Vibration reduction device and method for free piston Stirling generator

Abstract

The invention provides a damping device for a free piston Stirling generator, and particularly relates to the technical field of power generation equipment.The damping device for the free piston Stirling generator comprises a generator body and a damping mechanism, the vibration reduction mechanism comprises an inertia pipe and a vibration damper, the vibration damper is fixed to the outer side of the generator body, a vibration reduction piston is arranged in the vibration damper, and a flowing working medium led out of the compression cavity flows into the vibration damper through the inertia pipe and drives the vibration damper to conduct movement vibration reduction. Passive vibration reduction can be achieved, self vibration reduction of the generator can be achieved without external energy input, and the structure is simpler.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation equipment, and particularly to a vibration damping device and method for a free piston Stirling generator. Background Art

[0002] A Stirling generator is an external combustion generator with a closed cycle. It can not only utilize renewable energy such as solar energy, geothermal energy, and hydrogen energy, but also utilize low-quality heat sources such as industrial waste heat and urban waste heat. It has a wide range of application scenarios and does not produce polluting gases during the heat conversion process to pollute the environment.

[0003] Since a Stirling generator has two pistons with high-frequency motion, the vibration of the pistons will cause the vibration of the entire generator, affecting the reliability and stability of the system. This will lead to inaccurate experimental data or equipment failure. Therefore, it is necessary to solve the vibration problem of the generator. The existing vibration damping methods for Stirling generators are mainly divided into active and passive vibration damping. The methods represented by the vibration damping methods of dual-machine opposed vibration damping, sharing an expansion chamber or a compression chamber by two generators, and adding an active damper will cause the volume of the entire device to be too large, or require external energy input to achieve vibration damping, resulting in a complex overall structure. Summary of the Invention

[0004] In order to solve the problems that the existing vibration damping devices will make the generator too large in volume or the overall system complex, etc., the present invention proposes a vibration damping device and method for a free piston Stirling generator.

[0005] The present invention is achieved through the following technical solutions:

[0006] The vibration damping device for a free piston Stirling generator proposed by the present invention includes a generator main body and a vibration damping mechanism, wherein:

[0007] A compression chamber is provided inside the generator main body. The vibration damping mechanism includes a generator main body and a vibration damping mechanism, wherein:

[0008] A compression chamber is provided inside the generator main body. The vibration damping mechanism includes an inertia tube and a damper. The damper is fixed outside the generator main body. A vibration damping piston is provided inside the damper. The flowing working medium led out from the compression chamber flows into the damper through the inertia tube and drives the damper to perform motion vibration damping.

[0009] Further, the damper includes an additional housing, the additional housing is hermetically arranged outside the generator main body, a vibration damping cylinder is provided inside the additional housing, a damping piston is provided inside the vibration damping cylinder, a vibration damping chamber is provided between the top of the vibration damping cylinder and the additional housing, and both ends of the inertia tube are connected to the compression chamber and the vibration damping chamber.

[0010] Further, the damping mechanism further includes a needle valve, and the needle valve is arranged on the inertia tube.

[0011] Further, the generator main body further includes a housing, and the housing is connected to the damping mechanism.

[0012] Further, a power piston and a gas distribution piston are arranged inside the housing. The power piston is arranged at the top of the housing, and the gas distribution piston is arranged at the bottom of the housing. An expansion chamber is formed at the bottom of the gas distribution piston, and the compression chamber is located between the gas distribution piston and the power piston.

[0013] Further, the generator main body further includes a motor arranged at the bottom of the power piston. A main body cylinder is arranged inside the motor. The power piston cooperates with the main body cylinder. A coil is wound around the side of the power piston. The power piston drives the coil to move, and electric energy is generated in cooperation with the motor.

[0014] Further, a plurality of leaf springs are further included. The leaf springs are respectively arranged at the top of the gas distribution piston, the top of the power piston, and the bottom of the damping piston. The top of the gas distribution piston penetrates through the power piston and is connected to the leaf spring.

[0015] Further, a power piston bracket and a gas distribution piston bracket are further included. The power piston bracket is arranged at the bottom of the leaf spring connected to the power piston and is fixed to the leaf spring. The gas distribution piston bracket is arranged at the bottom of the leaf spring connected to the gas distribution piston and is fixed to the leaf spring.

[0016] Further, a heater, a regenerator, and a cooler are further arranged between the housing and the gas distribution piston. The cooler, the regenerator, and the heater are arranged in sequence from top to bottom. The working medium flows between the compression chamber, the cooler, the regenerator, the heater, and the expansion chamber to form a complete thermodynamic cycle.

[0017] Further, a method for damping a free piston Stirling generator includes the following steps:

[0018] When the generator main body is running, under the action of the motor, the pressure wave drives the power piston to reciprocate at the equilibrium position. The working medium led out from the compression chamber with fluctuating pressure of the working medium sequentially passes through the inertia tube and the needle valve and flows into the damping chamber, and drives the damping piston to move, adjusting the diameter, length of the inertia tube, and the opening of the needle valve, so that the sum of the momenta of the power piston, the gas distribution piston, and the damping piston is zero.

[0019] Advantages of the present invention:

[0020] (1) The damping device for a free piston Stirling generator proposed by the present invention uses the form of an additional damping piston, which can achieve passive damping and can achieve the damping of the generator itself without external energy input.

[0021] (2) The vibration damping device for a free piston Stirling generator proposed by the present invention utilizes an additional vibration damping mechanism. Compared with the active vibration damping and the dual-machine opposed vibration damping methods, the experimental device has a smaller volume and lighter weight.

[0022] (3) The vibration damping device for a free piston Stirling generator proposed by the present invention uses the pressure change in the compression chamber to drive the movement of the vibration damping piston, without the need to change the original structure of the generator, with lower cost and simpler structure. Brief Description of the Drawings

[0023] Figure 1 is a structural diagram of the vibration damping device for a free piston Stirling generator of the present invention;

[0024] In the figure: heater 1, regenerator 2, cooler 3, compression chamber 4, motor 5, power piston 6, leaf spring 7, damping piston 8, additional housing 9, expansion chamber 10, gas distribution piston 11, outer shell 12, main cylinder 13, inertia tube 14, power piston bracket 15, gas distribution piston bracket 16, needle valve 17, damping cylinder 18, damping chamber 19;

[0025] The realization, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0026] In order to more clearly and completely illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0027] Please refer to Figure 1 , the present invention proposes a vibration damping device for a free piston Stirling generator 5, which includes a generator 5 main body and a vibration damping mechanism, wherein:

[0028] A compression chamber 4 is arranged inside the generator 5 main body. The vibration damping mechanism includes an inertia tube 14 and a shock absorber. The shock absorber is fixed outside the generator 5 main body. A damping piston 8 is arranged inside the shock absorber. The flowing working medium led out from the compression chamber 4 flows into the shock absorber through the inertia tube 14 and drives the shock absorber to perform vibration damping.

[0029] In the specific embodiment, when the generator 5 main body is running, an alternating pressure fluctuation will be generated inside the compression chamber 4. Part of the flowing working medium led out from the compression chamber 4 flows into the shock absorber through the inertia tube 14 and drives the damping piston of the shock absorber to move, thereby completing the vibration damping. The vibration damping is realized by using the pressure fluctuation in the pressure chamber, and the vibration damping of the generator 5 itself can be realized without external energy, and the operation is more convenient.

[0030] Furthermore, the shock absorber includes an additional housing 9, which is hermetically arranged outside the main body of the generator 5. An anti-vibration cylinder 18 is arranged inside the additional housing 9, and a shock piston is arranged inside the anti-vibration cylinder 18. An anti-vibration cavity 19 is arranged between the top of the anti-vibration cylinder 18 and the additional housing 9. Both ends of the inertia tube 14 are connected to the compression cavity 4 and the anti-vibration cavity 19.

[0031] In a specific embodiment, the shock piston 8 is arranged inside the anti-vibration cylinder 18. The anti-vibration cavity 19 is formed between the top of the shock piston 8 and the anti-vibration cylinder 18. The anti-vibration cavity 19 is communicated with the compression cavity 4 through the inertia tube 14. When the internal pressure of the compression cavity 4 fluctuates, part of the working medium enters the anti-vibration cavity 19. The fluctuating pressure in the anti-vibration cavity causes the shock piston to reciprocate on both sides of the equilibrium position.

[0032] Furthermore, the shock absorption mechanism further includes a needle valve 17, which is arranged on the inertia tube 14.

[0033] In a specific embodiment, the needle valve 17 is used to control the on-off of the inertia tube 14. By adjusting the opening degree of the needle valve 17, the amplitude of the pressure wave in the anti-vibration cavity 19 can be adjusted.

[0034] In one embodiment, the phase and amplitude of the pressure wave can be adjusted by adjusting the diameter, length of the inertia tube 14 and the opening degree of the needle valve 17, thereby adjusting the changes in the amplitude and phase of the shock piston 8 and achieving the shock absorption effect.

[0035] Furthermore, the main body of the generator 5 further includes a housing 12, which is connected to the shock absorption mechanism.

[0036] Furthermore, a power piston 6 and a gas distribution piston 11 are arranged inside the housing 12. The power piston 6 is arranged at the top of the housing 12, and the gas distribution piston 11 is arranged at the bottom of the housing 12. An expansion cavity 10 is formed at the bottom of the gas distribution piston 11. The compression cavity 4 is located between the gas distribution piston 11 and the power piston 6.

[0037] Furthermore, the main body of the generator 5 further includes a motor 5 arranged at the bottom of the power piston 6. A main body cylinder 13 is arranged inside the motor 5. The power piston 6 cooperates with the main body cylinder 13. A coil is wound around the side of the power piston 6. The power piston 6 drives the coil to move and generates electric energy in cooperation with the motor 5.

[0038] Furthermore, a heater 1, a regenerator 2 and a cooler 3 are arranged on the inner wall of the bottom of the housing 12. The cooler 3, the regenerator 2 and the heater 1 are arranged in sequence from top to bottom.

[0039] Further, it also includes a power piston 6 bracket 15 and a gas distribution piston 11 bracket 16. The power piston 6 bracket 15 is arranged at the bottom of the leaf spring 7 connected to the power piston 6 and fixed to the leaf spring 7. The gas distribution piston 11 bracket 16 is arranged at the bottom of the leaf spring 7 connected to the gas distribution piston 11 and fixed to the leaf spring 7.

[0040] Further, a heater 1, a regenerator 2, and a cooler 3 are also arranged between the outer shell 12 and the gas distribution piston 11. The cooler 3, the regenerator 2, and the heater 1 are arranged in sequence from top to bottom. The working medium flows between the compression chamber 4, the cooler 3, the regenerator 2, the heater 1, and the expansion chamber 10 to form a complete thermodynamic cycle.

[0041] In the specific implementation, the main body of the generator 5 is the structure of an existing free piston Stirling generator 5. The heater 1 is used to absorb external heat to heat the working medium in the expansion chamber 10. The cooler 3 is used to cool the working medium in the compression chamber 4. The regenerator 2 absorbs and releases heat during the working medium cycle to further improve the thermal efficiency of the Stirling generator. The regenerator 2 recovers and utilizes the heat energy lost during the cooling process, and the heater 1 is responsible for providing new heat energy to maintain the operation of the system.

[0042] In one embodiment, when assembling, the following steps are included:

[0043] S1. First, install the heater 1 into the outer shell 12, fix it by brazing, and fill it with wire mesh to form the regenerator 2. The upper part of the regenerator 2 is fixed to the cooler 3 by screws.

[0044] S2. Fix the motor 5 to the cooler 3 by screws. Then, install the main body cylinder 13 into the hole in the middle of the motor 5 and fix it to the motor 5. Subsequently, install the gas distribution piston 11 into the main body cylinder 13.

[0045] S3. Fix the power piston 6 bracket 15 and the motor 5 by screws. Subsequently, combine the leaf spring 7 and the power piston 6 into a whole and install them into the hollow position of the motor 5.

[0046] S4. Fix one leaf spring 7 to the power piston 6 bracket 15 and cooperate with the bottom of the gas distribution piston 11 bracket 16 at the same time. Then, fix the other leaf spring 7 to the top of the gas distribution piston 11 bracket 16 to support the gas distribution piston 11 and enclose and install the entire outer shell 12 of the generator 5 main body.

[0047] S5. Install the damping cylinder 18 into the additional housing 9 and fix it by screws. Subsequently, fix the third leaf spring 7 to the damping piston 8 and install it into the damping cylinder 18 to form a damper.

[0048] S6. Fix the shock absorber and the main body of the generator 5 together with screws, and connect the compression chamber 4 and the shock absorption chamber 19 through the inertia tube 14.

[0049] Furthermore, a method for damping the free piston Stirling generator 5 includes the following steps:

[0050] When the main body of the generator 5 operates, under the action of the motor 5, the pressure wave drives the power piston 6 to reciprocate at the equilibrium position. The working medium drawn from the compression chamber 4 with fluctuating working medium pressure flows through the inertia tube 14 and the needle valve 17 in sequence and then flows into the shock absorption chamber 19, driving the shock absorption piston 8 to move. Adjust the diameter, length of the inertia tube 14 and the opening degree of the needle valve 17 so that the sum of the momenta of the power piston 6, the gas distribution piston 11 and the shock absorption piston 8 is zero.

[0051] In the specific implementation, assume m p 、m d 、m a are the masses of the power piston 6, the gas distribution piston 11 and the shock absorption piston 8 respectively, and v p 、v d 、v a are the moving speeds of the power piston 6, the gas distribution piston 11 and the shock absorption piston 8 respectively. Adjust the diameter, length of the inertia tube 14 and the opening degree of the needle valve 17 to adjust the phase and amplitude of the pressure wave, and further adjust the changes in the piston amplitude and phase, so that m p v p +m d v d +m a v a = 0, achieving the purpose of no vibration of the housing 12.

[0052] Certainly, the present invention may also have many other implementation manners. Based on this implementation manner, other implementation manners obtained by those of ordinary skill in the art without any creative labor belong to the scope protected by the present invention.

Claims

1. A vibration reduction device for a free piston Stirling generator, characterized in that: It includes a generator body and a vibration reduction mechanism, wherein: A compression chamber is arranged inside the generator body, and the vibration reduction mechanism includes an inertia tube and a vibration reduction device. The vibration reduction device is fixed to the outside of the generator body, and a vibration reduction piston is arranged inside the vibration reduction device. The flowing working medium drawn out of the compression chamber flows into the vibration reduction chamber through the inertia tube, and drives the vibration reduction device to perform motion vibration reduction.

2. The vibration reduction device for a free piston Stirling generator according to claim 1, characterized in that: The shock absorber comprises an additional shell, which is sealed and arranged on the outside of the generator body. A shock-absorbing cylinder is arranged inside the additional shell, a shock-absorbing piston is arranged inside the shock-absorbing cylinder, a shock-absorbing chamber is arranged between the top of the shock-absorbing cylinder and the additional shell, and two ends of the inertia tube are connected to the compression chamber and the shock-absorbing chamber.

3. The vibration reduction device for a free piston Stirling generator according to claim 1, characterized in that: The vibration reduction mechanism further includes a needle valve, and the needle valve is arranged on the inertia tube.

4. The vibration reduction device for a free piston Stirling generator according to claim 1, characterized in that: The generator body further includes a casing, and the casing is connected to the vibration reduction mechanism.

5. The vibration reduction device for a free piston Stirling generator according to claim 4, characterized in that: The shell is internally provided with a power piston and a gas distribution piston, wherein the power piston is arranged at the top of the shell, and the gas distribution piston is arranged at the bottom of the shell. An expansion chamber is formed at the bottom of the gas distribution piston, and the compression chamber is located between the gas distribution piston and the power piston.

6. The vibration reduction device for a free piston Stirling generator according to claim 5, characterized in that: The generator body also includes a motor arranged at the bottom of the power piston, a main cylinder is arranged inside the motor, the power piston cooperates with the main cylinder, a coil is wound on the side of the power piston, and the power piston drives the coil to move, thereby generating electrical energy in cooperation with the motor.

7. The vibration reduction device for a free piston Stirling generator according to claim 6, characterized in that: It also includes a plurality of leaf springs, which are respectively arranged on the top of the gas distribution piston, the top of the power piston and the bottom of the damping piston. The top of the gas distribution piston passes through the power piston and is connected with the leaf springs.

8. The vibration reduction device for a free piston Stirling generator according to claim 7, characterized in that: It also includes a power piston bracket and a gas distribution piston bracket. The power piston bracket is arranged at the bottom of the leaf spring connected to the power piston and is fixed to the leaf spring. The gas distribution piston bracket is arranged at the bottom of the leaf spring connected to the gas distribution piston and is fixed to the leaf spring.

9. The vibration reduction device for a free piston Stirling generator according to claim 8, characterized in that: A heater, a regenerator and a cooler are also provided between the shell and the valve piston. The cooler, the regenerator and the heater are arranged in sequence from top to bottom so that the working fluid flows between the compression chamber, the cooler, the regenerator, the heater and the expansion chamber to form a complete thermodynamic cycle.

10. A method for reducing vibration of a free piston Stirling generator, using the vibration reduction device for a free piston Stirling generator according to any one of claims 1 to 9, characterized in that: The following steps are involved: When the generator body is running, under the action of the motor, the pressure wave drives the power piston to reciprocate at the equilibrium position, and the working fluid drawn out from the compression chamber where the working fluid pressure fluctuates flows into the damping chamber through the inertia tube and the needle valve in sequence, and drives the damping piston to move. The diameter and length of the inertia tube and the opening of the needle valve are adjusted to make the sum of the momentum of the power piston, the valve piston and the damping piston zero.

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