FR2631384A1 - Outlet for exhaust for gas turbine - consists of perforated tube mounted coaxially in cylindrical housing - Google Patents

Abstract

The exhaust gas from an internal combustion engine or gas turbine, flows from the exhaust pipe (1) into a device (10) which directs the gases vertically upwards into the atmosphere. The device consists of a cylindrical outer housing (20) which supports a cylindrical diffuser . The diffuser consists of a tube with perforations over most of its surface apart from a zone over its upper surface which extends over an arc of angle (alpha) and over the length of the tube. The outer housing has a longitudinal slot (23) in its upper surface which forms the outlet for the gas USE - Gas turbine and internal combustion engines.

Description

Device for venting gases ejected from an exhaust tube.

 The present invention relates to a device for venting gases ejected from an exhaust tube, this exhaust tube possibly being, for example, the output tube of an engine test bench or the outlet tube of a gas turbine installation whose motor shaft is located on the suction side.

 We know, from patent application FR-85.15894, and in particular from its FIG. 4, such a venting device comprising a horizontal cylindrical box extending the exhaust tube and enveloping a diffuser basket pierced with orifices which let the gases escape perpendicular to its axis, the box being extended by an elbow rejecting the gases vertically, into the atmosphere. This elbow provides the elbow effect necessary to reduce the noise level. This essential elbow is an important mechanical part therefore of a high cost.

 The present invention aims to eliminate this bend and to achieve the bend effect by another means, simpler and therefore less expensive.

 This elbow effect is obtained by not practicing orifices on the upper part of the basket and by making a slit over the entire length of the box, opposite this non-pierced part of the basket so as not to let the gases exit directly into the 'atmosphere.

 The present invention relates to a device for venting gases ejected from an exhaust tube, comprising a horizontal box in the axis of the exhaust tube, a diffuser basket installed in the box coaxially with that -this, and pierced with holes regularly distributed over its length, characterized in that the basket has no holes on its upper part and in that the box has, on its upper generatrix and opposite the non-pierced part of the basket, a slit allowing the vertical outlet of the gases, the slit-of the box being extended by two vertical sides constituting a conduit.

 In order to improve the homogeneity of the profile of the gas velocities, the section of the orifices varies decreasingly and logarithmically as the distance from the outlet of the exhaust tube increases.

 A device according to the invention is described below, by way of example and with reference to the appended drawing.

 Figure 1 shows such a device, with partial cutaway.

 FIG. 2 is a section along II of FIG. 1.

 Figure 3 shows an alternative embodiment of this device, with partial cutaway.

 FIG. 4 is a section on IV of FIG. 3.

 Figure 5 shows another embodiment, applicable to the device and its variant.

 In Figures 1 and 2, the exhaust device 10 is connected to an exhaust tube 1 and fixed to the ground 2 by flanges 3. This device 10 consists of a box 20 and a diffuser basket 30 The box 20 is cylindrical and it has, on its upper part and over its entire length, a slot 21 extended by two lateral and vertical walls 22, these two walls constituting an exhaust duct 23 of rectangular section.

 The two walls are clearly visible in FIG. 2. The box is completely covered on its internal walls by an absorbent material 28. This material can also be covered by metal plates 29 pierced with orifices.

 The basket 30, placed inside the box, is concentric with it, and it extends the exhaust tube 1.

 This basket is pierced with orifices over its entire length and over almost its entire periphery, except on the part located opposite the slot 21, to force the gases to meet a face provided with an absorbent material 28, this being clearly visible. in Figure 2. In this case, the angle i of the non-drilled part is about a right angle.

 In order to make the gas velocity profile homogeneous, the cross-section of the orifices decreases as one moves away from the outlet of the tube 1. This decrease can follow a logarithmic law to further improve the homogeneity of the speed profile.

 The basket is closed by a curved bottom 32, and at this level, the layer of absorbent material is reinforced.

 In FIGS. 3 and 4 showing an alternative embodiment, the conduit 23 comprises, over its entire length, a central vertical partition 24.

 This partition 24 has, in its lower part, two wings 25 which are supported on the basket 30, at the level of the part not pierced with orifices.

 The conduit 23 also has transverse walls 26 clearly visible in Figure 3. The central partition 24 and the transverse walls 26 are made of absorbent panels covered or not by metal plates pierced diorifices ~.

 Of course, the conduit 23 may comprise only a central partition 24 or only transverse partitions 26.

 The presence of one or other of these partitions improves the acoustic performance.

 FIG. 5 shows an exemplary embodiment in which the box 20 is surmounted by a transformation piece 40 ensuring the connection of the box with a vertical and cylindrical chimney 50.

Claims (6)

CLAIMS: 1 / Device (10) for venting gases ejected from an exhaust tube (1), comprising a horizontal box (20) in the axis of the exhaust tube, a diffuser basket (30) installed in the box coaxial thereto, and pierced with orifices (31) regularly distributed over its length, characterized in that the basket (30) does not have orifices on its upper part and in that the box ( 20) comprises, on its upper generatrix and in front of the non-pierced part of the basket, a slot (21) allowing the vertical outlet of the gases, the slot of the box being extended by two vertical sides (22) constituting a conduit (23 ). 2 / Device characterized in that the section of the orifices varies decreasingly and logarithmically as one moves away from the outlet of the exhaust tube (1). 3 / Device according to claim 2, characterized in that the conduit (23) is equipped with a central vertical wall (24). 4 / Device according to one of claims 2 or 3, characterized in that the conduit (23) is equipped with transverse walls (26). 5 / Device according to one of the preceding claims characterized in that the box is covered with an absorbent material (28). 6 / Device according to one of the preceding claims, characterized in that the box is surmounted by a vertical cylindrical chimney (50), the connection between the duct (23) of the box (20) and the chimney (50) being provided by a transformation part (40).