High-temperature air expander for 50 MW heat pump energy storage system

Abstract

A high-temperature air expander for a 50 MW heat pump energy storage system, belonging to the field of compressed gas energy storage. In order to solve the problems of existing air expanders being unable to quickly participate in power grid regulation, exhibiting poor adaptability of operating parameters, and failing to meet the requirements of strong volatility, variable operating conditions, etc., a rotor (3) of the high-temperature air expander provided herein has two ends respectively mounted on a front bearing seat (6) and a rear bearing seat (7) and can rotate; a high-pressure inner cylinder (2) and a high-pressure outer cylinder (1) are sequentially sleeved on the outside of the rotor (3), and a cavity is formed between the high-pressure inner cylinder (2) and the high-pressure outer cylinder (1); the high-pressure inner cylinder (2) is provided with two air inlets, and the two air inlets are centrally symmetrically arranged on two sides of a shaft of the high-pressure inner cylinder (2); two blade groups are provided between the high-pressure inner cylinder (2) and the rotor (3), and the two blade groups are arranged on two sides of each air inlet of the high-pressure inner cylinder (2); a high-pressure No. 1 partition sleeve (4) and a high-pressure No. 2 partition sleeve (5) are sleeved on the outside of the rotor (3), and blade groups are arranged between the rotor (3) and each of the high-pressure No. 1 partition sleeve and the high-pressure No. 2 partition sleeve; and the high-pressure No. 1 partition sleeve (4) and the high-pressure No. 2 partition sleeve (5) are connected to the inner wall of the high-pressure outer cylinder (1).

Description

A high-temperature air expander for a 50MW heat pump energy storage system Technical Field

[0001] This application belongs to the field of compressed gas energy storage, and in particular relates to a high-temperature air expander for a 50MW heat pump energy storage system. Background Technology

[0002] As an important energy conversion component in novel thermodynamic cycle energy storage systems, turboexpanders have complex flow characteristics such as high load, unsteady operation, transonic speed, and transcriticality. The working fluid flow has unique problems such as strong three-dimensional effects, shock waves / boundary layer disturbances. At the same time, it is necessary to cope with the strong fluctuations, high uncertainties, and variable operating conditions of the source and load sides of compressed gas energy storage systems. Existing energy storage gas turbines have poor capabilities in participating in grid regulation, adapting to operating parameters, operating under a wide range of conditions, high flexibility, fast response, and high reliability. Summary of the Invention

[0003] This application proposes a 50MW high-temperature air expander to address the shortcomings of existing air expanders, such as their inability to quickly participate in grid regulation, poor adaptability to operating parameters, and inability to meet the demands of compressed gas energy storage systems with strong fluctuations and varying operating conditions on the source-load side.

[0004] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows:

[0005] A high-temperature air expander for a 50MW heat pump energy storage system includes a high-pressure outer cylinder, a high-pressure inner cylinder, a rotor, a high-pressure No. 1 partition sleeve, a high-pressure No. 2 partition sleeve, a front bearing housing, a rear bearing housing, and four sets of blades. The rotor is horizontally mounted on the front and rear bearing housings at both ends and is rotatable. The high-pressure inner cylinder and the high-pressure outer cylinder are sequentially fitted onto the rotor from the inside to the outside, forming a cavity between them. The high-pressure inner cylinder has two air inlets, which are symmetrically arranged on both sides of the shaft of the high-pressure inner cylinder. Two sets of blades are arranged between the high-pressure inner cylinder and the rotor, respectively on both sides of the air inlets of the high-pressure inner cylinder. The high-pressure No. 1 partition sleeve and the high-pressure No. 2 partition sleeve are fitted onto the rotor, and blades are respectively arranged between them and the rotor. The high-pressure No. 1 partition sleeve and the high-pressure No. 2 partition sleeve are connected to the inner wall of the high-pressure outer cylinder.

[0006] Furthermore, an intake channel is provided on the high-pressure outer cylinder at the position corresponding to the air inlet of the high-pressure inner cylinder. Each of the two air inlet sides of the high-pressure inner cylinder is provided with an intake short pipe and a butterfly valve. The intake short pipe is inserted into the intake channel of the high-pressure outer cylinder. One end of the intake short pipe is sealed to the air inlet of the high-pressure inner cylinder, and the other end is flush with the port of the intake channel of the high-pressure outer cylinder. The butterfly valve is located at the port of the intake channel of the high-pressure outer cylinder and is fixedly installed on the high-pressure outer cylinder.

[0007] Furthermore, the blade assembly between the high-pressure inner cylinder and the rotor includes five sets of moving blades and four sets of stationary blades. One end of the moving blade is fixed to the rotor, and the other end extends toward the inner wall of the high-pressure inner cylinder. One end of the stationary blade is fixed to the inner wall of the high-pressure inner cylinder, and the other end extends toward the rotor. The moving blades and stationary blades are arranged alternately in the axial direction.

[0008] Furthermore, the blade assembly between the high-pressure No. 1 diaphragm sleeve or the high-pressure No. 2 diaphragm sleeve and the rotor includes seven sets of moving blades and seven sets of stationary blades. One end of the moving blade is fixed to the rotor, and the other end extends toward the high-pressure No. 1 diaphragm sleeve or the high-pressure No. 2 diaphragm sleeve. One end of the stationary blade is fixed to the high-pressure No. 1 diaphragm sleeve or the high-pressure No. 2 diaphragm sleeve, and the other end extends toward the rotor. The moving blades and stationary blades are arranged alternately axially.

[0009] Furthermore, both the moving and stationary blades adopt a wide-load airfoil.

[0010] Furthermore, a small-gap air seal design is adopted between the moving blades and the rotor, as well as between the stationary blades and the rotor.

[0011] Furthermore, air seals are installed at both ends of the high-pressure outer cylinder and between them and the rotor.

[0012] Furthermore, a centering beam is connected between the high-pressure outer cylinder and both the front and rear bearing housings.

[0013] Furthermore, the high-pressure outer cylinder is cast from alloy steel.

[0014] Furthermore, the high-pressure outer cylinder includes an upper cylinder and a lower cylinder, which are sealed by tightening with double-ended bolts; and the lower cylinder is provided with four support claws, which are respectively supported on the front bearing seat and the rear bearing seat.

[0015] The beneficial effects of this application compared to the prior art are:

[0016] 1. The high-temperature expander of this application adopts a wide-load blade profile and small-clearance air seal design for both the moving and stationary blades, ensuring high flow efficiency. The high-temperature expander has two-stage end air seals on both sides, with calculated leakage not exceeding 0.1% of the inlet flow rate, demonstrating reasonable leakage control. The calculated cylinder efficiency of the high-temperature expander is 93.2%, and the overall thermodynamic scheme exhibits good performance, making the design feasible.

[0017] 2. The total pressure drop of the inlet cylinder of the high-temperature expander in this application is 0.28%, as shown in Figure 6. The overall flow within the flow field is relatively uniform, with no obvious vortices generated. The total pressure drop of the exhaust cylinder of the high-temperature expander is 1.06%, as shown in Figure 7. Its internal flow exhibits a certain degree of left-right asymmetry, but no obvious vortices appear. The overall flow is uniform, consistent with the internal flow of a conventional high-pressure outer cylinder (exhaust chamber) exhaust structure. The flow-through blades of the high-temperature expander adopt a small enthalpy drop, reaction type, post-loading, and pre-torsion design, with full three-dimensional bending and torsion forming. The intra-stage and inter-stage aerodynamic matching is good, the airflow is uniform, and it has good aerodynamic performance. As shown in Figures 8-11, the blades exhibit good aerodynamic matching, the overall flow on the blade surface and within the channel is uniform, with no separation vortices. The CFD isentropic efficiency of the flow-through (including the gas seal) of the high-temperature expander is 94.92%. The intake and exhaust performance is excellent, and the flow-through aerodynamic performance calculation shows that the expander has excellent performance and meets the performance design requirements.

[0018] 3. The high-temperature expander of this application adopts an axial flow form and a double-cylinder structure. The main air valve consists of two butterfly valves arranged on both sides of the high-temperature expander, which are connected to the high-pressure inner cylinder through a short air inlet pipe for easy maintenance. The cylinder has a double-layer structure, and the flow passage is arranged in a 2×12 stage double-flow configuration, so that the axial thrust can be self-balanced, effectively reducing the axial force borne by the rotor.

[0019] 4. The high-temperature expander of this application uses a 180° anti-symmetrical tangential volute intake method, with simultaneous intake of the upper and lower halves of the high-pressure inner cylinder. This reduces the temperature difference between the upper and lower halves of the inner cylinder and improves intake efficiency. As shown in Figure 5, high-temperature air enters the high-pressure inner cylinder directly through a butterfly valve. After entering the high-pressure inner cylinder, it is split into two ends and enters the high-pressure No. 1 baffle sleeve and the high-pressure No. 2 baffle sleeve respectively after five stages of work. The external temperature and pressure of the high-pressure inner cylinder are the same as the temperature and pressure of the gas after the fifth stage. This reduces the temperature and pressure difference between the inside and outside of the high-pressure inner cylinder, increases the temperature change rate of the high-pressure inner cylinder, reduces the expansion difference between the rotor and stator components, and reduces the thermal stress of the high-pressure inner cylinder caused by temperature changes. This allows it to adapt to the needs of rapid changes in operating conditions and flexible start-stop, thus improving the service life of the unit. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are provided to further illustrate this application.

[0021] Figure 1 is a longitudinal sectional view of the expander;

[0022] Figure 2 is a front view of the expander;

[0023] Figure 3 is a top view of the expander;

[0024] Figure 4 is a schematic diagram of the structure at the air inlet of the high-pressure inner cylinder;

[0025] Figure 5 is a schematic diagram of the air seal with small gap between the comb teeth;

[0026] Figure 6 shows the pressure cloud diagram and streamline diagram of the intake area of ​​the high-pressure inner cylinder;

[0027] Figure 7 is a three-dimensional streamline diagram of the high-pressure outer cylinder;

[0028] Figure 8 is a streamline diagram of high-temperature gas flowing through the 2nd to 4th stage moving blades;

[0029] Figure 9 is a streamline diagram of high-temperature gas flowing through the 5th to 7th stage moving blades;

[0030] Figure 10 is a streamline diagram of high-temperature gas flowing through the 8th-10th stage moving blades;

[0031] Figure 11 is a streamline diagram of high-temperature gas flowing through the 11th-12th stage moving blades.

[0032] Explanation of reference numerals in the attached drawings: 1. High-pressure outer cylinder; 2. High-pressure inner cylinder; 3. Rotor; 4. High-pressure No. 1 partition sleeve; 5. High-pressure No. 2 partition sleeve; 6. Front bearing seat; 7. Rear bearing seat; 8. Support cat claw; 9. Centering beam; 10. Intake short pipe; 11. Butterfly valve; 12. Horizontal stationary blade. Detailed Implementation

[0033] The invention described in this application will be explained in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Referring to Figures 1, 2, and 3, the high-temperature air expander of a 50MW heat pump energy storage system in this embodiment includes a high-pressure outer cylinder 1, a high-pressure inner cylinder 2, a rotor 3, a high-pressure No. 1 diaphragm sleeve 4, a high-pressure No. 2 diaphragm sleeve 5, a front bearing housing 6, a rear bearing housing 7, and four sets of blades. The rotor 3 is horizontally mounted on the front bearing housing 6 and the rear bearing housing 7 at both ends and is rotatable. One end of the rotor 3 is connected to the compressor's external shaft via a diaphragm shaft assembly, and the other end is rigidly connected to the generator via bolts. The turbine speed is 3000 r / min. The rotor 3 is limited on both sides by thrust support bearings within the front bearing housing 6 and the rear bearing housing 7. The high-pressure inner cylinder 2 and the high-pressure outer cylinder 1 are sequentially fitted onto the rotor 3 from the inside out, forming a cavity between them. Referring to Figure 4, the high-pressure inner cylinder 2 is provided with two air inlets, which are symmetrically arranged on both sides of the shaft of the high-pressure inner cylinder 2. Two sets of blades are provided between the high-pressure inner cylinder 2 and the rotor 3, and the two sets of blades are respectively provided on both sides of the air inlet of the high-pressure inner cylinder 2. The high-pressure No. 1 partition sleeve 4 and the high-pressure No. 2 partition sleeve 5 are sleeved on the outside of the rotor 3, and blades are provided between them and the rotor 3 respectively. The high-pressure No. 1 partition sleeve 4 and the high-pressure No. 2 partition sleeve 5 are connected to the inner wall of the high-pressure outer cylinder 1.

[0035] Referring to Figure 2, the high-pressure outer cylinder 1 in this embodiment is cast from alloy steel. The high-pressure outer cylinder 1 includes an upper cylinder and a lower cylinder, which are tightened and sealed by double-ended bolts. Four integrally cast support claws 8 are provided on the lower cylinder, located above the horizontal flange of the lower cylinder, thus making the support surface flush with the horizontal split surface. The high-pressure outer cylinder 1 is supported by these four support claws 8 on the front bearing seat 6 and the rear bearing seat 7. Each support claw is connected to the front or rear bearing seat by double-ended bolts to prevent the high-pressure outer cylinder from coming loose from the front or rear bearing seat. An appropriate gap is left between the locking nut and the support claw to allow for free expansion and contraction of the support claw when the temperature of the high-pressure outer cylinder changes. A centering beam 9 is provided between the high-pressure outer cylinder 1 and both the front and rear bearing seats 6 and 7. One end of the centering beam 9 is connected to the high-pressure outer cylinder 1 by bolts and locating pins, and the other end is connected to the corresponding bearing seat by bolts and locating pins. The centering beam 9 ensures that the high-pressure outer cylinder 1 has correct axial and lateral positioning relative to the front or rear bearing seat and bears the axial thrust of the expander.

[0036] Referring to Figure 4, the high-pressure inner cylinder 2 in this embodiment is cast from high-temperature alloy steel and includes an upper cylinder and a lower cylinder, which are tightened and sealed by double-ended bolts. One air inlet of the high-pressure inner cylinder 2 is located on the upper cylinder, and the other air inlet is located on the lower cylinder. An air intake channel is provided on the high-pressure outer cylinder 1 corresponding to the air inlet of the high-pressure inner cylinder 2. Each of the two air inlet sides of the high-pressure inner cylinder 2 is provided with an air intake short pipe 10 and a butterfly valve 11. The air intake short pipe 10 is inserted into the air intake channel of the high-pressure outer cylinder 1. One end of the air intake short pipe 10 is sealed to the air inlet of the high-pressure inner cylinder 2, and the other end is flush with the port of the air intake channel of the high-pressure outer cylinder 1. The butterfly valve 11 is located at the port of the air intake channel of the high-pressure outer cylinder 1 and is fixedly mounted on the high-pressure outer cylinder 1. The main air valve consists of two butterfly valves 11 arranged on both sides of the high-pressure outer cylinder 1. For ease of maintenance, they are connected to the high-pressure cylinder through the air intake short pipe 10, and the valves themselves are supported on the foundation by elastic brackets.

[0037] Referring to Figure 1, the blade assembly between the high-pressure inner cylinder 2 and the rotor 3 in this embodiment includes five sets of moving blades and four sets of stationary blades, with the moving and stationary blades arranged alternately along the axial direction. One end of the moving blade is fixed in the T-shaped groove of the rotor 3 by the blade root, and the other end extends towards the inner wall of the high-pressure inner cylinder 2. One end of the stationary blade is fixed in the T-shaped groove on the inner wall of the high-pressure inner cylinder 2 by the blade root, and the other end extends towards the rotor 3. The stationary blades are pre-twisted and pressed together to form a whole, which can better control the flow area of ​​the baffle and ensure the consistency of design and installation.

[0038] Among them, the volute chamber of the high-pressure inner cylinder 2 is also laterally inlaid with a horizontal stationary blade 12, which together with the volute steam passage provides good steam intake performance.

[0039] Referring to Figure 1, the blade group between the high-pressure 1 diaphragm sleeve 4 or the high-pressure 2 diaphragm sleeve 5 and the rotor 3 in this embodiment includes seven sets of moving blades and seven sets of stationary blades. One end of the moving blade is fixed on the rotor 3, and the other end extends toward the high-pressure 1 diaphragm sleeve 4 or the high-pressure 2 diaphragm sleeve 5. One end of the stationary blade is fixed on the high-pressure 1 diaphragm sleeve 4 or the high-pressure 2 diaphragm sleeve 5, and the other end extends toward the rotor 3. The moving blades and stationary blades are arranged alternately in the axial direction.

[0040] Among them, the stationary blades between the high-pressure No. 1 diaphragm sleeve 4, the high-pressure No. 2 diaphragm sleeve 5, and the rotor 3 are all reaction-type blades, adopting a pre-twisted assembly design. After the stationary blades of the pre-twisted assembly diaphragm are processed, they are assembled by pre-twisting, and there are no welded parts. There is contact pre-tightening force between the shrouds and between the blade roots of the diaphragm stationary blades, which can maintain the stability of the interconnection and ensure the safe and stable operation of the unit.

[0041] The moving and stationary blades adopt a wide-load airfoil design, and both the moving blades and rotor 3, as well as the stationary blades and rotor 3, employ a small-clearance air seal design. The blade height of the moving and stationary blades ranges from 96.5 to 207.5 mm. Furthermore, the 12-stage moving blades have a similar structural form, all featuring a "T"-shaped blade root, a working section with a bellows-like profile, and a self-crowned structure at the top, forming a parallelogram at a 30° angle to the axial direction.

[0042] In this embodiment, the air intake method is a 180° anti-symmetrical tangential volute intake, which can reduce the temperature difference between the upper and lower halves of the high-pressure inner cylinder 2 and improve intake efficiency. High-temperature air enters the high-pressure inner cylinder 2 directly through the butterfly valve 11, the intake short pipe 10, and the air inlet of the high-pressure inner cylinder 2. Then, the high-temperature air is split into two streams on either side of the air inlet of the high-pressure inner cylinder 2. Each stream of high-temperature air passes through the blade assembly between the high-pressure inner cylinder 2 and the rotor 3, achieving five stages of work. Then, these two streams of high-temperature air respectively pass through the blade assembly between the high-pressure 1 partition sleeve 4 and the rotor 3, and the blade assembly between the high-pressure 2 partition sleeve 5 and the rotor 3, achieving seven stages of work. This achieves a symmetrical double-splitting arrangement of 2×12 stages of reaction stages in the flow path. At the same time, the high-temperature air after five stages of work flows from the gap between the high-pressure inner cylinder 2 and the high-pressure 1 partition sleeve 4 and the high-pressure 2 partition sleeve 5 into the cavity between the high-pressure inner cylinder 2 and the high-pressure outer cylinder 1. The external temperature and pressure of the high-pressure inner cylinder 2 are the same as the temperature and pressure of the gas after five stages of work, which reduces the temperature difference and pressure difference between the high-pressure inner cylinder 2 and the high-pressure outer cylinder 1, and improves the service life of the unit.

[0043] Referring to Figure 1, comb-tooth small-gap air seals are respectively provided at both ends of the high-pressure outer cylinder 1 and between the rotor 3.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions created in this application, and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions created in this application without departing from the substance and scope of the technical solutions created in this application.

Claims

1. A high temperature air expander for a 50 MW heat pump energy storage system, characterized in that, It includes a high-pressure outer cylinder, a high-pressure inner cylinder, a rotor, a high-pressure No. 1 diaphragm sleeve, a high-pressure No. 2 diaphragm sleeve, a front bearing housing, a rear bearing housing, and four sets of blades. The rotor is horizontally mounted on the front and rear bearing housings at both ends and can rotate. The high-pressure inner cylinder and the high-pressure outer cylinder are sequentially fitted onto the outside of the rotor from the inside to the outside, and a cavity is formed between the high-pressure inner cylinder and the high-pressure outer cylinder. The high-pressure inner cylinder has two air inlets, which are symmetrically arranged on both sides of the shaft of the high-pressure inner cylinder. Two sets of blades are arranged between the high-pressure inner cylinder and the rotor, and the two sets of blades are respectively arranged on both sides of the air inlet of the high-pressure inner cylinder. The high-pressure No. 1 diaphragm sleeve and the high-pressure No. 2 diaphragm sleeve are fitted onto the outside of the rotor, and blades are respectively arranged between them and the rotor. The high-pressure No. 1 diaphragm sleeve and the high-pressure No. 2 diaphragm sleeve are connected to the inner wall of the high-pressure outer cylinder.

2. A high temperature air expander for a 50 MW heat pump energy storage system according to claim 1, characterized in that, An intake channel is provided on the high-pressure outer cylinder at the position corresponding to the air inlet of the high-pressure inner cylinder. Each of the two air inlet sides of the high-pressure inner cylinder is provided with an intake short pipe and a butterfly valve. The intake short pipe is inserted into the intake channel of the high-pressure outer cylinder. One end of the intake short pipe is sealed to the air inlet of the high-pressure inner cylinder, and the other end is flush with the port of the intake channel of the high-pressure outer cylinder. The butterfly valve is located at the port of the intake channel of the high-pressure outer cylinder and is fixedly installed on the high-pressure outer cylinder.

3. A high temperature air expander for a 50 MW heat pump energy storage system according to claim 1, characterized in that, The blade assembly between the high-pressure inner cylinder and the rotor includes five sets of moving blades and four sets of stationary blades. One end of the moving blade is fixed to the rotor, and the other end extends toward the inner wall of the high-pressure inner cylinder. One end of the stationary blade is fixed to the inner wall of the high-pressure inner cylinder, and the other end extends toward the rotor. The moving blades and stationary blades are arranged alternately axially.

4. The high-temperature air expander of a 50MW heat pump energy storage system according to claim 1, characterized in that, The blade assembly between the high-pressure No. 1 diaphragm sleeve or the high-pressure No. 2 diaphragm sleeve and the rotor includes seven sets of moving blades and seven sets of stationary blades. One end of the moving blade is fixed to the rotor, and the other end extends toward the high-pressure No. 1 diaphragm sleeve or the high-pressure No. 2 diaphragm sleeve. One end of the stationary blade is fixed to the high-pressure No. 1 diaphragm sleeve or the high-pressure No. 2 diaphragm sleeve, and the other end extends toward the rotor. The moving blades and stationary blades are arranged alternately axially.

5. A high-temperature air expander for a 50MW heat pump energy storage system according to claim 3 or 4, characterized in that, Both the moving and stationary blades adopt a wide-load airfoil.

6. A high-temperature air expander for a 50MW heat pump energy storage system according to claim 3 or 4, characterized in that, Both the moving blades and the rotor, as well as the stationary blades and the rotor, employ a small-gap air seal design.

7. The high-temperature air expander of a 50MW heat pump energy storage system according to claim 1, characterized in that, Air seals are installed at both ends of the high-pressure outer cylinder and between it and the rotor.

8. The high-temperature air expander of a 50MW heat pump energy storage system according to claim 1, characterized in that, The high-pressure outer cylinder is connected to both the front and rear bearing housings by a centering beam.

9. The high-temperature air expander of a 50MW heat pump energy storage system according to claim 1, characterized in that, The high-pressure outer cylinder is made of alloy steel casting.

10. A high-temperature air expander for a 50MW heat pump energy storage system according to claim 1, characterized in that, The high-pressure outer cylinder consists of an upper cylinder and a lower cylinder, which are connected by bolts; and the lower cylinder is equipped with four support claws.

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