RU184774U1 - GAS-TURBINE ENGINE OUTPUT DEVICE - Google Patents

Abstract

Field of technology: turbine engineering. The output device contains an annular axial radial diffuser and a cochlea connected to an annular diffuser. The cochlea is made with two symmetrical outlet pipes directed in opposite directions tangentially to the axial direction of the flow inlet. The axis of the nozzles are located in planes that have an inclination (β) to the horizontal plane and are equally spaced (HP) from the axis of the output device, in addition, the axis of the nozzles are located at an angle of more than 90 ° (α> 90 °) relative to the axial direction of the flow inlet. The utility model provides separation of the flow on two sides relative to the direction of entry, reducing the loss of total pressure, simplicity and manufacturability of the design, improved characteristics of the structure of the flow of exhaust gases.

Description

The utility model relates to the field of turbine construction. The device is designed for a turboprop engine, but can be used for other aircraft engines of helicopters and aircraft, and in industrial installations.

Exit devices (VU) for exhaust gas design in such a way as to minimize pressure losses associated with the exhaust of combustion gases. Such pressure losses can significantly reduce the performance of a gas turbine engine.

The flow of exhaust gases leaving the turbine section often has a relatively complex flow field with swirls. The utility model is aimed at revealing the design of the device, which should redirect the flow of combustion gases in a direction other than the incoming. Complex fields of the flow of combustion gases can create pressure drops, which, in turn, can cause the separation of the flow along the internal surfaces of the channel inside the WU itself. Separation of the flow increases the resistance imposed on the flow of combustion gases, and also increases the pressure loss associated with the exhaust of the combustion gases.

It is known WU with a bypass channel for directing the flow of combustion gases into a gas turbine engine, disclosed in the description of patent US 8099943 B2, F02C 7/08, publ. 01/24/2012. The device comprises an inlet for receiving a flow of combustion gases from a turbine section of a gas turbine engine; an outlet in fluid communication with the inlet; and a transition portion forming a passage between the inlet and outlet openings. The transition part comprises a discontinuous annular region having a first side part and a second side part, which are separated by a flow splitter. At least one bypass channel connects the first side part and the second side part of the discontinuous annular region.

The transition part of the device in the form of a discontinuous annular part with a flow splitter and a bypass channel has a complex structure that requires complex technological equipment. In addition, the device is made with one output pipe.

It is known WU for a gas turbine engine according to the application for invention US 2016177872 A1, F02K 1/40, publ. 06/23/2016.

The device described in the application contains an annular inlet pipe located on the input axis. At least two outlet nozzles branch off from the outlet of the inlet along respective center lines that are different from each other. The central lines of the outlet pipes, when projected onto a plane perpendicular to the input axis, are spaced apart from the input axis so as not to intersect. The device allows for the output of the exhaust gas flow on two sides radially outward relative to the inlet pipe. However, in such an embodiment, there are many vortex zones and reverse flow zones. These disadvantages are solved in additional particular aspects of the invention by making dividers at the intersection of the exhaust pipes and the restrictive wall of the annular inlet pipe.

Such a device was developed by Pratt & Whitney Corporation for RT-6 turboprop engines. Nevertheless, visualization of the flow pattern of the exhaust gas flow in the analog device, carried out according to the results of three-dimensional calculation in CFD ANSYS, showed that there are distinct zones with a reverse flow at the outlet of the nozzles, and explicit vortex zones are also noted. The uneven flow of exhaust gases leads to an increase in hydraulic losses. The complexity of the design in combination with the disadvantages of the flow structure are the disadvantages of this analogue.

A device according to the copyright certificate SU 436163 A, F01D 25/30, publ. 07/15/1974. The device is a diffuser containing axial, transitional and radial parts formed respectively by the outer and inner walls, while the outer wall of the radial part is made in the form of an arc of a circle.

The radial part of the device with the outer wall, which is made in the form of an arc of a circle, has satisfactory characteristics for aligning the structure of the exhaust gas flow only in the case of large axial dimensions. Another disadvantage of the known device is its low efficiency due to large losses of the total pressure of the exhaust gases.

Closest to the claimed is a device for the release of gases from a turbomachine RU 2144986 C1, F01D 25/30 (2000.01), F04D 29/54 (2000.01), publ. 01/27/2000, selected as a prototype. The device is made with an annular diffuser, which contains the axial and radial parts formed respectively by the outer and inner walls, while the outer wall of the radial part is made in the form of an arc of a circle. The ratio of the radius R of the circular arc to the width H of the annular gap at the exit from the axial part of the diffuser is 0.4-1.1, and ΔH / R <1, where ΔH is the difference between the widths of the annular gaps at the outputs of the radial and axial parts of the diffuser. The ratio of the areas of the input and output sections of the axial part of the diffuser is in the range of 1.5-2.0. This embodiment of the device for the release of gases leads to a decrease in losses compared with the previous analogue. In addition, in the prototype, the radial part is made with a cochlea formed by the front, side and rear walls. The cochlea allows to reduce the axial dimensions of the exhaust device, has good characteristics of aligning the structure of the exhaust gas flow in combination with the simplicity and manufacturability of its design.

The disadvantage of the prototype is a one-way exhaust. The energy of the exhaust gas jet is higher than in the case of a two-sided exhaust, which is why the exhaust jet cools much more slowly. One-way exhaust can additionally create a reactive moment when using the device on aircraft.

The objective of the utility model is to create an output device in which the flow of combustion gases is divided into two sides relative to the direction of flow inlet. This embodiment leads to a decrease in the total pressure loss in the WU. Moreover, the design of the device is simple and technologically advanced and has improved characteristics of the structure of the flow of exhaust gases.

The problem is solved by improving the output device, which contains an annular diffuser having axial and radial parts formed respectively by the outer and inner walls, and a cochlea connected to the annular diffuser. The outer wall of the radial part of the diffuser is made in the form of an arc of a circle. According to a utility model, the cochlea is made with two outlet nozzles directed in opposite directions tangentially to the axial direction of the flow inlet, and the axis of the nozzles are located in planes having an inclination (β) to the horizontal plane and located at an equal distance (HP) from the axis of the VU, in addition , the axis of the nozzles are located at an angle of more than 90 ° (α> 90 °) relative to the axial direction of the flow inlet.

In one specific embodiment of the utility model, the angles of inclination of the exhaust pipes are α = 102 ° and β = 11.25 °, and the distance HP is 90 mm.

This embodiment leads to a decrease in losses in the WU, the creation of a fading reactive moment from the propeller-propeller in the case of application on an airplane, which improves the directional stability of the airplane in flight. The separation of the gas stream behind the engine into the left and right nozzle also leads to the separation of the total energy of the stream, as a result of which when the exhaust mixes and cools the gas jets with a turbulent flow from the screw, which ensures minimal impact of the exhaust jet on the casing of the installation.

According to a preferred embodiment of the utility model for the radial section of the diffuser, the ratio of the radius R of the arc of the circumference of the outer wall of the radial part of the diffuser to the width H of the annular gap at the entrance to the diffuser lies in the range 2.5-3, and the ratio ΔH / H <0.6, where ΔH - the difference between the width of the annular gap at the exit of the radial part of the diffuser and the entrance to the diffuser.

In this case, there is a continuous flow of gases at the outlet of the diffuser and minimal loss of total pressure. At R / H> 3, there is a sharp increase in total pressure loss in the exhaust system. For the same reason, the difference between the widths of the annular gaps at the exit from the radial part of the diffuser and the inlet to the diffuser (AN) should not exceed the width of the annular gap at the inlet (ΔН / Н <0.6).

In addition, the ratio of the areas of the input and output sections of the diffuser S1 / S2 is in the range of 1.5-2.0 ..

The choice of such a ratio of the areas of the input (S1) and output (S2) cross-sections of the diffuser provides an equivalent diffuser angle of not more than 34 °, as well as a minimum length L of the axial part of the diffuser. If the ratio S1 / S2 and the equivalent angle do not fit into the corresponding intervals, then it is impossible to provide the necessary minimum axial length of the diffuser, there is a separation of the air flow from the walls of the diffuser, which leads to an increase in the total pressure loss.

The utility model is illustrated by the following figures.

In FIG. 1 shows a partial section of the inventive device, which explains the device of the diffuser and the cochlea.

In FIG. 2 is a transverse view of the device on which the output pipes and the location of their axes relative to the horizontal plane are displayed, the arrow in the figure indicates the direction of flow swirl.

In FIG. 3 is a top view of the device, which shows the location of the nozzles relative to the axis of the inlet flow.

WU contains an annular diffuser 1 containing a cylindrical axial part and a radial part, a scroll 11 and two exhaust pipes 9] 10. The cylindrical axial part of the diffuser is formed by the inner 2 and outer 3 walls. The radial part is formed by the inner 7 and outer 6 walls. The generatrix of the outer wall 6 has the shape of a circular arc with a radius R and a height ΔH. An annular gap at the inlet of the axial part of the diffuser 1 is designated N. The snail is formed by the front wall 4, the outer wall 5 and the rear wall 8, connected by a radial transition with the inner wall of the radial diffuser 7.

The outlet pipes are located symmetrically relative to the central axis of the VU (Fig. 2) tangentially to the axial direction of the flow inlet into the diffuser, and are directed in opposite directions each in the direction of the flow swirl direction. The exhaust pipes 9 and 10 are located at an angle greater than 90 ° (α = 102 °) to the axis of the WU. The axes of the exhaust pipes are not coaxial and are located in planes equidistant from the axis of the VU, in a specific example, at distances HP = 90 mm, and having an inclination β = 11.25 ° to the horizontal plane.

During the operation of the exhaust system of a gas turbine installation, the gas exiting the turbine enters the diffuser 1, passes through the axial and radial parts, and, reducing the flow rate, enters the cochlea. The exhaust gas leaving the axial part of the diffuser 1, due to the Coanda effect known from aerodynamics, flows along the outer wall 6, and ensures a continuous flow along the outer wall of the diffuser over its entire cross section. In the cochlea, the flow changes its radial direction to the tangential direction, is leveled, and, being separated, is discharged into the atmosphere by means of two exhaust pipes at an angle of 102 ° to the axial direction at the inlet of the hydraulic unit. Due to this nature of the flow stream, losses in the exhaust system are minimal.

Claims (4)

1. The output device of a gas turbine engine containing an annular diffuser having an axial and radial parts formed respectively by the outer and inner walls, and a cochle connected to the annular diffuser, while the outer wall of the radial part of the diffuser is made in the form of an arc of a circle, characterized in that the cochlea made with two symmetric outlet nozzles directed in opposite directions tangentially to the axial direction of the flow inlet, and the axis of the nozzles are located in planes having a slope n (β) to the horizontal plane and equally spaced (HP) from the axis of the output device, in addition, the axis of the nozzles are located at an angle of more than 90 ° (α> 90 °) relative to the axial direction of the flow inlet. 2. The device according to claim 1, characterized in that the angles of inclination of the axes of the nozzles are β = 11.25 ° and α = 102 °, and the distance HP is 90 mm. 3. The device according to claim 1 or 2, characterized in that for the radial part of the diffuser the ratio R / H = 2.5-3, where R is the radius of the arc of the circumference of the outer wall of the radial part of the diffuser, N is the width of the annular gap at the entrance to the diffuser and the ratio ΔН / Н <0.6, where ΔН is the difference between the width of the annular gap at the exit from the radial part of the diffuser and the entrance to the diffuser. 4. The device according to any one of paragraphs. 1-3, characterized in that the ratio of the area (S1) of the input and the area of the output (S2) of the cross sections of the diffuser S1 / S2 is in the range of 1.5-2.0.

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