RU2773719C1 - Air turbine for wave power plant - Google Patents

Abstract

FIELD: a wave power plants.

SUBSTANCE: invention relates to an air turbine for a wave power plant. The turbine contains an impeller, consisting of a hub and rotary working and control blades 3 and 4 of a symmetrical aerodynamic profile. The axis of rotation O of each blade 3 and 4 lies in the plane of symmetry of the profile parallel to its nose and perpendicular to the axis of rotation of the wheel. For blades 3, axis O is aligned with the center of pressure of profile C. In the blades 4, the axis O is located between the center C and its nose. For all blades 3 and 4, the center of mass coincides with their axes O. At the ends of the trunnions of the blades 4, bevel gear wheels 6 are rigidly fixed. At the ends of the trunnions of the blades 3, similar wheels 6 are fixed with the possibility of rotation in both directions relative to the plane of symmetry of the profile at an angle equal to the optimal angle of attack α of the blade profile 3. By fixing on the ends of the trunnions of the blades 3 of the fingers, perpendicular to the plane of symmetry of the profile and placed between the thrust pins fixed on the wheels 6, between the wheels 6 belonging to the alternating blades 3 and 4, free-rotating wheels 6, identical with them, are placed in engagement with them.

EFFECT: invention is aimed at improving the efficiency of the air turbine.

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Description

The invention relates to the field of wave energy, in particular to wave installations using the energy of an oscillating water column.

A Wells air turbine is known, the direction of rotation of which does not depend on the direction of air or liquid flow, having blades of a symmetrical profile, planes whose symmetries are perpendicular to the axis of rotation of the turbine impeller (Information resource: https://amp.ru.google-info.cn/ 2239578/l/turbina-uelsa.html).

The disadvantages of analogue include the fact that to ensure efficient operation of the turbine requires that the peripheral speed of the blade several times higher than the axial flow rate. For example, for a symmetrical blade profile with a critical angle of attack of 15°, the tangent of which is equal to the ratio of the axial velocity V to the circumferential velocity U, tg15°=V/U=0.268, U>V/0.268>3.73V. That is, for stable operation of the turbine without flow stall, its preliminary spin-up and provision of a reserve of kinetic energy is required to prevent a rapid drop in the rotation speed when changing the direction of the axial flow.

A turbine of a wave power plant is known (AS USSR No. 1783140, publ. 23.12.1992, BI No. 47), in which it is possible to use a variable air flow direction, its impeller contains a hub with rotary blades of a symmetrical airfoil, axes, rotation of which lie in the planes of symmetry of the profiles parallel to their spouts and perpendicular to the axis of rotation of the impeller. The axis of rotation of each profile is located between the center of pressure and the nose, and the center of mass is located between the center of pressure and the trailing edge of the profile.

This turbine for the largest number of similar features and the result achieved when using is selected as a prototype of the claimed invention.

The disadvantages of the prototype are that the inertial forces arising from the acceleration and deceleration of the impeller and applied to the centers of mass of the blades do not directly affect the installation of the blades at optimal angles of attack. In addition, with a vertical orientation of the impeller rotation axis, the torque generated by the weight of the blade can be added or subtracted from the torque generated by the inertia force, depending on the direction of the axial air flow, i.e. for updrafts and downdrafts, the blade must be set at different angles of attack.

The technical result to which the present invention is directed is to increase the efficiency of the air turbine using the energy of the oscillating water column of the wave power plant.

To achieve the specified technical result in an air turbine for a wave power plant, containing an impeller consisting of a hub and rotary blades of a symmetrical aerodynamic profile, the rotation axis of each blade lies in the plane of symmetry of the profile parallel to its nose and perpendicular to the axis of rotation of the impeller, the rotation axis of the working blades is aligned with the center of pressure of the profile, and for the control blades the axis of rotation is located between the center of pressure of the profile and its nose, for all the blades the center of mass coincides with their axes of rotation, on the ends of the pins of the control blades, bevel gears are rigidly fixed, and on the ends of the pins of the working blades similar bevel gears with the possibility of rotation in both directions relative to the plane of symmetry of the profile at an angle equal to the optimal angle of attack of the aerodynamic profile of the working blade, due to the fixation on the ends of the trunnions of the fingers perpendicular to the plane of symmetry of the profile and placed between the thrust pins fixed on the bevel gears, between the bevel gears belonging to the alternating working and control blades, free-rotating bevel gears identical with them are placed in engagement with them.

Distinctive features of the proposed air turbine are:

- alignment of the axis of rotation of the working blades with the center of pressure of the profile,

- the location of the control blades of the axis of rotation between the center of pressure of the profile and its nose,

- coincidence of the center of mass of all blades with their axes of rotation,

- rigid fastening of bevel gears on the ends of the pins of the control blades,

- fixing bevel gears on the ends of the trunnions of the working blades with the possibility of their rotation in both directions relative to the plane of symmetry of the profile at an angle equal to the optimal angle of attack of the aerodynamic profile of the working blade,

- fixing on the end face of the pins of the working blade of the fingers perpendicular to the plane of symmetry of the profile, placed between the thrust pins fixed on the bevel gears,

- placement of free-rotating bevel gears belonging to alternating working and control blades that engage with them.

Due to the presence of these features, the time for the air turbine to reach maximum speed is reduced and its aerodynamic efficiency is increased by installing the working blades at optimal angles of attack.

The present invention is illustrated by the drawings shown in Fig. 1-3.

In FIG. 1 shows a diagram of the interaction of the control and working blades.

In FIG. 2 - section of an air turbine with a plane passing through the axis of rotation of the control blades and perpendicular to the axis of rotation of the impeller.

In FIG. 3 - section of an air turbine with a plane passing through its axis of rotation and the axis of rotation of the working blade.

An air turbine for a wave power plant contains a hub 1, bushings 2, rotary blades are divided into alternating working blades 3 and control blades 4, trunnions 5, bevel gears 6, pins 7, thrust pins 8. α is the optimal angle of attack corresponding to the maximum value of aerodynamic quality . C is the center of aerodynamic pressure. O - axis of rotation of the control blade 4. U - average circumferential speed of the working blade 3. V - speed of the axial flow. W is the direction of the air flow.

The proposed air turbine works as follows.

In the initial position, when the impeller of the air turbine is stationary, the development of waves in the water area causes the appearance of a direction-variable air flow in its flow path.

Since the center of aerodynamic pressure "C" of the control blade 4 is shifted relative to its axis of rotation "O" towards the trailing edge, the air flow turns the blade 4 in the direction of the air flow "W" (at the initial stage "V"). In this case, the gear bevel wheel 6 rigidly fixed on the end face of the pin 5 of the control blade 4 through the intermediate gear bevel wheel 6 rotates the gear bevel wheel 6 fixed on the pin 5 of the working blade 3 until the finger 7 touches the thrust pin 8, after which the blades 3 and 4 turn synchronously. Working blades 3 alternate with control blades 4.

The present invention always ensures that the air flow "W" flows around the working blade 3 at the optimal angle a, regardless of the ratio of the axial flow velocities V and the average circumferential velocity "U".

To reduce friction losses of the trunnion 5 rotary blades 3 and 4 are placed inside the bushings 2 fixed on the inner surface of the hub 1 and equipped, for example, with rolling bearings.

Claims (1)

An air turbine for a wave power plant, containing an impeller consisting of a hub 1 and rotary blades 3 and 4 of a symmetrical airfoil, the rotation axis of each blade 3 and 4 lies in the profile symmetry plane parallel to its nose and perpendicular to the impeller rotation axis, characterized in that for the working blades 3, the axis of rotation is aligned with the center of pressure of the profile, and for the control blades 4, the axis of rotation is located between the center of pressure of the profile and its nose, for all blades 3 and 4, the center of mass coincides with their axes of rotation, at the ends of the trunnions 5 of the control blades 4 are rigid geared bevel wheels 6 are fixed, on the ends of pins 5 of the working blades 3 similar bevel gears 6 are fixed with the possibility of rotation in both directions relative to the plane of symmetry of the profile by an angle equal to the optimal angle of attack of the aerodynamic profile of the working blade 3, due to fixing on the ends of the pins 5 fingers 7, perpendicular to the plane of symmetry of the profile and p located between the thrust pins 8, fixed on the gear bevel wheels 6, between the gear bevel wheels belonging to the alternating working and control blades, free-rotating identical gear bevel wheels are placed in engagement with them.

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