A needle rib type flue gas waste heat efficient heat collector

Abstract

This utility model relates to the field of solar collector technology and discloses a needle-ribbed flue gas waste heat high-efficiency solar collector, including a gradient flow channel pipe. A base tube assembly is arranged inside the gradient flow channel pipe. The base tube assembly includes a water-cooled head. Multiple needle-ribbed ribs are fixedly installed on the water-cooled head, and the multiple needle-ribbed ribs form a needle-rib array on the side wall of the water-cooled head. When the device is in use, high-temperature flue gas is introduced into the gradient flow channel pipe. Upon reaching the base tube assembly, it enters through the inlet pipe and generates a horseshoe vortex through the front turbulence ribs. This disrupts the laminar flow of the bottom layer of flue gas near the wall. In the transition section, a high-speed jet is formed, which scours the rib group and enhances convective heat transfer. The gradient flow channel design causes the flue gas to undergo an acceleration-deceleration-re-acceleration process. The velocity pulsation enhances turbulent mixing, thereby promoting full contact between the high-temperature flue gas and the water-cooled head and improving the heat collection efficiency.

Description

Technical Field

[0001] This utility model relates to the field of solar collector technology, and in particular to a needle-ribbed type high-efficiency flue gas waste heat collector. Background Technology

[0002] In energy-intensive industries such as metallurgy and chemical engineering, the waste heat recovery rate of flue gas directly determines the level of comprehensive energy utilization. Existing flue gas waste heat collectors mostly employ extended surface enhancement heat transfer technology, primarily including traditional finned tube structures and corrugated plate heat exchangers. Traditional finned tube structures increase the heat transfer area by increasing the height of the fins outside the tube (typically 8-15mm), but the flue gas easily forms a laminar boundary layer between the fins, resulting in a temperature difference of 50-80℃ between the fin tip and root.

[0003] Existing high-efficiency flue gas waste heat collectors generally face the problem of rapid heat transfer efficiency decay and limited contact area between flue gas and heat exchanger in actual operation, resulting in low heat exchange efficiency. Utility Model Content

[0004] Purpose of the utility model: The purpose of this utility model is to provide a needle-ribbed flue gas waste heat high-efficiency collector to solve the above-mentioned shortcomings in the prior art.

[0005] Technical solution: A needle-ribbed flue gas waste heat high-efficiency collector includes a gradient flow channel pipe, a base tube assembly is provided inside the gradient flow channel pipe, the base tube assembly includes a water cooling head, and multiple needle-ribbed ribs are fixedly installed on the water cooling head, the multiple needle-ribbed ribs forming a needle-rib array on the side wall of the water cooling head.

[0006] As a further description of the above technical solution: the plurality of needle-rib type ribs are arranged at a 45° staggered angle.

[0007] As a further description of the above technical solution: the gradient flow channel includes an inlet pipe, one end of which is fixedly connected to a transition pipe, and the end of the transition pipe away from the inlet pipe is fixedly connected to an outlet pipe.

[0008] As a further description of the above technical solution: the surface of the needle-ribbed column is coated with... The gradient coating consists of, from the inside out, an adhesive layer, a thermally conductive layer, and a functional layer.

[0009] As a further description of the above technical solution: a connector is fixedly connected to the end of the inlet pipe away from the transition pipe.

[0010] As a further description of the above technical solution: a flow-deflecting rib is fixedly installed inside the inlet pipe.

[0011] As a further description of the above technical solution: a flow rectifier is fixedly installed on the outlet pipe.

[0012] As a further description of the above technical solution: two water guide pipes are fixedly installed on the water cooling head.

[0013] Beneficial effects: This utility model uses staggered ribs to increase the contact area between flue gas and heat exchanger, and also improves heat collection efficiency through disturbance.

[0014] Flue gas enters from the collector inlet and flows axially through a three-stage variable cross-section flow channel. In the inlet duct, pre-positioned turbulence ribs divide the flue gas into multiple high-speed jets, while the impact pin rib array generates intense turbulence. In the transition duct, the flue gas is constrained by V-shaped guide channels, forming a secondary flow perpendicular to the base pipe axis. This reduces the volume of the flue gas recirculation zone between the ribs to one-third of that in traditional designs, effectively eliminating heat transfer dead zones. The rectifier grid in the outlet duct corrects the flue gas flow direction to axial, preventing pressure loss. At this point, the flue gas temperature drops to Tout = 95-110℃ and is discharged from the system through the outlet flange.

[0015] The materials and functions of the coatings in this utility model are as follows: Adhesive layer: plasma-sprayed NiCrAlY alloy; Thermally conductive layer: laser cladding. Composite ceramic (TiN content 15-20 vol%), functional layer: magnetron sputtered superhydrophobic Cu nanowire array. This coating system reduces the adhesion of dust accumulation to 1 / 6 of that of traditional spray coatings. When the flue gas velocity v > 8 m / s, it can achieve zero dust accumulation on the surface through pneumatic shear self-cleaning. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural schematic diagram of a needle-ribbed type high-efficiency flue gas waste heat collector proposed in this utility model.

[0017] Figure 2 This is a schematic diagram of the three-dimensional unfolded structure from another perspective of the present invention;

[0018] Figure 3 This is a three-dimensional exploded structural diagram of the present invention;

[0019] Figure 4 This is a three-dimensional structural schematic diagram of the base tube assembly of this utility model;

[0020] Figure 5 This is a three-dimensional structural diagram of the surface layer of the needle-ribbed column of this utility model.

[0021] Legend:

[0022] 1. Gradient flow channel pipe; 2. Water cooling head; 3. Needle-rib type rib column; 4. Inlet pipe; 5. Transition pipe; 6. Outlet pipe; 7. Adhesive layer; 8. Thermal conductive layer; 9. Functional layer; 10. Connector; 11. Baffle rib; 12. Rectifier grid; 13. Water guide pipe. Detailed Implementation

[0023] To make the technical solution of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Reference Figure 1-5 A needle-ribbed flue gas waste heat high-efficiency collector includes a gradient flow channel pipe 1, inside which a base tube assembly is installed. The base tube assembly includes a water-cooled head 2, on which multiple needle-ribbed ribs 3 are fixedly installed. The multiple needle-ribbed ribs 3 form a needle-ribbed array on the side wall of the water-cooled head 2. In use, the device introduces high-temperature flue gas into the gradient flow channel pipe 1. Upon reaching the base tube assembly, the gas enters through the inlet pipe 4 and is vortexed by the front turbulence ribs 11. This vortex disrupts the laminar flow of the bottom flue gas near the wall in the transition section, forming a high-speed jet that scours the ribbed group and enhances convective heat transfer. The gradient flow channel design causes the flue gas to undergo an acceleration-deceleration-re-acceleration process. The velocity pulsation enhances turbulent mixing, thereby promoting full contact between the high-temperature flue gas and the water-cooled head 2 and improving the heat collection efficiency.

[0025] As a preferred technical solution in this embodiment, the plurality of needle-ribbed columns 3 are arranged at a 45° staggered angle; each needle-ribbed column 3 has a frustum-shaped topology with the following dimensions: top diameter Φ1.2-1.8mm, bottom diameter Φ2.5-3.2mm, height h=15-22mm, axial spacing between adjacent columns S1=3h±0.2h, and circumferential spacing S2=2h±0.15h. This design generates directional vortices on the leeward side of the column through the boundary layer secondary flow excitation mechanism, thereby increasing the mainstream velocity gradient of the flue gas by 2-3 times. The measured Nusselt number (Nu) is 40%-55% higher than that of traditional needle-ribbed columns.

[0026] As a preferred technical solution in this embodiment, the gradient flow channel duct 1 includes an inlet duct 4, one end of which is fixedly connected to a transition duct 5, and the end of the transition duct 5 away from the inlet duct 4 is fixedly connected to an outlet duct 6; the dimensions of the inlet duct 4 are: flow channel height H1 = 35-40 mm, the dimensions of the transition duct 5 are: flow channel height H2 = 0.7 H1, and the dimensions of the outlet duct 6 are: flow channel height H3 = 1.2 H1. This layout causes the flue gas Reynolds number (Re) to pulsate periodically within the flow channel, increasing the proportion of the turbulent core area from 58% to 82%, while reducing the pressure loss coefficient (f) to 0.65 times that of the traditional structure.

[0027] As a preferred technical solution in this embodiment, the surface of the needle-ribbed rib 3 is coated with... The gradient coating, from the inside out, comprises: an adhesive layer 7, a thermally conductive layer 8, and a functional layer 9; wherein the adhesive layer 7 is a plasma-sprayed NiCrAlY alloy with a thickness of... =80-100μm, thermally conductive layer 8: laser cladding Composite ceramic (TiN content 15-20 vol%), thermal conductivity λ > 28 W / (m·K), thickness =150-200μm, functional layer 9: magnetron sputtered superhydrophobic Cu nanowire array (wire diameter Φ50-80nm, contact angle θ>160°), surface energy γ<18mJ / m², this coating system reduces the adhesion of dust accumulation to 1 / 6 of the traditional spray coating, and can maintain zero dust accumulation on the surface through pneumatic shear self-cleaning when the flue gas velocity v>8m / s.

[0028] As a preferred technical solution in this embodiment, a connector 10 is fixedly connected to the end of the inlet pipe 4 away from the transition pipe 5; this facilitates the connection of the flue gas conveying pipe to the inlet pipe 4 and facilitates the conveying of flue gas into the inlet pipe 4.

[0029] As a preferred technical solution in this embodiment, a turbulence rib 11 is fixedly installed inside the inlet pipe 4; after the flue gas enters the gradient flow channel pipe 1, at the inlet pipe 4, the flue gas is divided into multiple high-speed jets by the front turbulence rib 11, and the impact needle rib array generates strong turbulence.

[0030] As a preferred technical solution in this embodiment, a rectifier grid 12 is fixedly installed on the outlet pipe 6; the rectifier grid 12 in the outlet section corrects the flue gas flow direction to the axial direction to avoid pressure loss. At this time, the flue gas temperature drops to Tout=95-110℃ and is discharged from the system through the outlet flange.

[0031] As a preferred technical solution in this embodiment, two water pipes 13 are fixedly installed on the water cooling head 2 to facilitate the water inlet and outlet of the water cooling head 2.

[0032] General working principle:

[0033] High-temperature flue gas (Tin=220-280℃) enters from the inlet channel and generates a horseshoe vortex at the front turbulence rib 11, which disrupts the laminar flow near the wall. The bottom flue gas is guided by the V-shaped guide groove at the transition pipe 5 to form a high-speed jet, which washes over the needle-rib type rib column group 3 and enhances the convective heat transfer gradient channel design so that the flue gas undergoes an acceleration-deceleration-re-acceleration process. The velocity pulsation enhances turbulent mixing, and the measured convective heat transfer coefficient h>135W / (m²·K).

[0034] The superhydrophobic properties of the nano-coating make it difficult for micro-dust particles (particle size dp < 30 μm) to wet the surface. Only through the weak adsorption of van der Waals forces under the action of the mainstream shear force of flue gas (shear stress τ > 0.8 Pa), more than 90% of the accumulated dust particles are peeled off, ensuring the surface cleanliness of the needle-ribbed column 3 and extending the cleaning cycle.

[0035] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A needle-ribbed type high-efficiency flue gas waste heat collector, characterized in that, It includes a gradient flow channel pipe (1), and a base pipe assembly is provided inside the gradient flow channel pipe (1). The base pipe assembly includes a water cooling head (2), and multiple needle-rib type ribs (3) are fixedly installed on the water cooling head (2). The multiple needle-rib type ribs (3) form a needle-rib array on the side wall of the water cooling head (2).

2. The needle-ribbed type high-efficiency flue gas waste heat collector according to claim 1, characterized in that, The multiple needle-ribbed ribs (3) are arranged at a 45° staggered angle.

3. A needle-ribbed type high-efficiency flue gas waste heat collector according to claim 2, characterized in that, The gradient flow channel (1) includes an inlet pipe (4), one end of which is fixedly connected to a transition pipe (5), and the end of the transition pipe (5) away from the inlet pipe (4) is fixedly connected to an outlet pipe (6).

4. A needle-ribbed type high-efficiency flue gas waste heat collector according to claim 3, characterized in that, The surface of the needle-ribbed rib (3) is coated The gradient coating consists of, from the inside out: an adhesive layer (7), a thermally conductive layer (8), and a functional layer (9).

5. A needle-ribbed type high-efficiency flue gas waste heat collector according to claim 4, characterized in that, The inlet pipe (4) is fixedly connected to a connector (10) at the end away from the transition pipe (5).

6. A needle-ribbed type high-efficiency flue gas waste heat collector according to claim 5, characterized in that, The inlet pipe (4) is fixedly equipped with a baffle rib (11).

7. A needle-ribbed type high-efficiency flue gas waste heat collector according to claim 6, characterized in that, A rectifier grid (12) is fixedly installed on the outlet pipe (6).

8. A needle-ribbed type high-efficiency flue gas waste heat collector according to claim 1, characterized in that, Two water pipes (13) are fixedly installed on the water cooling head (2).

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