A bend in the hot air duct of a heat exchanger

Abstract

A bend in a hot air duct for heat exchangers belongs to the technical field of hot air ducts for heat exchangers. It addresses the problem of undesirable flow phenomena such as eddies and turbulence in existing ductwork, leading to reduced overall heat exchange efficiency and poor guidance of hot air, thus affecting the transmission and heat exchange performance of hot air within the duct. The bend includes a tapered-expanding straight pipe section and a double-curvature composite bend section, which are vertically connected, with the lower end of the tapered-expanding straight pipe section connected to the upper end of the double-curvature composite bend section. This invention improves the hot air flow state, effectively reducing the generation of eddies and turbulence within the duct, resulting in smoother and more stable hot air flow. The optimized duct structure reduces energy loss during hot air flow and lowers pressure loss within the duct, thereby reducing energy consumption of power equipment such as fans and saving energy.

Description

Technical Field

[0001] This utility model belongs to the technical field of heat exchanger hot air ducts, and particularly relates to a bend for heat exchanger hot air ducts. Background Technology

[0002] In the hot air duct system of heat exchangers, bends are common connecting components used to change the flow direction of hot air. However, traditional bends have relatively simple structures, and when hot air passes through a bend, the abrupt change in pipe shape significantly impedes the airflow, easily generating undesirable flow phenomena such as eddies and turbulence. These undesirable flow phenomena not only increase the pressure loss of hot air within the pipe, increasing the energy consumption of power equipment such as fans, but also cause uneven heat exchange between the hot air and the pipe wall, reducing the overall heat exchange efficiency of the heat exchanger. Furthermore, traditional bends have poor guiding effect on hot air, failing to effectively guide the hot air along an ideal path, further affecting the transmission effect and heat exchange performance within the pipe. Therefore, developing a bend for heat exchanger hot air ducts that can effectively improve the hot air flow state and increase heat exchange efficiency is of significant practical importance. Utility Model Content

[0003] The purpose of this invention is to provide a bend in the hot air duct of a heat exchanger to solve the problem that existing ducts are prone to generating eddies and turbulence, leading to reduced overall heat exchange efficiency and poor guidance of the hot air, thus failing to effectively guide the hot air flow and affecting the transmission effect and heat exchange performance of the hot air within the duct.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a bend for a heat exchanger hot air duct, comprising a tapered-expanding straight pipe section and a double-curvature composite bend section, wherein the tapered-expanding straight pipe section and the double-curvature composite bend section are connected vertically, and the lower end of the tapered-expanding straight pipe section is connected to the upper end of the double-curvature composite bend section.

[0005] Furthermore, the tapered-expanding straight pipe section is vertically arranged, and the tapered-expanding straight pipe section includes an inlet end, a middle section and an outlet end, which are connected sequentially from top to bottom.

[0006] Furthermore, the inlet end is cylindrical, with an inner diameter D1=D and a length L1=3D.

[0007] Furthermore, the middle section is a tapered converging tube with a cone angle α = 15° and a length L2 = 2D.

[0008] Furthermore, the outlet end is a tapered expanding pipe with a cone angle β=10° and a length L3=2D. The lower end of the outlet end is connected to the upper end of the double curvature composite bend pipe section.

[0009] Furthermore, the double-curvature composite bend section includes a first bend section and a second bend section, wherein the upper end of the first bend section is connected to the lower end of the outlet end, and the lower end of the first bend section is connected to the upper end of the second bend section.

[0010] Furthermore, the radius of curvature of the first bend is R1=2D, and the central angle is θ1=60°.

[0011] Furthermore, the second bend has a radius of curvature R2=1.2D and a central angle θ2=30°. The first and second bends transition through a rounded corner with a radius r=0.2D, forming a 90° turn as a whole.

[0012] Furthermore, diverter plates are inclinedly arranged at both the outlet end and the second bend, and each diverter plate is provided with multiple diverter holes.

[0013] Furthermore, two spiral guide vane assemblies are provided in the first bend section. The two spiral guide vane assemblies are inclinedly arranged in the first bend section along the curvature direction of the first bend section, and both ends of the spiral guide vane assemblies are fixedly connected to the inner sidewall of the first bend section.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] 1. This utility model can improve the hot air flow state. Through the unique design of the gradually narrowing-expanding straight pipe section and the double curvature composite bend pipe section, as well as the setting of the flow divider plate and the spiral guide vane group, the generation of eddies and turbulence in the hot air in the pipe is effectively reduced, making the hot air flow more stable and smooth.

[0016] 2. This utility model can reduce pressure loss. The optimized pipeline structure reduces energy loss during the hot air flow process and reduces the pressure loss of hot air in the pipeline, thereby reducing the energy consumption of power equipment such as fans and saving energy.

[0017] 3. This utility model can improve heat exchange efficiency. The spiral guide vane group enhances the contact and heat exchange between hot air and the pipe wall, while the diverter plate makes the hot air more evenly distributed in the pipe, improving the heat exchange uniformity between hot air and the pipe wall, thereby improving the overall heat exchange efficiency of the heat exchanger.

[0018] 4. This utility model has high structural strength and good high temperature resistance. It is made of high-strength, high-temperature resistant alloy steel, which can withstand the high temperature environment of hot air and ensure the structural stability and reliability of the pipeline during long-term use. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model. Figure 1 ;

[0020] Figure 2This is a schematic diagram of the overall structure of this utility model. Figure 2 ;

[0021] Figure 3 This is a schematic diagram of the overall structure of this utility model. Figure 3 ;

[0022] Figure 4 This is a schematic diagram of the overall structure of this utility model. Figure 4 ;

[0023] Figure 5 This is a schematic diagram of the overall structure of this utility model. Figure 5 ;

[0024] Figure 6 This is a cross-sectional view of the present invention;

[0025] Figure 7 yes Figure 6 Enlarged view of point A.

[0026] The component names and reference numerals in the above figures are as follows:

[0027] 1. Gradual contraction-expansion straight pipe section; 2. Hypercurvature composite bend pipe section; 3. Inlet end; 4. Intermediate section; 5. Outlet end; 6. First bend section; 7. Second bend section; 8. Flow divider plate; 9. Spiral guide vane assembly; 10. Flow divider hole. Detailed Implementation

[0028] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0029] Detailed implementation methods: such as Figures 1-7 As shown, this embodiment discloses a bend for a heat exchanger hot air duct, including a tapered-expanding straight pipe section 1 and a double-curvature composite bend section 2. The tapered-expanding straight pipe section 1 and the double-curvature composite bend section 2 are connected vertically, and the lower end of the tapered-expanding straight pipe section 1 is connected to the upper end of the double-curvature composite bend section 2.

[0030] Furthermore, the tapered-expanding straight pipe section 1 is vertically arranged, and the tapered-expanding straight pipe section 1 includes an inlet end 3, a middle section 4 and an outlet end 5, which are connected sequentially from top to bottom.

[0031] Furthermore, the inlet end 3 is cylindrical and made of high-strength, high-temperature resistant alloy steel, such as 316L stainless steel, which has good corrosion resistance and high-temperature stability, and can withstand the high-temperature environment of hot air. The inner diameter of the inlet end 3 is D1=D, and the length is L1=3D. This size design allows the hot air to enter the pipe relatively smoothly and reduces the generation of turbulence at the inlet.

[0032] Furthermore, the intermediate section 4 is a tapered converging pipe. The intermediate section 4 also uses the same alloy steel as the inlet end 3, with a cone angle α=15° and a length L2=2D. The converging design can gradually increase the flow velocity of the hot air. According to the principle of fluid mechanics, when the mass flow rate is constant, the flow velocity will increase accordingly when the cross-sectional area of ​​the pipe decreases, so that the hot air can obtain higher kinetic energy before entering the bend section.

[0033] Furthermore, the outlet end 5 is a tapered expanding pipe. The material of the outlet end 5 is the same as that of the inlet end 3 and the middle section 4. The cone angle β=10° and the length L3=2D. The lower end of the outlet end 5 is connected to the upper end of the double curvature composite bend section 2. The expanding design can gradually slow down the high-speed hot air flow, convert some of the kinetic energy into pressure energy, reduce the impact of hot air on the bend section, and also help the hot air to flow smoothly in the bend section.

[0034] Furthermore, the double curvature composite bend section 2 includes a first bend section 6 and a second bend section 7. The upper end of the first bend section 6 is connected to the lower end of the outlet end 5, and the lower end of the first bend section 6 is connected to the upper end of the second bend section 7. The double curvature composite bend section 2 also uses the same alloy steel as the tapered-expanding straight pipe section 1 to ensure the strength and high temperature resistance of the overall structure.

[0035] Furthermore, the radius of curvature of the first bend 6 is R1=2D and the central angle is θ1=60°. The larger radius of curvature allows the hot air to flow more smoothly within the first bend 6, reducing the generation of eddies.

[0036] Furthermore, the second bend 7 has a radius of curvature R2=1.2D and a central angle θ2=30°. The first bend 6 and the second bend 7 are transitioned by a rounded corner with a radius r=0.2D, forming a 90° turn. This design, which combines double curvature with rounded corner transition, can further optimize the flow path of hot air, making the hot air flow more smoothly during the turn and reducing pressure loss.

[0037] Furthermore, diverter plates 8 are inclinedly installed within both the outlet end 5 and the second bend 7. Each diverter plate 8 has multiple diverter holes 10. The diverter plates 8 are made of the same alloy steel as the main body of the pipe and are fixed to the inner wall of the outlet end 5 and the second bend 7 by welding. The inclination angle of the diverter plates 8 is optimized according to the flow direction and velocity of the hot air. The diverter holes 10 are evenly distributed on the diverter plates 8, and their diameter and number are determined according to the pipe size and the flow rate of the hot air. The purpose is to divert the hot air, making the hot air distribution more uniform within the pipe and reducing the generation of local eddies.

[0038] Furthermore, two helical guide vane assemblies 9 are provided within the first bend 6. These two helical guide vane assemblies 9 are inclined along the curvature direction of the first bend 6, and both ends of each helical guide vane assembly 9 are fixedly connected to the inner wall of the first bend 6. The helical guide vane assemblies 9 can be connected by welding or bolting. The helical guide vane assemblies are made of high-strength, wear-resistant alloy materials, such as nickel-based alloys. The pitch and helical angle of the helical guide vanes are designed according to the dimensions of the first bend and the flow velocity of the hot air. Their function is to guide the hot air to flow along a helical path, enhance the rotational momentum of the hot air, and ensure more sufficient contact between the hot air and the pipe wall, thereby improving heat exchange efficiency. Simultaneously, it also helps to reduce eddies and turbulence in the hot air within the first bend 6.

[0039] This utility model discloses a bend for a heat exchanger hot air duct, wherein the tapered-expanding straight pipe section 1 and the double-curvature composite bend section 2 are connected vertically by welding to ensure the sealing and structural strength of the connection. During installation, it is ensured that the axes of each part are aligned to avoid installation deviations that may affect the flow of hot air.

[0040] Detailed installation and working principle of each part:

[0041] Shrinking-expanding straight pipe section 1:

[0042] Inlet 3: Hot air enters the pipe from inlet 3. Due to the cylindrical shape and reasonable size design of inlet 3, the hot air can flow into the middle section 4 relatively smoothly. The design of the inner diameter D1=D and length L1=3D of inlet 3 provides sufficient space for the hot air to make initial flow velocity adjustments at the inlet, reducing turbulence caused by sudden changes at the inlet.

[0043] Intermediate Section 4: After the hot air enters Intermediate Section 4, as the cross-sectional area of ​​the pipe gradually decreases, according to the fluid mechanics continuity equation Q=A×v (where Q is the mass flow rate, A is the pipe cross-sectional area, and v is the flow velocity), the flow velocity v will gradually increase when the mass flow rate Q is constant. The design of the cone angle α=15° and the length L2=2D of Intermediate Section 4 allows the hot air velocity to increase smoothly, avoiding the generation of eddies due to excessively rapid changes in flow velocity.

[0044] Outlet 5: After the high-speed hot air enters outlet 5, the flow velocity gradually decreases as the cross-sectional area of ​​the pipe gradually increases. The design of the cone angle β=10° and length L3=2D of outlet 5 can convert some kinetic energy into pressure energy, reduce the impact of hot air on the hyperbolic composite bend section 2, and at the same time make the flow velocity of hot air tend to be stable before entering the bend section, thus preparing for the smooth flow of hot air in the bend section.

[0045] Hypercurvature composite bend section 2:

[0046] First bend 6: After the hot air enters the first bend 6 from the outlet 5, due to the relatively large radius of curvature R1=2D of the first bend 6, the hot air can begin to turn relatively smoothly. Simultaneously, the two spiral guide vane assemblies 9 installed within the first bend 6 begin to function, guiding the hot air along a spiral path and enhancing its rotational momentum. This rotational flow ensures more thorough contact between the hot air and the pipe wall, improving heat exchange efficiency, while also reducing eddies and turbulence generated during the bend.

[0047] Second bend 7: After passing through the first bend 6, the hot air enters the second bend 7. The radius of curvature of the second bend 7, R2=1.2D, is relatively small, and the central angle θ2=30°. It transitions with the first bend 6 through a rounded corner with a radius r=0.2D. This design allows the hot air to complete the remaining turns within a smaller space, while the rounded corner transition reduces the flow resistance of the hot air at the bend. The flow divider 8 installed in the second bend 7 further divides the hot air, making the hot air distribution more uniform within the second bend 7 and further reducing the generation of local eddies.

[0048] 8 and spiral guide vane assembly 9:

[0049] Diverter plate 8: The diverter plate 8 at the outlet end 5 and the second bend 7 is fixed to the inner wall by welding, with an inclination angle of 30°-45°. When hot air flows through the diverter plate 8, it is diverted by multiple diversion holes 10 on the diverter plate 8, making the distribution of hot air in the pipe more uniform, avoiding the concentrated flow of hot air in local areas, thereby reducing the generation of eddies and improving the heat exchange uniformity between hot air and the pipe wall.

[0050] Helical guide vane assembly 9: Two helical guide vane assemblies 9 within the first bend 6 are inclined along the curvature direction of the first bend 6, with both ends fixedly connected to the inner wall of the first bend 6. The pitch and helical angle of the helical guide vanes are optimized to guide the hot air to flow along a helical path. When the hot air passes through the helical guide vane assembly 9, it generates rotational momentum under the action of the vanes, causing the hot air to form a helical flow within the first bend 6. This helical flow not only enhances the contact and heat exchange between the hot air and the pipe wall, but also reduces energy loss and pressure loss during the bend.

[0051] Work process:

[0052] When hot air enters the bend of this invention from the hot air outlet of the heat exchanger, it first enters the inlet end 3 of the gradually narrowing-expanding straight pipe section 1. Within inlet end 3, the hot air initially adjusts its velocity, then enters the middle section 4. As the pipe cross-sectional area decreases, the hot air velocity gradually increases. Next, the high-speed flowing hot air enters the outlet end 5, where the velocity gradually decreases, and some kinetic energy is converted into pressure energy. Afterward, the hot air enters the first bend 6 of the double-curvature composite bend section 2. Within the first bend 6, the spiral guide vane assembly 9 guides the hot air to flow along a spiral path, enhancing the rotational momentum and heat exchange effect. After passing through the first bend 6, the hot air transitions through a rounded corner into the second bend 7. Within the second bend 7, the diverter plate 8 further divides the hot air, making the hot air distribution more uniform. Finally, the hot air completes a 90° turn and flows out of the bend into the subsequent hot air duct system. Throughout the process, the bend in this invention, through its unique structural design, effectively improves the flow of hot air, reduces pressure loss, and increases heat exchange efficiency.

[0053] The heat exchanger hot air duct bend of this utility model optimizes the flow path of hot air in the duct through a unique structural design, reduces the generation of eddies and turbulence, reduces pressure loss, and improves the heat exchange uniformity between hot air and the duct wall, thereby improving the overall heat exchange efficiency of the heat exchanger and reducing the energy consumption of the power equipment.

[0054] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A bend for a heat exchanger hot air duct, characterized by: It includes a tapered-expanding straight pipe section (1) and a double-curvature composite bend pipe section (2), which are connected vertically. The lower end of the tapered-expanding straight pipe section (1) is connected to the upper end of the double-curvature composite bend pipe section (2).

2. The elbow for a heat exchanger hot air duct according to claim 1, characterized by: The converging-expanding straight pipe section (1) is set vertically. The converging-expanding straight pipe section (1) includes an inlet end (3), a middle section (4) and an outlet end (5). The inlet end (3), the middle section (4) and the outlet end (5) are connected sequentially from top to bottom.

3. The elbow for a heat exchanger hot air duct according to claim 2, characterized by: The inlet end (3) is cylindrical, with an inner diameter D1=D and a length L1=3D.

4. The elbow for a heat exchanger hot air duct according to claim 3, characterized by: The middle section (4) is a tapered tube with a cone angle α=15° and a length L2=2D.

5. A bend for a heat exchanger hot air duct according to claim 4, characterised in that: The outlet end (5) is a tapered expanding pipe with a cone angle β=10° and a length L3=2D. The lower end of the outlet end (5) is connected to the upper end of the double curvature composite bend pipe section (2).

6. A bend for a heat exchanger hot air duct according to claim 5, characterised in that: The double curvature composite bend section (2) includes a first bend section (6) and a second bend section (7). The upper end of the first bend section (6) is connected to the lower end of the outlet end (5), and the lower end of the first bend section (6) is connected to the upper end of the second bend section (7).

7. A bend for a heat exchanger hot air duct according to claim 6, characterised in that: The radius of curvature of the first bend (6) is R1=2D, and the central angle is θ1=60°.

8. The elbow for a heat exchanger hot air duct according to claim 7, characterized by: The second bend (7) has a radius of curvature R2=1.2D and a central angle θ2=30°. The first bend (6) and the second bend (7) are connected by a rounded corner with a radius r=0.2D, forming a 90° turn as a whole.

9. The bend for a heat exchanger hot air duct according to claim 8, characterized in that: Both the outlet end (5) and the second bend (7) are provided with diverter plates (8) at an incline, and each diverter plate (8) is provided with multiple diverter holes (10).

10. The bend for a heat exchanger hot air duct according to claim 9, characterized in that: Two spiral guide vane groups (9) are provided in the first bend (6). The two spiral guide vane groups (9) are inclined in the first bend (6) along the curvature direction of the first bend (6). Both ends of the spiral guide vane groups (9) are fixedly connected to the inner sidewall of the first bend (6).

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