RU2457336C1 - Higher-efficiency turbine blading (versions) - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: methods of designing axial or radial turbine blading whereby turbine cascade blade channel is divided into two sections. Channel meridional outline height is varied or not on entire section of bend in blade channel or its part. Second section of acceleration with additional bend or without it comprises skew edge of blade channel wherein said height is decreased toward channel outlet to verge coupled with mouth cross-section. Behind said verge, height is varied to increase open flow area. Narrow area of every blade channel is formed. At second acceleration section, arranged are multiple possible locations of mouth are including that whereat mouth area center is located on turbine cascade front outlet cross-section. Ring ledges are arranged behind outlet area, on periphery, or nearby barrel, or on periphery and barrel at a time.

EFFECT: higher efficiency, lower hydraulic losses.

8 cl, 14 dwg

Description

The invention is used in the design and construction of gas, steam and other turbines of blade machines of increased efficiency.

Existing gas turbines have reached a certain limit level of efficiency. A further increase in their efficiency is possible with a change in the design of the lattice itself.

To substantiate the proposed method for changing the design of the crown of the turbine (VT) can be as follows.

We apply the momentum theorem in a blade machine, use the Euler equation relating the power of the turbine stage N (or the specific work of the turbine L _T ) and the speed of the working fluid at the exit of the nozzle and working gratings

N = G (c _1u · u ₁ -c _2u · u ₂ ), L _T = N / G = (c _1u · u ₁ -c _2u · u ₂ ), see [1]

where G is the flow rate of the working fluid through the turbine;

c _1u is the projection of the output absolute speed from ₁ working fluid from the nozzle lattice to the direction of the front of the lattice, that is, to the peripheral velocity vector u ₁ at the entrance to the impeller;

c _2u is the projection of the output absolute velocity c _{2 of the} working fluid from the working grating on the direction of the front of the grating, that is, on the vector of peripheral speed u ₂ at the exit of the impeller.

и при той же скорости c₁ на выходе из венца повышает приведенную скорость λ_вых=с₁/а_кр>λ^*). Снижение температуры газа перед турбиной при обеспечении одной и той же мощности турбины приводит к снижению расхода топлива и тем самым увеличивает КПД двигателя.To ensure the operation of L _T at a flow rate G, it is necessary to obtain the peripheral velocity components c _1u , c _2u at any temperature and pressure of the gas flow in the turbine, as well as at outlet angles α ₁ and β ₂ from the nozzle and working gratings, i.e., obtain the necessary speeds c ₁ and c ₂ . The flow rate G in the turbine blade rim is determined by the narrowest point of the crown interscapular canal - throat a _g , located at the outlet edge of the blade profile and the beginning of the oblique cut, see (1) of FIG. 1, for gas flow in the turbine crown interscapular channel. The gas flow moving in the interscapular canal from the throat to the outlet cross section, expanding from the throat a _g to a ₁ ≥ a _g + r + r ₂ is the flow width in the outlet cross section of the crown (here: r is the radius of the outlet edge; r ₂ is the radius of the circle inscribed in the profile at the place of touching the throat of the back of the scapula), loses speed. In addition, the flow rate drops even more due to the expansion of the flow part in height in the meridional section and the deflection angle in the oblique section. In existing turbine designs, the height of the turbine crown increases in the meridional section from the entrance to the exit, in rare cases it remains constant and never decreases towards the exit from the crown, which is associated with a decrease in the density of the working fluid along the turbine path, see [1]. When the first critical pressure drop is reached in the throat of the grate at a gas flow rate of λ _g = 1 and G _g1 through the grate, there is some limit value λ ^* <λ _g ≤1 in the outlet cross section of the grate. In the constructions of modern turbines, starting from the value of λ ^* , it is impossible to obtain a subsonic gas flow in the outlet cross section of the lattice λ _o = λ ₁ in the range λ ^* <λ _oo ≤1. Only averaged flow consisting of supersonic and subsonic components has such a speed. Estimates show that increasing the reduced speed λ _o in the outlet cross section above the limiting λ ^* (λ _o > λ ^* ) can give a significant economic effect by lowering the gas temperature in front of the turbine (lowering the gas temperature T ^* _g in front of the turbine reduces the critical speed of sound

and at the same speed c ₁ at the exit from the crown increases the reduced speed λ _o = = ₁ / a _cr > λ ^* ). Reducing the temperature of the gas in front of the turbine while providing the same turbine power leads to lower fuel consumption and thereby increases engine efficiency.

Based on the foregoing, the task arises of eliminating the loss of speed in an oblique section and further reducing the losses associated with the rotation of the flow in the turbine grill.

The solution to the problem of eliminating the loss of speed after the throat in the output section of the VT turbine blade rim can be a method of constructing a high-efficiency turbine rim design (VTE) with the following measures:

- in contrast to existing VT turbine crowns, in which the blade height in the meridional section increases from entrance to exit or is constant, in the HTPE turbine crowns the interscapular channel of the turbine lattice is divided into two sections: the first part of the rotation of the working fluid flow, where the height of the meridional contours of the channel is changed in the entire first section (that is, the height is either increased or decreased, but the height of the flow part of the channel of the HTPE crown is greater than the height of the channel of the VT crown in the corresponding place of the channel) or leave the height constant either on the entire first section or on its part, while changing the height on the remaining parts or parts of the first section, where the flow velocity around the blade profile is reduced when the flow is rotated in comparison with a conventional VT rim, and create a second flow acceleration section with an additional rotation or without it, the interscapular canal, with a decrease in the height of the meridional contours of the lattice, the area of the passage section of the interscapular canal to a certain boundary associated with the throat section or the surface in swirling blades (in some cases it can be a conditional throat section, which is explained below), after which the height of the channel is changed so as to provide an increase in the area of the passage section, while the height can decrease, but with a different rate of change in height, be constant or increase, and behind the front output section the crown is installed on top of the periphery and below the annular protrusions - visors at the bushing of the flow part;

- form the throat, narrowest, cross section of the interscapular channel of the HTPE turbine lattice (at the VT lattice the throat section is at the beginning of the oblique cut) in the second section of the acceleration of the lattice, where there are many possible locations of the throat section, including a subset of the region near the front output section lattice, see (4) of Fig. 3, including, including the location of the throat section, when the conditional center or center of the conditional throat section, see (14) of Fig. 3, is located on the front surface of the outlet cross section of the turbine rim (the conditional throat section does not coincide, but only intersects with the front output section, see below for the definition of the conditional throat section and center), that is, in the second section of the flow acceleration, the rim has many possible locations for the throat section of the interscapular canal, depending from the constructive implementation of the crown, see figure 2, 3, 4.

Figure 1 ... 8 shows the crowns VT and VTPE with elements of the geometry of the crowns.

Figure 1 - gas flow in the interscapular channel of the crown of the turbine VT.

Figure 2 - comparison of the meridional contours of the crowns VT and VTPE.

Figure 3 is a comparison of the cross sections of the interscapular channels and profiles of a conventional VT blade and a VTPE blade.

Figure 4 - option crown WTPE.

5 is a meridional section of the nozzle and impeller of a radial-axial turbine with VT and VTPE.

6 is a cross section of the interscapular channel of the impeller of a radial-axial turbine with VT and VTPE.

7 is a meridional section of the nozzle and impeller of a radial centrifugal turbine with VT and VTPE.

Fig. 8 shows a meridional section of a nozzle and impeller of a radial turbine with VT and VTPE.

Figure 1 ... 8 numbers show the following lattice elements:

1 - throat of the crown of a turbine VT with a circle inscribed in the interscapular canal; 2 - frontal, output section of the crown of the turbine VT; 3 - profile of the blade of the crown of a turbine VT; 4 - the area of the front output section and possible locations of the throat of the crown of the VTPE turbine; 5 - frontal, output section of the crown of the turbine VTPE; 6 - profile of the blades of the crown of the turbine VTPE; 7 - annular protrusions-visors surrounding the flow part of the turbine at the exit of the WTPE crown; 8 - contours of the flow part of the crown of an axial or radial turbine VT; 9 - contours of the flow part of the crown of the axial or radial turbine VTPE, 10 - the scapular wall of the expanded interscapular channel, 11 - the conditional gas wall of the expanded interscapular channel, 12 - the last section of the expanded interscapular channel, 13 - the narrow section of the cross section of the interscapular channel VTPE, coinciding with the throat surface only in a particular case; 14 - the optimal and most effective throat section of the interscapular canal of the crown of VTPE with an inscribed circle; 15a is a meridional section of a nozzle apparatus of a radial or radial-axial turbine VT; 15b is a cross-section of the interscapular channel of the nozzle apparatus of a radial or radial-axial turbine; 16a is a meridional section of a nozzle apparatus of a radial or radial-axial turbine with WTPE measures; 16b is a cross-section of the interscapular channel of the nozzle apparatus of a radial or radial-axial turbine with the WTPE measures; 17 - the impeller of the radial-axial turbine; 18 - nozzle apparatus of a radial centrifugal turbine; 18a is a meridional section of a nozzle apparatus of a radial centrifugal turbine; 18b is a cross-sectional view of the interscapular channel of a nozzle apparatus of a radial-centrifugal turbine; 19a is a meridional section of a nozzle apparatus of a radial centrifugal turbine with WTPE measures; 19b is a cross-section of the interscapular channel of the nozzle apparatus of the radial-centrifugal turbine with the WTPE measures; 20 - impeller of a radial centrifugal turbine; 20a is a meridional section of the impeller (crown) of a radial centrifugal turbine; 20b is a cross-section of the interscapular channel of the impeller (crown) of the radial centrifugal turbine; 21a is a meridional section of the impeller (crown) of the radial-centrifugal turbine with the measures of VTPE; 21b is a cross-section of the interscapular channel of the impeller (crown) of the radial-centrifugal turbine with the WTPE measures; 22A - meridional section of the impeller (crown) of the radial turbine; 22b is a cross section of the interscapular channel of the impeller (crown) of the radial turbine; 23a - meridional section of the impeller (crown) of the radial turbine with the activities of the WTPE; 23b is a cross-section of the interscapular channel of the impeller (crown) of the radial turbine with the WTPE measures; 24 - output device of the radial turbine.

When forming the neck section of the interscapular canal in the region of the front exit section, that is, in the area of the oblique cut of the crown, see (4) of Fig. 3, we expand the concept of the interscapular canal by constructing the channel so that part of the neck section of the interscapular canal has a solid wall in the form of a feather blades see (10) of FIGS. 1, 3, surfaces of rotation formed by the meridional contours of the flow part of the grate around the axis of the turbine and the annular protrusions behind the front output section of the grate, and part of the conditional gas wall - the boundary surface along the gas flow that coincides with the averaged boundaries of the jets descending from the opposite wall of the channel (the use of the conditional averaged boundary of the section is due to the fact that due to the mixing of gas flows flowing from two adjacent interscapular channels, the boundary between these gas flows becomes blurred and disappears with distance from the outlet edge of the feather pen blades, averaging, for example, the mixing zone of adjacent channels, taking into account the angle of deviation of the flow in an oblique section and the approximate constancy of the flow rate interscapular body through one channel), i.e. effluent of one channel, and interblade determined gas laws of mechanics, see (11) 1, 3. Consider the conditional part of the wall of the gas flow cross section enlarged interblade channel. The conditional duration of the interscapular canal together with the solid and gas walls is determined to the last section, normal to the flow of the working fluid and forming an expanded interscapular canal, following the direction of flow of the working fluid up to the end of the profile of the scapula, which is the solid wall of the interscapular canal, see (12) of FIG. 1, 3. In the design of the HTPE blade, the influence and significance of the oblique cut on the parameters of the turbine lattice changes, since the flow rate of the working fluid in the interscapular channel will have max the maximum value in the frontal section of the lattice or somewhere in the region of the oblique cut, and the flow deviation in the oblique cut can be easily compensated by an additional rotation in the first section of the HTPE crown, given that the flow around the profile on it is significantly lower than in the VT crowns, and that will have little effect on profile losses. If one of the annular protrusions is absent - peaks or even both, or the peaks are not long enough to be longer than the output frontal section of the extreme points of individual sections of the expanded interscapular channel along the height of the scapula, then the averaged conditional boundaries of the outflow of jets from the peripheral and sleeve are also an extension of the interscapular channel forming surfaces of the interscapular canal after the output frontal section, short visors of the crown. Further, in the description of the invention, where the term "interscapular canal" is used, it is understood that this is an extended interscapular canal. An expanded interscapular canal is shown on a conventional VT turbine rim (10, 11, 12, FIG. 1), and in the same way it is defined for an expanded interscapular canal of an HTPE rim (10, 11, 12, FIG. 3).

For a qualitative assessment of the geometry of the turbine rim, we define the bore section of the expanded interscapular canal in such a way that we consider the bore section, in the case of an untwisted blade of small height, the normal section of the midline of the interscapular canal in the meridional section of the rim, and in the plane of development of the intersection of the interscapular canal (made by the axisymmetric mean lines in the meridional section of the crown) normal to the midline of the channel. Hereinafter, by the middle line in any section of the interscapular channel or the contours of the flowing part obtained by the meridional section of peripheral and sleeve axisymmetric surfaces, we mean a smooth line passing through the centers of the circles inscribed in the channel. For long and swirling blades, the bore or surface is constructed with normally axisymmetric, idealized streamlines in the meridional section and idealized streamlines in the interscapular channel of the crown, constructed as a flat scan along axisymmetric, idealized streamlines, see [1]. We call both these versions of the passage section the same term: "the passage section of the interscapular canal of the crown." The throat, narrowest, section of the crown interscapular canal will be a special case of the passage section, and we define the throat section as the smallest passage section of the expanded interscapular channel, in front of which the passage section area is larger (or in some cases equal to the throat section) of the throat, and after the throat section, any the cross section has a large area.

Such a definition of the passage section is an approximation to the actual passage section of the interscapular canal of the crown, which occurs when the working medium flows around the crown, and serves only to assess the design of the crown of the HTPE.

In the description of the invention, the term “throatiest, narrowest, interscapular canal section” has a generalized interpretation and is applied to an expanded interscapular canal, since in some cases a number of passage sections of such an canal will have a conditional gas wall and the throat section here will be a conditional throat, narrowest , section, and in other cases, when forming the throatiest, narrowest section of the interscapular canal, all boundaries will be solid, located on the walls of the blades, peripheral and sleeve contours of the flow Since the channel of the lattice has no gas boundaries (for example, a supersonic lattice), then we combine both of these cases into one generalized concept of the throat. The generalized concept of the throat section allows you to more clearly and easily explain and tie the maximum averaged speed to the front output section of the turbine rim and ensure the continuity of the parameters in the extended interscapular channel. In swirling blades, the throat section may be a throat surface of complex shape and it is understood that the throat section combines both the simplest flat section and a complex throat, swirling surface.

By the center of the throat section we mean either the conditional center of gravity of the throat surface, or the conditional center of pressure on the throat surface, or some point obtained by optimization and which is the objective function in determining the maximum, average speed on the front output surface of the crown and the like, depending on the method, with the help of which it is supposed to place the throat section relative to the surface of the front output section of the crown, using one point for this - the conditional center of the section to bind to the front of the throat section of the outlet section of the crown.

The height of the flow part of the interscapular canal is tied to the middle flat line between the contours of the interscapular canal in the meridional section, which forms the middle axisymmetric surface. For simple, slightly twisted or untwisted blades, this is the middle line — approximately straight, forming a conical or cylindrical surface. For a swirling blade, this is an axisymmetric surface, idealized, built along the axisymmetric midline of the stream in the meridional section of the channel. The midline of the canal is plotted at the section of the interscapular canal located in this axisymmetric surface. The height of the expanded interscapular canal at any point in the midline of the channel section and the height of the flow part of the rim will define a straight line segment normal to the axisymmetric middle surface (the line in this case passes through the turbine axis) at this point and intersecting (or touching) its ends with axisymmetric contour surfaces channel on the sleeve and periphery. The height is determined by the midline, since in one passage section, the height at individual intersection points with the axisymmetric average surface will be different. It follows that the height is normal to the generatrix of the axisymmetric middle surface in the plane passing through the axis of the turbine and the point at which the height of the flow part of the crown is measured on the middle line of the channel and on the axisymmetric middle surface. The height of the meridional contours of the interscapular canal is the segment normal to the generatrix of the axisymmetric middle surface (the midline of the contour of the interscapular canal) and intersecting (or touching) the generatrices of the sleeve and peripheral axisymmetric surfaces. It should be noted that the height of the interscapular channel along the midline on the axisymmetric middle surface and the height of the meridional contours of the channel in the meridional section are equal, since any channel height located on a straight line passing through the axis of the turbine can be easily rotated around the axis of the turbine by a certain angle to the meridional plane and it coincides with the height of the meridional contours. Thus, the meridional contours of the lattice are formed in height on the midline of the interscapular canal and vice versa. Therefore, the terms used in the description: “the height of the interscapular canal”, “the height of the meridional contours of the channel” and the like are identical.

The boundary associated with the throat section, we consider the totality of the geometric elements of the crown, separating the characteristic parts of the crown before and after the throat section. The boundary elements include:

- the boundary height and the corresponding midline boundary point of intersection of the throat section with the median line of the canal on the axisymmetric middle surface, which divide the heights of the interscapular canal and the median line of the canal before and after the throat;

- the boundary height intersects the axisymmetric surfaces of the sleeve and peripheral contours of the interscapular canal of the crown at two boundary points and the planes passing through these two boundary points, the normal axis of the turbine intersect the axisymmetric surfaces of the crown contours along two boundary rings separating the axisymmetric surfaces of the sleeve and peripheral parts of the circumferential contour parts parts before and after the throat.

After this boundary, a change in height along the expanded interscapular canal and meridional contours of the flow part of the crown corresponding to this height should provide an increase in the area of the passage section.

Simplistically, taking into account the height of the turbine blade swirl, we determine the area of the front output section of the grating, where there are many possible locations of the neck section, depending on the design of the crown, according to the point of intersection of the neck surface with the middle line in the intersection section of the interscapular canal by the axisymmetrical middle surface of this area. The intersection point should belong to this region if it is located inside a circle centered at the intersection of the midline of the interscapular canal and the front of the outlet cross-section of the grating. In a different way, the region includes an oblique section of the WTPE crown, counting along the midline of the channel from its beginning to the last section of the expanded interscapular canal, see (4), Fig. 3. Separate parts of the throat section may not be included in the indicated area, it is enough that this point of intersection of the throat section with the middle line of the interscapular canal enters.

To ensure the transfer of the throat to the desired location, taking into account the twist of the feather blade in height and to implement various design options for the crown of VTPE, it is necessary to apply the following principles for constructing a turbine grate:

- VTPE turbine crowns, where in the first section of the working medium rotation in the interscapular canal, the interscapular channel height increases (in this embodiment, there may also be small sections with the same height), we relate to the main, basic class of VTPE crowns, see, Fig. 2. These crowns can be used in turbines of any kind and purpose;

- crowns, where the height of the interscapular canal decreases or is constant in part of the section or in the whole of the first section, and in the section of acceleration of the flow, the height of the contours of the flowing section decreases up to the border associated with the throat section, we refer to a special class of WTPE crowns, see figure 4. This option is used on the first nozzle apparatus: after the combustion chamber, after the transition channel to the free turbine, or when moving to the turbine of the next cascade of the gas turbine engine, see, Fig. 2, Fig. 4. In this embodiment, the gain in losses is obtained due to the long and smooth supply of the working fluid in the transition channel to the WTPE crown or after the combustion chamber and smaller losses during rotation in the first section of the crown rotation, where the rotation speed is lower than in the basic version, see FIG. 2;

- in addition to reducing the height of the flowing part, annular protrusions are installed behind the frontal cross-section of the crown - peaks above and below the flowing section of the meridional cross-section of the crown, with their inner contours continuing the meridional contours of the turbine’s crown after the front-facing output cross-section of the crown and helping to position the throat cross-section in the required place, taking into account the conditional gas walls expanded interscapular canal;

- in some special variants of the lattice design, the absence of annular protrusions - peaks after the front cross-section of the lattice or the presence of only one of the two, above the periphery or below the flow duct sleeve is required, which may reduce the efficiency of such a lattice design and the maximum flow velocity in the front output section crown. In the design with one visor, either from above on the periphery, or from below at the bushing of the flow part of the crown, or without visors, the transfer of the throat section to the front output surface of the crown will be difficult. The transfer of the throat can be carried out by increasing the rate of decrease in the height of the flowing part of the rim near the front output section of the rim to compensate for the appearing angle of expansion of the jet, which disappears after the front section where there is no visor, which is the conditional boundary of the expanded interscapular canal and similarly in other cases. Obviously, with this compensation, hydraulic losses increase and part of the efficiency of the WTPE crown is lost;

- the rate or speed of decreasing the height of the interscapular canal of the crown in the second section along the turbine axis to the border associated with the throat section, see Figs. 2, 4, should be higher than the corresponding increase in the width of the flow part along the interscapular channel (if there is such an extension) with taking into account the change in width along the height in flat reamers of sections of the blades of the interscapular channel when they intersect with idealized axisymmetric surfaces of the current, and should ensure a reduction in the area of the passage section of the interscapular anal until the neck section, see Figure 3;

- change accordingly, taking into account the spin of the blade, the dimensions of the chords of the profiles in sections along the height of the blade to form a throat section in the desired location of the interscapular canal, taking into account that the profile of the VTPE blade in the second acceleration section after turning the interscapular channel has an additional elongation compared to the blades BT;

- in the second section of the crown, the height of the channel decreases to the boundary, including the boundary height, and this height may not be the smallest in the meridional section of the channel, but after which there is a kink in the peripheral and sleeve components of the meridional section of the channel in order to increase the area of the passage sections of the expanded interscapular channel after the throat section;

- if the crown works with supersonic speeds at the exit of the crown or as an option for the implementation of the subsonic crown, then in the second section of the acceleration of the crown, the channel height decreases to the border associated with the formation of the throat section. After constructing the throat section of the channel, the height of the flow part can continue to decrease, but with a lower rate of decrease along the turbine axis, it can either be constant or increase in order to provide an increase in the passage area of the interscapular channel after the throat section, Fig. 3. That is, after this boundary associated with the throat, in the second section of the crown, the height of the channel should be changed so as to provide an increase in the area of the passage section of the expanded interscapular canal;

- the optimal and most effective for obtaining the maximum averaged flow rate of the working fluid in the front output section of the crown for subsonic or transonic turbine gratings, we determine the location of the neck section when the center of the neck section is located on the surface of the front output section of the turbine ring, keeping in mind that the maximum the speed in the front exit section will be at the intersection of the neck surface with the front exit section and it decreases significantly its, the farther the point is located on the frontal exit section from the throat surface. The best option will be when the neck section crosses the front exit surface, somewhere in the middle between the outlet edges of the interscapular canal, see (14), Fig. 3. The throat section in height-swirled blades, as mentioned above, is a surface of complex shape and it is necessary to place it relative to the front output section in such a way as to obtain the maximum averaged speed on the front output surface of the turbine crown. The center of the section will have a conditional character due to the difficulty of obtaining a solution, but it is obvious that this solution exists when the neck section crosses the front output surface of the crown in the region of the front output section of the crown (4), Fig. 3;

- the method of forming the meridional contours of the axial turbines can be successfully applied to the radial lattices of the turbines, where a turn in the meridional section is added to the section of rotation in the circumferential direction, and then the section of acceleration of the flow with a decrease in the height of the wheel contours follows. Figure 5, 6, 7, 8 depicts several options for radial turbines, including: radial-axial, Fig. 5, 6, radial-centrifugal, Fig. 7, radial, Fig. 7 of the conventional design of the VT crowns and with the event WTPE. In radial turbines, the height is approximately normal to the midline of the channel in the meridional section (or some other line selected for some installations), as well as for axial turbines, which have an angle between the axis of the turbine and the direction of flow of the working fluid in the meridional section. Radial turbines use the same Euler equation, which after conversion is as follows:

,

,

where c ₁ , w ₁ , u ₁ - absolute, relative and peripheral speeds at the entrance to the stage,

c ₂ , w ₂ , u ₂ - absolute, relative and peripheral speeds at the exit of the stage.

положителен и является более существенной величиной, превосходящей два других члена уравнения. В центробежной турбине этот член отрицателен, что и является главным преимуществом центростремительной турбины над центробежной. Однако при одинаковых значениях L_T в центробежной и центростремительной турбинах скорости на входе и выходе в проточной части центростремительной турбины значительно меньше. Применение мероприятия ВТПЭ с переносом горлового сечения в фронтальное выходное сечение в центробежной турбине, смотри фиг.7, может дать больший эффект, чем в центростремительной турбине, смотри фиг.5, 6, 8. Чередуя рабочие венцы только радиальной (23а), фиг.8, или венцы только центробежной турбин (21а), фиг.7, с разными направлениями вращения и с разными направлениями обхода потоком газа (по часовой или против часовой) лопаток в венцах можно реализовать венцы с ВТПЭ для создания турбин типа Юнгстрема;Member in centripetal turbine

positive and is a more significant quantity, superior to the other two terms of the equation. In a centrifugal turbine, this term is negative, which is the main advantage of a centripetal turbine over a centrifugal one. However, with the same values of L _T in a centrifugal and centripetal turbine, the inlet and outlet speeds in the flow part of the centripetal turbine are much lower. The use of the VTE event with the transfer of the throat section to the front output section in a centrifugal turbine, see Fig. 7, can give a greater effect than in a centripetal turbine, see Figs. 5, 6, 8. Alternating working crowns only radial (23a), Fig. 8, or crowns of only centrifugal turbines (21a), FIG. 7, with different directions of rotation and with different directions of gas flow (clockwise or counterclockwise) of the blades in the crowns, crowns with HTPE can be realized to create Jungstrom type turbines;

- considering the most general case of constructing an HTPE crown, it can be assumed that, for example, for supersonic gratings with a large expansion, the throat section can be placed on the second section of the flow acceleration to an oblique cut of the interscapular channel of the HTPE crown, outside the area of the front output section. Thus, the entire region of possible locations of the formed neck section includes the entire second acceleration section of the working fluid, which, in turn, includes the region of possible locations of the neck section near the front output section, which, in turn, includes the most optimal location of the neck section, when the center it is located on the surface of the front output section;

- in addition to changing the contours of the meridional cross-section of the grating, a fundamentally new profile of the grating blade is required, see figure 3. The meridional contours of the turbine impeller, forming the interscapular channel of the WTPE crowns, are formed either by special retaining shelves, or the impeller is solid, that is, the blades, and the meridional contours of the turbine impeller form a single unit with the disk or part of the disk. To significantly reduce losses in the crown of HTPE compared to VT crowns, it is necessary to optimize the profile of the shoulder blade for height and, especially, at the hub and at the periphery of the crown due to the complex flow lines of the working fluid in the meridional section.

The geometry of the WTPE turbine crown allows one to obtain the maximum flow velocity in the throat section, the center of which coincides with the frontal section of the grating or is displaced together with the throat section inside the interscapular channel to obtain supersonic speed in a supersonic grating or options of a subsonic grating with some peculiarities.

An increase in the speed and value of the number λ _o in the front output section of the HTPE crown is greater than in the initial VT crown, and does not lead to an increase in the pressure drop in the HTPE crown. In order to increase the speed as a result of the thermodynamic process in the crown of HTPE while maintaining the differential pressure in the crown π = P ^* ₀ / P ₁ , it is necessary to take into account the following features of the proposed method of forming the geometry and design of the crown of HTPE.

Using the first and second laws of thermodynamics, we can carry out transformations and obtain the following expression:

.

, (ф.1), смотри (ф.7.12) [2] или [3],According to the second law of thermodynamics

.

, (f.1), see (f.7.12) [2] or [3],

where q is the specific heat supplied to the gas (q = q _a + q _r );

q _a is the specific heat of exchange with the environment;

q _r is the specific heat of friction released during the gas flow in the interscapular channel during the adiabatic process in the crown (there is no heat exchange with the environment q _a = 0);

u is the specific internal energy, J / kg;

p is the gas pressure, Pa;

v is the specific volume, m ³ / kg;

i - specific enthalpy, J / kg;

T is the absolute temperature, K;

R is the gas constant, J / (kg · K);

c _p , c _v - specific heat at the processes p = const, v = const;

s is the specific entropy, J / (kg · K).

The process of accelerating the movement of gas in the blade of the turbine can be represented on the i-s diagram, Fig.9.

Integrate the expression (f 1.)

where s ₀ , s ₁ - specific entropy at the entrance and exit of the crown, J / (kg · K);

,

- заторможенные давление и температура на входе в венец, Па, К;

,

- inhibited pressure and temperature at the entrance to the crown, Pa, K;

P ₁ , T ₁ - static pressure and temperature at the outlet of the crown, Pa, K.

We use the obtained formula (f.2) to compare the thermodynamic processes occurring in the crowns of VT and VTPE. For this, we subtract from the expression for the VT the expression for the VTE, taking into account that the pressure at the inlet to the rim p ^* ₀ and the static pressure at the outlet p ₁ are the same for the VT and VTE.

According to the second law of thermodynamics, the change in entropy ds = dq / T

or

where t is a certain parameter depending on which the friction heat is supplied and the static flow temperature changes (for example: if t is the length of the interscapular channel in the lattice in arbitrary units, the length of the interscapular channel VT corresponds to t = 0.65, and the length of the interscapular channel VTPE t = 1.0).

If we assume that the losses q _r in the VT and VTPE lattices are the same, then the entropy value by the formula (f.4) is determined by the distribution of the static temperature in the interscapular channel.

. На фиг.11 представлены изменения статической температуры T(t) вдоль межлопаточного канала в ВТ и ВТПЭ при условии, что начальная температура

,

.Figure 10 presents examples of changes in static temperature T (t) along the interscapular canal in VT and VTPE, provided that the initial temperature

. Figure 11 shows the changes in the static temperature T (t) along the interscapular canal in the VT and VTPE, provided that the initial temperature

,

.

статическая температура в ВТПЭ выше, чем в ВТ, и как следует из (ф.4) значение подынтегрального выражения в интеграле энтропии ВТПЭ и всей энтропии Δs_втпэ меньше, чем энтропия Δs_ВТ в ВТ вдоль межлопаточного канала. Из термодинамического соотношения (ф.3) для ВТ тогда следует, что при положительной разности Δs_ВТ-Δs_ВТПЭ>0 необходимо, чтобы и правая часть выражения была положительна. Это обеспечивается, только если скорость с_1ВТПЭ>c_1ВТ.As can be seen in figures 10 and 11, at the same initial temperature

the static temperature in the HTPE is higher than in the HT, and as follows from (4), the value of the integrand in the integral of the entropy of the HTPE and the entire entropy Δs of the _{HTPE is} less than the entropy Δs of the _HT in the VT along the interscapular canal. From the thermodynamic relation (f.3) for VT then it follows that for a positive difference Δs _VT -Δs _HTPE > 0, it is necessary that the right side of the expression be positive. This is provided only if the speed with _1VTPE > c _1W .

перед ВТПЭ до некоторого значения, можно добиться такого состояния термодинамического процесса в решетке, когда с_1ВТПЭ=с_1ВТ. Энтропия Δs_ВТПЭ, определяемая по (ф.4), в этом случае увеличивается, так как статическая температура в знаменателе подынтегрального выражения уменьшается по сравнению с исходной из-за меньшей начальной температуры

в ВТПЭ. Следовательно, вся энтропия приближается к энтропии Δs_ВТ в ВТ, уменьшая разность Δs_ВТ-Δs_ВТПЭ до тех пор, пока не наступит баланс в уравнении (ф.3) и С_1ВТПЭ=c_1BT. Например, при

,

статическая температура в ВТПЭ в отдельных участках больше статической температуры в ВТ, а где-то меньше, и поэтому из (ф.4) значение энтропии ВТПЭ Δs_ВТПЭ на выходе из венца несколько меньше энтропии Δs_ВТ в ВТ вдоль межлопаточного канала. Из левой части термодинамического соотношения (ф.3) разность Δs_ВТ-Δs_ВТПЭ>0, что означает, что в правой части выражения должно быть

Using the resulting pattern and lowering the temperature

Before HTPE to a certain value, it is possible to achieve such a state of the thermodynamic process in the lattice when with _1WTPE = with _1W . The entropy Δs of the _HTPE , determined by (f.4), in this case increases, since the static temperature in the denominator of the integrand decreases compared to the initial one due to the lower initial temperature

in the WTPE. Consequently, all entropy approaches the entropy Δs of _VT in VT, decreasing the difference Δs of _VT -Δs of _HTPE until there is a balance in equation (f.3) and С _1ВТПЭ = c _1BT . For example, when

,

the static temperature in the HTPE in some sections is higher than the static temperature in the VT, and somewhere less, and therefore from (f.4) the entropy of the HTPE Δs of the _HTPE at the exit from the crown is slightly lower than the entropy Δs of the _VT in the VT along the interscapular canal. From the left side of the thermodynamic relation (f.3), the difference Δs _VT -Δs _HTPE > 0, which means that the right side of the expression should be

левая часть (ф.3) больше нуля и наступает равновесие левой и правой частей уравнения.A calculated estimate of this ratio shows that at С _1ВТ = С _1ВТПЭ due to the fact that

the left side (f.3) is greater than zero and the equilibrium of the left and right sides of the equation occurs.

Thus, in the proposed design of the blade rim, including the nozzle apparatus and the impeller of the turbine, it becomes possible with the same pressure drop and the same heat of loss q _r to obtain:

, где q₁ - удельная теплота, подведенная к двигателю (к единице массы), q₂ - удельная теплота, отведенная от двигателя, Δq - удельное тепло, использованное в двигателе для совершения полезной работы, или удельная работа цикла (единицы массы), эквивалентная мощности турбины Δq~N, то есть всей работы в промежуток времени Δt к Δt, T₁ - температура перед турбиной, смотри (ф.3.3), стр.45 [2]. Если T₁ одинакова для турбины ВТ и ВТПЭ, а мощность на турбине N увеличивается, то увеличивается и Δq~N и чем больше Δq, то тем выше КПД цикла двигателя (η_tВТПЭ>η_tВТ);- at the same inhibited temperature T ₁ at the inlet to the VT and VTPE turbines, an increase in the gas velocity at the outlet of the VTPE crowns (from _{1 VTPPE} , from _{2 VTPPE} and from _1uVTPPE , from _{2u VTPPE} ), increase in turbine power N (see Euler equation above), turbine efficiency and engine by increasing the thermal efficiency of the cycle

where q ₁ is the specific heat supplied to the engine (per unit mass), q ₂ is the specific heat withdrawn from the engine, Δq is the specific heat used in the engine to perform useful work, or the specific work of the cycle (mass units), equivalent turbine power Δq ~ N, that is, all work in the time interval Δt to Δt, T ₁ is the temperature in front of the turbine, see (Section 3.3), p. 45 [2]. If T _{1 is the} same for the turbine VT and VTPE, and the power on the turbine N increases, then Δq ~ N also increases and the greater Δq, then the higher the efficiency of the engine cycle (η _tBTPE > η _tBT );

Если мощность N одинакова для турбины ВТ и ВТПЭ, то у них одинакова и Δq и тогда чем меньше Т₁ в турбине с ВТПЭ, то тем выше КПД двигателя с турбиной ВТПЭ (η_tВТПЭ>η_tВТ).- at a lower inhibited temperature T ₁ at the inlet of the VTPE turbine, the same gas velocity at the outlet of the VT and VTPE crowns, the same power N of the VT and VTPE turbines. The efficiency of the turbine and the thermodynamic efficiency of the engine are increased by lowering the temperature of the working fluid in front of the HTPE turbine, using the same amount of heat both in the turbine with VT and in the turbine with HTPE. We get:

If the power N is the same for the turbine VT and HTPE, then they have the same Δq and then the less T ₁ in the turbine with HTPE, the higher the efficiency of the engine with the turbine HTPE (η _tHTPE > η _tHT ).

The design of the HTPE crown allows one to obtain lower hydraulic losses and heat of losses q _r (q _{r HTHE} <q _rWT ) than in the VT crown, taking into account the lower flow velocity around the profile of the HTPE crown, transferring the throat to the outlet cross section of the turbine crown and obtain an additional gain in Efficiency.

On Fig shows the change in the area of the passage section along the interscapular canal in the VT and VTPE, where it is seen that the throat in the VTPE is shifted to the output section, and in the VT the throat is located in front of the oblique section, not reaching the output section of the crown.

, которая в диапазоне от 0 до 1 одинакова для решеток ВТ и ВТПЭ,On Fig shows the change in gas velocity in the interscapular channel for VT and VTPE depending on the relative length of the interscapular channel

, which in the range from 0 to 1 is the same for VT and HTPE lattices,

where l _max - the total length of the interscapular canal VT or VTPE,

l is the length of the position of the individual section from the input section of the interscapular channel.

The meridional projection and three three-dimensional views of the HTPE lattice are presented in the example in Fig. 14.

Estimated estimates show that the use of the HTPE design on the nozzle apparatus (SA) of the first stage of the turbine reduces the temperature of the working fluid in front of the turbine by ~ 50 ... 100 ° С and more, which increases the efficiency of the entire engine, see [2]. Transferring the throat to the exit section of the crown for the nozzle apparatus and turbine rotor blades can increase the turbine efficiency by ~ 3 ... 4%, improve the thermodynamic cycle and, accordingly, increase the engine efficiency. But in this case, it is necessary to combine the proposed turbine design for all upcoming and subsequent turbine crowns, since at a lower temperature at the inlet of the turbine CA, other traditional crown designs will not have enough energy to operate individual turbine stages.

Disclosure of invention

The claimed method of designing the crown of the axial turbine VTPE, characterized in that they divide the interscapular channel of the turbine lattice into two sections: the first section of rotation of the interscapular channel, where they change the height of the meridional contours of the channel in the entire first section or leave the height constant either in the entire first section or in it parts, while changing the height on the remaining part or parts of the first section, and the second acceleration section with or without additional rotation of the interscapular channel, including an oblique section of the interscapular channel, where the height of the meridional contours of the channel is reduced towards the exit from the channel up to the border associated with the throat section, after which the height is changed so as to increase the area of the passage section of the channel, the throatiest, narrowest section of each interscapular channel of the turbine grate with taking into account changes in the width of the interscapular canal and twist of the scapula along the height of the interscapular canal, the boundaries of the decrease in the height of the meridional contours of the channel associated with the throat section in the second section on, where many possible locations of the throat section are located, including, but not limited to, the region of the throat section locations near the front output section of the grating, including the location of the throat section when the center of the throat section of the interscapular channel is placed on the surface of the front output section of the turbine grating, preferably set annular protrusions - visors either only from above on the periphery, or only from below at the sleeve, or simultaneously from above on the periphery and from below in at the hub of the running ring.

For the main class of HTPE crowns in the first section of the interscapular canal rotation, the height of the meridional contours of the interscapular canal is increased in the direction from the entrance to the crown to the exit from the first section, allowing in some cases a constant height in part of the first section.

For a special class of HTPE crowns, the height of the meridional contours of the interscapular canal monotonously decreases the height of the meridional contours of the interscapular canal in the first section of the interscapular canal, in some cases allowing the presence of a constant height, i.e., sections with increasing channel height in the direction from the entrance to the border are excluded associated with the throat section, after which the height is changed so as to increase the area of the passage section of the channel.

Also claimed is a method of constructing a crown of a radial turbine lattice of an HTPE, characterized in that the same method of constructing interscapular channels between the guide vanes of the wheel and the meridional contours of the lattice is used, which for axial turbines, taking into account an additional rotation in the meridional section, that is, to the plot of rotation in the circumferential direction , add a turn in the meridional section with increasing height relative to the midline of the channel and form the narrowest section of the interscapular channel in the acceleration section or in areas of the front exit section of the grating, including including the location of the throat section when the center of the throat section of the interscapular channel is placed on the surface of the front exit section of the radial turbine grating with a decrease in the height of the channel to the boundary associated with the throat section, after which the height is changed so as to increase channel cross-sectional area.

Literature

1. Kholshchevnikov K.V. “Theory and calculation of aircraft blade machines”, Moscow, “Mechanical Engineering”, 1986

2. Under. ed. V.I. Krutova "Technical Thermodynamics", third edition, Moscow, "Higher School", 1991

3. Rivkin S.L. “Thermodynamic properties of gases”, Moscow, “Energy”, 1973

Claims (8)

1. The method of designing the crown of the axial turbine VTPE (crown of the turbine increased efficiency), characterized in that they divide the interscapular channel of the turbine lattice into two sections: the first section of rotation of the interscapular channel, where they change the height of the meridional contours of the channel in the entire first section or leave the height constant or the entire first section, or in its part, while changing the height in the remaining part or parts of the first section, and the second acceleration section with or without additional rotation of the interscapular channel, an oblique oblique slice of the interscapular canal, where the height of the meridional contours of the canal is reduced towards the exit from the canal up to the border associated with the throat section, after which the height is changed so as to increase the area of the passage section of the channel, the throatiest, narrowest section of each interscapular is formed channel of the turbine grate, taking into account changes in the width of the interscapular channel and the swirling of the blade along the height of the interscapular channel, the boundaries of the decrease in the height of the meridional contours of the channel associated with the throats m section in the second acceleration section, where many possible locations of the throat section are located, including including the region of the throat section locations near the front output section of the grating, including the location of the throat section when the center of the throat section of the interscapular channel is placed on the surface of the front output section of the turbine grate , behind which they establish annular protrusions - visors either only from above on the periphery, or only from below at the sleeve, or simultaneously from above periphery and bottom of the sleeve in the flow part of the crown. 2. The method of designing the crown of the axial turbine VTPE according to claim 1, characterized in that for the main class of crowns VTPE in the first section of the interscapular channel turning, the height of the meridional contours of the interscapular channel is increased in the direction from the entrance to the crown to the exit from the first section, allowing in some cases the presence of a constant height in part of the first section. 3. The method of designing the crown of the axial turbine VTPE according to claim 1, characterized in that for a special class of crowns VTPE in the first section of rotation of the interscapular canal monotonically reduce the height of the meridional contours of the interscapular canal, allowing in some cases for part or whole section the presence of a constant height, that is, in the meridional section exclude areas with increasing channel height in the direction from the entrance to the border associated with the throat section, after which the height is changed so as to increase the area cross section of the channel. 4. The method of constructing the crown of the radial turbine lattice of VTPE, characterized in that the same method of constructing interscapular channels between the guide vanes of the wheel and the meridional contours of the lattice is used, which is for axial turbines according to any one of claims 1-3, taking into account the additional rotation in the meridional section, that is, a turn in the meridional section is added to the plot of turning in the circumferential direction with increasing height relative to the midline of the channel and the narrowest cross section of the interscapular channel is formed in the acceleration section whether in the region of the front exit section of the grating, including including the location of the throat section, when the center of the throat section of the interscapular channel is placed on the surface of the front exit section of the radial turbine grating with a decrease in the height of the channel to the boundary associated with the throat section, after which the height is changed in such a way to increase the passage area of the channel. 5. The method of designing the crown of the axial turbine VTPE, characterized in that they divide the interscapular channel of the turbine lattice into two sections: the first section of rotation of the interscapular channel, where the height of the meridional contours of the channel in the entire first section is changed or the height is left constant either in the entire first section or in its parts, while changing the height on the remaining part or parts of the first section, and the second acceleration section with or without additional rotation of the interscapular canal, including an oblique cut of the interscapular canal where the height of the meridional contours of the channel is reduced in the direction of the exit from the channel up to the border associated with the throat section, after which the height is changed so as to increase the area of the channel passage section, the throatiest, narrowest section of each interscapular channel of the turbine grate is formed taking into account changes in the width of the interscapular canal and twist of the scapula along the height of the interscapular canal, the boundaries of the decrease in the height of the meridional contours of the channel associated with the throat section in the second acceleration section, where there are many possible locations of the throat section, including including the region of the throat section locations near the front output section of the grating, including the location of the throat section when the center of the throat section of the interscapular channel is placed on the surface of the front output section of the turbine grate. 6. The method of designing the crown of the axial turbine VTPE according to claim 5, characterized in that for the main class of crowns VTPE in the first section of the interscapular channel turning, the height of the meridional contours of the interscapular channel is increased in the direction from the entrance to the crown to the exit from the first section, allowing in some cases the presence of a constant height in part of the first section. 7. The method of designing the crown of the VTPE axial turbine according to claim 5, characterized in that for a special class of VTPE crowns in the first section of the interscapular channel rotation, the height of the meridional contours of the interscapular channel is monotonously reduced, allowing in some cases a part or whole section to have a constant height, that is, in the meridional section exclude areas with increasing channel height in the direction from the entrance to the border associated with the throat section, after which the height is changed so as to increase the area cross section of the channel. 8. The method of designing the crown of the radial turbine lattice of VTPE, characterized in that the same method of constructing interscapular channels between the guide vanes of the wheel and the meridional contours of the lattice is used, which is for axial turbines according to any one of claims 5-7, taking into account additional rotation in the meridional section, that is, a turn in the meridional section is added to the plot of turning in the circumferential direction with increasing height relative to the midline of the channel and the narrowest cross section of the interscapular channel is formed in the acceleration section whether in the region of the front exit section of the grating, including including the location of the throat section, when the center of the throat section of the interscapular channel is placed on the surface of the front exit section of the radial turbine grating with a decrease in the height of the channel to the boundary associated with the throat section, after which the height is changed in such a way to increase the passage area of the channel.

Images