CN115492698A - Fuel inlet structure for annular liquid collection cavity - Google Patents
Fuel inlet structure for annular liquid collection cavity Download PDFInfo
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- CN115492698A CN115492698A CN202211071575.3A CN202211071575A CN115492698A CN 115492698 A CN115492698 A CN 115492698A CN 202211071575 A CN202211071575 A CN 202211071575A CN 115492698 A CN115492698 A CN 115492698A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K7/00—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof
- F02K7/10—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines
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- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
The invention belongs to the technical field of air-breathing ramjet engines, and particularly relates to a fuel inlet structure aiming at an annular liquid collecting cavity, which comprises the annular liquid collecting cavity, a fuel input head and an injection hole, wherein the fuel input head is of an elbow structure, an outlet of the fuel input head is communicated with the annular liquid collecting cavity, and an inner cavity of the fuel input head is expanded from the inlet to the outlet.
Description
Technical Field
The invention belongs to the technical field of air-breathing ramjet engines, and particularly relates to a fuel inlet structure for an annular liquid collection cavity.
Background
The air-breathing ramjet engine has the advantages of simple structure, high specific impulse and the like, and can provide power support for the hypersonic aircraft. The total temperature of supersonic incoming flow is very high, and especially the wall stagnation temperature under high Mach flight condition can even reach 3000K, which is far beyond the temperature resistance limit of the existing high-temperature alloy material. The method takes meeting the power demand in long endurance as traction, and adopts an active cooling scheme based on liquid fuel as one of the most promising technical approaches.
The basic principle of the active cooling air-breathing ramjet engine is that liquid fuel is used as a cooling working medium, and the physical and chemical heat sinks of the liquid fuel are utilized to absorb the heat of a wall surface, so that the temperature of the wall surface is controlled within a safe range; the small molecular fuel generated by cracking effectively reduces the ignition delay time, further improves the chemical reaction rate, and simultaneously releases the recovered heat into the combustion chamber again to participate in acting. The liquid fuel after absorbing heat is subjected to boiling, vaporization and cracking processes in the cooling channel, and various modes such as liquid phase, gas phase and supercritical state exist along the process, so that the physical property changes very severely in the space. Although the density is decreased, the temperature of the supercritical fluid after heat absorption is significantly increased, the molecular mass of the cleavage product becomes large, and thus the absolute pressure in the tube is increased under the same flow rate condition. In order to improve the heat exchange capacity of the cooling channel, designing a reciprocating flow channel is a technical way for prolonging the cooling distance, but the flow resistance along the path is increased inevitably. The load of the fuel supply system is increased no matter the local pressure is increased or the pipeline flow resistance is increased, the range is reduced under the condition of certain total weight constraint, and the range is contrary to the design goal that the power needs to be traction in long voyage, so that the reduction of the flow loss in the cooling flow channel is important in the system design stage.
The currently generally used fuel inlet cooling solution is shown in fig. 1, i.e. the fuel enters the annular liquid collecting cavity in a tangential way, which avoids the energy loss caused by the flow impact to some extent, but there are also obvious drawbacks, in particular: burning deviceThe material enters the annular liquid collecting cavity along the tangential direction, the flowing path is about the circumference of the whole annular structure, and in addition, the moving speed of the fluid in the tangential direction in a fixed geometric section is higher under the condition of the same flow rate. Under the condition of not greatly changing the physical property of the fuel, an equation F is calculated according to the estimation of the flow resistance d ＝f(m&U, l) in which m&Denotes the mass flow rate, u is the flow velocity and l represents the flow path. Considering that the flow velocity of the tangential entry scheme is fast and the flow path is too long, the flow resistance generated by the fuel flow process is large. In addition, excessive tangential velocity can result in high jet tangential velocity injected into the combustion chamber, which can result in high flow loss due to the velocity component, reduced penetration depth, and easy near-wall combustion, and thus can also adversely affect thermal protection.
Disclosure of Invention
The invention aims to solve the technical problem of providing a fuel inlet structure aiming at an annular liquid collecting cavity, which can simultaneously reduce the tangential speed and the flow resistance of fuel in the annular liquid collecting cavity.
The fuel injection device comprises an annular liquid collecting cavity, a fuel input head and an injection hole, wherein the fuel input head is of an elbow structure, an outlet of the fuel input head is communicated with the annular liquid collecting cavity, and an inner cavity of the fuel input head is expanded from an inlet to an outlet.
Furthermore, the cross section of the fuel inlet head is in an oval shape with a horizontal axis becoming longer from the inlet to the outlet.
Furthermore, the cross section of the inlet of the fuel input head is circular, and the cross section of the fuel input head from the inlet to the outlet is elliptical, which is as long as the cross shaft is increased from the circular shape.
Furthermore, the difference between the diameter of the inlet of the fuel input head and the diameter of the cavity of the annular liquid collecting cavity is 0-3 mm.
Furthermore, the inner cavity of the fuel input head is of a left-right symmetrical structure.
Furthermore, two sides of the outlet end part of the fuel input head are tangentially arranged with two sides of the annular liquid collecting cavity.
Furthermore, the cross section of the outlet of the fuel input head is perpendicular to the annular surface of the annular liquid collecting cavity.
Further, the inlet axis of the fuel inlet head is parallel to the axis of the annular liquid collection chamber.
Furthermore, a plurality of injection holes are formed in the inner wall of the annular liquid collecting cavity, and the injection holes are arranged in an annular array along the axis of the annular liquid collecting cavity.
Further, one of the injection holes is arranged opposite to the outlet center of the fuel input head.
The invention has the advantages that the tangential speed of the fuel in the annular liquid collection cavity ring is reduced and the flow path of the fuel is reduced by changing the structure of the fuel input head, so that the flow resistance is reduced, the pressure potential energy of the tangential motion loss in the injection process of the injection hole is reduced, the along-path pressure loss of the fuel in the liquid collection cavity is finally reduced, the electric energy consumed by a fuel supply system is further saved, and the ultimate design goal of reducing the weight of the engine is realized.
Drawings
Fig. 1 is a schematic structural diagram of a prior art solution.
Figure 2 is a velocity vector diagram of a prior art scheme.
Fig. 3 is a pressure distribution cloud of the prior art solution.
Fig. 4 is a schematic structural diagram of the present invention.
Fig. 5 is a front view of the present invention.
Fig. 6 isbase:Sub>A sectional view taken along linebase:Sub>A-base:Sub>A in fig. 5.
Fig. 7 is a schematic structural view of the present invention after the injection hole is hidden.
Fig. 8 is a top view of the present invention with the injection hole concealed.
Fig. 9 is a sectional view taken along line B-B in fig. 8.
Fig. 10 is a front view of the present invention with the injection hole hidden.
Fig. 11 is a sectional view taken along line C-C in fig. 10.
Fig. 12 is a sectional view taken along line D-D in fig. 10.
Fig. 13 is a sectional view taken along line E-E in fig. 10.
Fig. 14 is a velocity vector diagram of the present invention.
FIG. 15 is a cloud view of the pressure distribution of the present invention.
In the figure, 1-annular liquid collection chamber; 2-a fuel input head; 21-an inlet; 22-an outlet; 23-round corners; 3-injection hole.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, descriptions such as "first", "second", etc. in the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; the connection can be mechanical connection, electrical connection, physical connection or wireless communication connection; either directly or indirectly through intervening media, either internally or in any combination, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.
In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
As shown in fig. 1-15, the present invention includes an annular liquid collecting chamber 1, a fuel inlet header 2 and an injection hole 3, wherein the fuel inlet header 2 is of an elbow structure, that is, the direction of the inlet 21 and the direction of the outlet 22 are at a certain angle, mainly in order to adapt to the conventional fuel entering scheme, the engine does not need to be designed again, secondly, the direction of the inlet 21 and the direction of the outlet 22 are at a certain angle, so that the fuel can be in diffusion transition through flow distribution when passing from the inlet 21 with a small cross-sectional area to the outlet 22 through the middle section with a gradually enlarged cross-sectional area, the outlet 22 of the fuel inlet header 2 is communicated with the annular liquid collecting chamber 1, so that the fuel entering the fuel inlet header 2 can enter the annular liquid collecting chamber 1, the inner cavity of the fuel inlet header 2 has an expanding trend from the inlet 21 to the outlet 22, so that the cross-sectional area of the inner cavity of the fuel inlet header 2 is gradually enlarged, and the fuel can enter the annular liquid collecting chamber 1 from both sides of the outlet 22, wherein the inlet 21 and the outlet 22 respectively represent both ends of the fuel inlet header 2, and the downstream end of the annular liquid collecting chamber 1 are connected with the downstream end of the outlet 22.
Specifically, the mass flow rate m &in the fuel inlet head 2 is calculated according to the flow formula
Where ρ and u represent the fluid density and fluid velocity, respectively, and a represents the cross-sectional area. The cross-sections of the inlet 21 and outlet 22 of the fuel inlet head 2 are respectively A 1 And A 2 Assuming that the fluid density is almost constant, the flow velocity decreases by Δ u:
therefore, the flow speed of the fuel in the annular liquid collecting cavity 1 can be effectively reduced by the design that the inner cavity of the fuel input head 2 is in an expanding trend from the inlet 21 to the outlet 22. And under the certain circumstances of flow, the flow resistance is positively correlated with movement velocity, the flow resistance absolute value reduces to some extent, in addition, the fuel input head 2 is the design of expansion trend, realize the fuel of the upper reaches to the both sides reposition of redundant personnel of annular collecting chamber 1 simultaneously, at this moment, become two-way circulation from original one-way circulation, so instantaneous flow area has improved one time on original basis, at this moment, under the unchangeable prerequisite of total flow, the average flow of both sides all reduces in the annular collecting chamber 1, and then showing and reducing tangential velocity, reduced the pressure potential energy Δ p that the 3 spouting holes spout the loss of tangential motion, specifically:
wherein p is 0 And p s Total and static pressure, u, at the location of the injection openings 3, respectively r And u t Respectively the radial and tangential velocity of the position of the injection orifice 3 of the flow. And the pressure potential energy loss caused by tangential motion can be obviously reduced by reducing the tangential speed.
In addition, the fuel at the upstream is divided to two sides of the annular liquid collecting cavity 1, so that the flow path of the fuel is reduced by half, namely the flow path is only half of the circumference, backflow cannot be generated in the annular liquid collecting cavity 1, and the flow resistance is further reduced.
On the premise of only changing the structure of the fuel input head 2, the invention can effectively reduce the flow speed and the flow resistance of the annular liquid collecting cavity 1, also can reduce the flow loss generated by collision with the wall surface of the annular liquid collecting cavity 1, further obviously reduces the pressure loss caused by the injection process, and in the field of engines, reduces the on-way pressure loss of the fuel in the liquid collecting cavity, further saves the electric energy consumed by a fuel supply system, and realizes the ultimate design goal of reducing the weight of the engine.
As shown in fig. 10-13, the cross section of the fuel inlet head 2 is an oval shape with a horizontal axis being longer from the inlet 21 to the outlet 22, so that the cross section of the fuel inlet head 2 is enlarged without affecting the thickness dimension of the short axis on the cross section, and the overall height of the fuel inlet head 2 is ensured to be basically close to the height of the annular liquid collecting cavity 1.
The cross section of the inlet 21 of the fuel input head 2 is circular, and the cross section of the part of the fuel input head 2 from the inlet 21 to the outlet 22 is elliptical, which is continuously lengthened from the circular shape to the horizontal axis.
The difference between the diameter of the inlet 21 of the fuel input head 2 and the diameter of the annular liquid collecting cavity 1 is 0-3mm, and the local pressure loss caused by the generation of vortex due to sudden expansion or contraction of the fluid can be reduced.
The inner cavity of the fuel input head 2 is of a bilateral symmetry structure, so that the consistency of fluid is ensured when fuel flows in from two sides of the annular liquid collecting cavity 1, and the uniformity of fuel circulation is ensured.
As shown in fig. 7, 12 and 13, the outlet 22 of the fuel input head 2 and the circular collecting cavity 1 are provided with the round corners 23, so that two sides of the end part of the outlet 22 of the fuel input head 2 are tangentially arranged with two sides of the circular collecting cavity 1, the movement of the fuel in two directions is favorably guided, and the flow loss caused by backflow or collision is reduced.
The cross section of the outlet 22 of the fuel input head 2 is vertical to the ring surface of the annular liquid collecting cavity 1, namely the outflow direction of the fuel from the outlet 22 is vertical to the inner wall of the annular liquid collecting cavity 1, the fuel is uniformly distributed to two sides of the annular liquid collecting cavity 1, the movement direction component inclined to the ring surface can not occur, and the flow loss of the fuel is further reduced.
The axis of the inlet 21 of the fuel input head 2 is parallel to the axis of the annular liquid collecting cavity 1, namely, the fuel input head 2 is preferably in a 90-degree elbow structure, and the inflow direction of the fuel from the inlet 21 and the outflow direction of the fuel from the outlet 22 are perpendicular to each other, so that the fuel input device is suitable for the conventional engine fuel inlet scheme.
In the embodiment, as shown in fig. 6, one of the injection holes 3 is arranged right opposite to the center of the outlet 22 of the fuel input head 2, so that the fuel flowing to the position can directly enter the injection hole 3 without vertical collision with the annular liquid collecting cavity 1, and pressure loss is reduced, and the arrows in fig. 6 indicate the flowing direction of the fuel.
The simulation was carried out by taking as an example that the fuel flow rate at the inlet 21 was 0.280kg/s, the temperature at the inlet 21 was 807.55K, and the static pressure at the injection hole 3 was 0.8 MPa.
FIG. 2 is a velocity vector diagram under a prior art scheme, with the magnitude of the velocity in the annular plenum 1 being in the order of 40-100 m/s. The tangential velocity in the annular liquid collecting cavity 1 is high, the frictional resistance in the cavity is increased, and meanwhile, a high tangential velocity component is generated in the fuel injection process, namely, the fuel enters the combustion chamber and does not face the vertical wall, so that the near-wall combustion is easily caused, and the difficulty of thermal protection is increased.
FIG. 14 is a velocity vector diagram of the present invention with velocity amplitudes in the annular plenum 1 on the order of 2-50 m/s. The tangential velocity in the annular liquid collecting cavity 1 is small, which is beneficial to reducing the flow pressure loss of the fuel in the cavity.
The pressure of the injection hole 3 and the flow of the inlet 21 are kept the same under the two schemes of the prior art scheme and the scheme of the invention, and the performance of the configuration is optimized by comparison analysis compared with the performance of the original scheme.
FIG. 3 is a pressure distribution cloud chart of the fluid domain of the original scheme model, the local static pressure of the area where the fluid enters along the tangential direction is the smallest, the static pressure gradually rises along the axial movement process, and the mass weighted average pressure of the inlet 21 is 1.4901MPa.
Fig. 15 is a pressure distribution cloud chart of a fluid domain of a model designed according to the scheme, fluid enters the liquid collecting cavity along two directions, the maximum value of pressure distribution is 1.321MPa at the position where one injection hole 3 faces the outlet 22, the pressure distribution in the whole liquid collecting cavity is relatively uniform, the average value is 1.28MPa, and the mass weighted average pressure on the boundary of the inlet 21 is 1.2726MPa.
The pressure of the injection hole 3 under the two schemes is the same as 0.8MPa, and the flow resistance under the two schemes can be calculated. By optimizing the fuel inlet header 2 scheme, the flow resistance in the liquid collection cavity is reduced by about 31.52% compared to the original benchmark scheme.
Those not described in detail in this specification are well within the skill of the art.
Claims (10)
1. A fuel inlet structure for an annular liquid collecting cavity is characterized by comprising the annular liquid collecting cavity (1), a fuel input head (2) and an injection hole (3), wherein the fuel input head (2) is of an elbow structure, an outlet (22) of the fuel input head (2) is communicated with the annular liquid collecting cavity (1), and an inner cavity of the fuel input head (2) tends to expand from an inlet (21) to the outlet (22).
2. A fuel inlet arrangement for an annular plenum as claimed in claim 1, wherein the cross-section of the fuel inlet head (2) from the inlet (21) to the outlet (22) is elliptical with increasing transverse axis.
3. A fuel inlet structure for an annular liquid collecting chamber as claimed in claim 1, wherein the cross section of the inlet (21) of the fuel inlet head (2) is circular, and the cross section of the fuel inlet head (2) from the inlet (21) to the outlet (22) is elliptical with increasing length from circular to horizontal axis.
4. A fuel inlet arrangement for an annular plenum as claimed in claim 3, wherein the difference between the diameter of the inlet (21) of the fuel inlet head (2) and the diameter of the cavity of the annular plenum (1) is between 0 and 3 mm.
5. The fuel inlet structure for the annular liquid collecting cavity as claimed in claim 1, wherein the inner cavity of the fuel inlet head (2) is of a left-right symmetrical structure.
6. A fuel inlet arrangement for an annular plenum as claimed in claim 5, wherein the outlet (22) of the fuel inlet head (2) is provided tangentially on either side of the annular plenum (1).
7. A fuel inlet arrangement for an annular liquid collection chamber as claimed in claim 1 wherein the cross-section of the outlet (22) of the fuel inlet head (2) is perpendicular to the annular face of the annular liquid collection chamber (1).
8. A fuel inlet arrangement for an annular plenum as claimed in claim 1, wherein the inlet (21) of the fuel inlet head (2) has an axis parallel to the axis of the annular plenum (1).
9. A fuel inlet structure for an annular liquid collection chamber according to any of claims 1 to 8, characterized in that said injection holes (3) are provided in plurality in the inner wall of the annular liquid collection chamber (1), the plurality of injection holes (3) being arranged in an annular array along the axis of the annular liquid collection chamber (1).
10. A fuel inlet arrangement for an annular plenum as claimed in claim 9, wherein one of the injection orifices (3) is centrally located opposite the outlet (22) of the fuel inlet head (2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211071575.3A CN115492698A (en) | 2022-09-02 | 2022-09-02 | Fuel inlet structure for annular liquid collection cavity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211071575.3A CN115492698A (en) | 2022-09-02 | 2022-09-02 | Fuel inlet structure for annular liquid collection cavity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115492698A true CN115492698A (en) | 2022-12-20 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211071575.3A Pending CN115492698A (en) | 2022-09-02 | 2022-09-02 | Fuel inlet structure for annular liquid collection cavity |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115492698A (en) |
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2022
- 2022-09-02 CN CN202211071575.3A patent/CN115492698A/en active Pending
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