An air-water dual-purpose cross-medium axial-flow turbine engine

Abstract

The present invention discloses an air-water dual-purpose cross-medium axial-flow turbine engine, which is suitable for a drilled nozzle underwater and a rectangular beveled nozzle on the water surface. The inlet ends of the two nozzles face the combustion chamber and the outlet ends face the blade grid. The use of the two nozzles can make the turbine engine suitable for a water-air environment and provide sufficient power requirements for the take-off process of a cross-medium aircraft.

Description

Technical Field

[0001] The present invention belongs to the technical field of cross-medium vehicles, and in particular relates to an air-water dual-purpose cross-medium axial-flow turbine engine. Background Art

[0002] The cross-medium vehicle is a new type of cross-medium weapon that can freely shuttle between underwater and surface, and can achieve high-speed surface maneuvers and silent underwater diving. It has good ability to quickly conceal close enemies, and the ability to repeatedly enter and exit the water to avoid enemy detection and interception.

[0003] Generally, traditional underwater vehicles can only sail underwater. Due to the large underwater navigation resistance, small platform space and weight restrictions, they cannot effectively break through the enemy's defense circle, and the position of the mother ship is easily exposed after launch. Traditional missiles launched from the air are difficult to penetrate because the enemy's fleet has a three-dimensional air defense system of near, medium, far, low, medium and high airspace. Traditional vehicles that use launch vehicles, gliders and other flight assistance cannot be launched underwater due to platform restrictions. They can only implement a single-mode cross-medium solution from air to water, resulting in poor launch concealment and lack of penetration means, affecting their combat effectiveness.

[0004] The cross-medium vehicle needs to have the ability to work well under surface conditions and the ability to work well under underwater conditions, and needs a cross-medium vehicle power system that supports its good operation under both surface and underwater conditions. At present, the power system of dual-purpose air-water cross-medium vehicles is mainly based on two sets of power systems on the water / underwater, and its implementation methods are: one is driven by a thermal power system, which has the disadvantages of high fuel consumption rate and large volume; the other is driven by electric power, which has the disadvantages of weak workmanship and low navigation speed. In addition, the dual-power system cross-medium vehicle has the disadvantage of insufficient intake pressure of the water power system in the cross-medium mode of taking off from underwater and entering the water surface, resulting in take-off failure; in the cross-medium mode of landing from the water surface and entering underwater, there is a disadvantage of difficulty in re-igniting the underwater power system.

[0005] Therefore, the realization of an air-water dual-purpose cross-medium vehicle requires a set of support for its good operation in both surface and underwater conditions, and the ability to switch freely between two cross-medium modes, namely, taking off from underwater and entering the surface cross-medium mode, and landing on the surface and entering the underwater cross-medium mode, without affecting its working efficiency. The new air-water dual-purpose cross-medium power device is characterized by having two combustion chambers and an engine device. The difficulty lies in how to realize the gas transmission between the two combustion chambers and the engine device, and how to provide sufficient power for the vehicle's take-off process when crossing the medium. Summary of the invention

[0006] The purpose of the present invention is to provide an air-water dual-purpose cross-medium axial-flow turbine engine, which uses a drilled nozzle and a rectangular beveled nozzle to form an air-water dual-purpose turbine power system.

[0007] The technical solution adopted by the present invention is an air-water dual-purpose cross-medium axial-flow turbine engine, including a shell connected to a turbine combustion chamber, a shaft passing through the middle of the shell, a wheel connected to the shaft, the edge of the wheel connected to the turbine blade grid, a nozzle is provided on the shell, the inlet end of the nozzle faces the combustion chamber, and the outlet end faces the turbine blade grid. The nozzle includes a plurality of drilled beveled nozzles adopting a partial air intake installation mode and a plurality of rectangular beveled nozzles adopting a full-circle air intake installation mode. The drilled beveled nozzles and the rectangular beveled nozzles are on the same circumference, and the drilled beveled nozzles and the rectangular beveled nozzles are arranged at equal angles on the circumference.

[0008] The present invention is also characterized in that:

[0009] The specific structure of the drilled bevel nozzle is as follows: it includes a contraction section a, a throat a, and an expansion section a which are opened on the shell from the outside to the turbine blade grid. The central axes of the contraction section a, the throat a, and the expansion section a coincide with each other. The throat a is rounded and is used to transitionally connect the contraction section a and the expansion section a. The cross-sectional line shape of the contraction section a adopts the Soviet Vickers line shape.

[0010] The Soviet Vickers linear formula is:

[0011]

[0012] In the formula, x represents the axial coordinate of the nozzle; r represents the cross-sectional radius of the nozzle at x, and d cr represents the diameter of the throat a, r1 represents the fillet radius of the throat a, and l1 represents the length of the contraction section a.

[0013] The design parameter expression of throat a is:

[0014] The diameter of the nozzle throat a is:

[0015]

[0016] Where m is the mass flow rate of the working fluid, B cr is the nozzle critical pressure ratio, T0 is the stagnation temperature of the working fluid at the nozzle inlet, P0 is the stagnation pressure of the working fluid at the nozzle inlet, R g is the working gas constant, C cr is the critical velocity at the nozzle throat;

[0017] Minimum nozzle outlet diameter:

[0018]

[0019] Where, d eo is the effective outlet diameter of the drilled bevel nozzle, a 1，0 is the bevel angle of the drilled bevel nozzle, y0 is the expansion angle of the drilled bevel nozzle;

[0020] The effective diameter of the nozzle outlet is:

[0021]

[0022] In the formula, C ft The absolute exit velocity of the nozzle is calculated.

[0023] The included angle between the central axis of the flow channel of the drilled beveled nozzle and the edge tangent of the shell is the nozzle bevel angle, and the nozzle bevel angle is 16°.

[0024] The expansion angle of the expansion section a of the drilled-hole bevel nozzle is 8°.

[0025] The specific structure of the rectangular beveled nozzle is as follows: it includes a contraction section b, a throat b, and an expansion section b which are opened on the shell from the outside to the turbine blade row. The central axes of the contraction section b, the throat b, and the expansion section b coincide. The throat b is rounded and is used to transitionally connect the contraction section a and the expansion section a. The cross-sectional line shape of the throat b is an S-shaped curve formed by connecting two circular arcs with the same radius. The cross-sectional line shape of the expansion section b of the rectangular beveled nozzle is a Bezier curve and a straight line segment. One end of the Bezier curve is connected to the throat b, and the other end is connected to the straight line segment.

[0026] The minimum diameter of the throat b is the throat width, and the ratio of the arc radius of the throat b to the throat width is 0.5.

[0027] The angles of the two arcs of the throat b are both 5°.

[0028] The relative outlet angle is equal to the relative inlet angle β1 = β2, and the blade height H1 = 1.2d e , blade width B b =1.48d e , cascade intercept t b =0.85d e , blade edge thickness S b =0.06d e , cascade number Z n =πD / t b , pressure surface arc radius R1 = B b / 2cosβ1, radius of suction surface arc R2=R1-t b sinβ1, where D is the turbine mid-diameter, t b represents the cascade intercept, d e Indicates the nozzle outlet diameter.

[0029] The beneficial effects of the present invention are:

[0030] The present invention is an air-water dual-purpose cross-medium axial-flow turbine engine, which is suitable for a drilled nozzle underwater and a rectangular beveled nozzle on the water surface. The inlet ends of the two nozzles face the combustion chamber, and the outlet ends face the blade grid. The use of the two nozzles can make the turbine engine suitable for a water-air environment and provide sufficient power requirements for the take-off process of a cross-medium aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of an air-water dual-purpose cross-medium axial-flow turbine engine of the present invention;

[0032] Figure 2 It is a schematic diagram of the structure of the drilled bevel cutting nozzle in the present invention;

[0033] Figure 3 It is a line diagram of a rectangular beveled nozzle in the present invention;

[0034] Figure 4 is a cross-sectional line diagram of a rectangular beveled nozzle in the present invention;

[0035] Figure 5 This is a working principle diagram of an air-water dual-purpose cross-medium axial-flow turbine engine of the present invention;

[0036] Figure 6 This is a working state diagram of an air-water dual-purpose cross-medium axial-flow turbine engine of the present invention. DETAILED DESCRIPTION

[0037] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] For the dual-purpose air-water cross-medium axial-flow turbine engine, part of its air intake device is composed of two sets of nozzles with different structures, so that the aircraft can be launched from weapon platforms such as surface ships, submarines, and aircraft. The dual-purpose air-water cross-medium axial-flow turbine engine can be launched underwater, approach the enemy at low altitude and high speed after crossing the medium, and re-enter the water after being intercepted by the enemy, so that the aircraft weapon has good strike effectiveness.

[0039] The present invention provides an air-water dual-purpose cross-medium axial flow turbine engine, such as Figure 1 As shown, it includes a shell connected to the turbine combustion chamber, a shaft passing through the middle of the shell, a wheel connected to the shaft, an edge of the wheel connected to the turbine blade grid, a nozzle is provided on the shell, the inlet end of the nozzle faces the combustion chamber, and the outlet end faces the turbine blade grid, the nozzle includes a plurality of drilled beveled nozzles adopting a partial air intake installation mode and a plurality of rectangular beveled nozzles adopting a full-circle air intake installation mode, the drilled beveled nozzles and the rectangular beveled nozzles are on the same circumference, and the drilled beveled nozzles and the rectangular beveled nozzles are arranged at equal angles on the circumference.

[0040] The drilled nozzle is selected as the air intake device for the underwater operation of the air-water dual-purpose turbine. The flow channel does not have any bends in the airflow direction, the airflow and the wall will not separate, it has a small loss and a small friction area, and can achieve a higher dimensional accuracy and a lower surface roughness by reaming. Therefore, the air intake device for the underwater operation of the air-water dual-purpose turbine adopts a drilled bevel nozzle. The drilled bevel nozzle is as follows: Figure 2 As shown, the specific structure is as follows: it includes a contraction section a, a throat a, and an expansion section a which are opened on the casing from the outside to the turbine blade row. The central axes of the contraction section a, the throat a, and the expansion section a coincide with each other. The throat a is rounded and is used to transitionally connect the contraction section a and the expansion section a. Figure 2 Medium cr is the nozzle throat diameter, d l is the minimum nozzle outlet diameter, d e is the effective diameter of the nozzle outlet, α is the nozzle bevel angle, γ is the nozzle expansion angle, d e It is the actual outlet section of the drilled beveled nozzle; the cross-sectional line shape of the contraction section a adopts the Soviet Vickers line shape, which can reduce the loss of the working fluid in the nozzle during underwater navigation.

[0041] The Soviet Vickers linear formula is:

[0042]

[0043] In the formula, x represents the axial coordinate of the nozzle; r represents the cross-sectional radius of the nozzle at x, and d cr represents the diameter of the throat a, r1 represents the fillet radius of the throat a, and l1 represents the length of the contraction section a.

[0044] Considering that the underwater working conditions of the cross-medium vehicle are that the stagnation pressure before the turbine is 23MPa, the stagnation temperature is 1500K, the reference back pressure is 0.4MPa, the flowing medium is OTTO-II gas, and the flow rate of the working medium flowing into a single turbine nozzle is 0,3656kg / s. After calculation, the theoretical throat diameter d of the nozzle is obtained. cr The theoretical nozzle outlet diameter d is 5 mm. e is 12.8 mm, the nozzle expansion angle γ is 10°, and the theoretical velocity c at the nozzle outlet ft It is 1737m / s, the length l1 of the contraction section of the drilling nozzle is 5mm, and the length l2 of the expansion section a of the drilling bevel nozzle is 44.5mm.

[0045] The design parameter expression of throat a is:

[0046] The diameter of the nozzle throat a is:

[0047]

[0048] Where m is the mass flow rate of the working fluid, Bcr is the nozzle critical pressure ratio, T0 is the stagnation temperature of the working fluid at the nozzle inlet, P0 is the stagnation pressure of the working fluid at the nozzle inlet, R g is the working gas constant, C cr is the critical velocity at the nozzle throat;

[0049] Minimum nozzle outlet diameter:

[0050]

[0051] Where, d eo is the effective outlet diameter of the drilled bevel nozzle, a 1，0 is the bevel angle of the drilled bevel nozzle, y0 is the expansion angle of the drilled bevel nozzle;

[0052] The effective diameter of the nozzle outlet is:

[0053]

[0054] In the formula, C ft The absolute exit velocity of the nozzle is calculated.

[0055] The angle between the center axis of the bore-shaped beveled nozzle flow channel and the edge tangent of the shell is the nozzle bevel angle. In the underwater vehicle turbine, since there is a nozzle bevel angle α between the center line of the turbine nozzle flow channel and the rotation plane of the turbine blade grid, when the pressure outside the beveled cut is lower than the calculated outlet section pressure, the working fluid will expand in the beveled cut of the nozzle, causing the working fluid airflow to cause boundary layer separation in the second half of the nozzle and produce losses. The larger the bevel angle of the bore-shaped beveled nozzle, the more obvious the boundary layer separation phenomenon of the airflow is. After calculation and comparison, a nozzle bevel angle of 16° is more appropriate.

[0056] The expansion angle of the nozzle also affects the air flow velocity at the nozzle outlet. The smaller the expansion angle of the drilled bevel nozzle, the longer the length of its expansion section, and the greater the viscosity loss of the working fluid in the drilled bevel nozzle, resulting in increased velocity loss. As the expansion angle of the drilled bevel nozzle continues to increase, the velocity coefficient of the nozzle continues to increase. However, due to the bevel angle of the nozzle, the nozzle expansion angle cannot be too large. After calculation and comparison, the expansion angle of the expansion section a of the drilled bevel nozzle is more appropriate to be 8°.

[0057] The rectangular beveled nozzle is selected as the air intake device for the air-water dual-purpose turbine under water navigation conditions. It adopts a contracted nozzle line shape and is suitable for the case where the design pressure ratio of the air-water dual-purpose turbine under water conditions is higher than the critical pressure ratio of the working fluid. Figure 3 As shown, the contraction section of the rectangular bevel nozzle consists of two sections with a radius of r 1,r The arc is tangent to the arc of the throat transition section at point c. The position of point c is affected by the arc transition angle γ rcontrolled, horizontally tangent to the rear end of the nozzle and point d, B cr is the nozzle throat width, B e is the nozzle outlet width, H e is the nozzle height, l 1,r is the axial length of the Bezier curve, i.e. the length of the nozzle expansion section, l 2,r It is the length from the nozzle throat to the nozzle outlet.

[0058] Rectangular bevel nozzles such as Figure 3 As shown, the specific structure is: including a contraction section b, a throat b, and an expansion section b opened on the shell from the outside to the turbine blade row, the central axes of the contraction section b, the throat b, and the expansion section b coincide, the throat b is a rounded corner, which is used to transitionally connect the contraction section a and the expansion section a, the cross-sectional line shape of the throat b is an S-shaped curve formed by connecting two circular arcs with the same radius, and the cross-sectional line shape of the expansion section b of the rectangular beveled nozzle is a Bezier curve and a straight line segment, one end of the Bezier curve is connected to the throat b, and the other end is connected to the straight line segment.

[0059] The minimum diameter of the throat b is the throat width. When the kerosene and gas working medium gas flows in the contraction section of the rectangular beveled nozzle, Figure 3 As shown in the figure, the working fluid airflow will generate disturbances at a and b. When the linear radius of the arc of the throat transition section of the rectangular beveled nozzle is larger, the disturbances generated at a and b will be larger, and the influence on the expansion process of the working fluid in the nozzle contraction section will be greater; when the working fluid airflow flows from the nozzle throat transition section to the nozzle expansion section, expansion waves will be generated at c and d. The larger the linear radius of the arc of the throat transition section of the rectangular beveled nozzle, the smaller the expansion area of ​​the expansion waves generated at c and d, and the shorter the acceleration process of the working fluid airflow. Considering the influence of the four points a, b, c, and d on the flow of the working fluid in the rectangular beveled nozzle, when the ratio of the linear radius to the throat width of the arc of the throat transition section of the rectangular beveled nozzle is 0.5, the velocity coefficient of the rectangular beveled nozzle reaches the optimal value.

[0060] The expansion section of the rectangular beveled nozzle is composed of a second-order Bezier curve and is tangent to the nozzle throat transition arc at point c. The position of point c is determined by the nozzle arc transition angle γ r Control. As the arc transition angle of the throat of the rectangular beveled nozzle increases, the curvature of the nozzle expansion linearity, i.e., the second-order Bezier curve, at the transition point a becomes larger, and the expansion wave generated by the working fluid here and the compression wave generated by the expansion wave hitting the wall become larger. After calculation, when the arc transition angle γ of the rectangular beveled nozzle increases, the curvature of the nozzle expansion linearity, i.e., the second-order Bezier curve, at the transition point a becomes larger. r When 5° is selected, the Mach number curve of the working fluid airflow after entering the nozzle expansion section is relatively smooth, so the speed loss is small.

[0061] The linearity of the rectangular bevel nozzle is not only constrained by the curvature of the throat transition section and the arc transition angle, but also by the axial length l of the Bezier curve of the expansion section. r,1After calculation, it is found that the axial length of the Bezier curve of the expansion section of the rectangular beveled nozzle has little effect on the nozzle performance and can be arbitrarily selected within a reasonable range.

[0062] The blade design parameters are: the relative outlet angle is equal to the relative inlet angle β1 = β2, and the blade height H1 = 1.2d e , blade width B b =1.48d e , cascade intercept t b =0.85d e , blade edge thickness S b =0.06d e , cascade number Z n =πD / t b , pressure surface arc radius R1 = B b / 2cosβ1, radius of suction surface arc R2=R1-t b sinβ1, where D is the turbine mid-diameter, t b represents the cascade intercept, d e Indicates the nozzle outlet diameter.

[0063] It can be seen from the working principle of the partial intake turbine that the turbine blade grid has an installation angle, so when the turbine nozzle exists at a certain bevel angle, the working medium airflow obtains better aerodynamic parameters in the turbine blade grid flow channel, thereby improving the performance of the turbine. In order to apply the rectangular bevel nozzle to the partial intake turbine, it is necessary to improve the line type of the bevel form of the rectangular bevel nozzle (bevel rectangular bevel nozzle).

[0064] like Figure 4 As shown in the figure, the expansion segment b of the rectangular bevel nozzle consists of a Bezier curve and a straight line, where α r is the bevel angle of the rectangular nozzle. The rectangular nozzle outlet section ed intersects with the Bezier curve at point e and intersects with the straight line segment at point d. The contraction segment line shape of the beveled rectangular nozzle is composed of ac and if, where the ac segment line shape is composed of the radius r 1,r The arcs ab and bc intersect the entrance section at point a; if the line type consists of a radius of r 1,r The arc fg with radius r 2,r The arc fg and the straight line hi are composed of the arc gh and the straight line hi, where g and h are the tangent points. The central angles of the arcs fg and bc are equal, both γ 2,r ; The tangent point h of arc gh is on the extension line of the radius of arc bc.

[0065] The present invention is an air-water dual-purpose turbine engine, which is a rotary impeller engine using high-pressure, high-temperature combustion gas as a working medium. Figure 5The figure shows a cross-sectional schematic diagram of a single-stage impulse turbine. Its main parts can be divided into guide parts and working parts. The guide part is mainly composed of a nozzle 4, which has a specific cross-sectional shape, and its airway cross section changes according to a certain rule. When the working medium passes through the nozzle 4, it will flow into the working blade cascade airway at a certain speed and direction. The working part is composed of a wheel disc 2, a turbine blade cascade 3 and a shaft 1. The turbine blade cascade 3, i.e., the rotor of the turbine, is the rotating part of the turbine. The high-speed medium ejected from the nozzle 4 at a certain speed and angle impacts the turbine blade cascade, driving the working wheel (wheel disc 2, with turbine blade cascade 3 installed on the periphery) to rotate, and output shaft work through the shaft 1. The installation method of the turbine blade cascade 3 is that the drilled bevel nozzle adopts a partial air intake installation mode, which is only installed at the entrance of part of the blade cascade, while the rectangular bevel nozzle adopts a full-circle air intake installation mode, which is installed at the entrance of other blade cascades except the drilled nozzle blade cascade.

[0066] The present invention is an air-water dual-purpose cross-medium axial flow turbine engine. Figure 5 As shown, the working process is:

[0067] Underwater navigation status, such as Figure 6 As shown in (a), the underwater combustion chamber is working, and the high-temperature combustion gas is ejected from the drilled bevel nozzle 4 at a certain speed and angle to impact the turbine blades, driving the working wheel (wheel disc 2, with turbine blades 3 installed on the periphery) to rotate and output shaft work through the shaft 1.

[0068] Air navigation status, such as Figure 6 As shown in (b), the surface combustion chamber is working, and the high-temperature combustion gas is ejected from the rectangular bevel nozzle 4 at a certain speed and angle to impact the turbine blades, driving the working wheel (wheel disc 2, whose periphery is equipped with turbine blades 3) to rotate and output shaft work through the shaft 1.

[0069] Fly out of water state, such as Figure 6 As shown in (c), when the trans-medium vehicle takes off from the water surface, its power system is in the take-off condition. Under this condition, the work done by the aircraft's aviation kerosene working medium alone is not enough to meet the aircraft's thrust requirements. At this time, the OTTO-Ⅱ gas working medium is required to work to compensate for the engine's power requirements. At this time, the OTTO-Ⅱ gas working medium and the aviation kerosene gas working medium work together on the air-water dual-purpose turbine. The OTTO-Ⅱ gas working medium is ejected from the drilled bevel nozzle, and the aviation kerosene gas working medium is ejected from the rectangular bevel nozzle, and they jointly impact the turbine blades, driving the working wheel (wheel disc 2, whose periphery is equipped with turbine blades 3) to rotate, and output shaft work through shaft 1, providing sufficient power requirements for the take-off process of the trans-medium vehicle.

[0070] Through the above method, the present invention provides an air-water dual-purpose cross-medium axial-flow turbine engine, which is suitable for a drilled nozzle underwater and a rectangular beveled nozzle on the water surface. The inlet ends of the two nozzles face the combustion chamber and the outlet ends face the blade grid. The use of the two nozzles can make the turbine engine suitable for a water-air environment and provide sufficient power requirements for the take-off process of a cross-medium aircraft.

Claims

1. An air-water dual-purpose cross-medium axial-flow turbine engine, comprising a shell connected to a turbine combustion chamber, a shaft passing through the middle of the shell, a wheel connected to the shaft, an edge of the wheel connected to a turbine blade row, a nozzle is provided on the shell, an inlet end of the nozzle faces the combustion chamber, and an outlet end faces the turbine blade row, characterized in that: The nozzles include a plurality of drilled beveled nozzles using a partial air intake installation mode and a plurality of rectangular beveled nozzles using a full-circle air intake installation mode, wherein the drilled beveled nozzles and the rectangular beveled nozzles are on the same circumference, and the drilled beveled nozzles and the rectangular beveled nozzles are arranged at equal angles on the circumference; The drilled hole-shaped beveled nozzle is specifically constructed as follows: it includes a contraction section a, a throat a, and an expansion section a, which are opened on the shell from the outside to the turbine blade row. The central axes of the contraction section a, the throat a, and the expansion section a coincide with each other. The throat a is a rounded corner, which is used to transitionally connect the contraction section a and the expansion section a. The cross-sectional line shape of the contraction section a along the central axis adopts the Soviet Vickers line shape, and the cross-sectional line shape of the expansion section a along the central axis is a cone shape. The Soviet Vickers linear formula is: In the formula, x represents the axial coordinate of the nozzle; r Indicates that the nozzle is x The corresponding cross-sectional radius is d cr represents the diameter of the throat, r 1 represents the radius of the throat fillet. l 1 represents the length of the contraction segment a; The design parameter expression of the throat a is: The diameter of the nozzle throat a is: In the formula, m is the working fluid mass flow rate, B cr is the nozzle critical pressure ratio, T 0 is the stagnation temperature of the working fluid at the nozzle inlet, P 0 is the stagnation pressure of the working fluid at the nozzle inlet, R g is the working gas constant, C cr is the critical velocity at the nozzle throat; Minimum nozzle outlet diameter: In the formula, d e,o The effective outlet diameter of the drilled bevel nozzle is a 1,0 is the bevel angle of the drilled bevel nozzle, γ 0 position: the expansion angle of the drilled bevel nozzle; The effective diameter of the nozzle outlet is: In the formula, C ft The absolute exit velocity of the nozzle is calculated; The angle between the central axis of the borehole-shaped beveled nozzle flow channel and the edge tangent of the shell is the nozzle bevel angle, and the nozzle bevel angle is 16°; The rectangular beveled nozzle is specifically constructed as follows: it includes a contraction section b, a throat b, and an expansion section b which are opened on the casing from the outside to the turbine blade row, the central axes of the contraction section b, the throat b, and the expansion section b coincide, the throat b is a rounded corner, and is used to transitionally connect the contraction section a and the expansion section a, the cross-sectional line shape of the throat b is an S-shaped curve formed by connecting two arcs with the same radius, and the cross-sectional line shape of the expansion section b of the rectangular beveled nozzle is a Bezier curve and a straight line segment, one end of the Bezier curve is connected to the throat b, and the other end is connected to the straight line segment; The blade design parameters are: the relative outlet angle is equal to the relative inlet angle , cascade height H 1=1.2 d e , cascade width B b =1.48 d e , cascade intercept t b =0.85 d e , blade edge thickness S b =0.06 d e , number of cascades , pressure surface arc radius , radius of suction surface arc ,in D represents the turbine mid-diameter, t b represents the cascade intercept, d e Indicates the nozzle outlet diameter.

2. The air-water dual-purpose cross-medium axial flow turbine engine according to claim 1, characterized in that: The expansion angle of the expansion section a of the drilled hole-shaped beveled nozzle is 8°.

3. The air-water dual-purpose cross-medium axial flow turbine engine according to claim 1, characterized in that: The minimum diameter of the throat b is the throat width, and the ratio of the arc radius of the throat b to the throat width is 0.

5.

4. The air-water dual-purpose cross-medium axial flow turbine engine according to claim 1, characterized in that: The angles of the two arcs of the throat portion b are both 5°.

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