JPH0557324U - Exhaust gas temperature reduction device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an exhaust gas temperature reduction device capable of uniformly mixing high-temperature exhaust gas and outside air with a short distance and a minimum pressure loss to reduce the temperature as a whole. . A fold-shaped outside air guide groove 3 is formed in the circumferential wall of the exhaust nozzle 2 from the outlet end downward to the center from the outer circumference, and the degree of the concave entry gradually decreases downward. It is formed at equal intervals.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an exhaust gas temperature reduction device having a function of reducing the temperature of high-temperature exhaust gas discharged from an exhaust pipe of a ship or a vehicle.

[0002]

[Prior Art]

 In particular, when a gas turbine engine is used, the exhaust gas becomes extremely hot (500 ° C or higher). Such exhaust gas is emitted from the chimney (exhaust pipe) in ships and the like, but when electronic devices such as radar are installed around the chimney, the electronic devices are thermally affected by the exhaust gas and normally operate. It may cause a malfunction or malfunction. Further, the hot exhaust gas also has a problem in that it emits a large amount of infrared rays.

Therefore, conventionally, a short pipe having a diameter slightly larger than that of the exhaust pipe is continuously provided at the outlet end of the exhaust pipe with a certain gap around the outlet pipe, and cooling air is supplied from the gap to the inner peripheral wall of the short pipe. There is proposed a device (No. Sho 63-19540) for preventing the temperature rise at the outlet of the exhaust pipe by cutting off the contact between the high-temperature exhaust gas and the inner peripheral wall of the short pipe by flowing it along the pipe.

[0004]

[Problems to be solved by the device]

 However, the device described in the above publication has room for improvement in the following points. That is, since the short pipe, which is the outlet from which the exhaust gas is discharged, is cooled by the cooling air, the temperature rise can be avoided, but the exhaust gas itself is hardly cooled. As a result, high-temperature exhaust gas is discharged, and the exhaust gas may have a bad thermal effect on the electronic device or emit a large amount of infrared rays.

The present invention has been made in view of the above points, and exhaust gas that can mix the high temperature gas and the outside air uniformly and uniformly over a short distance and with a minimum pressure loss, and can reduce the temperature as a whole. An object is to provide a temperature reduction device.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the exhaust gas temperature reducing device of the present invention comprises: a) a mixing pipe having a flare whose diameter gradually increases toward the downstream side at the downstream end, and an exhaust gas exhaust pipe outlet end. In the exhaust gas temperature reducing device extending from the vicinity to the upstream side, b) The peripheral wall of the outlet portion of the exhaust pipe enters a concave shape toward the center and the degree of the concave shape gradually decreases from the outlet end to the downstream side. Folded outside air guiding grooves are formed at intervals in the circumferential direction.

Further, as described in claim 2, it is preferable that c) the depth of depression and the groove length of each of the outside air guiding grooves are alternately deep and long and shallow and short.

Further, as described in claim 3, d) each of the outside air guiding grooves may be formed in a spiral shape in the same direction from the downstream side to the upstream side.

[0009]

[Action]

 According to the exhaust gas temperature reducing device of the present invention having the above-mentioned configuration, the high-temperature exhaust gas passes through the exhaust pipe at a relatively high speed and flows from the outlet of the exhaust pipe toward the upstream mixing pipe. This high-temperature exhaust gas flow causes a kind of suction force to guide the outside air along the outside air guide grooves around the outlet of the exhaust pipe, and together with the exhaust gas flowing out from the outlet of the exhaust pipe, the downstream side of the mixing pipe. A large amount of outside air is sucked into the mixing pipe through the gap between the flare of the exhaust pipe and the outlet of the exhaust pipe. In this way, the ambient air is sucked into the mixing pipe from the surroundings by the exhaust gas flow, so there is no need for equipment such as a fan or its drive.

In addition, each of the outside air guide grooves enters a concave shape from the outer periphery of the exhaust pipe toward the center, and the outside air is almost evenly distributed from the peripheral portion of the outlet of the exhaust pipe to the center portion with respect to the exhaust gas discharged from the exhaust pipe. While being mixed and passing through the mixing pipe, the exhaust gas and the outside air are mixed uniformly as a whole. Therefore, the temperature of exhaust gas discharged from the outlet of the mixing pipe is reduced substantially uniformly, and the mixing efficiency is good, so that the mixing distance is short. Furthermore, since the outlet of the exhaust pipe is gradually narrowed toward the outlet by the plurality of outside air guide grooves, the flow velocity of the exhaust gas gradually increases toward the outlet, enhancing the action of sucking outside air. When the outlet of the exhaust pipe is squeezed into a simple conical shape toward the upstream side, the temperature distribution of the exhaust gas discharged from the outlet of the mixing pipe becomes mountain-shaped and the temperature rises at the center, According to the device of the present invention, it becomes almost uniform as a whole.

Particularly, in the exhaust gas temperature lowering device according to the second aspect, the degree of entering the concave shape from the outer periphery of the exhaust pipe toward the center is alternately shallow and deep, and the length of the groove is also alternately short and long. Therefore, the exhaust gas exhausted from the exhaust pipe is evenly mixed with the outside air from the peripheral portion to the central portion of the outlet of the exhaust pipe, and while passing through the mixing pipe, the exhaust gas and the outside air are surely ensured throughout. Mix evenly.

According to the exhaust gas temperature reduction device of the third aspect, the outside air flows into the mixing pipe so as to be twisted in a spiral shape along each of the outside air guiding grooves and becomes a swirling flow in the mixing pipe. On the other hand, the outside air is mixed more efficiently.

[0013]

【Example】

 An embodiment of an exhaust gas temperature reduction device of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially omitted perspective view showing an exhaust gas temperature reduction device according to an embodiment of the present invention. As shown in the figure, the exhaust pipe 1 is composed of an exhaust pipe main body 4 and an exhaust nozzle 2, and a flange 2a is integrally provided around the lower end of the exhaust nozzle 2 and is provided around the upper end of the exhaust pipe main body 4. It is connected to the flange 4a with a plurality of bolts and nuts.

A fold-shaped outside air guide groove 3 is formed in the circumferential wall of the exhaust nozzle 2 from the outlet end downward to the center from the outer circumference, and the degree of the concave entry gradually decreases downward. It is formed at equal intervals. Further, the outside air guiding grooves 3 are alternately set to have a concave depth and a long depth 3a and a shallow short depth 3b.

Immediately above the exhaust nozzle 2, a mixing tube 5 having a diameter slightly larger than that of the nozzle 2 is arranged. At the lower end of the mixing tube 5, a flare 6 whose diameter is gradually increased downward is integrally attached.

2A is a view taken along the line AA of FIG. 1, and FIG. 2B is a sectional view taken along the line BB of FIG. 2A. As shown in these figures, in this embodiment, eight outside air guiding grooves 3 are formed at equal intervals in the circumferential direction, and a concave portion 3a having a deep degree of depression and a long groove length and a concave portion 3a are formed. The shallow groove 3b and the short groove 3b face each other and are alternately arranged. Although the dimensions and the like are not limited, when the diameter of the nozzle 2 is 386 mm and the length is 550 mm, the depth of penetration of the outside air guiding groove 3a toward the center is 160 mm, the groove length is 437 mm, and the inclination is α'is set to 25 °, the depth of entry of the outside air guiding groove 3b toward the center is 77 mm, the groove length is 217 mm, and the inclination α is set to 20 °. In this way, the width of each of the grooves 3a and 3b was set to 38 mm, and the opening cross section of the outlet end of the exhaust nozzle 2 was narrowed to 70% of the opening cross section of the portion where the outside air guide groove 3 was not provided.

In the exhaust pipe 1 equipped with the exhaust nozzle 2 described above, as shown in FIG. 3, exhaust gas a at 500 ° C. is exhausted through the exhaust nozzle 2 into the upper mixing pipe 5, and the outlet of the mixing pipe 5 is discharged. The mixing distance L of the exhaust gas discharged from was set to 2D (D: diameter of the exhaust pipe 1), and the temperature distribution of the exhaust gas at the same distance was measured. The flow rate of the exhaust gas a at this time was 300 m ³ / min, and the flow rate was 43 m / sec. As a result of the experiment, a uniform temperature distribution was obtained with a normal temperature of about 390 ° C and a maximum temperature of about 415 ° C. Further, when the exhaust gas a is discharged from the exhaust nozzle 2, the outside air b is guided along each outside air guide groove 3 around the exhaust nozzle 2, and a large amount of the outside air is discharged together with the exhaust gas a at the lower end of the mixing pipe 5. It was confirmed that it was sucked into the mixing tube 5 through the gap between the flare 6 and the outlet of the exhaust nozzle 2.

On the other hand, in order to compare with the exhaust nozzle 2 of the present invention, although not shown, a device was produced in which the outlet of the exhaust pipe was conically narrowed to an opening ratio of 70%, and an experiment was conducted under the same conditions as above. However, the temperature distribution of the exhaust gas discharged from the mixing pipe 5 had a mountain shape, and the maximum temperature in the central portion was 497 ° C., which showed almost no reduction in temperature.

FIG. 4 is a perspective view showing an exhaust nozzle according to another embodiment of the present invention. The exhaust nozzle 12 of the present embodiment is different from the exhaust nozzle 2 of the above embodiment in that each of the outside air guiding grooves 13 is formed by spirally inclining in the same direction from the lower end to the upper end. Therefore, the outside air around the nozzle 12 is guided along the spiral-shaped outside air guide groove 13 and flows into the mixing pipe 5 (FIG. 1), thereby forming a swirling flow inside the mixing pipe 5 and exhaust gas and efficiency. Well mixed.

By the way, in each of the above embodiments, the exhaust nozzle 2 or 12 is connected to the exhaust pipe body 4 (FIG. 1), but the exhaust nozzle 2 or 12 and the exhaust pipe body 4 are integrally formed. Good. In this case, the outlet of the exhaust pipe 1 corresponds to the exhaust nozzle 2 or 12. Further, although the exhaust pipe 1 and the mixing pipe 5 are arranged in the vertical direction, the present invention is not limited to this, and it goes without saying that the same can be achieved by arranging them in an oblique direction or a horizontal direction.

[0022]

[Effect of the device]

 As is clear from the above description, the exhaust gas temperature reduction device of the present invention has the following effects.

(1) Since the outside air is mixed evenly with the high temperature gas discharged from the outlet of the exhaust pipe, the temperature of the high temperature gas can be uniformly reduced and a large amount of outside air is introduced into the mixing pipe. Since it is mixed with the high temperature gas, the mixing distance required for uniform mixing can be short. In particular, the height of the chimney can be reduced in ships because the mixing distance becomes shorter. Further, in the conventional device described in the above publication, the vicinity of the inner peripheral wall of the short pipe connected to the upper end of the exhaust pipe is cooled by the outside air to suppress the temperature rise at the exhaust pipe outlet, whereas the conventional device of the present proposal. Since the device reduces the temperature of the hot gas itself, not only around the outlet of the exhaust pipe, but also the thermal effect of the gas after discharge is reduced, and the infrared radiation from the gas is also reduced.

Moreover, since the structure of the device is simple and the device can be made compact, it is easy to mount the device on a ship or a vehicle.

(2) In the exhaust gas temperature reduction device according to claim 2, the exhaust gas exhausted from the exhaust pipe is uniformly mixed with the outside air from the peripheral portion of the outlet of the exhaust pipe to the central portion thereof, and the inside of the mixing pipe is During passage, it ensures that the exhaust gas and the ambient air are mixed uniformly throughout.

(3) In the exhaust gas temperature reduction device according to the third aspect, the outside air is introduced into the mixing pipe so as to be twisted in a spiral shape along each of the outside air guiding grooves, and becomes a swirling flow in the mixing pipe. The outside air is mixed with the gas more efficiently.

[Brief description of drawings]

FIG. 1 is a partially omitted perspective view showing an exhaust gas temperature reduction device according to an embodiment of the present invention.

2 (a) is a view taken along the line AA of FIG. 1, and FIG. 2 (b) is a sectional view taken along the line BB of FIG. 2 (a).

FIG. 3 is a perspective view, partly omitted, schematically showing a usage state of an exhaust gas temperature reduction device.

FIG. 4 is a perspective view showing an exhaust nozzle according to another embodiment of the present invention.

[Explanation of symbols]

 1 Exhaust pipe 2/12 Exhaust nozzle 3.3a / 3b / 13 Outside air guide groove 4 Exhaust pipe body 5 Mixing pipe 6 Flare

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Nishikami 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries Ltd. Kobe factory (72) Yoshimasa Sakai Higashi-kawasaki, Chuo-ku, Kobe-shi, Hyogo 3-1, 1-1, Kawasaki Heavy Industries Ltd. Kobe factory

Claims (3)

[Scope of utility model registration request] 1. An exhaust gas temperature reduction device comprising a mixing pipe having a flare whose diameter is gradually increased toward the downstream side and which is provided at a downstream end of the flare and extends upstream from the vicinity of an exhaust gas exhaust pipe outlet end. In the peripheral wall of the outlet portion of the exhaust pipe, fold-shaped outside air guiding grooves are formed at intervals in the circumferential direction that enter the concave shape toward the center and gradually decrease the degree of the concave shape from the outlet end toward the downstream side. An exhaust gas temperature reduction device characterized in that 2. The exhaust gas temperature reduction device according to claim 1, wherein the depth of depression and the groove length of each of the outside air guiding grooves are alternately deep and long and shallow and short. 3. The exhaust gas temperature reduction device according to claim 1, wherein each of the outside air guide grooves is formed in a spiral shape in the same direction from the downstream side to the upstream side.