CN112012846A - A free-piston Stirling engine - Google Patents

Abstract

The invention relates to the technical field of engines, in particular to a free-piston Stirling engine. The free-piston Stirling engine includes two opposed Stirling mechanisms, a heat source is arranged between the two Stirling mechanisms, each Stirling mechanism includes a casing and a heat pipe heater, two Stirling mechanisms There are communication pipes connected between the forest mechanisms. The communication pipes are respectively connected with two expansion chambers, or the communication pipes are respectively connected with two compression chambers, or the communication pipes are respectively connected with two back chambers. The heat pipe heater includes a heater body and a plurality of heat pipes. The condensing end of each heat pipe is correspondingly arranged inside the embedding hole of each heat pipe, and the evaporating end of each heat pipe is respectively connected to the heat source through the shell. The free-piston Stirling engine of the present invention has a compact structure and reduces the vibration of the engine. Each Stirling mechanism adopts a heat pipe heater to realize heat transmission, which effectively reduces the heat loss in energy transmission. Improve the working efficiency of the engine.

Description

A free-piston Stirling engine

technical field

The invention relates to the technical field of engines, in particular to a free-piston Stirling engine.

Background technique

The free-piston Stirling engine is an externally heated closed-cycle piston engine with the advantages of simple structure, high efficiency and long service life. As a key component of a free-piston Stirling engine, the heater has an important impact on the performance of the engine. Traditional heaters have various specific structures, among which fin heaters and shell-and-tube heaters are widely used.

For a fin heater, the working medium inside the heater is usually gas, and the heat transfer working medium outside the heater is usually a heat transfer fluid. The heat transfer fluid absorbs heat in the heat source and then transfers the heat in the heat exchanger to the gas to be heated. Because the fin heater is processed by wire cutting, not only the processing cost is high, but also with the increase of size, the height of the fin increases, and the thermal conductivity temperature difference will increase.

For the shell-and-tube heater, the working air flows in the circular tube inside the heater, and the heat transfer fluid flows outside the circular tube. Since the heat transfer fluid is in contact with each circular tube, the outer wall temperature of each circular tube is relatively close, the gas in different circular tubes will not have a large temperature difference. However, this structure has the following problems: since the heat exchange of alternating flow is closely related to the heat penetration depth of the gas, in order to ensure better heat exchange, the circular tubes need to be arranged very closely. However, in the actual processing process, it is found that even if the circular tubes are very closely arranged, the flow area ratio of the heat exchanger is relatively small, and with the increase of the heater, the number of circular tubes will reach more than thousands, and the reliability very low.

It can be seen that in the process of heating the gas by the heat-carrying fluid in the traditional heater, there are problems such as complex energy transmission, large heat loss in energy transmission, and corrosion of the heater by the heat-carrying fluid. Moreover, for a single Stirling engine, due to the high-frequency motion of the piston in the engine, the alternating flow of gas and the pressure pulsation, the entire device will have a large vibration, which will affect the engine performance.

SUMMARY OF THE INVENTION

(1) Technical problems to be solved

The purpose of the present invention is to provide a free-piston Stirling engine, which solves the problems of complicated energy transmission and large heat loss in energy transmission in the heater in the existing engine, and the problem that a single Stirling engine is easy to appear when working. Big vibration problem.

(2) Technical solutions

In order to solve the above technical problem, the present invention provides a free-piston Stirling engine, comprising two Stirling mechanisms arranged oppositely, and a heat source is arranged between the two Stirling mechanisms;

Each of the Stirling mechanisms includes a casing and an expansion chamber, a compression chamber, a back chamber and a heat pipe heater respectively arranged in the casing, and the heat pipe heater is arranged in the expansion chamber;

A communication pipe is connected between the two Stirling mechanisms. one of said back cavities;

The heat pipe type heater includes a heater body and a plurality of heat pipes, the first end face of the heater body is provided with a plurality of heat pipe embedding holes corresponding to the heat pipes one-to-one, and the heat pipe embedding holes are staggered. A plurality of gas flow channels are arranged, each of the gas flow channels is arranged to pass through along the first end face of the heater body and the second end face, and each of the gas flow channels is respectively communicated with the expansion chamber; the heat pipe includes The evaporating end and the condensing end, the condensing end of each of the heat pipes are correspondingly arranged inside the embedding holes of each of the heat pipes, and the evaporating ends of each of the heat pipes are respectively connected to the heat source through the casing.

Specifically, a first central through hole is provided in the middle of the heater body, and the first central through hole is penetratingly arranged along the first end face of the heater body to the second end face.

Specifically, each of the heat pipe embedding holes is annularly arranged along the circumferential direction of the first central through hole.

Specifically, each of the gas flow passages is annularly arranged along the circumference of the first central through hole.

Specifically, heat exchange fins are respectively provided in each of the gas flow channels.

Further, a regenerator and a cooler are also arranged in the housing, and the heat pipe heater, regenerator and cooler are connected in sequence.

Further, the middle part of the regenerator is provided with a second central through hole, and the middle part of the cooler is provided with a third central through hole; an ejector is also arranged in the casing, and the ejector is passed through in sequence in the first central through hole, the second central through hole and the third central through hole.

Further, the end of the casing close to the heat source is a heating end, and the end of the casing away from the heat source is a cooling end; the heat pipe heater is located at the heating end of the casing.

Further, a power piston is further provided in the housing, and the power piston is located at the cooling end of the housing.

(3) Beneficial effects

The above-mentioned technical scheme of the present invention has the following advantages:

The free-piston Stirling engine provided by the present invention adopts two oppositely arranged Stirling mechanisms, which can not only reduce the vibration of the engine, but also make the structure more compact. At the same time, the two Stirling mechanisms both use heat pipe heaters. To achieve heat transfer, effectively improve the working efficiency of the engine.

In the free-piston Stirling engine provided by the present invention, the heat source is placed between the two Stirling mechanisms, so that the heat pipes in each heat pipe heater can be arranged in a straight line, and there is no need to set them in a bent structure, thereby reducing the heat pipe. Processing difficulty, thereby reducing manufacturing costs.

In the free-piston Stirling engine provided by the invention, when the heat pipe heater is in operation, when the evaporating end of the heat pipe is heated, the liquid working medium in the heat pipe evaporates rapidly, and the vapor flows to the condensation end of the heat pipe under a small pressure difference, condensing The end then transfers heat to the heater body through thermal conduction. Since the heater body is provided with a plurality of gas flow channels, the reciprocating motion of the gas working medium in the gas flow channel realizes the convection of the gas in the gas flow channel, thereby transferring heat from the heater body to the gas working medium. Compared with the traditional heat exchanger, the heat pipe heater used in the present invention does not need a heat carrier fluid as a heat transfer medium, which not only makes the heating process simpler, but also effectively reduces the heat loss in energy transmission and improves the efficiency of the heat transfer. The heating efficiency of the heater is solved, and the corrosion problem of the heat transfer fluid to the heat exchanger is solved, the life of the heat exchanger is increased, and the working performance of the engine is improved.

Description of drawings

1 is a schematic structural diagram of a free-piston Stirling engine according to an embodiment of the present invention;

2 is a schematic diagram of a Stirling mechanism in a free-piston Stirling engine according to an embodiment of the present invention;

3 is a schematic structural diagram of a heat pipe heater in a free-piston Stirling engine according to an embodiment of the present invention;

4 is a schematic structural diagram of a heater body in a free-piston Stirling engine according to an embodiment of the present invention.

In the figure: 1: Heater body; 101: Heat pipe embedding hole; 102: Gas flow channel; 103: First central through hole; 2: Heat pipe; 201: Evaporating end; 202: Condensing end; 3: Shell; 301: Heating end; 302: Cooling end; 4: Heat pipe heater; 5: Regenerator; 6: Cooler; 7: Expansion chamber; 8: Power piston; 9: Discharger; 10: Heat source; 11: First Stirling mechanism; 12: Second Stirling mechanism; 13: Support frame; 14: Connecting pipe; 15: Compression cavity; 16: Back cavity.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

As shown in FIGS. 1-4 , an embodiment of the present invention provides a free-piston Stirling engine, which includes two Stirling mechanisms arranged opposite to each other, and the two Stirling mechanisms are the first Stirling mechanism 11 and the first Stirling mechanism respectively. The second Stirling mechanism 12 is provided with a heat source 10 between the first Stirling mechanism 11 and the second Stirling mechanism 12 .

Each of the Stirling mechanisms includes a casing 3 and an expansion chamber 7 , a compression chamber 15 , a back chamber 16 and a heat pipe heater 4 respectively arranged in the casing 3 , wherein the heat pipe heater 4 is provided in the expansion chamber 7 .

A communication pipe 14 is connected between the first Stirling mechanism 11 and the second Stirling mechanism 12 . The communication pipes 14 are respectively connected with the two expansion chambers 7 , or the communication pipes 14 are respectively connected with the two compression chambers 15 , or the communication pipes 14 are respectively connected with the two back cavities 16 .

In this embodiment, the communication pipes 14 communicate with the two expansion chambers 7 respectively. By arranging the communication pipes 14, the same components inside the first Stirling mechanism 11 and the second Stirling mechanism 12, which are arranged opposite to each other, can be moved in opposite directions, thereby counteracting the inertial force of the moving components on both sides, thereby reducing the The purpose of small vibrations.

The heat pipe heater 4 includes a heater body 1 and a plurality of heat pipes 2 . The first end surface of the heater body 1 is provided with a plurality of heat pipe embedding holes 101 corresponding to the heat pipes 2 one-to-one, and a plurality of gas flow passages 102 are alternately arranged between the heat pipe embedding holes 101 . Each of the heat pipes 2 is extended from the first end face of the heater body 1 to the second end face, but none of the heat pipes 2 penetrates through the second end face of the heater body 1 . Each of the gas flow passages 102 is disposed through the first end face of the heater body 1 to the second end face, and each of the gas flow passages 102 communicates with the expansion chamber 7 respectively.

The heat pipe 2 includes an evaporation end 201 and a condensation end 202, wherein the condensation end 201 of each heat pipe 2 is correspondingly disposed inside each heat pipe embedding hole 101, and the evaporation end 201 of each heat pipe 2 passes through the heat pipe 2 respectively. The housing 3 is connected to the heat source 10 .

When the heat pipe heater 4 is working, the evaporating end 201 of each heat pipe 2 is heated in the heat source 10, so that the liquid working medium in the heat pipe 2 evaporates rapidly, and the vapor flows to the condensation of the heat pipe 2 under a small pressure difference. The condensing end 202 transfers heat to the heater body 1 through heat conduction. Since the heater body 1 is provided with a plurality of gas flow channels 102 that communicate with the expansion chamber 7 , the gas working medium in each expansion chamber 7 can reciprocate in the gas flow channel 102 , thereby realizing the gas flow in the gas flow channel 102 . Convection in the heater, and then transfer heat from the heater body 1 to the gas working medium to realize the heating of the gas working medium. When the temperature of the gas working medium in the expansion chamber 7 reaches the self-starting temperature, the power piston 8 in the housing 3 starts to vibrate, thereby converting the heat input from the outside into mechanical energy for the reciprocating motion of the power piston 8 .

Compared with the traditional heat exchanger, the heat pipe heater 4 used in this embodiment does not need a heat transfer fluid as a heat transfer medium, which not only makes the heating process simpler, but also effectively reduces the heat loss in energy transmission. The heating efficiency of the heater is improved, the corrosion problem of the heat transfer fluid to the heat exchanger is solved, and the service life of the heat exchanger is increased.

The free-piston Stirling engine described in the present application adopts two oppositely arranged Stirling mechanisms, which can not only effectively reduce the vibration of the engine, but also make the overall structure of the engine more compact. The heat pipe heater 4 is adopted to realize heat transfer, which effectively improves the working efficiency of the engine, thereby improving the working performance of the engine.

In the free-piston Stirling engine described in the present application, the heat source 10 is placed between the first Stirling mechanism 11 and the second Stirling mechanism 12 , so that the heat source 10 in each heat pipe heater 4 is The heat pipes 2 can all be arranged in a straight line, and it is not necessary to set the heat pipes 2 in a bent structure, thereby reducing the processing difficulty of the heat pipes 2 and further reducing the manufacturing cost.

In a further embodiment of the present application, a first central through hole 103 is provided in the middle of the heater body 1 , and the first central through hole 103 penetrates through the first end face of the heater body 1 toward the second end face set up.

In the specific embodiment of the present application, each of the heat pipe embedding holes 101 is uniformly arranged in an annular shape along the circumferential direction of the first central through hole 103 , so that the heater body 1 is uniformly heated by each of the heat pipes 2 .

In the specific embodiment of the present application, each of the gas flow channels 102 is uniformly arranged in an annular shape along the circumferential direction of the first central through hole 103 , so that the gas in each gas flow channel 102 is affected by the heater body 1 . Heat evenly.

In the specific embodiment of the present application, each of the gas flow channels 102 is provided with heat exchange fins (not shown in the figure), and the heat exchange fins are used to enhance the heat exchange effect of the gas in the gas flow channels 102 , thereby further improving the heating efficiency.

In a further embodiment of the present application, a regenerator 5 and a cooler 6 are further provided in the housing 3 , and the heat pipe heater 4 , the regenerator 5 and the cooler 6 are connected in sequence.

The middle part of the regenerator 5 is provided with a second central through hole, the middle part of the cooler 6 is provided with a third central through hole, the first central through hole 103 , the second central through hole and the third central through hole Center through holes are arranged concentrically.

Specifically, an ejector 9 is further provided in the housing 3 , and the ejector 9 penetrates through the first central through hole 103 , the second central through hole and the third central through hole in sequence.

In the specific embodiment of the present application, the end of the casing 3 close to the heat source 10 is the heating end 301 , and the end of the casing 3 away from the heat source 10 is the cooling end 302 .

Wherein, the heat pipe heater 4 is located at the heating end 301 of the casing 3 . Then, the evaporation ends 201 of the heat pipes 2 in the first Stirling mechanism 11 respectively pass through the heating ends 301 of the first Stirling mechanism 11 and are connected to the left end of the heat source 10 . The evaporating ends 201 of the heat pipes 2 in the second Stirling mechanism 12 respectively pass through the heating ends 301 of the second Stirling mechanism 12 and are connected to the right end of the heat source 10 .

In the specific embodiment of the present application, the casing 3 is further provided with a power piston 8 , and the power piston 8 is located at the cooling end 302 of the casing 3 .

In the specific embodiment of the present application, the heat source 10 can heat the evaporating end 201 of each heat pipe 2 by means of combustion heating, or can heat the evaporating end 201 of each heat pipe 2 by means of solar heat collection heating, The evaporation end 201 of each heat pipe 2 can also be heated by means of industrial waste heat, and the surface of the evaporation end 201 of each heat pipe 2 can also be directly heated by coating the surface of the evaporation end 201 of each heat pipe 2 with nuclear fuel.

In a further embodiment of the present application, the first Stirling mechanism 11 and the second Stirling mechanism 12 are connected through a support frame 13 .

Specifically, the support frame 13 is respectively connected to the casing 3 of the first Stirling mechanism 11 and the casing 3 of the second Stirling mechanism 12 , thereby ensuring the stability and strength of the connection.

To sum up, the free-piston Stirling engine according to the embodiment of the present invention adopts two Stirling mechanisms arranged opposite to each other, which can not only reduce the vibration of the engine, but also make the structure more compact. The forest mechanism adopts the heat pipe heater to realize the heat transfer, which effectively improves the working efficiency of the engine.

In the description of the present invention, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integral connection. Ground connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In the description of the present invention, unless otherwise specified, "several" means one or more; "multiple" means two or more; the terms "upper", "lower", "left", The orientation or positional relationship indicated by "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated device. Or elements must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (9)

1. a free-piston Stirling engine, characterized in that: comprising two oppositely arranged Stirling mechanisms, and being provided with a heat source between the two described Stirling mechanisms; Each of the Stirling mechanisms includes a casing and an expansion chamber, a compression chamber, a back chamber and a heat pipe heater respectively arranged in the casing, and the heat pipe heater is arranged in the expansion chamber; A communication pipe is connected between the two Stirling mechanisms. one of said back cavities; The heat pipe type heater includes a heater body and a plurality of heat pipes, the first end face of the heater body is provided with a plurality of heat pipe embedding holes corresponding to the heat pipes one-to-one, and the heat pipe embedding holes are staggered. A plurality of gas flow channels are arranged, each of the gas flow channels is arranged to pass through along the first end face of the heater body and the second end face, and each of the gas flow channels is respectively communicated with the expansion chamber; the heat pipe includes The evaporating end and the condensing end, the condensing end of each of the heat pipes are correspondingly arranged inside the embedding holes of each of the heat pipes, and the evaporating ends of each of the heat pipes are respectively connected to the heat source through the casing. 2 . The free-piston Stirling engine according to claim 1 , wherein a first central through hole is provided in the middle of the heater body, and the first central through hole is along the length of the heater body. 3 . The first end faces through the second end face. 3 . The free-piston Stirling engine according to claim 2 , wherein each of the heat pipe insertion holes is annularly arranged along the circumference of the first central through hole. 4 . 4 . The free-piston Stirling engine according to claim 2 , wherein each of the gas flow passages is annularly arranged along the circumference of the first central through hole. 5 . 5 . The free-piston Stirling engine according to claim 1 , wherein heat exchange fins are respectively provided in each of the gas flow channels. 6 . 6 . The free-piston Stirling engine according to claim 2 , wherein a regenerator and a cooler are further arranged in the casing, and the heat pipe heater, the regenerator and the cooler are connected in sequence. 7 . . 7 . The free-piston Stirling engine according to claim 6 , wherein a second central through hole is arranged in the middle of the regenerator, and a third central through hole is arranged in the middle of the cooler; 7 . An ejector is further provided in the housing, and the ejector is successively penetrated in the first central through hole, the second central through hole and the third central through hole. 8 . The free-piston Stirling engine according to claim 1 , wherein: the end of the casing close to the heat source is a heating end, and the end of the casing far from the heat source is a cooling end; the A heat pipe heater is located at the heating end of the housing. 9 . The free-piston Stirling engine according to claim 8 , wherein a power piston is further provided in the housing, and the power piston is located at the cooling end of the housing. 10 .

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