Stirling engine unit and Stirling engine

Abstract

The application provides a Stirling engine unit and a Stirling engine, wherein the Stirling engine unit comprises: a falling film evaporator, which has a liquid pool inside, the liquid pool is filled with active liquid, and the active liquid can change phase between liquid and gas; a regenerator, which is arranged on the falling film evaporator and communicates with the falling film evaporator, the regenerator is filled with the active liquid, and the gas flow channel of the regenerator is in a flow-through state; and a cooler, which is arranged on the regenerator and communicates with the regenerator; wherein the falling film evaporator, the regenerator and the cooler are filled with basic gas, and the basic gas and the active liquid perform evaporation Stirling cycle in the regenerator. The Stirling engine unit and the Stirling engine provided by the application aim to solve the problem that the traditional evaporation Stirling engine cannot operate stably.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine, in particular to a Stirling engine unit and a Stirling engine. BACKGROUND

[0002] Stirling engine is an external combustion engine, which has the advantages of high efficiency and long service life. However, compared with internal combustion engine and other heat engines that have been widely used, its power density is relatively low. One method to improve the power density is to combine the gas-liquid phase change with the traditional Stirling cycle, which is called the dual-working fluid Stirling cycle. This concept was proposed by American scholars in the 1970s, who found that by adding water to the traditional Stirling engine, the heating temperature of the system can be greatly reduced and the oscillation strength can be improved. However, they failed to build a stable prototype. The main reason is that they failed to realize that the energy conversion in the evaporative Stirling system mainly occurs in the regenerator, not in the expansion chamber and compression chamber, which leads to the design of the regenerator and heat exchanger cannot support the continuous evaporative Stirling cycle.

[0003] In addition, as a heat engine similar to Stirling heat engine in thermodynamics, the wet-type thermoacoustic cycle is found to strengthen the traditional thermoacoustic engine. Compared with the traditional thermoacoustic engine, the wet-type thermoacoustic engine has a lower driving temperature difference, but the existing wet-type thermoacoustic engine is only used for phenomenon demonstration and cannot achieve stable operation due to the lack of liquid circulation loop in the system. In addition, compared with the Stirling cycle, the thermoacoustic engine lacks a solid phase modulation device, so the specific power is lower. SUMMARY

[0004] The present application provides a Stirling engine unit and a Stirling engine to solve the problem that the traditional evaporative Stirling engine cannot operate stably.

[0005] In view of the problems existing in the prior art, the present application provides a Stirling engine unit, which comprises:

[0006] A falling film evaporator, which has a liquid pool inside, and the liquid pool is filled with active liquid that can undergo liquid-gas phase change;

[0007] A regenerator, which is arranged on the falling film evaporator and communicates with the falling film evaporator, and the regenerator is filled with the active liquid and the gas flow channel of the regenerator is in a flow-through state; and

[0008] A cooler, which is arranged on the regenerator and communicates with the regenerator;

[0009] The falling film evaporator, the regenerator and the cooler are filled with a basic gas, the basic gas includes one or more of helium, hydrogen and air, and the basic gas and the active substance undergoes evaporation type Stirling cycle in the regenerator.

[0010] The liquid pool is arranged at the bottom end of the falling film evaporator, the falling film evaporator includes a plurality of fins and a liquid return pipeline, each of the fins is arranged above the liquid pool and is used for evaporating the active substance liquid, and a channel communicating with the regenerator is formed between each of the fins;

[0011] One end of the liquid return pipeline is communicated with the liquid pool, and the other end corresponds to each of the channels, and is used for pumping the active substance liquid in the liquid pool to each of the fins.

[0012] The liquid return pipeline is communicated with a plurality of liquid distribution pipelines at the end away from the liquid pool, and each of the liquid distribution pipelines corresponds to each of the fins.

[0013] According to the Stirling engine unit provided by the application, each of the fins extends along the height direction of the falling film evaporator, and / or each of the fins extends along the width direction of the falling film evaporator.

[0014] According to the Stirling engine unit provided by the application, a one-way valve is arranged on the liquid return pipeline, and the one-way valve is used for unidirectional flow of the active substance liquid in the liquid return pipeline from bottom to top.

[0015] According to the Stirling engine unit provided by the application, the active substance liquid includes water, alcohol, isopropyl alcohol, n-pentane or ammonia.

[0016] According to the Stirling engine unit provided by the application, the regenerator is a porous medium, and the regenerator has a plurality of micro-channels parallel to each other and / or a plurality of micro-pores communicating with each other.

[0017] According to the Stirling engine unit provided by the application, the material of the regenerator has high hydrophilicity, water absorption and capillary effect.

[0018] According to the Stirling engine unit provided by the application, the material of the regenerator includes porous foam, wire mesh or cellulose film.

[0019] The application further provides a Stirling engine, which includes:

[0020] The Stirling engine unit is the Stirling engine unit as described in any one of the above, and the Stirling engine further includes:

[0021] The power unit comprises a linear motor and a displacer, and the power unit is formed with a compression cavity and an expansion cavity, both of which are communicated with the Stirling engine unit.

[0022] The Stirling engine unit provided by the application uses the phase change process of the active substance to strengthen the thermoacoustic conversion of the unit, and the falling film evaporator uses the evaporation of the active substance liquid to reduce the heat transfer temperature difference, which is conducive to reducing the requirement for the temperature of the heat source, and also provides sufficient active substance gas for the mixture working substance to prevent the active substance from being evaporated dry and causing the phase change to stop. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0024] Figure 1 is a cross-sectional view structure schematic diagram of an embodiment of the Stirling engine unit provided by the application;

[0025] Figure 2 is a cross-sectional view structure schematic diagram of an embodiment of the Stirling engine provided by the application;

[0026] Figure 3 is one of the schematic diagrams of the evaporative Stirling cycle (wet type thermoacoustic cycle);

[0027] Figure 4 is the second schematic diagram of the evaporative Stirling cycle (wet type thermoacoustic cycle).

[0028] Reference signs:

[0029] 1: Stirling engine; 2: Stirling engine unit 3: power unit;

[0030] unit;

[0031] 4: falling film evaporator; 5: liquid pool; 6: fin;

[0032] 7: liquid return pipeline; 8: liquid distribution pipeline; 9: one-way valve;

[0033] 10: regenerator; 11: cooler; 12: linear motor;

[0034] 13: ejector; 14: power piston. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of embodiments of the present application, but not all embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0036] In the description of the embodiments of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0037] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0038] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0039] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0040] The following will be described in combination with Figures 1-4 The Stirling engine unit 2 of the present application is described in combination with the Stirling engine 1.

[0041] As described previously, the conventional evaporative Stirling engine cannot be operated stably. In view of this, the present embodiment provides a Stirling engine unit 2, comprising: a falling-film evaporator 4, the falling-film evaporator 4 having a liquid pool 5 therein, the liquid pool 5 being filled with active liquid, the active liquid being capable of phase change between liquid state and gaseous state; a regenerator 10, provided on the falling-film evaporator 4 and in communication with the falling-film evaporator 4, the regenerator 10 being filled with active liquid, the active substance (active liquid + active gas) and the basic gas being subjected to evaporative Stirling cycle in the regenerator 10, it should be noted that the regenerator 10 comprises a solid region and a gas region, the gas region being a plurality of gas flow channels formed in the solid region (solid substance), in the technical solution provided by the present application, the active liquid is only filled in the solid region of the regenerator 10, while the gas flow channels remain in a flowing state; and a cooler 11, provided on the regenerator 10 and in communication with the regenerator 10; wherein the falling-film evaporator 4, the regenerator 10 and the cooler 11 are filled with basic gas, the basic gas comprising one or more of helium, hydrogen and air, of course, other basic gases such as oxygen and nitrogen can also be used, which are not limited by the present application.

[0042] It should be noted that before the system is operated, the regenerator 10 (solid region) needs to be fully wetted by the active liquid through soaking, spraying and the like, at the same time, it should also be ensured that the gas flow channels (micro flow channels) in the regenerator 10 are not blocked by the liquid. When the system is operated, the evaporative Stirling cycle will occur in the micro flow channels of the active substance in the regenerator 10, and the thermal energy will be converted into mechanical energy (acoustic oscillation). In this process, the active substance will undergo periodic evaporation and condensation due to pressure and velocity fluctuations, which is essentially close to a wet-type traveling wave type thermoacoustic cycle. The ideal thermodynamic cycle is as follows: Figures 3-4As shown, it includes four processes: (1) isobaric heat absorption accompanying active substance evaporation; (2) isothermal expansion accompanying active substance evaporation; (3) isobaric heat release accompanying active substance condensation; and (4) isothermal compression accompanying active substance condensation. The above-mentioned thermodynamic cycle will enhance the oscillation intensity of the Stirling cycle engine, improve the specific power and reduce the operating temperature difference of the system.

[0043] The Stirling engine in the prior art only relies on the expansion and compression of the basic gas to convert energy, and the Stirling engine unit 2 provided by the application adopts a mixed working medium to participate in energy conversion (basic gas + active substance gas). Since the active substance liquid can undergo phase change from liquid to gas, the evaporation type Stirling cycle (i.e. wet thermoacoustic effect) using the phase change of the active substance is used to strengthen energy conversion, which is conducive to reducing the required operating temperature difference of the engine system and improving the specific power of the Stirling engine under small temperature difference. In addition, the falling film evaporator 4 is arranged in the application, and the active substance liquid in the liquid pool 5 is evaporated in the falling film evaporator 4, which on the one hand reduces the heat transfer temperature difference and is conducive to reducing the requirement for the temperature of the heat source, and on the other hand provides sufficient active substance gas for the mixed working medium, prevents the active substance from being dried out to stop phase change, and enables the system to realize long-term stable operation.

[0044] Specifically, referring to Figure 1 and Figure 2 , the liquid pool 5 is arranged at the bottom end of the falling film evaporator 4, the falling film evaporator 4 includes a plurality of fins 6 and a liquid return pipeline 7, each fin 6 is arranged above the liquid pool 5 and is used to evaporate the active substance liquid and complete the heat input of the system (the falling film evaporator 4 has a heat source to heat the fins 6), and channels communicating with the regenerator 10 are formed between the fins 6; one end of the liquid return pipeline 7 communicates with the liquid pool 5, and the other end corresponds to each channel and is used to pump the active substance liquid in the liquid pool 5 to the upper end of each fin 6. It can be understood that, during system operation, the active substance liquid in the liquid pool 5 is pumped to the upper end of each fin 6 by the liquid return pipeline 7 under the action of pressure fluctuation, the fin 6 increases the contact area, and the active substance liquid forms a liquid film on the surface of the fin 6 under the action of gravity, evaporates under the heating of the surface of the fin 6, and the evaporated active substance gas rises to the regenerator 10 and the cooler 11 through the channel, and the active substance gas is absorbed by the regenerator 10 after condensation under the cooling action of the cooler 11. Since the active substance will be lost in actual operation, the evaporated active substance gas can ensure that there is always enough active substance to participate in the wet thermoacoustic conversion in the regenerator 10, thereby ensuring long-term stable operation of the system.

[0045] Further, the liquid return pipeline 7 is communicated with a plurality of liquid distribution pipelines 8 at the end away from the liquid pool 5, each liquid distribution pipeline 8 corresponds to each rib 6. The liquid distribution pipeline 8 distributes the active liquid, so that the active liquid can be uniformly distributed to the surface of each rib 6. In the embodiment provided by the application, the rib 6 extends along the height direction of the evaporator, and the liquid flow direction of the liquid return pipeline 7 is the same; of course, the rib 6 can also extend along the width direction of the evaporator, and the liquid flow direction of the liquid return pipeline 7 is orthogonal, and the application does not limit this.

[0046] Due to the influence of gravity, the liquid in the liquid return pipeline 7 will have a downward trend, in order to make the active liquid in the liquid return pipeline 7 flow from bottom to top in one direction, in the technical scheme provided by the application, a one-way valve 9 is arranged on the liquid return pipeline 7, which can ensure the flow direction of the liquid in the liquid return pipeline 7. Of course, the one-way valve 9 is not the only implementation, and the asymmetric structure can also be used to induce the same direction as the liquid flow direction (from bottom to top in the figure) to realize the straight flow, in theory, the gas micro-cluster reciprocates at a fixed position, but the asymmetric structure makes the gas move directionally, so it can push the liquid in a single direction, and the skilled person can select the appropriate way according to the actual situation, and the application does not limit this.

[0047] As described above, the basic gas in the traditional Stirling engine 1 does not change phase, but the active liquid provided by the application will change phase, and the selection of the active substance can be various, such as water, alcohol, isopropyl alcohol, n-pentane or ammonia, which can be selected according to the boiling point, latent heat of vaporization, environment and safety of each substance.

[0048] In the technical scheme provided by the application, the micro-channel in the regenerator 10 will occur the evaporative Stirling cycle, and the heat energy will be converted into mechanical energy (acoustic oscillation), specifically, the regenerator 10 is a porous medium, and the regenerator 10 has a plurality of micro-channels parallel to each other or a plurality of micro-pores communicating with each other. Further, the material of the regenerator 10 has high hydrophilicity, water absorption and capillary effect. Since the regenerator 10 needs to be kept wet, the wet heat sound effect occurs, the hydrophilicity and water absorption can ensure the adhesion and adsorption of the active substance, so that the regenerator 10 can absorb and save the active substance; the capillary effect is because as the reaction occurs, the cold end (the end close to the cooler 11) of the regenerator 10 is often wetter, and the hot end (the end close to the falling film evaporator 4) is drier, so the capillary effect is needed to continuously transport the active substance to the hot end, so that the regenerator 10 can always occur stable evaporative Stirling cycle. In the embodiment provided by the application, the parallel flow channel structure composed of porous foam, stacked wire mesh (surface plated with zeolite) or cellulose membrane can be used as the specific implementation of the regenerator 10.

[0049] On the basis of the above-mentioned Stirling engine unit 2, the application further provides a Stirling engine 1, comprising the Stirling engine unit 2; and a power unit 3, comprising a linear motor 12 and an expeller 13, and the power unit 3 is formed with a compression cavity and an expansion cavity. Figure 2 The compression cavity is communicated with the cooler 11 through a pipeline, and the expansion cavity is communicated with the falling-film evaporator 4 through a pipeline, so that the whole system is uniformly filled with the basic gas, and the expeller 13 is arranged between the compression cavity and the expansion cavity, the compression cavity is connected with the linear motor 12, and the linear motor 12 comprises a power piston 14, a coil, an inner return iron, an outer return iron, a coil support and an elastic member.

[0050] The working principle of the Stirling engine 1 provided by the application is as follows: when the working gas is heated in the falling-film evaporator 4 and the cooler 11 is cooled, the temperature gradient is formed on the wall surface of the regenerator 10. When the temperature gradient reaches a critical value, the self-excited oscillation of the gas in the regenerator 10 is stable wet-type thermoacoustic conversion, the oscillation of the gas is matched with the movement of the linear motor 12 and the expeller 13, so that the system is stably operated. Compared with the traditional free-piston Stirling engine, the phase change of the active substance will increase the oscillation amplitude in the conversion process, so as to improve the specific power and reduce the required operating temperature difference of the system. The movement of the power piston 14 will drive the coil of the linear motor 12 to cut the magnetic induction lines, so as to output electricity to the outside, so as to realize that the generator continuously converts the external heat energy into electrical energy. According to the theoretical calculation result, the system can be operated at a minimum temperature difference of 30 degrees, which is much smaller than the traditional Stirling engine of similar size.

[0051] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application, but not to limit it; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; 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 application.

Claims

1. A Stirling engine unit, characterized in that, include: A falling film evaporator, wherein the falling film evaporator has a liquid pool filled with an active liquid, the active liquid being capable of undergoing a liquid-to-gas phase change; A regenerator is disposed on and connected to the falling film evaporator. The regenerator includes a solid region and a gas region. The gas region consists of multiple gas channels formed within the solid region. The solid region is fully wetted by the active liquid through immersion or spraying. The gas channels of the regenerator are in a flowing state. as well as, A cooler is disposed on the regenerator and communicates with the regenerator; The falling film evaporator, the regenerator, and the cooler are filled with a basic gas, which includes one or more of helium, hydrogen, and air. The basic gas, active liquid, and active gas undergo an evaporative Stirling cycle within the regenerator.

2. The Stirling engine unit according to claim 1, characterized in that, The liquid pool is located at the bottom of the falling film evaporator. The falling film evaporator includes multiple fins and a return liquid pipeline. Each fin is located above the liquid pool and is used to evaporate the active liquid. A channel communicating with the regenerator is formed between each fin. One end of the return pipeline is connected to the liquid pool, and the other end corresponds to each of the channels, used to pump the active liquid in the liquid pool to each of the ribs.

3. The Stirling engine unit according to claim 2, characterized in that, The end of the return liquid pipeline away from the liquid pool is connected to multiple liquid distribution pipelines, and each liquid distribution pipeline corresponds to each of the ribs.

4. The Stirling engine unit according to claim 2, characterized in that, Each of the fins extends along the height direction of the falling film evaporator; and / or, each of the fins extends along the width direction of the falling film evaporator.

5. The Stirling engine unit according to claim 2, characterized in that, A one-way valve is installed on the return pipeline, which is used to allow the active liquid in the return pipeline to flow unidirectionally from bottom to top.

6. The Stirling engine unit according to claim 1, characterized in that, The active liquid includes water, alcohol, isopropanol, n-pentane, or ammonia.

7. The Stirling engine unit according to claim 6, characterized in that, The regenerator is a porous medium, and the regenerator has multiple parallel microchannels; and / or, the regenerator has multiple interconnected micropores.

8. The Stirling engine unit according to claim 7, characterized in that, The material of the regenerator has high hydrophilicity, water absorption and capillary effect.

9. The Stirling engine unit according to claim 7, characterized in that, The regenerator is made of porous foam, wire mesh, or cellulose film.

10. A Stirling engine, characterized in that, include: A Stirling engine unit, wherein the Stirling engine unit is the Stirling engine unit as described in any one of claims 1-9; as well as, The power unit includes a linear motor and an exhaust device. The power unit has a compression chamber and an expansion chamber, both of which are connected to the Stirling engine unit.

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