RU195337U1 - TURBINE ASSEMBLY OF A DEVICE FOR REMOVING KINETIC ENERGY OF A FLUID - Google Patents

Abstract

The invention relates to mechanical engineering, in particular to turbine engineering, and can be used to improve energy efficiency of the operation of bladeless turbine units. The problem solved by the utility model is the creation of a turbine unit device with enhanced energy efficiency characteristics. The turbine assembly of the device shown in FIG. 1, comprises a housing 1, with an inlet 2, in which a first group of discs 3 is attached, attached to a first hollow shaft with a hub 4, and a second group of discs 5, attached to a second shaft with a hub 6. The first shaft 4 is installed in the housing 1 on thrust bearings 7, and the second shaft 6 is mounted in the hollow shaft 4 on thrust bearings 8. The housing 1 is closed by a cover 9 with the release 10. The groups of disks 3 and 5 consist of disks 11 (Fig. 2) of different sizes. Concentric flanges 12 and blades 13 are located on the end surfaces of the disks. The size of the central outlet 14 of the disk, belonging to the first group of disks 3, is made with a diameter larger than the outer diameter of the disks belonging to the second group of disks 5, allowing them to enter it with a minimum clearance .5 ill.

Description

The utility model relates to mechanical engineering, in particular to turbine engineering, and can be used to increase the energy efficiency of operation of bladeless turbine units.

Known two-stage turbine according to the application of the Russian Federation No. 4903044/06, from 16.01.91 class. F01D 1/36, published on 05/15/1993 in bull. No. 18, containing axial and radial in the form of a friction turbine, a stage, in which the friction turbine is located behind the axial stage and consists of a group of thin disks, the last of which is made larger than the disks located in front of it, of a disk shape with a plate shape bent towards the exit from the axial stage with the edges.

The disadvantage of such a turbine is the inconsistency of the operating modes of its two heterogeneous steps, axial and radial, located on the same shaft. It is such an inconsistency of the regimes that inevitably leads to the loss of kinetic energy of the flow of the working fluid (fluid) at both stages, which reduces the overall energy efficiency of the turbine. With this turbine design, a coordinated operation of two stages is possible provided that the torques created by them on a common shaft are equal. The specialist understands that such a condition can be provided only for a very narrow area of operating modes.

In addition, the turbine design involves a housing consisting of two different compartments, which complicates its manufacture, as well as the assembly of the device as a whole.

A device is known by application No. 201700041, dated 06/19/2015 class., F01D 1/36 of the authors: Petrovich Vladimir M. (US) and Estiagi Amirhossein (US), published on July 24, 2018 in bull. No. 21, taken as a prototype, comprising: a housing with a hub located therein, connected to the turbine shaft and with a first group of disks attached to each other with an axial clearance, the end surface of the disks being selected depending on the fluid used and the corresponding Reynolds number this medium, and the diameter of the central outlet of the disks is chosen so as to optimize the length of the spiral path of the fluid in the interdisk space; at least one inlet, such as a Laval nozzle, which directs fluid from an external source (gas or liquid flow generator) into the turbine housing and into the interdisk space of the first group of disks for driving them into rotational motion; and at least one outlet that returns fluid from the turbine body to the external environment or to another apparatus using its residual energy or regenerating it for subsequent use in a closed cycle.

The disadvantage of the latter device is the low energy efficiency associated with power losses during extraction of the kinetic energy of the fluid in its turbine assembly, as well as the complexity of the system consisting of at least one group of turbines with such turbine assemblies. This disadvantage is explained by the fact that the residual vortex fluid flow is always present in the outlet central opening of the disk group, the angular velocity of rotation of which is determined by the rotational speed of the rotor of the turbine assembly consisting of the disk group. Although the energy efficiency of such turbine assemblies can be increased by cascading and parallel combining, as indicated in the prototype, however, it remains dependent on the total power of the input fluid stream and the changing total load. This circumstance is due to the fact that each such turbine unit, for a given input stream of the current medium, will have one optimal load, ensuring its maximum efficiency. In this case, a change in the load on any turbine unit or the total specific kinetic power of the input fluid stream will inevitably require a redistribution of loads between them to provide a new optimum, which in turn will require a complex common system for monitoring and controlling all turbine units.

The problem solved by the utility model is the creation of a turbine unit device with enhanced energy efficiency characteristics.

The technical result achieved by using the utility model is:

- increasing the specific power of energy conversion of the fluid by increasing the efficiency of the turbine unit;

- reduction of power losses due to the elimination of additional stages of conversion when matching variable output loads with a turbine unit operating at a variable specific power of the kinetic energy of the input fluid stream;

- simplification of the design of a system consisting of at least one group of turbines connected in parallel or in series (cascade) by reducing their number with equal indicators of overall energy efficiency.

The specified technical result is achieved by the fact that the turbine assembly of the device for extracting kinetic energy of the fluid comprising: a housing with a hub located therein, connected to the hollow shaft of the turbine and with a first group of disks attached to each other with an axial clearance, the end surface of the disks being selected depending on the fluid used and the corresponding Reynolds number of this medium, and the diameter of the central outlet of the disks is chosen so that it optimizes the length of the spiral path I interdisk fluid in the space; at least one inlet, such as a Laval nozzle, directing fluid from an external source (gas or liquid flow generator) into the turbine housing and into the interdisk space of the first group of disks for driving them into rotational motion; and at least one outlet that returns a moving fluid from the turbine housing to an external medium or to another apparatus using its residual energy or regenerating it for subsequent use in a closed cycle, according to a utility model, the turbine assembly further includes a second group of disks to convert the residual kinetic energy of the fluid exiting through the central outlet of the first group of disks in the form of a second hub with a second group of disks attached to it, to each of which has an external diameter less than the diameter of the central outlet of the first group of disks, arranged in its space coaxially with the hub shaft of the first group of disks, with a minimum radial clearance relative to the first group of disks, providing their mechanically unconnected rotation depending on the properties of the fluid; moreover, on the peripheral part of the adjacent end surfaces of the disks there are collars made in closed concentric circles with a radial step equal to twice the sum of the thickness of the collar and the difference in axial clearance between the disks and the height of the collars, the height of which is less than the interdisk axial distance, moreover, collars located on the opposite side the jointed end surface of an adjacent disc is radially offset by half a step; in addition, on one end surface of adjacent disks adjacent to their outlet central hole are blades with a height equal to the interdisk axial clearance, so that they form output channels in the interdisk space of these disks with equal circumferential pitch, in which the fluid flow reverses the direction of the tangential component of its velocity.

The technical solution proposed by the utility model provides a greater total output power on the device shafts, compared to a turbine assembly containing only one group of disks, with similar mass-dimensional parameters of their design and the same characteristics of the input fluid flows. This effect stems from the fact that the design of the turbine assembly consisting of two groups of disks not only uses the additional extraction of kinetic energy of the fluid stream remaining after passing through the first group of disks, but also enhances the interaction of the fluid flow with the surface of the disks, as on the peripheral part their end surfaces, where the maximum transfer of kinetic energy of the fluid to the rotating disks takes place, and on the other part adjacent to their central output from versts.

This is confirmed by the results of both theoretical modeling and practical tests. It has been practically established that an increase in the surface of the disk due to a decrease in the diameter of its outlet opening by less than half the outer diameter does not give a significant increase in efficiency. A further increase in the efficiency of the turbine assembly, while maintaining its mass-dimensional parameters, is possible by further enhancing the interaction of the fluid on the peripheral portion of the end surface of the disk and the rest of the disk adjacent to the outlet, as well as by additional conversion of the residual kinetic energy of the fluid flow in space outlet openings of the first group of discs.

Strengthening the interaction of the fluid with the end surface of the disk groups due to viscous friction is provided by the introduction of concentric collars located on the peripheral part of the disks on their end surfaces, which maximize the area of interaction of the fluid flow in this section of the flow path and prevent its displacement to the central outlet . The blades, located on another part of the end surface adjacent to the outlet of the disks, form channels in which the tangential velocity of the fluid flow in its final section of the trajectory reverses its direction, thereby creating additional reactive interaction of the fluid flow with the disk. Thus, the maximum interaction of the fluid flow with the surface of the disks due to the viscous friction forces at the peripheral section with the largest radius is ensured, creating a maximum torque on the shaft, additionally enhanced by the reactive component of the fluid flow resulting from the reactive component of the flow, when it is significantly reduced , the tangential speed of movement relative to the surface of the disk changes its direction in the opposite in the channels formed by the blades.

Similarly, there is an additional conversion of the residual energy of the fluid stream, which is provided by the second group of disks placed in the space of the outlet openings of the first group of disks. Each disk group has its own output shaft of rotation, which gives the torque to the load.

As practical tests have shown, due to the additional introduction of disks with concentric flanges and blades into the design of the turbine assembly, as well as the second group of disks, it allows increasing its efficiency by 7-9%.

When the device operates with one group of disks for a variable load, there is a discrepancy in the specific power of the kinetic energy of the fluid flow entering its input with the moment of load on its shaft, which leads to a loss of power on it. The claimed technical solution allows to reduce such power losses and maintain the overall efficiency of the device, by optimally redistributing the load between the two shafts of the device.

Practical tests showed that the design of the turbine assembly proposed by the utility model allows it to maintain its overall efficiency when changing the characteristics of the input fluid flow and load on one of the shafts within 20% of the nominal values.

Simplification of the device system consisting of at least one group of turbines can be achieved while maintaining a high level of overall efficiency of the device in a given range of characteristics of the input fluid flow and output load, exceeding the capabilities of one turbine unit. This problem can be solved by a smaller number of the same type of turbine units, consisting of two groups of disks, rather than from one group, since in the second case, to optimally configure the system for variable characteristics of the input fluid flow and load, a larger number of turbine units with different parameters will be required. In any case, to ensure equal energy efficiency when covering the operating range of one turbine consisting of two groups of disks, more than one turbine consisting of one group of disks will be required.

The utility model is illustrated by drawings. In FIG. 1 shows a General view of the device of the turbine assembly. In FIG. 2 shows the end surface of the disk with concentric flanges and blades located on it. In FIG. Figure 3 shows a fragment of one end surface of disks with flanges and blades and arrows located on it, showing the direction of fluid flow relative to these elements. FIG. 4 shows the relative position of the beads and vanes in the interdisk radial clearance between the surfaces of adjacent discs. FIG. 5 is a comparative graph of the dependence of the tangential component of the fluid flow rate in the inter-disk space for the execution of the turbine unit according to the claimed technical solution and prototype.

The turbine assembly of the device shown in FIG. 1 comprises a housing 1, with an inlet 2, in which a first group of discs 3 is attached, attached to a first hollow shaft with a hub 4, and a second group of discs 5, attached to a second shaft with a hub 6. The first shaft 4 is mounted in a housing 1 on thrust bearings 7, and the second shaft 6 is mounted in the hollow shaft 4 on the thrust bearings 8. The housing 1 is closed by a cover 9 with an outlet 10. The groups of disks 3 and 5 consist of disks 11 (Fig. 2) of different sizes. Concentric flanges 12 and blades 13 are located on the end surfaces of the disks. The size of the central outlet 14 of the disk relating to the first group of disks 3 is made larger in diameter than the outer diameter of the disks belonging to the second group of disks 5, allowing them to enter it with a minimum gap. On an enlarged fragment of the end surface of the disk 11 (Fig. 3), the arrows show the direction of fluid flow, which moves between concentric boutiques 12 mainly along circular paths, gradually shifting radially to the central part of the disk, and then the channels formed by the blades 13 pass and enters the Central outlet 14. With a radial displacement of the fluid flow on the peripheral portion of the surface of the disk, where the concentric flanges 12 are located, it passes through the gaps, formed by flanges and the surface of an adjacent disc along a winding path, as shown in FIG. 4, and in the final section, passing the section of the end surface of the disk adjacent to the central outlet of the disk on which the blades 13 are located, changes its direction of motion in the opposite direction, as shown by the arrow in FIG. 3.

The graph (Fig. 5) shows:

- curve A is the dependence of the fluid flow rate for the claimed technical solution;

- curve B is the dependence of the fluid flow rate for the prototype;

- straight line B is a linear dependence of the peripheral speed of the points on the surface of the disk

- R _in - the radius of the Central outlet;

- R _n - the outer radius of the disk;

- ν _about - the flow rate of the fluid when it enters the interdisk space.

The device operates as follows. The input fluid stream enters the turbine assembly through an inlet 2 of the type of a Laval nozzle directing the fluid from an external source (gas or liquid flow generator) into the turbine casing and into the interdisk space of the first group of disks for their rotational movement.

Next, the fluid flow moves in the interdisk space of the first group of disks 3, passing it to the output center hole of this group, in which the second group of disks 5 is placed. Then, this flow passes similarly to the second group of disks 5 and exits through its central outlet, passing the outlet 10 and further into the external environment or enters another device that uses its residual energy. When the fluid flow moves in the interdisk space, it interacts in the surface of the disks by means of the viscous friction forces of the surface layer, transferring part of its kinetic energy to the disks, which create torque on their shaft, with which their hub is connected. Theoretical modeling and calculations show that the relative fraction of the kinetic energy density of the fluid flow transmitted to the surface in this case is largely determined by the ratio of the flow rates and the surface of the disks. This transmission coefficient with some assumption is determined by the expression

Kр = N _W / P _n ~ [4⋅k _b ⋅ (1-k _t ) ² ] / [d⋅ρ⋅ν _tp ]

k _t = ν _od / ν _tp

Where

N _W - specific energy density transmitted by viscous friction forces at the point of interaction with the fluid flow;

P _n - kinetic energy density of the fluid flow at the point of interaction with the surface;

k _b is the coefficient of interaction of the fluid with the surface of the disks;

ρ is the density of the fluid;

d is the distance between the surfaces of adjacent discs;

k _t = ν _or / ν _tr ;

ν _tr is the average value of the tangential component of the fluid flow rate at the level of a circle of radius r;

ν _{or is the} circumferential velocity of the surface of the disk on a line of radius r;

k _t is the coefficient of the ratio of the tangential velocities of the fluid flow and the interaction surface point.

From the curves (Fig. 5) of the dependences of the fluid flow rates and points on the surface of the disk, it follows that the value of the last coefficient k _{t is} less than unity, since the relative tangential velocity of the fluid flow is always greater than the peripheral speed of the surface point of the rotating disk. Only for the points adjacent to the outlet central hole of the disk, the value of this coefficient can approach unity, since as the fluid flow moves to this hole, the tangential component of its velocity can decrease to the value of the peripheral velocity of the disk surface points close to the central exit hole. From the above relation and the graph in FIG. 5, it follows that most of the kinetic energy of the fluid stream is transferred to the disks in the peripheral portion adjacent to the outer diameter R _n . However, when the fluid stream enters the central outlet of the disk, its tangential velocity component is not zero, and therefore this output stream also has residual kinetic energy not transmitted to the disks. This circumstance is limited by the coefficient of conversion of the kinetic energy of the fluid flow into the rotation energy of turbines operating on the principle of viscous friction in the boundary layer.

The objective of the utility model to be solved is to raise the level of this restriction by simultaneously changing the type of characteristic of the dependence of the peripheral flow rate of the fluid on the radius (the profile of the circumferential speed along the radius) and additional conversion of the residual kinetic energy of the fluid flow entering the central outlet of the disk. The first is achieved by introducing concentric flanges 12 on the peripheral part of the end surfaces of the disks that impede the radial displacement of the flow and by introducing blades 13 adjacent to the outlet central opening 14, changing the direction of the flow velocity. Concentric flanges slow down the decrease in the characteristic in the area adjacent to the outer diameter of the disk, and the blades adjacent to the central outlet, on the contrary, accelerate it in the final section of the flow path. Comparison of the dependence of the fluid flow rates shown in FIG. 5 shows that the value of K _p will be greater in the initial section of the fluid flow path for disks with flanges (curve A), and the value of the flow velocity at the outlet, on the contrary, will be greater for disks without flanges (curve B). The value of this speed for rims with flanges, as curve A shows, can even be lower than the peripheral speed of the points of the disk surface (line B), which significantly reduces the residual, not converted, kinetic energy of the output stream. In this case, it is not so much the braking of the disks due to viscous friction forces, since the thickness of the boundary layer in this section is greater than the height of the concentric flanges 12, and the acceleration in the direction of their main rotation is due to the reactive force arising from such a change in the fluid flow rate. Thus, by introducing collars and blades on the end surfaces of the disks, a more complete conversion of the kinetic energy of the fluid input stream is ensured with the same other design parameters relating to disks without these elements and a decrease in its residual fraction entering the outlet central hole, which then additionally converted in a similar way to the second group of disks, increasing the overall efficiency of the turbine unit.

The introduction of the second group of disks into the turbine assembly makes it possible to easily differentiate the total load between them, adapting it optimally to the changing input fluid stream without additional conversion steps and expand the range of parameters at which the efficiency remains maximum. For a conventional turbine unit, without the use of additional stages of load balancing with the shaft of the turbine unit, at which additional energy conversion and associated losses usually occur, this is possible only with a single ratio of the load moment, the angular speed of rotation of the shaft and the specific power of the kinetic energy of the input stream . In the case of two groups of disks, the change in the load moment on one of the shafts can be compensated by the load of the second shaft while maintaining the maximum overall efficiency.

The technical solution and the design of the turbine unit using two groups of disks with shoulders and blades were checked by the authors when creating an experimental sample of the MTU-2.5 microturbine unit. The results of experimental tests of the MTU-2.5 microturbine unit confirming the technical result described in this utility model are presented in the Scientific and Technical Report on R&D: “Development of an Autonomous Microturbine Unit with a Power of 2.5 kW”, performed by a group of authors of this utility model. (UDC 620.9: 662.92; 658.264. State reg. No. AAAA-A18-118092190104-0).

Claims (1)

A turbine assembly of a device for extracting kinetic energy of a fluid, comprising: a housing with a hub located therein, connected to a hollow shaft of a turbine and with a first group of disks attached to each other with an axial clearance, the end surface of the disks having a surface, depending on the fluid used the medium and the corresponding Reynolds number of the fluid, at least one inlet, such as a Laval nozzle, directing the fluid from an external source into the turbine housing and into the interdisk space of the first disco group to drive them into a rotary motion; and at least one outlet, which returns the moving fluid from the turbine body to the external environment or to another apparatus, using its residual energy or regenerating it for subsequent use in a closed cycle, characterized in that for converting the residual kinetic energy of the fluid, exiting through the central outlet of the first group of disks, the turbine assembly additionally includes a second hub, with a second group of disks attached to it, located in the space one opening of the first group of disks coaxially with the shaft of the first group drives the hub with a minimum radial clearance relative to the first disk group, providing mechanically unconnected rotation thereof, depending on fluid properties; moreover, on the peripheral part of the adjacent end surfaces of the disks are placed collars made in closed concentric circles with a radial step equal to twice the sum of the thickness of the collar and the difference in axial clearance between the disks and the height of the collars, the height of which is less than the interdisk axial distance, with collars located on the opposite side of the jointed the end surface of an adjacent disk, radially offset by half a step; in addition, on one end surface of adjacent disks adjacent to their outlet central hole, there are blades with a height equal to the interdisk axial clearance, so that they form output channels in the interdisk space of these disks with an equal circle pitch in which the flow of fluid medium changes the direction of the tangential component of its velocity to the opposite.

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