Low-cost combustion chamber evaporating pipe based on isometric rifling design

Abstract

The invention discloses a low-cost combustion chamber evaporation pipe based on an equidistant rifling design, relates to the technical field of aero-engine combustion systems, and solves the problems that an existing micro aero-engine combustion chamber evaporation pipe is easy to block, low in evaporation efficiency and high in maintenance cost. The evaporation pipe comprises an evaporation pipe body, and the evaporation pipe body is arranged in an engine combustion chamber; a plurality of isometric riflings are arranged in the evaporation pipe body and extend from one end of the evaporation pipe body to the other end of the evaporation pipe body; the heat exchange area in the evaporation pipe is increased through the rifling lines, and fuel steam is induced to form rotating jet flow. Through the arrangement of the equidistant rifling, the rotation effect generated by forced airflow brings a strong shearing effect, the turbulence degree of fluid in the evaporation pipe is increased, the possibility that fuel oil is broken into tiny liquid drops under the action of aerodynamic force is greatly improved, and therefore the evaporation and atomization effects of the fuel oil in the evaporation pipe are improved; the heat exchange effect of fuel oil and fuel oil steam is enhanced, and the fuel oil combustion efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engine combustion systems, in particular to a low-cost combustion chamber evaporation tube based on an equidistant rifling design. Background Art

[0002] In recent years, with the development of aircraft engine related technologies and the increasing demand for micro power equipment in the market, micro aircraft engines have become a research hotspot. Micro aircraft engines have the advantages of low cost, high thrust-to-weight ratio, and small size. In its design process, the design of the micro aircraft engine combustion chamber has become a key link. Taking into account the influence of other factors such as combustion efficiency in the micro aircraft engine combustion chamber, the micro aircraft engine combustion chamber cannot be scaled proportionally with the size of the engine. Therefore, the smaller the engine size, the greater the proportion of the combustion chamber in the overall space. Compared with conventional combustion chambers, the main characteristics of micro aircraft engine combustion chambers are: low combustion efficiency, large flow loss, limited spatial layout, and poor combustion stability. The new generation of high-performance micro aircraft engines mainly use direct current annular combustion chambers. This type of combustion chamber generally uses evaporator tubes with simple structure and low fuel supply pressure to achieve fuel evaporation and atomization.

[0003] The combustion chamber with evaporator tube structure has the advantages of simple structure, easy processing, low production cost and good comprehensive performance, but it also has its own defects. First, the evaporation and atomization effect of the fuel in the evaporator tube is not ideal. Due to the low oil supply pressure, the spray cannot be formed at the outlet of the evaporator tube. At the same time, the air flow in the simple straight evaporator tube is smooth and there is no large-scale vortex. In addition, the heat exchange between the fuel and the tube wall is very limited. Therefore, the evaporation and atomization effect of the fuel in the evaporator tube is not ideal, which leads to low combustion efficiency. Second, the straight jet flame stabilization structure is relatively rough, resulting in poor combustion stability. Third, the evaporator tube has very high requirements for the uniformity of oil supply. Since the evaporator tube is a number of independent thin tubes, it is difficult to ensure the consistency of the oil supply in each evaporator tube during the actual processing and assembly process, resulting in asymmetric flame structure and uneven outlet temperature distribution.

[0004] The design of the evaporator tube in the combustion chamber of a micro-aircraft engine is crucial to achieve high-performance combustion of fuel. Most of the evaporator tubes in the combustion chamber of a micro-aircraft engine are straight, T-shaped or L-shaped structures, and a small number of them use spiral tube evaporator tubes or electric heating evaporator tubes. However, the spiral tube evaporator tube is easy to clog and the evaporation efficiency is not high, and the electric heating evaporator tube is too complicated and has high maintenance costs. Therefore, designing a low-cost evaporator tube that can better organize fuel evaporation and atomization has become a key technology in the development of micro-aircraft engine combustion chambers. Summary of the invention

[0005] In order to solve the above-mentioned problems of easy clogging, low evaporation efficiency and high maintenance cost of the existing micro-aeroengine combustion chamber evaporator tube, the present invention proposes a low-cost combustion chamber evaporator tube based on equidistant rifling design. The present invention uses the equidistant rifling to force the airflow to produce a strong shearing effect, increase the turbulence of the fluid inside the evaporator tube, and greatly increase the possibility of the fuel being broken into tiny droplets by the aerodynamic force, thereby improving the evaporation and atomization effect of the fuel in the evaporator tube, enhancing the heat exchange effect of the fuel and the fuel vapor, and improving the fuel combustion efficiency.

[0006] The present invention proposes a low-cost combustion chamber evaporator tube based on an equidistant rifling design, which specifically includes an evaporator tube body, and a plurality of evaporator tube bodies are arranged in the engine combustion chamber; a plurality of riflings are arranged in the evaporator tube body, and the riflings extend from one end of the evaporator tube body to the other end; the heat exchange area in the evaporator tube is increased by the arranged plurality of riflings, and the fuel vapor is induced to form a rotating jet.

[0007] Furthermore, the rifling is equidistant rifling.

[0008] Furthermore, the pitch of the rifling is equal to the length of the evaporation tube body.

[0009] Furthermore, the rifling includes a plurality of negative lines and a plurality of positive lines, the negative lines and the positive lines are arranged alternately, and the depth of the negative lines is 5% to 10% of the inner diameter of the evaporation tube body.

[0010] Furthermore, the evaporation tube body has a length of 50 mm to 120 mm.

[0011] Furthermore, the inner diameter of the evaporation tube body is 2.5 mm to 5.0 mm.

[0012] Furthermore, the degree of the center angle of the negative line is equal to the degree of the center angle of the positive line.

[0013] Furthermore, the number of the rifling grooves is 6, 8 or 10.

[0014] Furthermore, the rifling is arranged inside the evaporator tube body by using a wire extrusion processing method.

[0015] Furthermore, the rotation direction of the rifling is left-handed.

[0016] The beneficial effects of the low-cost combustion chamber evaporation tube based on the equidistant rifling design described in the present invention are:

[0017] (1) The low-cost combustion chamber evaporator tube based on equidistant rifling design described in the present invention adopts a combustion chamber evaporator tube based on equidistant rifling design. Under the action of the equidistant rifling, the rotation effect of the airflow is forced to produce brings about a strong shearing effect, which increases the turbulence of the fluid inside the evaporator tube, greatly increases the possibility of the fuel being broken into tiny droplets by the aerodynamic force, thereby improving the evaporation and atomization effect of the fuel in the evaporator tube.

[0018] (2) The low-cost combustion chamber evaporator tube based on the equidistant rifling design described in the present invention increases the effective heat exchange area of ​​its inner wall based on the equidistant rifling design, so that the fuel and fuel vapor can more fully exchange heat with the outside world; the combustion chamber evaporator tube based on the equidistant rifling design also increases its internal flow space, which makes the mixing space between the fuel and fuel vapor and the air wider. The combustion chamber evaporator tube based on the equidistant rifling design also increases the flow distance of the internal fluid in a disguised manner, which makes the fuel and fuel vapor stay in the evaporator tube for a longer time, and also achieves the purpose of enhancing the heat exchange effect of the fuel and fuel vapor.

[0019] (3) The low-cost combustion chamber evaporator tube based on the equidistant rifling design described in the present invention has better evaporation and atomization effects of the fuel in the evaporator tube, and more uniform mixing of the fuel and fuel vapor with air, which can make the fuel burn more completely, thereby improving the combustion efficiency.

[0020] (4) The low-cost combustion chamber evaporator tube based on the equidistant rifling design described in the present invention has a structure in which, after the fuel vapor is rectified by the combustion chamber evaporator tube based on the equidistant rifling design, the fuel vapor enters the flame tube in the form of a rotating jet, which can not only reduce the heat dissipation loss of the flame in the reaction zone, but also maintain the high temperature conditions in the reaction zone, thereby improving the flame stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] In the attached picture:

[0023] Figure 1 It is a longitudinal cross-sectional view of a low-cost combustion chamber evaporation tube based on an equidistant rifling design according to the present invention;

[0024] Figure 2 It is a radial cross-sectional view of a low-cost combustion chamber evaporation tube based on an equidistant rifling design according to the present invention;

[0025] Figure 3It is a schematic diagram of the positional relationship between a low-cost combustion chamber evaporation tube based on an equidistant rifling design and a micro-aero engine combustion chamber according to the present invention;

[0026] Among them: 1-evaporation tube, 2-evaporation tube body, 3-rifling, 4-yang line, 5-yin line. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the 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 a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0029] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" 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 indirectly connected 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 invention can be understood according to specific circumstances.

[0030] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] Specific implementation method 1: See Figure 1-Figure 3 The present embodiment is described in detail. The low-cost combustion chamber evaporator tube based on the equidistant rifling design described in the present embodiment specifically includes an evaporator tube body 2, which is arranged in the engine combustion chamber; a plurality of riflings 3 are arranged in the evaporator tube body 2, and the riflings 3 extend from one end of the evaporator tube body 2 to the other end; the heat exchange area in the evaporator tube 1 is increased by the arranged plurality of riflings 3, and the fuel vapor is induced to form a rotating jet. The riflings 3 are equidistant riflings, and the rotation direction of the riflings 3 is left-handed.

[0032] The pitch of the rifling 3 is equal to the length of the evaporation tube body 2 .

[0033] The rifling 3 includes a plurality of negative lines 5 and a plurality of positive lines 4, which are arranged alternately, and the depth c of the negative lines 5 is 5% to 10% of the inner diameter D2 of the evaporation tube body 2; in this embodiment, the depth c of the negative lines 5 is 6% of the inner diameter D2 of the evaporation tube body 2.

[0034] The length of the evaporation tube body 2 is 50 mm to 120 mm. In this embodiment, the length of the evaporation tube body 2 is 62 mm.

[0035] The inner diameter D2 of the evaporation tube body 2 is 2.5 mm to 5.0 mm, and the outer diameter D1 is 3.5 mm to 6.0 mm. In this embodiment, the inner diameter D2 of the evaporation tube body 2 is 2.5 mm, and the outer diameter D1 is 3.5 mm.

[0036] The central angle a corresponding to the negative line 5 and the central angle b corresponding to the positive line 4 are equal in degree, both of which are 30 degrees.

[0037] The number of the rifling grooves 3 is 6, 8 or 10. In the present embodiment, the number of the rifling grooves 3 is 6.

[0038] The rifling 3 is arranged inside the evaporator tube body 2 by using a wire extrusion processing method.

[0039] like Figure 3 As shown, the micro-aircraft engine combustion chamber is provided with 6 evaporation tubes 1, and the 6 evaporation tubes 1 are evenly arranged on the same circumference of the flame tube end face. The evaporation tube 1 is connected to the flame tube end face by welding. In order to ensure the welding quality, the connection between the flame tube end face and the evaporation tube 1 should be cut with a groove in advance. During welding, the axis of the evaporation tube 1 should also be kept parallel to the axis of the flame tube, which is conducive to forming a symmetrical structure of the airflow at the outlet of the evaporation tube 1, thereby improving the flame stability and fuel combustion efficiency.

[0040] like Figure 1 As shown, the evaporator tube 1 in this embodiment is designed based on equidistant rifling. The pitch of the rifling 3 on the inner wall of the evaporator tube body 2 is numerically the same as the length of the evaporator tube body 2, so that the rifling 3 just rotates one circle in the evaporator tube 1. In this way, after being rectified by the evaporator tube 1, the fuel vapor enters the flame tube in the form of a rotating jet, which can not only reduce the heat dissipation loss of the flame in the reaction zone, but also maintain the high temperature conditions in the reaction zone, thereby improving the flame stability. In the present invention, the rotation direction of the rifling 3 on the inner wall of the evaporator tube body 2 can be left-handed or right-handed. Left-handed means that the rifling rotates counterclockwise when viewed from the inlet to the outlet, and right-handed means the opposite. In this embodiment, the rotation direction of the rifling 3 is left-handed. In this embodiment, the rifling 3 is processed by wire extrusion, which is a mature technology and has a low production cost.

[0041] like Figure 3 As shown, in this embodiment, the number of rifling 3 (i.e., the number of rifling heads) on the inner wall of the evaporation tube body 2 is 6. Too few rifling 3 is not conducive to forming a stable rotating airflow in the evaporation tube 1, and also makes the fluid in the evaporation tube 1 unable to have sufficient turbulence (i.e., the degree of fluid velocity fluctuation); while too many rifling 3 will not only increase the processing difficulty and manufacturing cost, but also interfere with the formation of the rotating airflow in the evaporation tube 1. Figure 3 The number of rifling grooves on the inner wall of the evaporation tube body 2 is 6. The width of the negative line 5 of the rifling groove 3 is the same as the width of the positive line 4 (equivalent to evenly dividing the circumference of the inner wall of the evaporation tube body 2 into 12 equal parts, in which the negative lines 5 and the positive lines 4 are distributed alternately). In this embodiment, the depth c of the rifling groove 3 on the inner wall of the evaporation tube body 2 (the difference between the negative line 5 and the positive line 4 in the radial direction) is 5% to 10% of the inner diameter D2 of the evaporation tube body 2. Figure 3 The depth c of the rifling 3 on the inner wall of the evaporator tube body 2 is taken as 6% of the inner diameter D2 of the evaporator tube body 2. If the depth c of the rifling 3 is too small, the effective heat exchange area of ​​the inner wall of the evaporator tube body 2 will be reduced, thereby affecting the heat exchange effect between the unevaporated fuel and fuel vapor in the combustion chamber and the outside world; if the depth c of the rifling 3 is too large, the wall thickness of the evaporator tube body 2 will be thinned in disguise, thereby affecting the rigidity and structural strength of the evaporator tube 1.

[0042] To summarize the above implementation cases, the low-cost combustion chamber evaporator tube based on equidistant rifling design described in the present invention adopts a combustion chamber evaporator tube based on equidistant rifling design. Under the action of the equidistant rifling, the rotation effect of the airflow is forced to bring about a strong shearing effect, which increases the turbulence of the fluid inside the evaporator tube 1, greatly increases the possibility of the fuel being broken into tiny droplets by the aerodynamic force, thereby improving the evaporation and atomization effect of the fuel in the evaporator tube 1. The low-cost combustion chamber evaporator tube based on equidistant rifling design described in the present invention increases the effective heat exchange area of ​​its inner wall based on the equidistant rifling design, which allows the fuel and fuel vapor to exchange heat with the outside more fully; the combustion chamber evaporator tube based on the equidistant rifling design also increases its internal flow space, which makes the mixing space of the fuel and fuel vapor and air wider. The combustion chamber evaporator tube based on the equidistant rifling design also increases the flow distance of the internal fluid in a disguised manner, which makes the fuel and fuel vapor stay in the evaporator tube for a longer time, and also achieves the purpose of enhancing the heat exchange effect of the fuel and fuel vapor. The low-cost combustion chamber evaporator tube based on the equidistant rifling design described in the present invention has better evaporation and atomization effects of the fuel in the evaporator tube 1, and more uniform mixing of the fuel and the fuel vapor with the air, all of which can make the fuel burn more fully, thereby improving the combustion efficiency. ... After the fuel vapor is rectified by the combustion chamber evaporator tube based on the equidistant rifling design, the fuel vapor enters the flame tube in the form of a rotating jet, which can reduce the heat dissipation loss of the flame in the reaction zone and maintain the high temperature conditions in the reaction zone, thereby improving the flame stability.

[0043] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the invention. It can also be a reasonable combination of the features recorded in the above implementation methods. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-cost combustion chamber evaporation tube based on an equidistant rifling design, characterized in that: The invention comprises an evaporator tube body (2), which is arranged in the engine combustion chamber; a plurality of riflings (3) are arranged in the evaporator tube body (2), and the riflings (3) extend from one end of the evaporator tube body (2) to the other end; the heat exchange area in the evaporator tube (1) is increased by the arranged plurality of riflings (3), and the fuel vapor is induced to form a rotating jet.

2. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 1 is characterized in that: The rifling (3) is an equidistant rifling.

3. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 2 is characterized in that: The pitch of the rifling (3) is equal to the length of the evaporation tube body (2).

4. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 2 or 3, characterized in that: The rifling (3) comprises a plurality of negative lines (5) and a plurality of positive lines (4), the negative lines (5) and the positive lines (4) are arranged alternately, and the depth of the negative lines (5) is 5% to 10% of the inner diameter of the evaporation tube body (2).

5. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 4 is characterized in that: The evaporation tube body (2) has a length of 50 mm to 120 mm.

6. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 4 is characterized in that: The inner diameter of the evaporation tube body (2) is 2.5 mm to 5.0 mm.

7. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 4 is characterized in that: The degree of the center angle of the negative line (5) is equal to the degree of the center angle of the positive line (4).

8. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 7 is characterized in that: The number of the rifling grooves (3) is 6, 8 or 10.

9. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to claim 1 is characterized in that: The rifling (3) is arranged inside the evaporator tube body (2) by using a wire extrusion processing method.

10. The low-cost combustion chamber evaporation tube based on equidistant rifling design according to any one of claim 1, characterized in that: The rotation direction of the rifling (3) is left-handed.

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