity (2) and enter the second jet oscillator (5), and a high-frequency oscillating jet is formed at the air outlet (6) to control the separation of the boundary layer on the upper surface of the airfoil to achieve the effect of increasing lift.

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