CN106762245B

CN106762245B - Mixer for gas engine and EGR mixer

Info

Publication number: CN106762245B
Application number: CN201710093556.3A
Authority: CN
Inventors: 陈友荣; 陈元滨; 陈勇
Original assignee: Chengdu Naierte Technology Co ltd
Current assignee: Chengdu Naierte Technology Co ltd
Priority date: 2017-02-21
Filing date: 2017-02-21
Publication date: 2023-06-06
Anticipated expiration: 2037-02-21
Also published as: CN106762245A

Abstract

The invention discloses a mixer and an EGR (exhaust gas recirculation) mixer for a gas engine, which comprises a through mixer body, wherein a disturbing fluid is arranged at an air inlet of the mixer body, a gas core is arranged at an air outlet of the mixer body, an EGR core is arranged between the disturbing fluid and the gas core, an exhaust gas air inlet and a gas air inlet are arranged on the mixer body, the EGR core is communicated with the exhaust gas air inlet, and the gas core is communicated with the gas air inlet. The mixer for the gas engine is suitable for various gas engines, has high mixing efficiency, ensures that the engine operates more stably, and has higher gas utilization efficiency. The requirements of peripheral conditions are lower than those of a separate gas mixer and an EGR mixer, the overall cost is lower, the safety and reliability are high, the sealing performance is good, and the market application value is good.

Description

Mixer for gas engine and EGR mixer

Technical Field

The invention belongs to the technical field of gas systems of gas engines, and particularly relates to a mixer and an EGR (exhaust gas Recirculation) mixer for a gas engine.

Background

Exhaust gas recirculation (Exhaust Gas Recirculation, abbreviated as EGR) is a technique in which a part of exhaust gas is separated after combustion in an internal combustion engine and introduced into an intake side to be burned again, and is mainly aimed at reducing nitrogen oxides (NOx) in the exhaust gas and increasing fuel consumption rate when sharing part of load. The oxygen content of the exhaust gas from the internal combustion engine after combustion is extremely low or even absent, and the oxygen concentration in the intake air is reduced after the exhaust gas is mixed with the intake air, so that the following phenomena occur: oxygen content lower than the atmosphere lowers the temperature at the time of combustion, and suppresses the generation of nitrogen oxides (NOx). When the combustion temperature is lowered, the heat energy dissipation from the cylinder, the wall surface of the combustion chamber and the piston surface is lowered, and the loss caused by thermal dissociation is slightly lowered.

With the increasing strictness of emission regulations and the rising price of fuel, EGR technology is becoming more and more widely used on engines. In the past, the recirculated exhaust gas had a long line to mix with fresh air before entering the cylinders, and the amount of recirculated exhaust gas introduced (EGR rate) was low, so the EGR mixer was not specifically designed. With the improvement and maturity of the EGR technology, the circulating exhaust gas amount (EGR rate) is larger and larger, and meanwhile, the requirement of the compactness of the engine makes the air inlet pipeline shorter, so that the uniformity of mixing the recirculated exhaust gas and the fresh air obtained by the traditional method can not meet the requirement of stable operation of the engine any more.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a mixer for a gas engine, in which two kinds of integrated air, exhaust gas, and gas are supplied together, and an EGR mixer.

The invention also provides a mixer for the gas engine, which comprises a through mixer body, wherein a disturbing fluid is arranged at the air inlet of the mixer body, a gas core is arranged at the air outlet of the mixer body, an EGR (exhaust gas Recirculation) core is arranged between the disturbing fluid and the gas core, an exhaust gas air inlet and a gas air inlet are arranged on the mixer body, the EGR core is communicated with the exhaust gas air inlet, and the gas core is communicated with the gas air inlet.

Preferably, the fuel gas core comprises a guide ring, a guide column arranged in the guide ring and a ventilation column arranged between the guide ring and the inner wall of the mixer body, and spray holes are formed in the guide column, the guide ring and the ventilation column; the guide post intersects in the centre of a circle position of guide ring and separates the guide ring into four even parts, and the ventilation post separates the space between guide ring and the blender body into four even parts.

Preferably, the cross sections of the flow guide column, the flow guide ring and the ventilation column are all in a water drop shape which is changed from big to small along the air flow direction, the flow guide column, the flow guide ring and the ventilation column are all in hollow structures, the spray holes are uniformly arranged on two sides of the flow guide column, the flow guide ring and the ventilation column, the tangent line of the position point of the spray holes is parallel to the air flow direction, and all spray holes are positioned on the same plane.

Preferably, the EGR core and the gas core are identical in structure.

Preferably, two circles of spray holes are annularly distributed on the inner wall of the mixer body, the first circle of spray holes and the spray holes of the EGR core are located on the same plane, and the second circle of spray holes and the spray holes of the gas core are located on the same plane.

Preferably, the spray hole of the EGR core and the spray hole of the first circle are communicated with the exhaust gas inlet, and the spray hole of the fuel gas core and the spray hole of the second circle are communicated with the fuel gas inlet.

Preferably, the spoiler comprises a spoiler ring and a spoiler arranged obliquely between the spoiler ring and the inner wall of the mixer body; the spoiler divides the space between the spoiler ring and the mixer body into six uniform portions.

Preferably, the oxygen sensor mounting hole, balance pipe mounting hole and pressure sensor mounting hole have been seted up on the blender body, install intelligent oxygen sensor in the oxygen sensor mounting hole, install the balance pipe in the balance pipe mounting hole, install pressure sensor in the pressure sensor mounting hole, intelligent oxygen sensor, balance pipe and pressure sensor all are located between EGR core and the gas core.

The invention also provides a mixer for the gas engine, which comprises a through mixer body, wherein a gas core is arranged at a gas inlet of the mixer body, a disturbing fluid is arranged at a gas outlet of the mixer body, an EGR (exhaust gas Recirculation) core is arranged between the gas core and the disturbing fluid, an exhaust gas inlet and a gas inlet are arranged on the mixer body, the EGR core is communicated with the exhaust gas inlet, and the gas core is communicated with the gas inlet; the fuel gas core comprises a guide ring, a guide column arranged in the guide ring and a ventilation column arranged between the guide ring and the inner wall of the mixer body, and spray holes are formed in the guide column, the guide ring and the ventilation column; the guide post intersects in the centre of a circle position of guide ring and separates the guide ring into four even parts, and the ventilation post separates the space between guide ring and the blender body into four even parts.

The invention also provides an EGR mixer, which comprises a mixer body, wherein an EGR core and a turbulent flow body are arranged in the mixer body along the air flow direction, an exhaust gas inlet is arranged on the mixer body, and the exhaust gas inlet is communicated with the EGR core; the EGR core comprises a guide ring, a guide column arranged in the guide ring and a ventilation column arranged between the guide ring and the inner wall of the mixer body, and spray holes are formed in the guide column, the guide ring and the ventilation column; the guide post intersects in the centre of a circle position of guide ring and separates the guide ring into four even parts, and the ventilation post separates the space between guide ring and the blender body into four even parts.

The beneficial effects of the invention are as follows: the mixer for the gas engine is suitable for various gas engines, has high mixing efficiency, ensures that the engine operates more stably, and has higher gas utilization efficiency. The requirements of peripheral conditions are lower than those of a separate gas mixer and an EGR mixer, the overall cost is lower, the safety and reliability are high, the sealing performance is good, and the market application value is good.

Drawings

Fig. 1 is a schematic perspective view of a mixer for a gas engine according to an embodiment.

Fig. 2 is a plan view of a mixer for a gas engine according to an embodiment.

Fig. 3 is a bottom view of a mixer for a gas engine according to an embodiment.

Fig. 4 is a side view of a mixer for a gas engine according to an embodiment.

Fig. 5 is a longitudinal sectional view of a mixer for a gas engine according to an embodiment.

FIG. 6 is a schematic view of a gas cartridge.

Fig. 7 is a left side view of fig. 4.

Fig. 8 is a schematic perspective view of a mixer for a secondary gas engine according to an embodiment.

Fig. 9 is a longitudinal sectional view of a mixer for a secondary gas engine of the embodiment.

Fig. 10 is a schematic perspective view of an embodiment three EGR mixer.

Fig. 11 is a longitudinal cross sectional view of the three EGR mixer of the embodiment.

Reference numerals illustrate: 1. a mixer body; 11. an inlet end cap; 12. an outlet end cap; 2. disturbing the fluid; 21. a turbulence ring; 22. a spoiler; 3. an EGR core; 4. a fuel gas core; 41. a guide ring; 42. a flow guiding column; 43. an air-passing column; 5. an exhaust gas inlet; 6. a gas inlet; 7. an oxygen sensor mounting hole; 8. an exhaust gas recirculation system mounting hole; 9. balance tube mounting holes; 10. and a pressure sensor mounting hole.

Detailed Description

The invention is further described with reference to the accompanying drawings and specific examples:

example 1

As shown in fig. 1 and 5, the mixer for a gas engine provided in this embodiment includes a mixer body 1 that is vertically penetrated, an air inlet is formed at an upper end of the mixer body 1, an air outlet is formed at a lower end of the mixer body, a disturbing fluid 2 is disposed at the air inlet of the mixer body 1, a gas core 4 is disposed at the air outlet, an EGR core 3 is disposed between the disturbing fluid 2 and the gas core 4, an exhaust gas air inlet 5 and a gas air inlet 6 are disposed on the mixer body 1, the EGR core 3 is communicated with the exhaust gas air inlet 5, and the EGR core is used for injecting exhaust gas accessed by the exhaust gas air inlet into the mixer body. The gas core 4 is communicated with the gas inlet 6, and is used for spraying the gas accessed by the gas inlet into the mixer. The EGR core 3 and the gas core 4 have the same structure, and the EGR core 3 and the gas core 4 will be further described below by taking the gas core as an example.

As shown in fig. 5 and 6, the gas core 4 includes a guide ring 41, a guide post 42 disposed in the guide ring 41, and a ventilation post 43 disposed between the guide ring 41 and the inner wall of the mixer body 1, wherein the cross sections of the guide post 42, the guide ring 41, and the ventilation post 43 are all in the shape of water drops from large to small along the air flow direction, and the guide post 42, the guide ring 41, and the ventilation post 43 are all in hollow structures. The flow guide column 42, the flow guide ring 41 and the ventilation column 43 are provided with spray holes, the spray holes are uniformly arranged at the widest positions of the sections of the two sides of the flow guide column 42, the flow guide ring 41 and the ventilation column 43, the tangent line of the position point of the spray holes is parallel to the flow direction of air from top to bottom, and all the spray holes are positioned on the same horizontal plane. The two guide posts 42 vertically intersect at the center of the guide ring 41 and divide the guide ring 41 into four uniform parts, and the four ventilation posts 43 divide the space between the guide ring 41 and the mixer body 1 into four uniform parts.

As shown in fig. 3, the EGR core 3 and the gas core 4 are different in that the EGR core 3 and the gas core 4 have an angle of 45 ° in the horizontal plane when they are installed in the mixer body, in which the gas column of the EGR core 3 communicates with the exhaust gas intake port 5 and the gas column of the gas core 4 communicates with the gas intake port 6. The size and length of the guide post, the guide ring and the ventilation post of the EGR core 3 and the gas core 4 can be flexibly set according to the practical application requirement, in this embodiment, the spray hole on the EGR core is lower, and the spray hole of the gas core is upper.

Two circles of spray holes are annularly distributed on the inner wall of the mixer body 1, the first circle of spray holes are positioned on the same plane with spray holes of the EGR core 3, and the second circle of spray holes are positioned on the same plane with spray holes of the gas core 4. The spray holes of the EGR core 3 and the first circle of spray holes are communicated with the exhaust gas inlet 5, and the spray holes of the gas core 4 and the second circle of spray holes are communicated with the gas inlet 6.

As shown in fig. 1 and 2, the spoiler 2 includes a spoiler ring 21 and a spoiler 22 obliquely disposed between the spoiler ring 21 and the inner wall of the mixer body 1; the spoiler 22 divides the space between the spoiler ring 21 and the mixer body 1 into six uniform portions.

In the mixer body, the guide ring, the guide column, the ventilation column and the inner wall of the mixer body form a plurality of venturi structures, air enters the mixer body from the air inlet and is disturbed by the turbulence body, and respectively enters the venturi structures, and due to the effect of venturi effect, the air flow rate at the position of the spray hole is increased, low pressure is generated at the position, the adsorption effect is generated on the air in the spray hole, the kinetic energy of the sprayed air in the spray hole is increased, so that the air and the air are mixed more uniformly, and the fuel gas, the air and the waste gas passing through the mixer have high mixing uniformity.

As shown in fig. 4, the mixer body 1 is further provided with a through oxygen sensor mounting hole 7, and an intelligent oxygen sensor is mounted in the oxygen sensor mounting hole 7 and is located between the EGR core 3 and the gas core 4 and closer to the gas core 4. The intelligent oxygen sensor is used for detecting the oxygen concentration in the mixer body and carrying out closed-loop control on the waste gas, so that the discharged harmful substances can be effectively controlled within a required range, and the utilization rate of the waste gas discharged by the engine is improved. The mixer body 1 is also provided with an exhaust gas recirculation system mounting hole 8 for mounting an exhaust gas recirculation system.

As shown in fig. 5 and 7, the mixer body 1 is provided with a balance pipe mounting hole 9 and a pressure sensor mounting hole 10, the balance pipe mounting hole 9 is positioned above the pressure sensor mounting hole 10, a balance pipe can be connected in the balance pipe mounting hole 9, a pressure sensor is arranged in the pressure sensor mounting hole 10, and the balance pipe and the pressure sensor are both positioned between the EGR core 3 and the gas core 4. The balance pipe is used for controlling the boost pressure, the pressure sensor is used for detecting the pressure of the mixed gas after the exhaust gas and the air are mixed and is used as a calculation parameter of the software early exhaust gas quantity so as to control the exhaust gas quantity, and therefore the utilization rate of the exhaust gas discharged by the engine is improved.

In actual production, as shown in fig. 5, in order to facilitate processing, the mixer is formed by splicing all parts manufactured by a casting process, and the turbulence body is integrally formed and comprises a turbulence ring, a turbulence sheet and an turbulence outer ring, wherein the turbulence ring and the turbulence outer ring are concentric circular rings, the turbulence ring is positioned in the turbulence outer ring, one end of the turbulence sheet is connected with the outer wall of the turbulence ring, the other end of the turbulence sheet is connected with the inner wall of the turbulence outer ring, and the turbulence outer ring is fixed with the inlet end cover 11 in a riveting manner; the inlet end cap 11 is fixed with the mixer body 1 by screws. If the reason for processing is not considered, the outer ring of turbulence can be considered as a part of the inner wall of the mixer body, with the turbulence plate being directly connected to the inner wall of the mixer body.

An outlet end cover 12 is arranged at the air outlet of the mixer body 1, the outlet end cover 12 is fixed with the mixer body 1 through screws, and the inner diameter of the outlet end cover 12 is gradually reduced along the air flow direction. In the process that part of air flows along the inner wall of the mixer body, little air is mixed with fuel gas, if the part of air is discharged through the air outlet, the mixing uniformity is reduced, the part of air flowing along the inner wall of the mixer body is blocked when flowing to the outlet end cover, and the blocked air can flow back and be mixed secondarily under the action of the inner inclined surface of the outlet end cover, so that the mixing uniformity is further improved.

The mixing uniformity of the mixer for the gas engine is analyzed and calculated, the mixing condition of gas, air and waste gas in the mixer for the gas engine is estimated, three-dimensional drawing software such as SolidWorks, UG is used for analysis and calculation to generate a three-dimensional model, the three-dimensional model is converted into files in the format of equal or equal steps and is imported into ANSYS, a Workbench is used for dividing flow fields of the air and the gas, an ICEM CFD is used for generating grids, FLUENT is finally used for calculation, a turbulence model used by the calculation model is a k-epsilon two-equation turbulence model, and a wall surface function method is adopted at a near wall surface.

The calculation uses steady state calculations, where the air inlet, gas inlet, and exhaust inlet are all given constant mass flow boundaries, the outlet is set to a constant pressure boundary, where the air component is set to consist of 79% nitrogen and 21% oxygen, the gas component is set to consist of 100% methane, and the exhaust component is set to consist of 6.8% oxygen, 13% carbon dioxide, 4.6% water, and 75.6% nitrogen.

The analysis and calculation adopts the uniformity of the area weighted oxygen volume content distribution as an evaluation standard, if the air and the waste gas are completely and uniformly mixed, the value should be 1, namely, the uniformity b is closer to 1, which indicates that the more uniformly mixed gas and air, the uniformity b of the oxygen volume content distribution is as follows:

wherein a is the average value of the oxygen volume content:

a _i oxygen volume content for each point;

s _i for each point on the measurement surface.

Analysis and calculation were performed using the external characteristic data of the 7L engine as boundary conditions, as shown in table 1:

scheme for the production of a semiconductor device	Gas mass flow Kg/s	Air mass flow Kg/s	Exhaust gas mass flow Kg/s	Outlet pressure kPa
					1	0.01649	0.27868	0.09839	114.1
2	0.01194	0.20179	0.05448	120.4

TABLE 1

The cross section is set at the detection port of the intelligent oxygen sensor, and the mixing uniformity obtained by calculation is shown in table 2:

scheme for the production of a semiconductor device	Cross-sectional oxygen mixing uniformity	Oxygen mixing uniformity at air outlet	Gas mixing uniformity of gas outlet
				1	0.98409235	0.99512368	0.96204692
2	0.98591352	0.9948507	0.95276946

TABLE 2

According to the mixer for the gas engine, waste gas is sprayed into the mixer body from the waste gas inlet through the EGR core and the spray holes arranged on the inner wall of the mixer body, and is mixed with air after turbulent flow through the turbulent flow ring, so that waste gas-air mixed gas is formed. The oxygen mixing uniformity of the exhaust gas-air mixed gas on the section of the intelligent oxygen sensor mounting hole reaches more than 98%, so that the detection value of the oxygen concentration is more practical. The fuel gas is sprayed into the mixer body from the fuel gas inlet through the fuel gas core and the spray holes arranged on the inner wall of the mixer body, and is mixed with the mixed gas of the waste gas and the air to form the mixed gas of the waste gas, the air and the fuel gas. At the air outlet, the oxygen mixing uniformity reaches more than 99 percent, the gas mixing uniformity reaches more than 96 percent, and the method has good market application value.

Example two

As shown in fig. 8 and 9, the present embodiment provides another mixer for a gas engine, which differs from the mixer for a gas engine in the first embodiment only in that the gas core 4 is provided at the gas inlet of the mixer body 1, the spoiler 2 is provided at the gas outlet of the mixer body 1, and the EGR core 3 is provided between the gas core 4 and the spoiler 2. The EGR core 3 communicates with the exhaust gas intake 5, the gas core 4 communicates with the gas intake 6, and the positions of the exhaust gas intake 5 and the gas intake 6 are adaptively changed according to the positional adjustment of the EGR core 3 and the gas core 4.

Example III

As shown in fig. 10 and 11, the EGR mixer provided in this embodiment includes a mixer body 1, an EGR core 3 and a spoiler 2 are disposed in the mixer body 1 along the air flow direction, an exhaust gas inlet 5 is disposed on the mixer body 1, and the exhaust gas inlet 5 is communicated with the EGR core 3.

The EGR core 3 in this embodiment has the same structure as the fuel gas core in the first embodiment, and includes a guide ring, a guide post arranged in the guide ring, and a ventilation post arranged between the guide ring and the inner wall of the mixer body, and spray holes are formed on the guide post, the guide ring, and the ventilation post; the guide post intersects in the centre of a circle position of guide ring and separates the guide ring into four even parts, and the ventilation post separates the space between guide ring and the blender body into four even parts. The cross sections of the flow guide column, the flow guide ring and the ventilation column are all in a water drop shape which is changed from big to small along the air flow direction, the flow guide column, the flow guide ring and the ventilation column are all in hollow structures, the spray holes are uniformly formed in the two sides of the flow guide column, the flow guide ring and the ventilation column, the tangent line of the position point of the spray holes is parallel to the air flow direction, and all spray holes are arranged on the same plane. A circle of spray holes are annularly distributed on the inner wall of the mixer body 1, and the spray holes of the mixer body and the spray holes of the EGR core 3 are positioned on the same plane.

The exhaust gas is sprayed into the mixer body from the exhaust gas inlet through spray holes arranged on the EGR core and the inner wall of the mixer body, and is mixed with air after turbulent flow through the turbulent flow ring, so that exhaust gas-air mixed gas is formed.

Those of ordinary skill in the art will recognize that the embodiments described herein are for the purpose of aiding the reader in understanding the principles of the present invention and should be understood that the scope of the invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific modifications and combinations from the teachings of the present disclosure without departing from the spirit thereof, and such modifications and combinations remain within the scope of the present disclosure.

Claims

1. A mixer for a gas engine, characterized in that: the device comprises a through mixer body (1), wherein a disturbing fluid (2) is arranged at an air inlet of the mixer body (1), a gas core (4) is arranged at an air outlet of the mixer body (1), an EGR (exhaust gas recirculation) core (3) is arranged between the disturbing fluid (2) and the gas core (4), an exhaust gas air inlet (5) and a gas air inlet (6) are arranged on the mixer body (1), the EGR core (3) is communicated with the exhaust gas air inlet (5), and the gas core (4) is communicated with the gas air inlet (6);

the gas core (4) comprises a guide ring (41), a guide column (42) arranged in the guide ring (41) and a ventilation column (43) arranged between the guide ring (41) and the inner wall of the mixer body (1), wherein spray holes are formed in the guide column (42), the guide ring (41) and the ventilation column (43); the guide posts (42) are intersected at the center of the guide ring (41) and divide the guide ring (41) into four uniform parts, and the air-through posts (43) divide the space between the guide ring (41) and the mixer body (1) into four uniform parts;

two circles of spray holes are annularly distributed on the inner wall of the mixer body (1), the first circle of spray holes are positioned on the same plane with spray holes of the EGR core (3), and the second circle of spray holes are positioned on the same plane with spray holes of the gas core (4); the spray hole and the first circle of spray holes of the EGR core (3) are communicated with the exhaust gas inlet (5), and the spray hole and the second circle of spray holes of the gas core (4) are communicated with the gas inlet (6);

the cross sections of the flow guide column (42), the flow guide ring (41) and the ventilation column (43) are all in a water drop shape which is changed from big to small along the air flow direction, the flow guide column (42), the flow guide ring (41) and the ventilation column (43) are of hollow structures, spray holes are uniformly formed in two sides of the flow guide column (42), the flow guide ring (41) and the ventilation column (43), tangents of the positions of the spray holes are parallel to the air flow direction, and all spray holes are located on the same plane.

2. The mixer for a gas engine according to claim 1, wherein: the EGR core (3) and the fuel gas core (4) have the same structure.

3. The mixer for a gas engine according to claim 1, wherein: the vortex body (2) comprises a vortex ring (21) and a vortex sheet (22) obliquely arranged between the vortex ring (21) and the inner wall of the mixer body (1); the spoiler (22) divides the space between the spoiler ring (21) and the mixer body (1) into six uniform parts.

4. The mixer for a gas engine according to claim 1, wherein: an oxygen sensor mounting hole (7), a balance pipe mounting hole (9) and a pressure sensor mounting hole (10) are formed in the mixer body (1), an intelligent oxygen sensor is arranged in the oxygen sensor mounting hole (7), a balance pipe is arranged in the balance pipe mounting hole (9), a pressure sensor is arranged in the pressure sensor mounting hole (10), and the intelligent oxygen sensor, the balance pipe and the pressure sensor are all located between the EGR core (3) and the gas core (4).