A low-resistance flow-guiding ventilation duct for multi-face ventilation in tunnels

Abstract

This utility model belongs to the technical field of ventilation equipment for tunnel engineering, and relates to a low-resistance guide-type air duct for multi-face air supply in tunnels, comprising: a direct current section and a guide section; the guide section includes: a direct current main trunk and guide branches, the direct current main trunk and the guide branches being integrally formed; the guide branches are generally arc-shaped; the guide branches include: an air inlet and an air outlet; the air inlet is connected to the direct current main trunk, and the air outlet is connected to the direct current section; the direct current section connected to the air inlet is perpendicular to the direct current section connected to the air outlet; the inner walls of the direct current section and the inner walls of the guide section have a spiral guide mechanism. This utility model improves the airflow state within the air duct by optimizing the structural design of the air duct and setting the guide mechanism, thereby reducing wind resistance and improving ventilation efficiency.

Description

Technical Field

[0001] This utility model belongs to the technical field of ventilation equipment for tunnel engineering, specifically relating to a low-resistance guide air duct for supplying air to multiple tunnel faces. Background Technology

[0002] During tunnel construction, especially in long-distance, multi-face simultaneous operations, the ventilation system plays a crucial role. It is responsible for supplying fresh air to each face, removing construction dust, harmful gases, and carbon dioxide exhaled by workers, ensuring the health and safety of construction personnel, and providing a good environment for the normal operation of construction equipment. However, current ventilation duct structures for multi-face tunnels have many problems: traditional ventilation ducts, when facing the ventilation needs of multiple faces, often use simple right-angle elbows or T-joints to connect the main ventilation duct to the branch ducts. This connection method causes severe impacts and turbulence at the turning and branching points of the airflow, forming a large amount of turbulence and eddies, resulting in a significant increase in local wind resistance, serious energy loss, and low ventilation efficiency. At the same time, due to the lack of effective airflow guiding structures, the airflow cannot flow stably along the preset path during the branching process, resulting in extremely uneven airflow distribution among the faces. Some faces may suffer from insufficient airflow, affecting the construction environment, while others may suffer from excessive airflow, leading to energy waste. Summary of the Invention

[0003] The technical problem to be solved by this utility model is that the existing ventilation ducts for multi-face tunnels have high wind resistance, serious energy loss and low flow diversion efficiency.

[0004] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0005] A low-resistance, flow-guiding ventilation duct for multi-face ventilation in tunnels is proposed, comprising: a direct current section and a flow-guiding section; the flow-guiding section includes: a direct current main trunk and flow-guiding branches, the direct current main trunk and flow-guiding branches being integrally formed; the flow-guiding branches are generally arc-shaped; the flow-guiding branches include: an air inlet and an air outlet; the air inlet is connected to the direct current main trunk, and the air outlet is connected to the direct current section; the direct current section connected to the air inlet is perpendicular to the direct current section connected to the air outlet; the inner walls of the direct current section and the inner walls of the flow-guiding section have a spiral flow-guiding mechanism.

[0006] Furthermore, the longitudinal section of the DC section is elliptical, and the major axis of the DC section is parallel to the height direction of the tunnel; the longitudinal section of the DC main trunk is elliptical, and the major axis of the DC main trunk is parallel to the height direction of the tunnel; except for the air inlet, the longitudinal section of the guide branch is elliptical, and the major axis of the guide branch is parallel to the height direction of the tunnel; the height of the air inlet is equal to the major axis of the longitudinal section of the DC section, and the major axis of the air outlet is equal to the major axis of the longitudinal section of the DC section; the width of the air inlet is greater than the minor axis of the longitudinal section of the air outlet, and the minor axis of the longitudinal section of the air outlet is equal to the minor axis of the longitudinal section of the DC section.

[0007] Furthermore, the DC section and the guide section have the same multi-layer composite structure; the multi-layer composite structure includes a guide layer, a load-bearing layer, a reinforcing layer and a protective layer bonded sequentially from the inner wall to the outer wall; the spiral guide mechanism is set on the side surface of the guide layer facing the inner cavity of the wind tunnel.

[0008] Furthermore, the spiral guide mechanism includes multiple spiral guide grooves; the distance between two adjacent spiral guide grooves is 3mm; the spiral angle of the spiral guide groove is 15°; and the depth of the spiral guide groove is 2.5cm.

[0009] Furthermore, the surface of the spiral guide mechanism is covered with a nano-coating.

[0010] Furthermore, within each spiral guide groove, multiple diamond-shaped ribs are provided along the extension direction of the spiral guide groove; the height of the diamond-shaped ribs is 2cm.

[0011] Furthermore, the nano-coating is a nano-polyethylene film; the spiral guiding mechanism is made of thermoplastic polyurethane; the load-bearing layer is a woven mesh of high-strength polyester fiber; the reinforcing layer is a woven mesh of aramid fiber; and the outer protective layer is a flame-retardant fluorinated ethylene propylene copolymer film.

[0012] Furthermore, the warp and weft density of the high-strength polyester fiber mesh is 12 threads × 12 threads / cm. 2 The high-strength polyester fiber woven mesh has a fiber diameter of 0.25mm; the tear-resistant reinforcement layer is made of aramid fiber, and the angle between two intersecting fibers in the woven mesh is 45°.

[0013] Furthermore, the thickness of the flow guiding layer is 3.5cm, the thickness of the load-bearing layer is 1.2cm, the thickness of the reinforcing layer is 0.8cm, the thickness of the protective layer is 0.5cm, and the thickness of the nano-coating is 0.1cm.

[0014] Furthermore, the low-resistance guide-type ventilation duct for multi-face ventilation in the tunnel also includes: a connecting mechanism; the connecting mechanism is located at the connection between DC sections, the connection between the DC section and the DC main trunk, and the connection between the DC section and the outlet of the guide branch; the connecting mechanism includes: a rigid inner steel ring and an elastic outer steel ring, the inner steel ring is closed, the outer steel ring has an opening for closing the outer steel ring, and a hose clamp is provided at the opening of the outer steel ring; one end of the DC section is fitted with the inner steel ring, and the other end of the DC section is fitted with the outer steel ring; one end of the DC main trunk is fitted with the inner steel ring, and the other end of the DC main trunk is fitted with the outer steel ring; the outlet of the guide branch is fitted with either the inner steel ring or the outer steel ring.

[0015] Compared with existing technologies, this invention has the following advantages and beneficial effects: By optimizing the structural design of the ventilation duct and setting a spiral guide mechanism, the airflow state within the ventilation duct is improved, thereby reducing wind resistance and increasing ventilation efficiency. On the one hand, the arc-shaped guide branches allow the airflow to smoothly transition when turning, avoiding the severe impact caused by right-angle turns and reducing energy loss. On the other hand, the spiral guide mechanism uses a spiral structure to guide the airflow, causing it to form an orderly spiral flow within the ventilation duct. This not only reduces mutual interference and friction between airflows, lowering wind resistance, but also allows the spiral flow to distribute the airflow more evenly within the ventilation duct, meeting the airflow requirements of different working faces. Furthermore, this invention adopts a spliced ​​structure of direct current section and guide section, which can adapt to different layouts of multiple working faces and dynamic changes during construction. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0017] Figure 1 A top view of a low-resistance flow-guiding ventilation duct structure for multi-face ventilation in tunnels, provided in an embodiment of this utility model.

[0018] Figure 2 A schematic diagram showing the positional relationship between the DC section and the current guiding section provided in this embodiment of the utility model;

[0019] Figure 3 A cross-sectional view of a multi-layered composite structure provided for an embodiment of this utility model.

[0020] The attached diagram shows the markings and corresponding component names:

[0021] 1-DC section, 2-Guiding section, 4-Connecting mechanism, 21-DC main trunk, 22-Guiding branch, 31-Spiral guide groove, 221-Air inlet, 222-Air outlet, a-Guiding layer, b-Supporting layer, c-Reinforcing layer, d-Protective layer, e-Nano coating. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. The illustrative embodiments and descriptions of this utility model are for explanation only and are not intended to limit the scope of the utility model. The embodiments described below are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0023] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the present invention. In other embodiments, well-known structures, materials, or methods are not specifically described to avoid obscuring the present invention. Unless otherwise specified, the materials, instruments, and reagents used in the following embodiments are commercially available. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] Example:

[0026] To address the problems of high wind resistance, severe energy loss, and low flow guiding efficiency in existing ventilation ducts for multi-face tunnels, this embodiment provides a low-resistance flow guiding ventilation duct for multi-face tunnel ventilation. The following is combined with... Figure 1 The overall structure of this low-resistance flow-guiding duct will be explained.

[0027] The low-resistance guide-type ventilation duct adopts a modular design, consisting of a direct current section 1 and a guide section 2. On one hand, the direct current section 1 can be flexibly extended and spliced ​​according to the location and distance of the tunnel face, and its straight structure can adapt to the spatial layout of different tunnel cross-sections. On the other hand, the outlet 222 of the direct current section 1 connects to the outlet of the guide section 2, meeting the layout requirements of multi-face dispersed operations. Specifically, the direct current section 1 is a straight tubular structure, serving as the final channel for delivering airflow to the tunnel face. The guide section 2 consists of an integrally formed direct current main trunk 21 and a guide branch 22. The guide branch 22 is generally arc-shaped, including an inlet 221 and an outlet 222. The inlet 221 connects to the direct current main trunk 21, and the outlet 222 connects to the direct current section 1; the direct current section 1 connected to the inlet 221 is perpendicular to the direct current section 1 connected to the outlet 222.

[0028] Continue to combine Figure 1 The principle and function of the aforementioned low-resistance flow-guiding duct are explained below:

[0029] The guide section 2 receives the airflow delivered by the fan through the DC main trunk 21 and achieves airflow diversion through the arc-shaped guide branch 22. The DC main trunk 21 serves as the air source channel, delivering the airflow to the air inlet 221 of the guide branch 22, and then guiding it to the air outlet 222 through the arc structure, and finally distributing it to the DC section 1 in different directions to meet the independent air supply needs of multiple working faces.

[0030] The DC main trunk 21 and the guide branch 22 are integrally formed, eliminating the gaps of traditional separate connections, which can reduce air leakage rate and reduce air volume loss.

[0031] The guide section 2 adopts an arc-shaped design, which reduces the impact angle when the airflow turns, reduces local wind resistance, and avoids energy loss caused by turbulence.

[0032] The air inlet 221 of the guide branch 22 is connected to the DC main trunk 21, and the air outlet 222 is connected to the DC section 1. The two DC sections 1 are perpendicular to each other. This structure allows the guide section 2 to flexibly turn the straight airflow 90°, which is suitable for the vertical distribution of multiple working faces in the tunnel (such as left and right tunnels, upper and lower layered working faces), and realizes precise air supply from one source in multiple directions.

[0033] In summary, the DC section 1 and the guide section 2 form a complete low-resistance ventilation link through the connection of "splitting-transportation": guide section 2 solves the problem of airflow splitting and low-resistance turning at multiple working faces, while DC section 1 solves the problem of stable airflow transportation after splitting, realizing full-process optimization of "low-resistance splitting-stable transportation-precise air supply" from the main air source to each working face, thus improving ventilation efficiency compared to traditional duct systems. It should be noted that if the air outlet 222 of guide section 2 does not need to be connected to DC section 1, then the air outlet 222 must be sealed.

[0034] Furthermore, such as Figure 2 As shown, the longitudinal section of DC section 1 is an ellipse, and the major axis of the longitudinal section of DC section 1 is parallel to the height direction of the tunnel; the longitudinal section of DC main trunk 21 is an ellipse, and the major axis of the longitudinal section of DC main trunk 21 is parallel to the height direction of the tunnel; except for air inlet 221, the longitudinal section of guide branch 22 is an ellipse, and the major axis of the longitudinal section of guide branch 22 is parallel to the height direction of the tunnel; the height of air inlet 221 is equal to the major axis of the longitudinal section of DC section 1, and the major axis of air outlet 222 is equal to the major axis of the longitudinal section of DC section 1; the width of air inlet 221 is greater than the minor axis of the longitudinal section of air outlet 222, and the minor axis of the longitudinal section of air outlet 222 is equal to the minor axis of the longitudinal section of DC section 1.

[0035] Continue to combine Figure 2 The principles and functions of the DC segment 1, DC main branch 21, and guiding branch 22 of the elliptical cross section are explained:

[0036] The longitudinal sections of DC section 1, DC main trunk 21, and guide branch 22 (except for air inlet 221) are all elliptical, with their major axes parallel to the tunnel's height. This elliptical structure design is based on the spatial characteristics of tunnels—tunnels typically have greater spatial redundancy in the height direction than in the width direction (due to limitations imposed by pipeline and equipment layout). The elliptical major axis along the height direction maximizes the cross-sectional area within a limited width, increasing ventilation volume while avoiding conflicts with facilities within the tunnel. Furthermore, for the same cross-sectional area, the perimeter of an elliptical ventilation duct is smaller than that of a cylindrical one. According to airflow resistance theory, the frictional resistance between the airflow and the duct wall is positively correlated with the contact area; the smaller the perimeter, the less frictional loss.

[0037] The height of the air inlet 221 is consistent with the long axis of the DC section 1, and the long axis of the air outlet 222 is consistent with the long axis of the DC section 1, ensuring that there is no sudden change in height direction of the airflow at the junction of the guide branch 22 and the DC section 1; the short axis of the air outlet 222 is consistent with the short axis of the DC section 1, ensuring the continuity of the airflow in the width direction; the width of the air inlet 221 is greater than the short axis of the air outlet 222, forming a gradual transition of "wide inlet and narrow outlet", which is adapted to the flow attenuation characteristics of the airflow from the DC main trunk 21 to the guide branch 22, and avoids eddies caused by sudden changes in cross-section.

[0038] Furthermore, such as Figure 3As shown, the DC section 1 and the flow guiding section 2 have the same multi-layer composite structure; the multi-layer composite structure includes a flow guiding layer a, a load-bearing layer b, a reinforcing layer c, a protective layer d, and a nano-coating e, which are sequentially bonded from the inner wall to the outer wall. A spiral flow guiding mechanism is also provided in the flow guiding layer a, and the nano-coating e covers the surface of the spiral flow guiding mechanism. The spiral flow guiding mechanism includes multiple spiral flow guiding grooves 31. In this embodiment, the thickness of the flow guiding layer a is 3.5 cm, the thickness of the load-bearing layer b is 1.2 cm, the thickness of the reinforcing layer c is 0.8 cm, the thickness of the protective layer d is 0.5 cm, and the thickness of the nano-coating e is 0.1 cm. The thickness of each layer can be reasonably adjusted according to actual conditions.

[0039] Continue to combine Figure 3 Explain the function of multilayer composite structures:

[0040] Both the DC section 1 and the guide section 2 adopt the same multi-layer composite structure, with each layer achieving "functional layering and synergistic effect" through complementary material properties. Specifically, the guide layer a directly contacts the airflow and needs to have a smooth surface and guide function; the load-bearing layer b and the reinforcing layer c bear the wind pressure load and need to have high strength and deformation resistance; the protective layer d and the nano-coating e resist the erosion of the tunnel environment and have weather resistance and wear resistance. The multi-layer composite structure breaks through the limitations of the "functional compromise" of traditional single-material wind tunnels, achieving a precise match of "guide-load-protection" through the selection of layered materials.

[0041] Multiple spiral guide channels 31 on the guide layer a are spirally distributed along the axis of the air duct. Using the principle of "boundary layer control" in fluid mechanics, the airflow is guided to flow along the channel direction, reducing the sliding friction and lateral diffusion of the airflow on the wall.

[0042] In this embodiment, the distance between two adjacent spiral guide grooves 31 is 3 mm; the spiral angle of the spiral guide groove 31 is 15°; and the depth of the spiral guide groove 31 is 2.5 cm. Within each spiral guide groove 31, multiple rhomboid ribs are provided along its extension direction; the height of the rhomboid ribs is 2 cm. It should be noted that the distance between two adjacent spiral guide grooves 31, the spiral angle of the spiral guide groove 31, and the depth of the spiral guide groove 31 can be adjusted according to the flow rate.

[0043] It should be noted that the rhomboid ribs installed within the spiral guide channel 31 utilize their asymmetric geometry to generate localized disturbances in the airflow within the channel. As the airflow flows along the spiral channel, small-scale vortices are formed on both sides of the rhomboid structure. These small vortices can interact with any large vortices that may be generated within the channel, breaking them down into micro-vortices with lower energy loss. This "small disturbance to large" approach reduces turbulent energy loss. The spiral guide channel 31 guides the airflow into a spiral flow pattern, and combined with the mixing effect of the rhomboid ribs, reduces the wind speed deviation across the cross-section of the duct. Furthermore, the rhomboid ribs can absorb the vibration energy generated by airflow disturbances, reducing the vibration frequency of the duct under high-speed airflow.

[0044] Furthermore, regarding the materials: the nano-coating e is a nano-polyethylene film; the spiral guiding mechanism is made of thermoplastic polyurethane; the load-bearing layer b is a woven mesh of high-strength polyester fiber; the reinforcing layer c is a woven mesh of aramid fiber; and the outer protective layer d is a flame-retardant fluorinated ethylene propylene copolymer film. Specifically, the warp and weft density of the high-strength polyester fiber woven mesh is 12 threads × 12 threads / cm²; the fiber diameter of the high-strength polyester fiber woven mesh is 0.25mm; and the areal density of the tear-resistant reinforcing layer c, the woven mesh of aramid fiber, is 220 g / m². 2 The tear-resistant reinforcement layer c is made of aramid fiber. The angle between two intersecting fibers in the woven mesh is 45°.

[0045] It should be noted that the material selection for each layer of the multi-layer composite structure is based on the logic of "inner layer adapting to airflow characteristics, middle layer strengthening mechanical properties, and outer layer resisting environmental erosion":

[0046] The spiral flow guiding mechanism uses thermoplastic polyurethane (TPU), which utilizes its high elasticity (elongation at break ≥400%) and smooth surface (coefficient of friction ≤0.3) to meet the airflow guidance requirements. The load-bearing layer b and the reinforcing layer c are made of high-strength polyester fiber and aramid fiber woven mesh, respectively. By combining the mechanical properties of different fibers (polyester fiber has high tensile strength and aramid fiber has excellent tear resistance), a composite mechanical system of "main load-bearing + tear resistance" is formed. The outer protective layer d and the nano-coating e are made of flame-retardant fluorinated ethylene propylene copolymer (FEP) and nano-polyethylene, which utilize their chemical resistance, flame retardancy and low surface energy to resist high temperature, dust and chemical corrosion in the tunnel. In addition, the warp and weft density of the high-strength polyester fiber woven mesh (12×12 threads / cm²) is matched with the fiber diameter (0.25mm), achieving a tensile strength of over 2000N / 5cm while ensuring a moderate areal density (approximately 180g / m²). The 45° angle design of the aramid fiber woven mesh ensures that the tear resistance of the structure is balanced in all directions (tear strength deviation between warp and weft directions ≤5%), and the areal density of 220g / m² balances weight and protective performance.

[0047] Furthermore, such as Figure 2As shown, the low-resistance guide air duct also includes: a connecting mechanism 4; the connecting mechanism 4 is located at the connection between DC section 1 and DC section 1, the connection between DC section 1 and DC main 21, and the connection between DC section 1 and the air outlet 222 of guide branch 22; the connecting mechanism 4 includes: a rigid inner steel ring and an elastic outer steel ring, the inner steel ring is closed, the outer steel ring has an opening for closing the outer steel ring, and a hose clamp is provided at the opening of the outer steel ring; one end of DC section 1 is fitted with an inner steel ring, and the other end of DC section 1 is fitted with an outer steel ring; one end of DC main 21 is fitted with an inner steel ring, and the other end of DC main 21 is fitted with an outer steel ring; the air outlet 222 of guide branch 22 is fitted with an inner steel ring or an outer steel ring.

[0048] The connecting mechanism 4 adopts a nested structure of "inner steel ring + outer steel ring," utilizing the difference in material properties to achieve double sealing. The inner steel ring (rigidly closed) serves as the connection reference, fitted inside the end of the duct to ensure geometric stability of the connection and prevent seal failure due to duct deformation. The outer steel ring (elastic opening, hose clamp) is fitted outside the end of another duct. The hose clamp tightens the opening, causing the outer steel ring to radially contract, tightly pressing the outer duct wall against the outer duct wall of the inner steel ring, forming a sealing surface of "rigid support + elastic compression." The connecting mechanism 4 covers all connection nodes between DC sections 1, between DC section 1 and the DC main 21, and between DC section 1 and the outlet 222 of the guide branch 22. Through the standardized configuration of "inner steel ring + outer steel ring," universal connections between different duct sections are achieved. For example, one end of DC section 1 has a pre-set inner steel ring, and the other end has a pre-set outer steel ring, allowing direct connection with the outer / inner steel ring of adjacent DC section 1 without distinguishing interface types, simplifying the installation process. The principle and connection method of the connecting mechanism can be found in the utility model patent with publication number CN209725518U, "A Quick Connection Structure for a Ventilation Duct".

[0049] It should be understood that the terms "system," "device," "unit," and / or "module" as used in this specification are a method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0050] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0051] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

[0052] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the disclosed technical content. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

Claims

1. A low-resistance flow guide air duct for tunnel multi-face air supply, characterized in that, include: DC section (1) and guide section (2); The guide section (2) includes: a DC main trunk (21) and a guide branch (22), the DC main trunk (21) and the guide branch (22) are integrally formed; the guide branch (22) is arc-shaped; the guide branch (22) includes: an air inlet (221) and an air outlet (222); the air inlet (221) is connected to the DC main trunk (21), and the air outlet (222) is connected to the DC section (1); the DC section (1) connected to the air inlet (221) is perpendicular to the DC section (1) connected to the air outlet (222); the inner wall of the DC section (1) and the inner wall of the guide section (2) have a spiral guide mechanism.

2. A low resistance flow guide air duct for supplying air to multiple tunnel faces according to claim 1, characterized in that, The longitudinal section of the DC section (1) is an ellipse, and the major axis of the longitudinal section of the DC section (1) is parallel to the height direction of the tunnel; the longitudinal section of the DC main trunk (21) is an ellipse, and the major axis of the longitudinal section of the DC main trunk (21) is parallel to the height direction of the tunnel; except for the air inlet (221), the longitudinal section of the guide branch (22) is an ellipse, and the major axis of the longitudinal section of the guide branch (22) is parallel to the height direction of the tunnel; the height of the air inlet (221) is equal to the major axis of the longitudinal section of the DC section (1), and the major axis of the air outlet (222) is equal to the major axis of the longitudinal section of the DC section (1); the width of the air inlet (221) is greater than the minor axis of the longitudinal section of the air outlet (222), and the minor axis of the longitudinal section of the air outlet (222) is equal to the minor axis of the longitudinal section of the DC section (1).

3. A low resistance air flow guide air duct with tunnel multi-face air supply according to claim 1, characterized in that, The DC section (1) and the guide section (2) have the same multi-layer composite structure; the multi-layer composite structure includes a guide layer (a), a load-bearing layer (b), a reinforcing layer (c) and a protective layer (d) bonded sequentially from the inner wall to the outer wall; the spiral guide mechanism is set on the side surface of the guide layer (a) facing the inner cavity of the wind tunnel.

4. A low resistance flow guide air duct for supplying air to multiple tunnel faces according to claim 3, characterized in that, The spiral guide mechanism includes multiple spiral guide grooves (31); the distance between two adjacent spiral guide grooves (31) is 3mm; the spiral angle of the spiral guide groove (31) is 15°; and the depth of the spiral guide groove (31) is 2.5cm.

5. A low-resistance guide-type ventilation duct for multi-face ventilation in tunnels according to claim 3 or 4, characterized in that, The surface of the spiral guide mechanism is covered with a nano-coating (e).

6. A low-resistance guiding ventilation duct for multi-face ventilation in tunnels according to claim 4, characterized in that, Within each spiral guide groove (31), multiple rhomboid ribs are provided along the extension direction of the spiral guide groove (31); the height of the rhomboid ribs is 2cm.

7. A low-resistance guiding ventilation duct for multi-face ventilation in tunnels according to claim 5, characterized in that, The nano-coating (e) is a nano-polyethylene film; the spiral guiding mechanism is made of thermoplastic polyurethane; the load-bearing layer (b) is a woven mesh made of high-strength polyester fiber; the reinforcing layer (c) is a woven mesh made of aramid fiber; and the outer protective layer (d) is a flame-retardant fluorinated ethylene propylene copolymer film.

8. A low-resistance guiding ventilation duct for multi-face ventilation in tunnels according to claim 7, characterized in that, The warp and weft density of the high-strength polyester fiber material woven net is 12x12 / cm 2 The fiber diameter of the high-strength polyester fiber material woven net is 0.25 mm; the included angle between the two intersecting fibers of the anti-tear reinforcing layer is 45°.

9. A low-resistance guiding ventilation duct for multi-face ventilation in tunnels according to claim 5, characterized in that, The thickness of the flow guiding layer (a) is 3.5 cm, the thickness of the load-bearing layer (b) is 1.2 cm, the thickness of the reinforcing layer (c) is 0.8 cm, the thickness of the protective layer (d) is 0.5 cm, and the thickness of the nano-coating (e) is 0.1 cm.

10. A low-resistance guide-type ventilation duct for multi-face ventilation in tunnels according to any one of claims 1-4 and 6-8, characterized in that, Also includes: Connection mechanism (4); Connection mechanism (4) is located at the connection between DC section (1) and DC section (1), the connection between DC section (1) and DC main trunk (21) and the connection between DC section (1) and the air outlet (222) of the guide branch (22); The connecting mechanism (4) includes: a rigid inner steel ring and an elastic outer steel ring, the inner steel ring being closed, the outer steel ring having an opening for closing the outer steel ring, and a hose clamp being provided at the opening of the outer steel ring; one end of the DC section (1) is fitted with an inner steel ring, and the other end of the DC section (1) is fitted with an outer steel ring; one end of the DC main (21) is fitted with an inner steel ring, and the other end of the DC main (21) is fitted with an outer steel ring; the air outlet (222) of the guide branch (22) is fitted with an inner steel ring or an outer steel ring.

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