A rotatable blunt-body micro-combustor with adaptive flow rate

Abstract

The present invention provides a rotatable blunt body micro burner with adaptive flow rate, the burner comprises a combustion chamber, the two ends of the combustion chamber are respectively a combustion chamber air outlet and a combustion chamber air inlet, a rotatable shaft is provided in the combustion chamber, and the axis of the shaft is perpendicular to the direction of gas flow in the combustion chamber; a plurality of blunt bodies are provided on the shaft, and the shaft is driven to rotate by a driving mechanism; at least one sensor directly or indirectly detects the flow rate of gas in the combustion chamber, and a controller controls the rotation of the shaft according to the flow rate detected by the sensor, so that the blunt body is perpendicular or parallel to the direction of gas flow in the combustion chamber. The blunt body rotated out at a high flow rate of the present invention can effectively suppress the blow-out phenomenon and expand the combustible limit.

Description

Technical Field

[0001] The invention relates to the technical field of micro-thermal photoelectric systems, and in particular to a rotatable blunt-body micro-combustor with adaptive flow rate. Background Art

[0002] The microthermal photoelectric system based on combustion converts the chemical energy of gaseous and liquid fuels into thermal energy by combustion, and the photovoltaic material generates electricity by absorbing the thermal radiation of the wall. However, as the size decreases, the residence time of the mixture in the channel decreases, and the heat dissipation of the wall intensifies, resulting in unstable combustion. In addition, the flame propagation speed at a microscale is different from that at a conventional scale. If the fuel mixture flow rate in the microburner is too fast, the flame will be blown out of the combustion chamber with the high-speed airflow, leading to blowout. For this reason, adding a bluff body structure to the microchannel is a common method to improve combustion. It can expand the combustion limit and improve the combustion efficiency at high flow rates. However, at a lower flow rate, the temperature of the flame is relatively low and the stability is also weakened. At this time, the presence of the bluff body is not conducive to flame stability, mainly because compared with the convective heat transfer at the gas-solid interface, the heat conduction inside the bluff body is more intense, which intensifies the heat dissipation of the gas in the channel to the outside world. The temperature in the channel is relatively low. Stronger heat dissipation leads to flame instability.

[0003] In summary, since the flow rate of the fuel mixture is usually adjusted within a certain range in actual applications, the problems currently faced by blunt body burners and conventional burners are: 1. In conventional burners, excessive flow rate will cause blowout, and a blunt body structure is required to maintain flame stability; 2. When the flow rate is low, the blunt body will reduce the stability of the flame. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a rotatable blunt-body micro-burner with adaptive flow rate. A series of blunt bodies that can rotate around an axis are added to the burner wall. The blunt bodies rotate 90° at high flow rates and are perpendicular to the wall, thereby playing the role of blunt body flow disturbance. The overall performance of the micro-burner is improved according to the blow-off limit at different flow rates.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] A rotatable blunt body micro burner with adaptive flow rate, the burner comprises a combustion chamber, two ends of the combustion chamber are respectively a combustion chamber air outlet and a combustion chamber air inlet, a rotatable shaft is arranged in the combustion chamber, and the axis of the shaft is perpendicular to the direction of gas flow in the combustion chamber; a plurality of blunt bodies are arranged on the shaft, and the shaft is driven to rotate by a driving mechanism;

[0007] At least one sensor directly or indirectly detects the flow rate of the gas in the combustion chamber, and the controller controls the rotation of the shaft according to the flow rate detected by the sensor so that the bluff body is perpendicular or parallel to the direction of the gas flow in the combustion chamber.

[0008] Furthermore, when the sensor detects that the flow rate of the gas in the combustion chamber exceeds a set value, the controller controls the rotation of the shaft so that the blunt body is perpendicular to the direction of gas flow in the combustion chamber, thereby disturbing the airflow; when the sensor detects that the flow rate of the gas in the combustion chamber is lower than a set value, the controller controls the rotation of the shaft so that the blunt body is parallel to the direction of gas flow in the combustion chamber.

[0009] Furthermore, the inner wall of the combustion chamber is provided with a plurality of pits, and the pits correspond to the bluff bodies one by one. When the bluff bodies are parallel to the direction of gas flow in the combustion chamber, the bluff bodies are located in the pits to prevent the bluff bodies from interfering with the airflow.

[0010] Furthermore, a photoelectric system is provided on the outer wall of the combustion chamber for generating electrical energy.

[0011] Furthermore, the sensor is used to detect the current generated by the photoelectric system; the controller calibrates the current generated by the photoelectric system at different gas flow rates in the combustion chamber to obtain a current threshold; when the current value detected by the sensor exceeds the current threshold, the controller controls the rotation of the shaft to make the blunt body perpendicular to the direction of gas flow in the combustion chamber; when the current value detected by the sensor is lower than the current threshold, the controller controls the rotation of the shaft to make the blunt body parallel to the direction of gas flow in the combustion chamber.

[0012] The beneficial effects of the present invention are:

[0013] The adaptive flow rate rotatable blunt body micro burner described in the present invention can achieve stable and efficient combustion at different flow rates. A micro burner equipped with a rotatable blunt body is designed. When the flow rate is high, the blunt body can rotate 90° to disturb the airflow and enhance the stability of the flame at high flow rates; when the flow rate is low, the blunt body rotates back to its original position and is parallel to the wall to avoid affecting the stability of the flame at low flow rates. The blunt body that can be rotated at high flow rates can effectively suppress the blow-out phenomenon and expand the combustible limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the rotatable bluff body micro-combustor with adaptive flow rate according to the present invention.

[0015] Figure 2 It is a front view of the combustion chamber described in the present invention.

[0016] Figure 3 It is a left side view of the combustion chamber described in the present invention.

[0017] Figure 4It is a schematic diagram of the bluff body described in the present invention.

[0018] Figure 5 This is a cloud diagram of the OH radical distribution in the burner of the present invention and the burner without a blunt body.

[0019] In the figure:

[0020] 1-controller; 2-photocell; 3-micro motor; 4-combustion chamber; 5-blunt body; 6-combustion chamber wall; 7-combustion chamber air inlet; 8-pit. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0022] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] like Figure 1 and Figure 2As shown, the rotatable blunt body micro burner with adaptive flow rate described in the present invention comprises a combustion chamber 4, the two ends of the combustion chamber 4 are respectively a combustion chamber outlet and a combustion chamber inlet 7, the combustion chamber 4 is provided with one or multiple rotatable shafts arranged side by side, and the axis of the shaft is perpendicular to the direction of gas flow in the combustion chamber; a plurality of blunt bodies 5 are arranged on the shaft, and the shaft is driven to rotate by a micro motor 3; at least one sensor directly or indirectly detects the flow rate of the gas in the combustion chamber 4, and the controller 1 controls the rotation of the shaft according to the flow rate detected by the sensor, so that the blunt body 5 is perpendicular or parallel to the direction of gas flow in the combustion chamber. When the sensor detects that the flow rate of the gas in the combustion chamber 4 exceeds the set value, the controller 1 controls the rotation of the shaft so that the blunt body 5 is perpendicular to the direction of gas flow in the combustion chamber 4, which is used to generate disturbances to the airflow; when the sensor detects that the flow rate of the gas in the combustion chamber 4 is lower than the set value, the controller 1 controls the rotation of the shaft so that the blunt body 5 is parallel to the direction of gas flow in the combustion chamber 4, so as to avoid affecting the stability of the flame at low flow rate. The sensor can be directly installed in the combustion chamber 4 to measure the flow rate of the gas.

[0026] like Figure 3 and Figure 4 As shown, the combustion chamber wall 6 is provided with a plurality of pits 8, and the pits 8 correspond to the bluff bodies 5 one by one. When the bluff bodies 5 are parallel to the direction of gas flow in the combustion chamber, the bluff bodies 5 are located in the pits 8, so that the bluff bodies 5 in the combustion chamber 4 will not protrude from the inner wall surface of the combustion chamber, so as to prevent the bluff bodies 5 from interfering with the airflow.

[0027] The outer wall of the combustion chamber 4 is provided with a photoelectric system, and the photoelectric system includes a photocell 2 for generating electric energy. The photocell 2 can provide electric energy for the micro motor 3. Since the direct measurement of the flow rate of the gas in the combustion chamber 4 has relatively high requirements on the sensor, the present invention indirectly measures the flow rate of the gas by detecting the current generated by the photoelectric system, and the sensor is used to detect the current generated by the photoelectric system; the controller 1 calibrates the current generated by the photoelectric system at different gas flow rates in the combustion chamber 4 to obtain a current threshold; when the current value detected by the sensor exceeds the current threshold, the controller 1 controls the rotation of the shaft to make the bluff body 5 perpendicular to the direction of gas flow in the combustion chamber 4; when the current value detected by the sensor is lower than the current threshold, the controller 1 controls the rotation of the shaft to make the bluff body 5 parallel to the direction of gas flow in the combustion chamber 4.

[0028] Working principle: The fuel mixture enters the combustion chamber 4 through the combustion chamber air inlet 7, the fuel gas burns in the combustion chamber 4, and the exhaust gas is discharged from the combustion chamber outlet. In the initial state, the bluff body 5 is located in the pit on the combustion chamber wall. After ignition, as the gas flow rate increases, the combustion intensity in the combustion chamber 4 increases, the flame temperature increases, the wall temperature increases, and the output current of the photocell 2 outside the combustion chamber increases. When the output current of the photocell 2 rises to the threshold value set by the controller 1, the micro motor 3 is controlled by the controller 1 to start, and the micro motor 3 drives the bluff body 5 to rotate 90°. At this time, the cross section of the bluff body is perpendicular to the direction of gas flow in the combustion chamber, which forms a disturbance to the incoming mixed gas, and the flame can be anchored on both sides of the bluff body to achieve the purpose of expanding the flammable limit. When the gas flow rate decreases, the combustion intensity in the combustion chamber 4 decreases, the flame temperature decreases, the wall temperature decreases, and the output current of the photocell 2 decreases. When the output current of the photocell 2 drops to the threshold value set by the controller 1, the micro motor 3 is controlled by the controller 1 to flip, so that the bluff body 5 returns to the initial position. At this time, the bluff body will not affect the flame stability at low flow rates.

[0029] In order to verify the feasibility of the bluff body design, the transient simulation of the conventional burner and the bluff body burner was carried out by numerical simulation. OH radicals are usually used to indicate the position of the flame front. Therefore, the OH radical distribution cloud diagram in the burner of the present invention and the burner without bluff body is compared. Figure 5 As shown. Due to the symmetrical structure of the burner, half of the burner is used as the calculation area in the numerical simulation. The fuel and oxidant are hydrogen and air respectively, and the inlet flow rate of the premixed gas is 15m / s. It can be seen that in a conventional burner without a blunt body, the OH radicals are offset downstream as a whole, and the OH radicals at the center of the channel are about to be pushed out of the combustion chamber. In the burner described in the present invention, the OH radicals are anchored in an M shape behind the blunt body, indicating that the flame front can be stabilized in the burner channel under the disturbance of the blunt body. Therefore, in the burner described in the present invention, when the blunt body is raised, the combustible limit can be effectively extended.

[0030] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0031] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rotatable blunt-body micro-combustor with adaptive flow rate, the burner comprising a combustion chamber (4), the two ends of the combustion chamber (4) are respectively a combustion chamber air outlet and a combustion chamber air inlet (7), characterized in that: A rotatable shaft is provided in the combustion chamber (4), and the axis of the shaft is perpendicular to the direction of gas flow in the combustion chamber; a plurality of blunt bodies (5) are provided on the shaft, and the shaft is driven to rotate by a driving mechanism; At least one sensor directly or indirectly detects the flow rate of gas in the combustion chamber (4); the controller (1) controls the rotation of the rotating shaft according to the flow rate detected by the sensor, so that the bluff body (5) is perpendicular or parallel to the direction of gas flow in the combustion chamber; the inner wall of the combustion chamber (4) is provided with a plurality of pits, the pits corresponding to the bluff bodies (5) one by one, and when the bluff body (5) is parallel to the direction of gas flow in the combustion chamber, the bluff body (5) is located in the pit, so as to prevent the bluff body (5) from interfering with the airflow; When the sensor detects that the flow rate of the gas in the combustion chamber (4) exceeds a set value, the controller (1) controls the rotation of the shaft so that the bluff body (5) is perpendicular to the direction of the gas flow in the combustion chamber (4), thereby generating disturbances in the gas flow; when the sensor detects that the flow rate of the gas in the combustion chamber (4) is lower than the set value, the controller (1) controls the rotation of the shaft so that the bluff body (5) is parallel to the direction of the gas flow in the combustion chamber (4).

2. The rotatable bluff body micro burner with adaptive flow rate according to claim 1, characterized in that: The outer wall surface of the combustion chamber (4) is provided with a photoelectric system for generating electrical energy.

3. The rotatable blunt body micro burner with adaptive flow rate according to claim 2, characterized in that: The sensor is used to detect the current generated by the photoelectric system; the controller (1) calibrates the current generated by the photoelectric system at different gas flow rates in the combustion chamber (4) to obtain a current threshold; when the current value detected by the sensor exceeds the current threshold, the controller (1) controls the rotation of the shaft to make the blunt body (5) perpendicular to the direction of gas flow in the combustion chamber (4); when the current value detected by the sensor is lower than the current threshold, the controller (1) controls the rotation of the shaft to make the blunt body (5) parallel to the direction of gas flow in the combustion chamber (4).

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