JPH0259284B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exhaust turbine for a turbocharger.

[Conventional technology]

To increase the charging efficiency of turbo engines,
2. Description of the Related Art Turbochargers are known that utilize the energy of exhaust gas to rotate an exhaust turbine, drive a compressor coaxial with the exhaust turbine, and supply compressed air to the intake system of a turbo engine.

By the way, as shown in FIG. 3, in the conventional exhaust turbine for turbocharging, the casing 1 at the two exhaust gas outlet portions 12a and 12b communicating with the two exhaust gas flow paths 11a and 11b, respectively.
No shape correction is performed on the inner surface of the exhaust gas outlet 3, and the cross-sectional shape of the exhaust gas outlet portions 12a and 12b is a normal tapered nozzle shape. This allows the exhaust gas to flow through the exhaust gas outlet portions 12a, 12.
When passing through b, the flow velocity increases, and the turbine wheel 14 can be rotated as it reaches the effective width on the inlet side of the turbine blades of the turbine wheel 14.

[Problem to be solved by the invention]

In the conventional turbocharger exhaust turbine described above, no treatment is applied to the inner surface of the casing at the exhaust gas outlet, and the cross-sectional shape of the exhaust gas outlet is a normal tapered nozzle. However, the pressure energy of the exhaust gas cannot necessarily be used effectively, and therefore the flow velocity of the exhaust gas cannot be sufficiently increased, resulting in a problem that the turbine efficiency is low.

The present invention has been made in view of the problems of the above-mentioned conventional technologies, and provides a turbochart that sufficiently increases the flow velocity of exhaust gas and improves turbine efficiency by effectively utilizing the pressure energy of exhaust gas. The purpose of the present invention is to provide an exhaust turbine for a wind turbine.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a casing having an annular exhaust gas flow path, and a turbine impeller rotated by exhaust gas ejected from the exhaust gas flow path through an annular exhaust gas outlet. In the exhaust turbine for a turbocharger, a plurality of annular ceramic coatings are applied to the inner surface of the casing at the exhaust gas outflow section to provide a throat section at the exhaust gas outflow section, and the cross-sectional shape of the exhaust gas outflow section is shaped like a bench. It is characterized by being shaped like an ellipse.

[Effect]

In the present invention configured as described above, the exhaust gas introduced into the casing passes through the exhaust gas passage toward the exhaust gas outlet. The exhaust gas that has flowed into the exhaust gas outflow section is throttled at the throat, and after the static pressure has sufficiently decreased and the flow velocity has increased sufficiently, it is immediately jetted out from the outlet without recovering the static pressure, and the turbine blade wheel corresponds to That is, it is possible to convert a sufficient static pressure drop in the exhaust gas due to the throttle of the exhaust gas into kinetic energy (dynamic pressure), and to effectively utilize the pressure energy of the exhaust gas.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, the turbocharger exhaust turbine 20a of the present embodiment has an inner surface of a spiral casing 22 at exhaust gas outlet portions 25a and 25b communicating with two annular exhaust gas flow paths 23a and 23b, respectively. By applying a plurality of annular ceramic coatings 26a to 26d, exhaust gas outlet portions 25a and 25b have throat portions 27a and 27b.
are provided respectively, and exhaust gas outlet portions 25a, 2
5b has a ventilate cross-sectional shape. Then, the exhaust gas ejected through the exhaust gas outflow portions 25a and 25b flows through the plurality of turbine blades 24.
The turbine blade 24 of the turbine wheel 24 having a
This corresponds to the effective width W on the entrance side of a.

Next, the operation of this embodiment will be explained.

In FIGS. 1 and 2, exhaust gas from the turbo engine 31 enters the casing 22 of the turbocharger exhaust turbine 20a;
The exhaust gas flows through two exhaust gas flow paths 23a and 23b toward exhaust gas outlet portions 25a and 25b. Then, the flow velocity of this exhaust gas is sufficiently increased due to the Ventury effect at the exhaust gas outlet portions 25a and 25b, and the exhaust gas hits the turbine blade 24a. That is, the exhaust gas that has flowed into the exhaust gas outlet portions 25a and 25b is throttled at the throat portions 27a and 27b, and after the static pressure is sufficiently lowered and the flow velocity is sufficiently increased, the exhaust gas is immediately discharged from the outlet without recovering the static pressure. It is ejected from the turbine wheel 24 and hits the turbine wheel 24. That is, it is possible to convert a sufficient static pressure drop in the exhaust gas due to the throttle of the exhaust gas into kinetic energy (dynamic pressure), and to effectively utilize the pressure energy of the exhaust gas.

This makes it possible to rotate the turbine wheel 24 at a high speed, drive the compressor 20b coaxially with the turbine wheel 24, and supply a large amount of compressed air to the intake system of the turbo engine 31.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

By effectively utilizing the pressure energy of the exhaust gas to sufficiently increase the flow velocity of the exhaust gas, the output of the turbine increases, resulting in improved turbine efficiency. This makes it possible to further increase the charging efficiency of the turbo engine and reduce fuel consumption. Also, since it is coated with ceramic, it has excellent heat resistance.

[Brief explanation of drawings]

FIG. 1 is an axial sectional view of an embodiment of an exhaust turbine for turbocharging according to the present invention, FIG. 2 is a schematic diagram of an engine system equipped with the exhaust turbine of this embodiment, and FIG. 3 is a conventional exhaust turbine. FIG. 2 is an axial cross-sectional view of the turbine. 20a...exhaust turbine for turbocharger, 20b...compressor, 21...rotating shaft,
22...Casing, 23a, 23b...Exhaust gas flow path, 24...Turbine wheel, 24a...Turbine blade, 25a, 25b...Exhaust gas outlet, 2
6a to 26d... cyclic ceramic coating,
27a, 27b... Throat, 31... Turbo engine.

Claims (1)

[Claims] 1. A casing 22 having annular exhaust gas flow paths 23a, 23b, and the exhaust gas flow paths 23a, 2
3b, the exhaust gas turbine 20 includes a turbine impeller 24 rotated by exhaust gas ejected from the annular exhaust gas outlet 25a, 25b from the exhaust gas outlet 25a, 25b.
A plurality of annular ceramic coatings 26a to 26 are provided on the inner surface of the casing 22 in a and 25b.
d to provide the exhaust gas outlet portions 25a, 25b with throat portions 27a, 27b, and the exhaust gas outlet portion 2
An exhaust turbine for a turbocharger, characterized in that the cross-sectional shapes of 5a and 25b are ventilated.