Separate Stirling engine heater with complementary heat sources
By using heat source complementary partition heaters in the Stirling engine, combining solar radiation and combustion heating, the double sides of the flow interlayer can achieve radiation and convection heat exchange respectively, which solves the stability of the Stirling engine when the solar radiation is insufficient. The operation problem improves the stability and efficiency of the engine.
Patent Information
- Application Number
- CN201811295459.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2018-11-01
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2038-11-01
AI Technical Summary
The existing Stirling engines are difficult to achieve stable operation when the solar radiation is insufficient or there is no time, and additional heat sources are required to provide heating to improve output power and cycling efficiency.
A heat source complementary partitioned Stirling engine heater is used to combine solar radiation and combustion heating, and the double sides of the flow interlayer are used to achieve radiation and convection heat exchange respectively to ensure stable heating of working gas.
It improves the stability and heat source applicability of the Stirling engine, realizes efficient complementarity between solar radiation and combustion heating, and enhances the output power and cycling efficiency of the engine.
Smart Images
Figure CN109404160B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a heat source complementary separated Stirling engine heater, and more specifically to a separated heater and an operating method thereof for realizing light-heat complementation in the Stirling engine heating process. Background Art
[0002] Dish-Stirling solar thermal power generation is the most efficient way of photoelectric conversion in solar thermal power generation technology. At the same time, due to its low power generation, it is suitable for small distributed energy systems. It uses a parabolic concentrator to collect sunlight and reflect it to the focus of the concentrator. The Stirling engine is usually placed near the spot at the focus of the concentrator. The concentrated, high-temperature, high-heat flux heat is absorbed by the Stirling engine heating tube, heating the internal working fluid, converting solar energy into thermal energy, ensuring the stable operation of the Stirling engine, and thus driving the generator to generate electricity.
[0003] The Stirling engine is a piston engine with external heating. The working fluid gas works in a closed heat regeneration cycle, and there is no mass exchange between the working fluid and the outside during the cycle. The Stirling engine has the advantages of low noise, environmental protection, high efficiency and wide applicability of heat sources. Generally, the external working temperature of the heater is high (can reach 850°C) and the internal working fluid pressure is high (maximum 150-250bar). The working volume of the Stirling engine is mainly composed of the following five parts: expansion chamber, compression chamber, heater, regenerator and cooler. Driven by the movement of the piston, the working fluid flows back and forth in the circuit, is heated by the external heat source in the heater, and is cooled by the external cold source in the cooler. Using different heating methods, the corresponding Stirling heater structure has different characteristics. According to existing relevant research, gas-heated heating tubes are generally U-shaped in-line tubes. The heater consists of a certain number of heating tubes evenly arranged along the circumference. A light energy conversion device is installed on the wall of the heating tube, which can transmit radiation of a specific wavelength to heat the corresponding working gas, making the gas absorb heat better. When solar radiation is weak, hot flue gas can be introduced to conduct convection heat exchange with the heating tube. Stirling heating tubes heated by solar radiation are often designed to stretch outward and be axisymmetric as a whole, so as to absorb more solar energy in a limited space. There is also a cavity-type insulation structure surrounding the heater tube to concentrate heat and reduce heat loss.
[0004] Due to the obvious instability of solar radiation, when there is insufficient or no solar radiation, the Stirling engine cannot meet the operating power requirements, so an additional heat source is needed for heating. Combining gas heating with solar heating is a more reasonable choice. Studies have shown that since the flue gas temperature generated by gas is generally below 1000°C and the particulate matter content is low, the convection heat transfer mode is dominant, and the radiation heat transfer accounts for about 31% of the total heat transfer. There are also a lot of studies on strengthening the convection heat transfer between the flue gas and the heating tube to improve the performance of the Stirling engine.
[0005] If the Stirling engine heater can achieve stable heating, the Stirling engine's applicability to heat sources will be improved, which will play an important role in improving the output power and cycle efficiency of the Stirling engine. Summary of the invention
[0006] The purpose of the present invention is to provide a heat source complementary separated Stirling engine heater and its operation method. Solar radiation and combustion heating are used as the heat source of the Stirling engine, and the working fluid gas inside the Stirling engine is heated by radiation and combustion convection heat exchange on both sides of the convection interlayer, which is suitable for the dish-Stirling solar thermal power generation system.
[0007] The use of a heat source complementary separated Stirling engine heater can achieve the complementarity of the heat source of the Stirling engine and improve the stability of the Stirling engine.
[0008] A heat source complementary separated Stirling engine heater of the present invention comprises a radiation heat collection cavity, a combustion nozzle, a combustion cavity, a regenerator, a smoke outlet, a circulation interlayer and a Stirling engine expansion cavity; the radiation heat collection cavity is surrounded by a combustion cavity arranged outside it; the combustion nozzle is located on the peripheral side of the outer wall of the combustion cavity, the smoke outlet is located on the upper and lower end surfaces of the combustion cavity, the circulation interlayer comprises a first channel, a second channel and a plurality of flow channels connecting the first channel and the second channel, each of the flow channels comprises an inner flow channel and an outer flow channel which are interconnected at the top; all the inner flow channels are connected to the first channel, and all the outer flow channels are connected to the second channel;
[0009] The flow channels are evenly arranged in the entity between the inner wall of the combustion chamber and the outer wall of the radiation heat collection chamber; the first channel and the second channel are both located in the lower part of the radiation heat collection chamber; the first channel is connected to the expansion chamber of the Stirling engine, and the second channel is connected to the regenerator. Preferably, the flow channels are arranged vertically. The function of the first channel is to connect the inner flow channel with the expansion chamber of the Stirling engine, respectively, and the function of the second channel is to connect the outer flow channel with the regenerator. When the above functions are met, there is no restriction on the specific structure of the first channel and the second channel.
[0010] The cross-section of the combustion chamber is an annular structure, the combustion nozzles are arranged on the outer wall of the combustion chamber and are evenly distributed circumferentially, and there is an angle between the inlet axis of the combustion nozzle and the normal direction of the outer wall of the combustion chamber at the installation position of the combustion nozzle; preferably, the angle of each combustion nozzle is equal.
[0011] Furthermore, the combustion nozzles are arranged in a single layer or multiple layers on the outer wall of the combustion chamber; when arranged in multiple layers, the combustion nozzles are also evenly distributed in the longitudinal direction.
[0012] Furthermore, there are two smoke outlets on the upper and lower end surfaces of the combustion chamber; the smoke outlets are symmetrically arranged up and down, and the smoke outlets on the same end surface are symmetrical about the center of the combustion chamber.
[0013] Furthermore, the inner flow channel and the outer flow channel are arranged alternately along the circumference of the radiation heat collection cavity; the inner flow channel is close to the outer surface of the radiation heat collection cavity, and the outer flow channel is close to the inner surface of the combustion cavity.
[0014] Furthermore, the working fluid gas in the expansion chamber of the Stirling engine enters the regenerator after being heated by the flow interlayer.
[0015] Furthermore, the side wall surface of the radiation heat collection cavity is provided with ribs or fins.
[0016] Furthermore, the inner wall of the combustion chamber is provided with ribs or fins.
[0017] Furthermore, the side wall of the radiation collection cavity absorbs solar radiation, and the side wall of the radiation collection cavity is coated with an absorption coating to enhance the absorption of radiation. At the same time, the bottom surface of the radiation collection cavity is coated with a reflective coating to reflect part of the radiation to the side wall of the radiation collection cavity.
[0018] In summary, the present invention has the following advantages compared with the prior art:
[0019] 1. Use a separate Stirling engine heater with complementary heat sources, which can use multiple heat sources such as solar radiation and combustion heating together to improve the stability of the Stirling engine.
[0020] 2. The Stirling engine uses a separate Stirling engine heater with complementary heat sources, which realizes separate heating by solar radiation and combustion heating, without affecting each other and achieving efficient heating. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a schematic diagram of the half-section structure of the heat source complementary separated Stirling engine heater of the present invention.
[0022] Figure 2It is a schematic diagram of a heat source complementary separated Stirling engine heater of the present invention.
[0023] Figure 3 It is the internal working fluid flow channel structure and streamline diagram.
[0024] Figure 4 This is a partial enlarged view of the internal working fluid flow channel structure.
[0025] Figure 5 It is a bottom view schematic diagram of the heat source complementary separated Stirling engine heater of the present invention. DETAILED DESCRIPTION
[0026] The present invention will be further described with reference to the accompanying drawings.
[0027] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, a heat source complementary separated Stirling engine heater of the present invention comprises a radiation heat collection cavity 1, a combustion nozzle 2, a combustion cavity 3, a regenerator 4, a smoke outlet 5, a circulation interlayer 6 and a Stirling engine expansion cavity 7; the radiation heat collection cavity 1 is surrounded by the combustion cavity 3 arranged outside it; the combustion nozzle 2 is located on the peripheral side of the outer wall of the combustion cavity 3, the smoke outlet 5 is located on the upper and lower end surfaces of the combustion cavity 3, the circulation interlayer 6 comprises a first channel 8, a second channel and a plurality of flow channels connecting the first channel 8 and the second channel 9, each of the flow channels comprises an inner flow channel 10 and an outer flow channel 11 which are interconnected at the top; the inner flow channel 10 is connected to the first channel 8, and the outer flow channel 11 is connected to the second channel 9;
[0028] The flow channels are evenly arranged in the entity between the inner wall of the combustion chamber 3 and the outer wall of the radiation heat collection chamber 1; the first channel 8 and the second channel 9 are both located in the lower part of the radiation heat collection chamber 1; the first channel 8 is connected to the Stirling engine expansion chamber 7, and the second channel 9 is connected to the regenerator 4.
[0029] In a specific embodiment of the present invention, the cross-section of the combustion chamber 3 is an annular structure, the combustion nozzles 2 are arranged on the outer wall of the combustion chamber 3 and are evenly distributed circumferentially, and there is an angle between the inlet axis of the combustion nozzle 2 and the normal direction of the outer wall of the combustion chamber 3 at the installation position of the combustion nozzle 2.
[0030] In a specific embodiment of the present invention, the combustion nozzles 2 are arranged in a single layer or multiple layers on the outer wall of the combustion chamber 3; when arranged in multiple layers, the combustion nozzles 2 are also evenly distributed in the longitudinal direction.
[0031] In a specific embodiment of the present invention, there are two smoke outlets 5 on the upper and lower end surfaces of the combustion chamber 3 ; the smoke outlets 5 are symmetrically arranged up and down, and the smoke outlets 5 on the same end surface are symmetrical about the center of the combustion chamber 3 .
[0032] In a specific embodiment of the present invention, the inner flow channel 10 and the outer flow channel 11 are arranged alternately along the circumference of the radiation heat collection cavity 1; the inner flow channel 10 is close to the outer surface of the radiation heat collection cavity 1, and the outer flow channel 11 is close to the inner surface of the combustion cavity 3; the inner flow channel 10 and the outer flow channel 11 of the present invention should avoid heat transfer to each other, so under the condition of meeting the heat exchange requirements with the outside world, the distance between the inner flow channel 10 and the outer flow channel 11 should be as far as possible, and in addition, a heat insulation material or a heat insulation unit can be arranged between the inner flow channel 10 and the outer flow channel 11 to strengthen the heat insulation, thereby ensuring that the inner flow channel 10 fully absorbs the radiation heat and the outer flow channel 11 fully absorbs the combustion heat.
[0033] In a specific embodiment of the present invention, the working gas in the expansion chamber 7 of the Stirling engine is heated by the flow interlayer 6 and then enters the regenerator 4.
[0034] In a specific embodiment of the present invention, the side wall surface of the radiation heat collector cavity 1 is provided with ribs or fins to enhance the radiation heat exchange between the inner flow channel 10 and the radiation heat collector cavity 1 .
[0035] In a specific embodiment of the present invention, the inner wall surface of the combustion chamber 3 is provided with ribs or fins to enhance the convection heat exchange between the outer flow channel 11 and the combustion chamber 3 .
[0036] In a specific embodiment of the present invention, the side wall surface of the radiation solar collection cavity 1 absorbs solar radiation, and the side wall surface of the radiation solar collection cavity 1 is coated with an absorption coating to enhance the absorption of radiation. At the same time, the bottom surface of the radiation solar collection cavity 1 is coated with a reflective coating to reflect a portion of the radiation to the side wall surface of the radiation solar collection cavity 1.
[0037] Example 1
[0038] like Figure 1-5 As shown, Example 1 adopts a mixed heating of radiation and combustion heating. The radiation heat collection cavity receives solar radiation heat, and the combustion cavity generates combustion heat by injecting combustible gas or combustible oil and combustion-supporting gas into the combustion nozzle. The working fluid gas inside the Stirling engine enters the circulation interlayer from the expansion cavity, absorbs radiation heat near the wall of the radiation heat collection cavity, and absorbs combustion heat near the wall of the combustion cavity, and then the high-temperature working fluid gas enters the regenerator.
[0039] In Example 1, there are 18 groups of working fluid flow channels of the heater, which are evenly distributed along the circumference. At the top of the radiation collector cavity, the inner and outer flow channels are connected to form a group of U-shaped flow channels. The outer diameter of the outer flow channel section is 160mm, the inner diameter of the outer flow channel section is 157mm, the outer diameter of the inner flow channel section is 157mm, the inner diameter of the inner flow channel section is 155mm, the inner diameter of the radiation collector cavity is 150mm, and the height of the radiation collector cavity wall is 110mm. . The heights of the first channel and the second channel are both 6mm. The first channel is distributed in 18 guide grooves, each guide groove has an angle of 6°, and the inner arc radius of the guide groove is 25mm. The diameter of the gas piston is 45mm and the stroke is 24.3mm. The average piston speed is 0.81m / s, and the piston cross-sectional area is 1590.4mm 2 , the average flow rate of the working fluid is 2.73m / s.
[0040] In Example 1, when the engine speed is 1000r / min, the working fluid is helium, the hot end working fluid temperature is 500℃, and the average working pressure is 2MPa, the actual heat input required is between 1300W and 1600W. The combustion reaction generates 1744.9W of heat, and the high-temperature flue gas transfers 889.4W of heat to the wall; the wall of the heat absorption cavity absorbs 1024W of light radiation heat. Part of the heat is absorbed by the material of the heater itself, and the working fluid side absorbs 1682W of heat. The maximum temperature on the wall of the flow channel on the working fluid heat exchange side is about 572℃.
[0041] The specific embodiments of the present invention are described above, but the present invention is not limited to the above embodiments. For those skilled in the art, any equivalent modification and substitution of the present invention is also within the scope of the present invention. Therefore, the equalization transformation and modification made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.
Claims
1. A heat source complementary separated Stirling engine heater, characterized in that The invention comprises a radiation heat collection cavity (1), a combustion nozzle (2), a combustion cavity (3), a regenerator (4), a smoke outlet (5), a circulation interlayer (6) and a Stirling engine expansion cavity (7); the radiation heat collection cavity (1) is surrounded by a combustion cavity (3) arranged outside the radiation heat collection cavity (1); the combustion nozzle (2) is located on the peripheral side of the outer wall of the combustion cavity (3); the smoke outlet (5) is located on the upper and lower end surfaces of the combustion cavity (3); the circulation interlayer (6) comprises a first channel (8), a second channel (9) and a plurality of flow channels connecting the first channel (8) and the second channel (9); each of the flow channels comprises an inner flow channel (10) and an outer flow channel (11) which are interconnected at the top; all the inner flow channels (10) are connected to the first channel (8), and all the outer flow channels (11) are connected to the second channel (9); The inner flow channel (10) and the outer flow channel (11) are arranged alternately along the circumference of the radiation heat collection cavity (1); the inner flow channel (10) is close to the outer surface of the radiation heat collection cavity (1), and the outer flow channel (11) is close to the inner surface of the combustion cavity (3); a heat insulation material or a heat insulation unit is arranged between the inner flow channel and the outer flow channel to strengthen the heat insulation, thereby ensuring that the inner flow channel fully absorbs the radiation heat and the outer flow channel fully absorbs the combustion heat; The flow channels are evenly arranged in a solid body between the inner wall of the combustion chamber (3) and the outer wall of the radiation heat collection chamber (1); the first channel (8) and the second channel (9) are both located at the lower part of the radiation heat collection chamber (1); the first channel (8) is connected to the Stirling engine expansion chamber (7), and the second channel (9) is connected to the regenerator (4); The separated Stirling engine heater adopts a mixed heating of radiation and combustion heating. The radiation heat collection cavity receives solar radiation heat, and the combustion cavity generates combustion heat by injecting combustible gas or combustible oil and combustion-supporting gas into the combustion nozzle. The working fluid gas enters the circulation interlayer from the expansion cavity, absorbs radiation heat near the wall of the radiation heat collection cavity, and absorbs combustion heat near the wall of the combustion cavity. Thereafter, the high-temperature working fluid gas enters the regenerator.
2. A heat source complementary separated Stirling engine heater as claimed in claim 1, characterized in that The cross section of the combustion chamber (3) is an annular structure, the combustion nozzles (2) are arranged on the outer wall surface of the combustion chamber (3) and are evenly distributed in the circumferential direction, and an angle exists between the inlet axis of the combustion nozzles (2) and the normal direction of the outer wall surface of the combustion chamber (3) at the installation position of the combustion nozzles (2).
3. A heat source complementary separated Stirling engine heater as claimed in claim 2, characterized in that The combustion nozzles (2) are arranged in a single layer or multiple layers on the outer wall surface of the combustion chamber (3); when arranged in multiple layers, the combustion nozzles (2) are also evenly distributed in the longitudinal direction.
4. A heat source complementary separated Stirling engine heater as claimed in claim 1, characterized in that The smoke outlets (5) are provided at two ends of the combustion chamber (3), respectively. The smoke outlets (5) are arranged symmetrically up and down, and the smoke outlets (5) on the same end face are symmetrical about the center of the combustion chamber (3).
5. A heat source complementary separated Stirling engine heater as claimed in claim 1, characterized in that The working fluid gas in the expansion chamber (7) of the Stirling engine is heated by the flow interlayer (6) and then enters the regenerator (4).
6. A heat source complementary separated Stirling engine heater as claimed in claim 1, characterized in that The side wall surface of the radiation heat collection cavity (1) is provided with ribs or fins.
7. A heat source complementary separated Stirling engine heater as claimed in claim 1, characterized in that The inner wall surface of the combustion chamber (3) is provided with ribs or fins.
8. A heat source complementary separated Stirling engine heater as claimed in claim 1, characterized in that The side wall surface of the radiation heat collection cavity (1) absorbs solar radiation. The side wall surface of the radiation heat collection cavity (1) is coated with an absorption coating to enhance the absorption of radiation. At the same time, the bottom surface of the radiation heat collection cavity (1) is coated with a reflection coating to reflect a part of the radiation to the side wall surface of the radiation heat collection cavity (1).