JPS6118161Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is applicable to turbomachines, especially turbines, compressors,
This invention relates to improved blowers and the like, that is, to turbomachines that have a simpler flow rate adjustment function than the conventional variable pitch stator vane system.

Conventionally, in order to adjust the flow characteristics of turbomachinery (the relationship between the rotational speed and the state quantity of the working gas and the flow rate), the stator blades at the front or rear of the impeller are generally made movable and mechanically static. A method is used to change the installation angle of the blades (so-called variable pitch vanes).

However, although this variable pitch stator vane system has an excellent ability to adjust flow characteristics, it is expensive to manufacture.

In the case of an exhaust turbine supercharger for an internal combustion engine, a turbine and a compressor, which do not have a normal flow adjustment function, are used in combination, but in general, when the engine is running at full power (at high rotation and high torque), the turbine and compressor are Since the flow characteristics of the engine are balanced, when the engine is operating at low speeds (at low rotation speeds), the flow characteristics mainly on the turbine side become relatively excessive, and the engine This results in insufficient air supply to the engine, causing poor combustion.

As a countermeasure to this problem, using a turbine with relatively small flow characteristics improves air supply conditions at low engine speeds, but conversely leads to excessive supply pressure and supercharger rotation speed when the engine is at full power, making safe operation difficult. becomes unable to hold.

On the other hand, even if the flow characteristics on the turbine side can be made variable by some means, unless the corresponding flow characteristics on the compressor side are made variable, problems such as reduced efficiency and surging will occur.

As mentioned above, in the case of an exhaust turbine supercharger for an internal combustion engine, adjusting the flow characteristics of the turbine and compressor according to the engine operating conditions leads to improved engine performance. It has been hoped that the appearance of

An object of the present invention is to provide a turbomachine that improves this point, that is, to develop a turbomachine that has a simpler flow rate adjustment function than the conventional variable pitch stator vane system.

That is, the present invention fixes one end of the leaf spring-like member on the upstream side with respect to the flow of the working fluid to a stationary wall on at least one side of the working fluid flow path on the upstream side or the downstream side close to the impeller, The turbomachine is characterized in that the downstream side of the leaf spring-like member is deformed in response to changes in the pressure of the flow of the working fluid itself, thereby automatically changing the cross-sectional area of the flow path.

The present invention will now be described in detail with reference to some preferred embodiments thereof, which are illustrated in the accompanying drawings.

The first embodiment shown in FIG. 1 is an application of the present invention to a centrifugal compressor, in which a casing 102 and a side plate 103 are connected to an impeller 101 which is driven and rotated by an external force.
Built-in. A vaneless differential user portion 104 is formed on the outer peripheral side of the impeller 101.
A plate spring-like member 105 is provided on one wall of this vaneless differential user section. Leaf spring-like member 1
In this embodiment, 05 has the shape of a ring-shaped disc spring, and is fixed to the side plate 103 on the inner diameter side. That is, the upstream side of the fluid flow is fixed.

The operation of this embodiment is as follows.

When the rotation speed of the impeller 101 and the flow path resistance after the compressor discharge port change, the flow rate and pressure conditions of the vaneless differential user section 104 change, and the leaf spring-like member 105 automatically changes in accordance with this. transform. That is, when the rotation speed of the impeller 101 is low, and therefore the flow rate and pressure conditions of the working fluid are low, the vane formed by the inner wall of the casing 102 and the leaf spring-like member 105 in the vaneless differential user section 104 The minimum passage width b of the non-defective user section is kept relatively small, forming a vaneless differential user section suitable for smaller flow rates.

Conversely, when the rotational speed of the impeller 101 is high, and therefore the flow rate and pressure conditions of the working fluid are high, the force of the working fluid that presses the leaf spring-like member 105 toward the side plate 103 causes the vaneless differential user section to The minimum passage width b is relatively large (enlarged to a maximum of b ₀ ) and the passage cross-sectional area is enlarged to form a vaneless diffuser section suitable for high flow rates.

The second embodiment shown in FIG. 2 is an example in which the present invention is applied to a radial turbine.

In this embodiment, as in the embodiment shown in FIG. be done. A leaf spring-like member 205 in the shape of a ring-shaped disc spring is fixed to one wall (in this case, the compartment side) of the vaneless nozzle portion 204.

In the second embodiment having such a configuration, the working fluid presses the leaf spring-like member 205 toward the side wall of the vehicle compartment of the vaneless nozzle portion depending on the pressure condition and flow rate of the working fluid, so the magnitude of this acting force is The leaf spring-like member 205 deforms accordingly, and the minimum passage width b of the vaneless nozzle portion changes.

Therefore, depending on the pressure conditions and flow rate of the working fluid,
By automatically changing the minimum passage width b of the vaneless nozzle portion, a radial turbine whose flow characteristics can be automatically adjusted can be obtained.

A more detailed explanation of the functions and effects of the first and second embodiments described above will be added below.

The main factor that determines the flow characteristics of a centrifugal compressor is the minimum passage area between the impeller inlet and the differential user section, and it is extremely difficult to change the dimensions of the impeller inlet section during operation. It is a good idea to make the minimum passage area of the part variable, and the simplest way to do this is to change the minimum passage width of that part.

On the other hand, in a radial turbine, the minimum passage width of the nozzle section corresponds to the minimum passage width of the diffuser section.

Fig. 1 shows a comparison of the flow characteristics of the centrifugal compressor and radial turbine of the first embodiment and the second embodiment of Fig. 2 with those of normal fixed dimensions, as shown in Figs. 3 and 4. Become.

That is, FIG. 3 is a diagram showing the flow rate G _c at the surging point with respect to the pressure ratio π _c of the compressor for a conventional fixed size centrifugal compressor and the first embodiment of the present invention. The shape is shown by a broken line, and the shape according to the present invention is shown by a solid line.

That is, it can be seen that the flow rate of the present invention is relatively small in the low pressure ratio region compared to the conventional type.

FIG. 4 is a diagram showing the flow rate G _T (approximately at the efficiency peak point) versus the pressure ratio π _T of the turbine for a conventional fixed size radial turbine and a second embodiment of the present invention; The conventional type is shown by a broken line, and the one according to the present invention is shown by a solid line. It can be seen that compared to the conventional type, the flow rate of the present invention is relatively small in the low pressure ratio region.

Now, by using an exhaust turbine supercharger that combines the centrifugal compressor of the first embodiment and the radial turbine of the second embodiment, the low-speed performance of the internal combustion engine can be greatly improved due to the above-mentioned effects. Good performance is also ensured.

In this way, inexpensive turbo engines with this type of flow adjustment function have stable operating ranges and
It has the advantage of expanding the high efficiency range.

The third embodiment shown in FIG. 5 shows an example in which the present invention is applied to a radial turbine having nozzle vanes, and FIG. 6 is a plan view showing only the leaf spring-like member in that case.

In this embodiment, the nozzle part has a side plate 203.
A leaf spring-like member 205' having a plurality of slits 205a through which the nozzle stator vanes 204' penetrate is provided with a plurality of nozzle stator vanes 204' fixed to the casing 202 on its outer diameter side. Fixed to the inner wall.

The functions and effects of this embodiment are the same as those of the second embodiment described above, so the details will be omitted.

Figure 7 shows a fourth example in which the present invention is applied to an axial flow turbine.
This is an example. In this embodiment, a plurality of nozzle vanes 304 are arranged upstream of the impeller 301. A plate spring-like member 305 having a slit through which the nozzle stator vane 304 passes is fixed to the nozzle stator vane inner ring 304' on the upstream side thereof.
The leaf spring-like member 305 may be provided with an appropriate slit as in the third embodiment or divided into multiple pieces due to problems in assembling it with the nozzle stator vane and problems in selecting the rigidity (spring characteristics) of the leaf spring itself. I do things like that.

The functions and effects of this embodiment are all the same as those of the third embodiment.

In the above, the present invention has been explained with reference to an example in which a leaf spring-like member is installed only on one side of the fluid passage. Twisting of the side fluid passages can also be prevented.

Even when the leaf spring-like member is installed only on one side of the fluid passage, it is preferable that the leaf spring-like member is appropriately divided in the circumferential direction so that adjacent portions overlap slightly.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts of the first embodiment of the present invention in which the present invention is applied to a centrifugal compressor, and Fig. 2 is a main part of the second embodiment of the invention in which the invention is applied to a radial turbine. Figure 3 is a graph comparing the characteristics of the centrifugal compressor shown in Figure 1 with that of a conventional fixed size compressor. Figure 4 is a graph showing the characteristics of the radial turbine shown in Figure 2 with a conventional fixed size. FIG. 5 is a cross-sectional view showing a third embodiment of a radial turbine having nozzle vanes, and FIG. 6 is a leaf spring-like member of the radial turbine shown in FIG. 5. FIG. 7 is a sectional view showing a fourth embodiment of an axial flow turbine. 101... impeller, 102... vehicle compartment, 103...
...Side plate, 104...Vaneless differential user part,
105... Leaf spring-like member, 201... Impeller, 2
02... Vehicle interior, 203... Side plate, 204... Vaneless nozzle portion, 205... Leaf spring-like member, 20
4'... Nozzle stationary blade, 205'... Leaf spring-like member,
205a...slit, 301...impeller, 30
2... Gas inlet casing, 303... Impeller outer cylinder, 304... Nozzle stationary blade, 304'... Nozzle stationary blade inner ring, 305... Leaf spring-like member.

Claims (1)

[Scope of utility model registration request] One end of a leaf spring-like member on the upstream side with respect to the flow of the working fluid is fixed to a stationary wall on at least one side of the working fluid flow path on the upstream side or the downstream side close to the impeller, and the flow of the working fluid is fixed to a stationary wall. A turbomachine characterized in that the downstream side of the leaf spring-like member is deformed in response to changes in the pressure of the turbomachine, thereby automatically changing the cross-sectional area of the flow passage.