An orc expander

Abstract

The application provides an ORC expander, and belongs to the technical field of ORC power generation equipment.The expander comprises a shell with an inner cavity, an inlet pipe assembly is arranged on the side of the shell, an outlet is arranged on the side of the shell, and an impeller is rotatably arranged in the inner cavity; the inlet pipe assembly comprises at least one inlet pipe, the inlet pipes are oppositely arranged, the outlet is arranged on the side of the shell, and the impeller is arranged in the inner cavity.High-pressure working medium uniformly impacts the impeller to do work after entering the inner cavity from both sides, and the working medium after doing work is discharged through the outlet.The expander adopts a symmetrical air inlet structure to realize uniform force bearing of the impeller in the circumferential direction, and is stable in operation; an annular taper flow channel reduces flow resistance and improves expansion efficiency; the shell and the cover plate are designed in a split mode, so that axial quick disassembly and maintenance are facilitated; a bearing support and a sealing ring are integrated at the rotating shaft to prevent leakage, and the structure is compact.The expander is suitable for various scenes, and has the characteristics of small size, high efficiency, reliable sealing and convenient maintenance.

Description

Technical Field

[0001] This invention belongs to the field of ORC power generation equipment technology, and specifically relates to an ORC expander. Background Technology

[0002] The Organic Rankine Cycle (ORC) is an effective technology for converting low-grade heat energy into electrical energy using low-boiling-point organic working fluids. It has significant application value in fields such as industrial waste heat recovery, geothermal power generation, solar thermal power generation, and waste heat recovery from vehicle engines. As the core working component of the ORC system, the expander's performance directly determines the overall energy conversion efficiency and operational reliability of the machine.

[0003] Currently, most small ORC expanders adopt piston or scroll structures, but each has its own insurmountable technical defects:

[0004] 1. The piston / scroll structure has many moving parts with friction pairs, resulting in high wear under high-speed conditions and poor compatibility with low-viscosity working fluid R245fa.

[0005] 2. Traditional turboexpanders have bulky chambers and flow channel designs that are designed for high-temperature steam. Low-boiling-point organic working fluids have high flow resistance and low expansion efficiency.

[0006] 3. The shaft end sealing structure is simple, and the low-boiling-point working fluid has strong permeability, making it prone to leakage during long-term operation;

[0007] 4. The split-type casing is complex to assemble, and the impeller is difficult to disassemble and maintain, making it unsuitable for the compact installation requirements of vehicle-mounted small ORC units.

[0008] Currently, there is a lack of compact, reliably sealed, and small-sized radial turbine expanders specifically optimized for R245fa cryogenic working fluid. Therefore, considering the shortcomings of the above-mentioned solutions in practical manufacturing and implementation, an ORC expander is provided to solve the aforementioned technical problems. Summary of the Invention

[0009] This invention proposes an ORC expander, which solves the problems in the prior art.

[0010] The technical solution of the present invention is implemented as follows: An ORC expander includes a housing, the housing having an inner cavity, an inlet pipe assembly disposed on the side of the housing, an outlet disposed on the side of the housing, and an impeller rotatably mounted inside the inner cavity; the inlet pipe assembly includes at least one first inlet pipe and one second inlet pipe, the first inlet pipe and the second inlet pipe being disposed opposite to each other, high-pressure working fluid entering the inner cavity through the first inlet pipe and the second inlet pipe impacts the impeller in the inner cavity to do work, and the working fluid after doing work is discharged through the outlet.

[0011] With the above settings, the dual-inlet symmetrical air intake ensures that the impeller is subjected to balanced forces on both sides, improves the smoothness of operation, extends the bearing life, and reduces the vibration and noise of the whole machine. The evenly distributed multiple inlets converge in the cavity to form an annular tapering guide channel, which solves the problem of uneven circumferential flow distribution in the annular channel of the single-inlet scheme and ensures that each blade is subjected to uniform forces.

[0012] In a preferred embodiment, the first inlet pipe and the second inlet pipe are respectively inclined, and the angle between the first inlet pipe, the second inlet pipe and the horizontal line is 10 degrees to 50 degrees.

[0013] The inlet pipe is tilted so that the direction of the working fluid injection is perpendicular to the impeller blade surface, reducing flow diversion losses; at the same time, this angle range makes the inlet pipe occupy less space in the horizontal direction, which is suitable for compact vehicle installation.

[0014] In a preferred embodiment, the housing includes an outer shell and a cover plate, the cover plate being fixedly connected to the outer shell, the space between the cover plate and the outer shell forming the inner cavity, the cover plate being provided with a channel, and the end of the channel away from the outer shell forming the outlet.

[0015] The outer shell and cover are designed separately, and the internal components can be installed and removed axially for easy maintenance; at the same time, the outlet is located in the middle of the cover, which matches the centripetal flow path of "in from the outer periphery and out from the center", resulting in low exhaust back pressure.

[0016] In a preferred embodiment, the cross-section of the outlet is rectangular or circular.

[0017] This design allows for easy connection of rectangular outlets to flat pipes, providing flexible interface adaptation in compact space scenarios, while also reducing the cost of processing rectangular cross-sections.

[0018] In a preferred embodiment, the impeller includes a turntable with multiple blades evenly distributed along the circumference of the turntable, forming a working fluid flow channel between adjacent blades.

[0019] With the above settings, the evenly distributed blades ensure excellent dynamic balance and require no additional balancing weight; the flow distribution of each blade is consistent, the stress is uniform, and the fatigue life is long; the channels between adjacent blades provide an orderly flow path for the working fluid to expand and do work.

[0020] In a preferred embodiment, a boss is provided at the center of the turntable, and multiple guide vanes are provided on the boss, which are evenly distributed along the circumference of the boss.

[0021] With the above configuration, the guide vanes on the boss rectify and guide the low-pressure working fluid after it has done work, reducing the outlet eddy current loss. At the same time, the evenly distributed guide vanes make the outlet flow symmetrical, avoiding the additional radial force on the bearing caused by the deflected flow.

[0022] In a preferred embodiment, the impeller is fixedly connected to a rotating shaft, which extends outward through the housing;

[0023] In a preferred embodiment, a fixing cylinder is fixedly provided on the side of the outer shell, and the rotating shaft passes through the fixing cylinder and extends out of the outer shell.

[0024] The fixed sleeve provides a supporting reference for the rotating shaft, ensuring coaxiality; the fixed sleeve also provides installation space for bearings and seals, facilitating axial integration.

[0025] In a preferred embodiment, the rotating shaft is fitted with a bearing, which is located between the inner wall of the fixed cylinder and the outer wall of the rotating shaft.

[0026] The bearings are designed to significantly reduce frictional losses, allowing for higher speeds; the bearings simultaneously bear radial and axial loads, ensuring precise alignment of the shaft.

[0027] In a preferred embodiment, the rotating shaft is fitted with a sealing ring, which is located at the end of the rotating shaft near the inner cavity.

[0028] A sealing ring is installed to block the working medium at the beginning of the leakage path, resulting in a good sealing effect.

[0029] The beneficial effects of this invention after adopting the above technical solution are as follows: This invention achieves uniform circumferential air intake and force balance of the impeller through the symmetrical intake of two inlets converging within the cavity to form an annular tapering flow channel, resulting in low operating vibration and long bearing life; the inlet pipe is inclined, minimizing flow loss and ensuring compact axial dimensions. The separate outer shell and cover plate allow for quick axial disassembly, eliminating the need for pipe disassembly during maintenance, making it suitable for confined vehicle spaces; the outlet is centrally located on the cover plate, resulting in low exhaust back pressure and smooth flow. The impeller uses evenly distributed radial blades, providing excellent dynamic balance, and the expansion channels formed between the blades enhance working efficiency; the central guide vane reduces outlet eddy current losses. The fixed cylinder and shell are integrated to ensure coaxiality, and the built-in bearing reduces friction loss and supports high-speed operation; the front-mounted sealing ring prevents working fluid leakage and protects the bearing. The overall design achieves axial integration of support, sealing, and transmission, resulting in a small size, high efficiency, and reliable sealing. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the prototype structure of the present invention;

[0033] Figure 3 for Figure 2 Schematic diagram of the AA structure (section view);

[0034] Figure 4 This is a schematic diagram of the structure of the cover plate;

[0035] Figure 5 This is a schematic diagram of the cross-sectional structure of the outer shell;

[0036] Figure 6 This is a schematic diagram of the impeller structure.

[0037] In the diagram, 1 is the outer casing; 101 is the first inlet pipe; 102 is the second inlet pipe; 2 is the cover plate; 201 is the bottom plate; 202 is the outlet; 203 is the channel; 3 is the impeller; 301 is the turntable; 302 is the blade; 303 is the boss; 304 is the guide vane; 305 is the shaft; 4 is the bearing; 5 is the sealing ring; 6 is the snap ring; and 7 is the high-pressure hose. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] like Figures 1 to 3As shown, an ORC expander includes a housing with an inner cavity. An inlet pipe assembly is provided on the side of the housing. The inlet pipe assembly includes at least one first inlet pipe 101 and a second inlet pipe 102. An outlet 202 is provided on the side of the housing. An impeller 3 is rotatably mounted in the inner cavity. Multiple sets of inlet pipe assemblies are evenly arranged along the circumference of the housing. In this embodiment, the inlet pipe assembly consists of one first inlet pipe 101 and one second inlet pipe 102. The first inlet pipe 101 and the second inlet pipe 102 are arranged opposite to each other. The working fluid entering the inner cavity through the first inlet pipe 101 and the second inlet pipe 102 converges in the inner cavity to form an annular tapered guide channel. The working fluid accelerated by the annular tapered guide channel impacts the impeller 3 to do work. The working fluid after doing work is discharged through the outlet 202.

[0040] Specifically, the first inlet pipe 101 and the second inlet pipe 102 are equipped with high-pressure hoses 7, through which the working medium is injected into the inner cavity.

[0041] In this embodiment, the outer shell 1 and the cover plate 2 are used. The outer shell 1 is a one-piece cast cavity with no seams. The side of the outer shell 1 has a first inlet pipe 101 and a second inlet pipe 102 for connecting the high-pressure gaseous R245fa working fluid from the heat exchanger.

[0042] The first inlet pipe 101 and the second inlet pipe 102 are respectively inclined, and the angle A between the first inlet pipe 101, the second inlet pipe 102 and the horizontal line is 10 degrees to 50 degrees. In this embodiment, it is 30 degrees.

[0043] The cover plate 2 is fixedly connected to the outer shell 1, and the space between the cover plate 2 and the outer shell 1 forms an inner cavity. The cover plate 2 is provided with a channel 203, and the end of the channel 203 away from the outer shell 1 forms an outlet 202. The cross-section of the outlet 202 is rectangular.

[0044] The impeller 3 includes a turntable 301, on which multiple blades 302 are provided. The multiple blades 302 are evenly distributed along the circumference of the turntable 301, and a working fluid flow channel 203 is formed between adjacent blades 302.

[0045] An annular tapering guide channel is formed inside the casing. The cross-sectional area of ​​this channel gradually decreases along the flow direction of the working fluid, and the channel outlet 202 faces the inlet direction of the outer peripheral blade 302 of the impeller 3. After the high-pressure gaseous working fluid enters from the first inlet pipe 101 and the second inlet pipe 102 of the ORC working fluid, it is accelerated by the annular tapering guide channel and evenly distributed along the circumference of the impeller 3, impacting the outer peripheral blade 302 of the impeller 3 at the designed angle.

[0046] A boss 303 is provided at the center of the turntable 301, and multiple guide vanes 304 are provided on the boss 303. The multiple guide vanes 304 are evenly distributed along the circumference of the boss 303.

[0047] The impeller 3 is fixedly connected to a rotating shaft 305, which extends outward through the housing; a fixed cylinder is fixedly installed on the side of the housing 1, through which the rotating shaft 305 passes and extends out of the housing.

[0048] Impeller 3 is located at the center of the flow channel inside the casing and adopts a radial turbine blade 302 structure. Several curved blades 302 are evenly distributed on the outer circumference of impeller 3, and the profile of each blade 302 is optimized according to the flow velocity field of R245fa gaseous working fluid under design conditions. During operation, the high-pressure working fluid flows radially inward from the outer circumference of impeller 3 (radial flow), driving the blades 302 to rotate, which in turn drives impeller 3 and the shaft 305 fixed at the center of impeller 3 to rotate, outputting mechanical torque. The shaft 305 of impeller 3 extends outward through bearing 4, and the end is provided with a power output interface (such as a keyway or spline) for connecting an external generator or other rotating load.

[0049] The rotating shaft 305 is fitted with a bearing 4, which is located between the inner wall of the fixed cylinder and the outer wall of the rotating shaft 305.

[0050] The rotating shaft 305 is fitted with a sealing ring 5, which is located at the end of the rotating shaft 305 near the inner cavity.

[0051] One end of the outer casing 1 is open, allowing the impeller 3, bearing 4, and sealing ring 5 to be installed along the shaft 305. The bearing 4 is axially fixed by a snap ring 6. This open end is sealed to the cover plate 2. The overall cavity volume of the casing is determined according to the design expansion ratio of the R245fa working fluid.

[0052] Bearing 4 is fitted onto the outside of rotating shaft 305, installed between the central bearing 4 seat of the housing and the central mating hole of outlet 202 cover plate 2, providing rotational support for rotating shaft 305 and ensuring that impeller 3 remains aligned during high-speed rotation. An annular sealing ring 55 is installed between the bearing 44 and the mating surfaces of the housing and outlet 202 cover plate 2. This sealing ring 5 performs two sealing functions simultaneously: one is located between the flange face of the open end of the housing and the flange face of outlet 202 cover plate 2, preventing leakage of the working medium outward along the flange gap; the other is located in the rotational fit gap between the central hole of outlet 202 cover plate 2 and rotating shaft 305, preventing leakage of the working medium outward along the main shaft. Both seals are simultaneously achieved by the same sealing ring 55 with a specific cross-sectional structure, forming a double sealing barrier.

[0053] In this embodiment, the cover plate 2 seals the open end of the outer casing 1 and is fastened to the outer casing 1 with bolts. A working fluid outlet 202 is opened in the middle of the cover plate 2, through which the low-pressure gaseous working fluid, after expansion and work, is discharged and sent to the condenser via an external pipeline. A sealing ring 5 is pressed between the inner end face of the cover plate 2 and the surface of the outer casing 1, while a dynamic seal is achieved between the inner wall of the central hole of the cover plate 2 and the outer wall of the main shaft by an extended sealing lip of the same sealing ring 5. The cover plate 2 and the outer casing 1 are detachably connected; after removing the cover plate 2, the impeller 3, bearing 4, and sealing ring 5 can be removed sequentially along the axial direction.

[0054] Working principle: High-pressure gaseous R245fa organic working fluid enters the annular tapering guide channel of the shell through the first inlet pipe 101 and the second inlet pipe 102. After being accelerated in the tapering channel, it is evenly distributed along the circumference of the impeller 3 and is injected into the radial blades 302 of the impeller 3 at the designed impact angle. The kinetic energy and internal energy of the working fluid act on the curved surface of the blades 302, generating a circumferential driving torque, which drives the impeller 32 and the main shaft to rotate at high speed, converting the thermal energy of the working fluid into the mechanical torque output by the main shaft.

[0055] During the work process, the temperature and pressure of the working fluid decrease significantly, turning into a low-pressure gaseous working fluid. It flows through the central region of the impeller 3 to the outlet 202 of the cover plate 23 and is discharged to the external condenser.

[0056] The rotating shaft 305 is supported by the bearing 4 to ensure high-speed and stable operation. The sealing ring 5 simultaneously blocks two leakage paths: (1) the static gap between the outer shell 1 and the cover plate 2; (2) the dynamic rotation gap between the center hole of the cover plate 2 and the shaft of the rotating shaft 305. The dual sealing works together to effectively prevent the leakage of the highly permeable R245fa working fluid and maintain the closed circulation of the system.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ORC expander, comprising a housing, characterized in that, The housing has an inner cavity, an inlet pipe assembly is provided on the side of the housing, an outlet (202) is provided on the side of the housing, and an impeller (3) is rotatably mounted in the inner cavity; the inlet pipe assembly includes at least one first inlet pipe (101) and one second inlet pipe (102). The first inlet pipe (101) and the second inlet pipe (102) are arranged opposite to each other. The high-pressure working medium entering the inner cavity through the first inlet pipe (101) and the second inlet pipe (102) impacts the impeller (3) in the inner cavity to do work. The working medium after doing work is discharged through the outlet (202).

2. An ORC expander according to claim 1, characterized in that, The first inlet pipe (101) and the second inlet pipe (102) are respectively or all of them are evenly distributed and inclined. The angle between the first inlet pipe (101) and the second inlet pipe (102) and the horizontal line is 10 degrees to 50 degrees.

3. An ORC expander according to claim 1, characterized in that, The housing includes an outer shell (1) and a cover plate (2). The cover plate (2) is fixedly connected to the outer shell (1). The space between the cover plate (2) and the outer shell (1) forms the inner cavity. The cover plate (2) is provided with a channel (203). The end of the channel (203) away from the outer shell (1) forms the outlet (202).

4. An ORC expander according to claim 3, characterized in that, The cross-section of the outlet (202) is rectangular or circular, which will be determined based on the condenser interface.

5. An ORC expander according to claim 1, characterized in that, The impeller (3) includes a turntable (301) on which multiple blades (302) are provided. The multiple blades (302) are evenly distributed along the circumference of the turntable (301), and a working fluid flow channel (203) is formed between adjacent blades (302).

6. An ORC expander according to claim 5, characterized in that, A boss (303) is provided at the center of the turntable (301), and a plurality of guide vanes (304) are provided on the boss (303). The plurality of guide vanes (304) are evenly distributed along the circumference of the boss (303).

7. An ORC expander according to claim 1, characterized in that, The impeller (3) is fixedly connected to a rotating shaft (305), which extends outward through the housing.

8. An ORC expander according to claim 1, characterized in that, A fixing cylinder is fixedly provided on the side of the outer shell (1), and the rotating shaft (305) passes through the fixing cylinder and extends out of the outer shell.

9. An ORC expander according to claim 7, characterized in that, The rotating shaft (305) is fitted with a bearing (4), which is located between the inner wall of the fixed cylinder and the outer wall of the rotating shaft (305).

10. An ORC expander according to claim 7, characterized in that, The rotating shaft (305) is fitted with a sealing ring (5), which is located at one end of the rotating shaft (305) near the inner cavity.

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