CN113586281A

CN113586281A - Ship gas turbine with non-uniform lobe injection mixer

Info

Publication number: CN113586281A
Application number: CN202110799049.8A
Authority: CN
Inventors: 栾一刚; 符昊; 胡筵晨; 殷越; 张力敏; 马鸿飞; 孙海鸥; 王忠义; 周少伟
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2021-07-15
Filing date: 2021-07-15
Publication date: 2021-11-02
Anticipated expiration: 2041-07-15
Also published as: CN113586281B

Abstract

The invention aims to provide a ship gas turbine with a non-uniform lobe injection mixer, which comprises the non-uniform lobe injection mixer, an upper coarse exhaust pipe and a gas turbine exhaust pipe orifice, wherein the uniform lobe injection mixer is arranged between the upper coarse exhaust pipe and the gas turbine exhaust pipe orifice, the gas turbine exhaust pipe orifice is connected with a gas outlet of the gas turbine through a gas turbine turning exhaust pipe, a bottom flange is arranged at the bottom of the non-uniform lobe injection mixer, the bottom flange is connected with a ring frame through a ring frame connecting piece, and the ring frame is sleeved below an annular bulge of the gas turbine exhaust pipe orifice. Compared with the conventional lobe injection mixer applied to an aviation gas turbine, the lobe injection mixer provided by the invention has the advantages that the effect of flow direction vortex is enhanced, the special design is carried out aiming at the arrangement mode of the pipe orifice, and the mixing length and the energy loss are considered at the same time. The non-uniform lobe ejector is additionally arranged at the exhaust pipe opening of the ship gas turbine, so that the ejection mixing performance can be improved by over 300% under a specific working condition.

Description

Ship gas turbine with non-uniform lobe injection mixer

Technical Field

The invention relates to a gas turbine, in particular to a ship gas turbine.

Background

The gas turbine has the characteristics of light weight, small volume, high single-machine power, quick start, less pollution, high thermal efficiency, good economy and the like, and is favored by the power of ships in multiple countries. However, when the gas turbine of the ship runs, the temperature is high, and if no temperature reduction measure is taken, the temperature in the engine box and the adjacent cabins of the engine box is overhigh, the service life of part of components is reduced, and the working stability of the gas turbine and the accessory systems of the gas turbine is reduced. Therefore, the ship gas turbine is designed into a set of air inlet and exhaust system, wherein the set of air inlet and exhaust system comprises an exhaust injection system. The exhaust injection system has the functions of introducing cold air into the engine compartment through airflow shearing force to reduce the temperature of the compartment and parts, and mixing the cold air into high temperature fuel gas to reduce the temperature before the fuel gas is exhausted to atmosphere. The exhaust nozzle of a ship gas turbine usually adopts a conventional injection mixing mode, namely: the gas blast pipe is convergent, and the mouth of pipe is circular, has certain to draw between and the outside box and penetrates the clearance to reach and draw the effect of penetrating the mixture. However, with the improvement of the performance of the combustion engine, the injection performance cannot meet the actual requirement.

The ejector mixer of the conventional spray pipe mainly depends on the action of viscous shear force of a main flow, pumps secondary flow and mixes the secondary flow with the main flow. The injection mixing rate is slow. For gas turbine applications, a longer mixing tube results in higher wall friction and a greater weight penalty. Thus, the use of such conventional shaped nozzles in jet mixers is greatly limited. Thus, the concept of enhanced mixing arises from changing the shape of the nozzle and using a cross-flow between the primary and secondary flows.

The thin wall of the exhaust pipe opening is added with a lobe spray pipe formed by bending into the shape of a periodic lobe, so that the flow field for injecting and mixing is changed. At the outlet cross section of the lobed nozzle, bounded by the profile of the lobe, the primary flow velocity has a lateral component outward of the crest and the secondary flow velocity has a lateral component inward of the trough. Thus, a pair of circulation currents with opposite directions are formed on two sides of the lobe, and the size of the circulation currents is related to the height of the lobe. The large scale reciprocal vortices thus generated are non-viscous and of a convective nature. The vortices are directed in line with the direction of flow, referred to as "streamwise vortices".

The lobe spray pipe in the shape has the advantages that the flow direction vortex enhances the mixing between the primary flow and the secondary flow, and the perimeter of the outlet boundary of the lobe spray pipe is increased under the condition of the same outlet sectional area, so that the viscous shearing mixing between the primary flow and the secondary flow is enhanced. Thus, he can achieve thorough mixing of the fluids in a shorter mixing tube. The experimental results show that: compared with the corresponding conventional jet pipe jet mixer, the lobe jet mixer with good performance has the advantages of short size and light weight, and the jet flow ratio of the lobe jet mixer is almost more than 2 times of that of the conventional jet pipe jet mixer.

The lobe injection mixer is mainly used for an infrared suppressor of a helicopter. An article "Internal Aerodynamics of extracted super for helicopters Engines" in Toulmay F. 1988 introduces the form of a lobe jet mixer mature and applied to the tail of a SA356C Helicopter and the working principle thereof in detail. The lobed jet mixer configurations mentioned herein are the most common and most widely used. The conventional lobe ejecting mixer is characterized in that the outward expansion angle and the inward contraction angle are fixed and do not change along with the height change of the ejecting mixer, namely the inner wall and the outer wall of the conventional lobe ejecting mixer are straight lines with fixed inclination angles along the axial direction, and the side walls of each outward expansion lobe are parallel to each other. This design is dependent on its operating environment. The gas exhausted from the tail part of the gas turbine of the helicopter is ejected from the rear lobe jet mixer without changing the direction, and the velocity field of the gas is almost uniform. And the diameter of the rear exhaust pipe opening is larger than the maximum diameter of the lobe, so that a larger mixing gap is formed, an undamaged mixing layer is easily generated, and a reasonable mixing length is designed. The general working environment and internal flow field of the lobe jet mixer mentioned in the article are quite different from those of jet mixers applied to ships.

Disclosure of Invention

The invention aims to provide a ship gas turbine with a non-uniform lobe injection mixer, which can improve the injection performance of an exhaust injection system of the ship gas turbine.

The purpose of the invention is realized as follows:

the invention relates to a ship gas turbine with a non-uniform lobe injection mixer, which is characterized in that: including inhomogeneous lobe draw the blender, the thick blast pipe of top, the gas turbine exhaust mouth of pipe, even lobe draw the blender to install between thick blast pipe of top and the gas turbine exhaust mouth of pipe, the gas turbine exhaust mouth of pipe passes through the gas turbine turn blast pipe and connects the gas outlet of gas turbine, and inhomogeneous lobe draws blender bottom to set up the bottom flange, and the bottom flange passes through ring frame connecting piece and connects the ring frame, and the ring frame cover is in gas turbine exhaust mouth's annular bulge below, inhomogeneous lobe draws the blender to draw the lobe to include outer expanding lobe, the interior lobe of contracting, and outer expanding lobe, the interior lobe of contracting set up along circumference interval.

The present invention may further comprise:

1. the outward expansion degree of the outward expansion lobe and the inward contraction degree of the inward contraction lobe are reduced along with the distance from the gas turbine.

2. The outer side of the outer expansion lobe is an outer wall, the inner side of the inner contraction lobe is an inner wall, the side faces of the outer expansion lobe and the inner contraction lobe are side walls, and the outer wall is tangent to the side walls and the inner wall is tangent to the side wall arcs.

3. The shape lines of the outer wall surface and the inner wall surface perpendicular to the flow direction are respectively a group of concentric arcs, the concentric axis of the outer wall surface arc line is closer to the gas turbine, the axis of the exhaust pipe orifice of the gas turbine is the axis of the inner wall surface arc line concentric circle, and the farthest axis is the axis of the inner wall surface arc line concentric circle.

4. The axial line of the outer wall surface is a circular arc line, and the radius of the circular arc line is reduced along with the increase of the outward expansion distance.

The invention has the advantages that: the invention can better adapt to the exhaust injection system of the ship gas turbine and better generate the entrainment cold air of the flow direction vortex and the orthogonal vortex. The invention can generate a free mixing layer with better performance by special-shaped structure design, particularly special design of different lobe sizes and shapes and arc-shaped outer walls while ensuring larger shearing perimeter and reasonable injection gap, fully utilizes the energy of uneven high-speed gas to obtain reasonable mixing length, and most importantly, avoids the condition that the high-speed gas impacts the wall surface too early, damages the vortex structure and the free mixing layer and shortens the mixing length.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2a is a view from perspective B, and FIG. 2B is a view from perspective C;

FIG. 3 is a D view;

FIG. 4 is a view from perspective E;

FIG. 5a is a view from perspective F, FIG. 5b is a view from perspective G, and FIG. 5c is a view from perspective H;

FIG. 6a is a view at I, and FIG. 6b is a view from J-J.

Detailed Description

The invention will now be described in more detail by way of example with reference to the accompanying drawings in which:

with reference to fig. 1-6b, the invention relates to a non-uniform lobe jet mixer 1 for a marine gas turbine exhaust nozzle, which is mounted above a gas turbine exhaust nozzle 2. When the gas turbine works, the main stream high-temperature gas is sprayed out from the tail gas outlet 2 and reaches the gas turbine exhaust pipe opening 2 through the gas turbine turning exhaust pipe 3. Then the gas flows upwards through the non-uniform lobe injection mixer 1, and meanwhile due to the shearing force and the entrainment effect, the cold air around the non-uniform lobe injection mixer 1 in the mixing box body 5 flows towards the upper coarse exhaust pipe 6 together to enter a subsequent exhaust structure. Due to the "pumping" action, the cold air inside the box 5 is dragged and mixed by the main flow of gas, requiring the cold air to be sucked from the outside. The flow direction of the cold air and the flow direction of the main flow are shown in fig. 1, and the cold air plays a role in cooling the box body and parts, so that the overall working stability is improved.

Referring to fig. 1, 2 and 3, the axis of the inlet of the ejector mixer 1 coincides with the axis of the exhaust nozzle 2 of the gas turbine. The number of

lobes

7, 8 is related to the size of the gas turbine exhaust nozzle 2 and casing 5 and the engine operating conditions, and the extent to which the

lobes

7, 8 expand and contract decreases as their distance from the engine increases. The size ratio of the non-uniform lobe ejecting mixer 1 and the box body 5 shown in fig. 1 is that the total number of the

lobes

7 and 8 is 12. The

lobes

7, 8 are evenly distributed along the circumference. The circular arc surfaces 11 and 12 connecting the inner and outer wall surfaces 13 and 14 and the side wall 9 are tangent to each other. The shape lines of the outer wall surface 12 and the inner wall surface 13 perpendicular to the flow direction are respectively a group of concentric arcs, the concentric axis of the arc line of the outer wall surface 12 is closer to the combustion engine, the axis of the exhaust pipe orifice 2 is next, and the axis of the concentric circle of the arc line of the inner wall surface 13 is farthest. At the lowermost end of the lobe, the three axes coincide. The flow direction of the inner wall surface 8 is a straight line forming a certain angle with the axis of the pipe orifice, and the angle is related to the retraction distance. The axial line of the outer wall surface 13 is a circular arc line, and the radius of the circular arc line is reduced along with the increase of the outward expansion distance. The radial shape line of the side wall 11 is vertical to the inner and outer wall surfaces, and the axial shape line is parallel to the axis of the pipe orifice.

With reference to fig. 1, 2 and 3, when the fuel gas flows through the lobe jet mixer, at the outlet section of the lobe, a flow direction vortex is formed to enhance the mixing between the primary flow and the secondary flow, and under the condition of the same outlet section area, the perimeter of the outlet boundary of the lobe nozzle is increased, so that the viscous shearing mixing between the primary flow and the secondary flow is enhanced. Thus, he can achieve thorough mixing of the fluids in a shorter mixing tube. The clearance between box 5 and exhaust pipe mouth 2 is very narrow, and the flow direction distance is short, and the gas direction can be adjusted when guaranteeing great expansion angle to curved outer wall 9. To a certain extent, a larger divergence angle can ensure the generation of "flow-wise vortices". The development of the mixing gap and the free mixing layer and the mixing length are important indexes of the injection mixer. Reasonable expansion angle and the radian of the outer wall 9 can obtain reasonable mixing clearance, and more importantly, better development condition of a free mixing layer is obtained. If the bending plate is used for replacing the cambered plate, namely two planes are bent, the formation of a flow direction vortex is limited, and the injection performance is reduced. Because the side walls of all the lobes are not parallel, low pressure is generated in the process that fuel gas flows to the outward-expanding lobes, the formation of flow direction vortex is promoted, and the injection performance is improved. In general, the axes of the exhaust pipe mouth 2 of the combustion engine and the upper coarse exhaust pipe 6 are not coincident, so that the uneven high-speed gas is difficult to fully mix cold air. Aiming at the arrangement mode of a gas turbine box body and a pipeline, uneven fuel gas is combined, uneven lobes are designed, then the mixing gap and the mixing length are adjusted, the energy of high-speed fuel gas is fully utilized, and the injection quantity is improved.

Under the working conditions that the gas flow is 85kg/s and the temperature is 773K, the wall surface is assumed to be heat-insulating, and the temperature of cold air is 300K. The non-uniform lobe jet mixer and box ratio for the exhaust nozzle of the ship gas turbine of the invention is shown in fig. 1, for example, and the main structural dimensions of the non-uniform lobe jet mixer for the exhaust nozzle of the ship gas turbine of the invention are as follows: the total number of lobes is 12, and the lobes are uniformly distributed along the circumference of the circular exhaust pipe orifice 2. The inner contraction lobes are 12, the small outer expansion lobes are 1, and the large outer expansion lobes are 1. The size of the exhaust pipe orifice 2 is 1330 mm. Perpendicular to the flow direction, the minimum diameter of the concentric circle of the arc line of the inner wall is 1000mm, and the maximum diameter of the concentric circle of the arc line of the outer wall is 1530 mm. And the radius of the arc-shaped line of the outer wall of the lobe with the largest outward expansion distance is 180mm, the radius of the arc-shaped line of the outer wall of the lobe with the smallest outward expansion distance is 240mm, and the difference between the radii of the arc-shaped lines of the outer walls of the adjacent lobes is 10 mm. The lobe height was 145 mm. The diameter of the arc wall surface connecting the side wall and the inner and outer walls is 50 mm. The inner diameter of the flange connected with the exhaust pipe orifice is 1330mm, the outer diameter is 1440mm, and the height is 10 mm. Numerical simulation is carried out on a ship exhaust injection system with a certain specific size, and the size can refer to the proportion in a figure. The flow of the gas outlet is 85kg/s, the total temperature is 773K, the wall surface is set to be a heat insulation wall surface, the external environment is the atmospheric environment, and the temperature is 300K. The system injection amount without the lobe injection mixer is 2.6kg/s, and the injection performance of the system with the non-uniform lobe injection mixer is improved by over 300 percent.

With reference to fig. 1, 3 and 4, the invention relates to a non-uniform lobed jet mixer 1 for a marine gas turbine exhaust nozzle, which is mounted above a gas turbine exhaust nozzle 2. Usually, a circular bulge is reserved above the gas turbine exhaust nozzle 2 so that parts can be added later. The flange 15 at the bottom of the non-uniform lobe injection mixer is connected with the ring frame 17 through bolts, and the ring frame 17 is clamped outside the circular bulge of the exhaust pipe orifice 2 to realize additional installation. For operational stability, 30 bolts are suggested. A flange 15 at the bottom of the injection mixer is provided with a polished through hole, and a ring frame 17 is provided with a screw through hole. The design can facilitate disassembly and assembly of the non-uniform lobed jet mixer for repair or special cases.

Referring to fig. 4 and 5, the ring frame 17 is composed of two semicircles, each semicircle has connectors at both ends, each connector suggests 3 bolts for fixing, and a total of 6 bolts are needed for assembly. Holes in the connecting piece are all unthreaded hole through holes, and the bolt needs a matched nut. In consideration of assembly and stress release, a 10mm gap is left between the connecting pieces after the ring frame is clamped. The shape of the inside of the ring 17 needs to match the shape of the annular projection reserved above the gas turbine exhaust nozzle 2, the height of the ring being about 10mm below the projection in view of assembly.

In connection with fig. 2, 3 and 6, during the installation and disassembly of the non-uniform lobe ejecting mixer 1, a 'chain block' is required for lifting, and four lifting lugs 14 are suggested for lifting and placing. The proposed mounting positions are given in fig. 2 and 3, and the proposed machining dimensions are given in fig. 6.

Claims

1. The utility model provides a take inhomogeneous lobe to draw boats and ships gas turbine who penetrates blender which characterized by: including inhomogeneous lobe draw the blender, the thick blast pipe of top, the gas turbine exhaust mouth of pipe, even lobe draw the blender to install between thick blast pipe of top and the gas turbine exhaust mouth of pipe, the gas turbine exhaust mouth of pipe passes through the gas turbine turn blast pipe and connects the gas outlet of gas turbine, and inhomogeneous lobe draws blender bottom to set up the bottom flange, and the bottom flange passes through ring frame connecting piece and connects the ring frame, and the ring frame cover is in gas turbine exhaust mouth's annular bulge below, inhomogeneous lobe draws the blender to draw the lobe to include outer expanding lobe, the interior lobe of contracting, and outer expanding lobe, the interior lobe of contracting set up along circumference interval.

2. The marine gas turbine with non-uniform lobed ejector mixer of claim 1, wherein: the outward expansion degree of the outward expansion lobe and the inward contraction degree of the inward contraction lobe are reduced along with the distance from the gas turbine.

3. The marine gas turbine with non-uniform lobed ejector mixer of claim 1 or 2, wherein: the outer side of the outer expansion lobe is an outer wall, the inner side of the inner contraction lobe is an inner wall, the side faces of the outer expansion lobe and the inner contraction lobe are side walls, and the outer wall is tangent to the side walls and the inner wall is tangent to the side wall arcs.

4. The marine gas turbine with non-uniform lobed ejector mixer of claim 3, wherein: the shape lines of the outer wall surface and the inner wall surface perpendicular to the flow direction are respectively a group of concentric arcs, the concentric axis of the outer wall surface arc line is closer to the gas turbine, the axis of the exhaust pipe orifice of the gas turbine is the axis of the inner wall surface arc line concentric circle, and the farthest axis is the axis of the inner wall surface arc line concentric circle.

5. The marine gas turbine with non-uniform lobed ejector mixer of claim 4, wherein: the axial line of the outer wall surface is a circular arc line, and the radius of the circular arc line is reduced along with the increase of the outward expansion distance.