High-efficiency heat transfer impinging jet array structure for physical toughening of ultrathin glass

Abstract

The present application belongs to the field of ultra-thin glass physical toughening manufacturing, and particularly relates to a high-efficiency heat transfer impact jet array structure for ultra-thin glass physical toughening. The structure comprises a jet orifice plate with backflow holes and a jet target plate. The ratio H / D of the distance H from the jet orifice plate to the jet target plate to the equivalent diameter D of the jet orifice is only 0.1-0.2, and the jet orifices and backflow holes on the jet orifice plate are distributed in a staggered manner. Under the small gap, the jet flow pattern in the limited cavity is a wall-attached jet pipe flow, which causes high local turbulent intensity, thereby enhancing local heat transfer. In addition, the three-dimensional development of the triangular jet orifice is strong, which improves the heat transfer uniformity of the impact surface. Through the design of adding backflow holes, the interference effect of adjacent jets is reduced, the cross-flow deterioration effect is eliminated, the heat transfer uniformity is further improved, and the heat transfer rate is improved. At the same time, the high-temperature gas flowing out of the backflow holes can enter the heat circulation system, realizing recycling.

Description

Technical Field

[0001] This invention belongs to the field of physical tempering manufacturing of ultra-thin glass, specifically a high-efficiency heat transfer impact jet array structure for physical tempering of ultra-thin glass. Background Technology

[0002] With the introduction of the "dual carbon" plan, solar power generation will occupy an increasingly important position in the future energy structure. Photovoltaic glass, as a crucial auxiliary material for photovoltaic modules, significantly impacts the weight, cost, and lifespan of the modules. Furthermore, the thinner the photovoltaic glass in solar cells, the higher its light transmittance and photoelectric conversion efficiency. Currently, battery modules are developing towards higher power and larger sizes, and large-size ultra-thin photovoltaic glass (1.2*2.2m, thickness less than 1.6mm) will be the future development direction.

[0003] The heating process of physical tempering glass is a stress relaxation process for flat glass. The relaxation rate depends on the heat transfer rate. The faster the stress relaxation, the greater the stress generated after tempering. At the same time, uneven heating can easily cause glass deformation, surface cracks and optical distortion. The thinner and larger the glass, the more serious these problems become.

[0004] Currently, the heating section of glass physical tempering mainly employs jet impingement heat transfer. Patent CN107503801A invented a high-efficiency heat transfer array jet structure, which uses tapered, chamfered, or rounded designs and conical ribs to increase the flow coefficient of the impingement holes. While this improves the heat transfer rate and uniformity of the impingement jet to some extent, it has little impact on the flow near the wall, limiting the effectiveness of enhanced heat transfer. Furthermore, jet interference, crossflow, and interactions between jets still strongly influence jet heat transfer. Patent CN108223022B, although reducing the effects of adjacent jet interactions and crossflow, improves heat transfer to some extent, but simultaneously increases air resistance within the confined cavity and has a complex structure, making it difficult to apply to heat processing processes. Summary of the Invention

[0005] To address the limitations of existing impingement jet array structures in meeting the requirements for heat transfer rate and uniformity in large-area ultrathin glass tempering, this invention proposes a high-efficiency heat transfer impingement jet array structure to achieve physical tempering manufacturing of large-size ultrathin glass.

[0006] The purpose of this invention is to improve the heat transfer rate and uniformity during the physical tempering process of large-size ultra-thin glass, and to solve the problem of efficient heat transfer in the heating section of the physical tempering process of ultra-thin glass.

[0007] To achieve the above objectives, this invention proposes a high-efficiency heat transfer impact jet array structure for the physical tempering of ultrathin glass, specifically a small-gap array jet impact structure with return orifices. The technical solution of this invention is as follows: The small-gap array jet impact structure with return orifices includes a jet orifice plate and a jet target plate with return orifices. The small gap refers to the ratio H / D of the distance H from the jet orifice plate to the jet target plate to the equivalent diameter D of the jet orifice, which is only 0.1-0.2. The jet orifices and return orifices on the jet orifice plate are staggered, wherein the cross-sectional shape of the jet orifice on the array jet orifice plate is triangular, circular, or square, the equivalent diameter D of the jet orifice on the jet orifice plate is 3-5 mm, and the jet orifices are arranged in a 6×6 square array in a periodic distribution.

[0008] Furthermore, the single reflux hole is located at the center of each 2×2 jet hole array, and has a circular or square cross-sectional shape. The reflux holes are arranged in a 5×5 square array.

[0009] Furthermore, the spacing S between the jet holes should not be too small or too large. If S is too large, the heat exchange area will be reduced. If S is too small, the jet interference before impact will be stronger, resulting in reduced heat transfer and reduced heat transfer effect. Preferably, the ratio of the spacing S between the jet holes to the equivalent diameter D of the jet holes, S / D, is in the range of 3-5.

[0010] Furthermore, the ratio of the diameter D1 of the return hole on the jet orifice plate to the equivalent diameter D of the jet orifice is in the range of 2-3, and the ratio of the spacing S1 between the return holes to the diameter D1 of the return hole is in the range of 1-2.5.

[0011] Furthermore, the material of the jet orifice plate is preferably heat-resistant stainless steel plate, which is corrosion-resistant and has a long service life.

[0012] Furthermore, the high-temperature gas discharged from the reflux hole enters the thermal circulation system and recovers heat energy through the gas waste heat recovery device, thereby saving energy and reducing industrial energy consumption.

[0013] Compared with existing jet impact structures, the present invention has the following significant advantages:

[0014] 1. Under small gaps, the jet flow pattern in the confined cavity is a wall-mounted jet pipe flow. This flow causes high local turbulence intensity, thereby enhancing local heat transfer. At the same time, at extremely low jet height, jet interference and crossflow effects are reduced, improving heat transfer uniformity.

[0015] 2. By setting backflow holes between the jet holes in the jet orifice plate, the influence of adjacent jet interactions and turbulence intensity within the confined cavity on heat transfer is minimized. This reduces the impact of backflow and flow resistance within the confined cavity, improves heat transfer, lowers the pressure on the entire impact surface, and ensures the surface flatness of the impact target.

[0016] 3. The high-temperature gas flowing out of the reflux hole enters the heat circulation system through the reflux pipe. The high-temperature gas can be used through the gas waste heat recovery device to reduce energy consumption.

[0017] 4. With a small gap, the three-dimensional development of the triangular nozzle jet is stronger, which increases the heat exchange area and improves the heat transfer uniformity of the glass surface. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of a high-efficiency heat transfer impact jet array structure for physical tempering of ultrathin glass.

[0019] Figure 2 This is a schematic diagram of a jet orifice plate with reflux holes.

[0020] Figure 3 This is a schematic diagram of the jet flow field structure in a small-gap array jet.

[0021] Figure 4 This is a schematic diagram of the jet flow field structure in the return orifice of a small-gap array jet.

[0022] Figure 5 This is a comparison diagram of the transient Nusselt numbers of the impact jet array structure of the present invention and the circular nozzle jet array structure without return holes under large spacing and small gap.

[0023] Figure 6 This is a comparison diagram of the transient temperature standard deviation of the impact jet array structure of the present invention, the triangular nozzle jet array structure with large spacing and small gap, and the circular nozzle jet array structure with small gap and return hole.

[0024] In the figure: 1—jet orifice plate; 1-1—jet orifice; 1-2—return orifice; 2—jet target plate Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings. The present invention can be implemented in a variety of hot processing processes. Here, only a specific example of the ultra-thin glass tempering heating section process will be described in detail.

[0026] like Figure 1 , Figure 2 As shown, a high-efficiency heat transfer impact jet array structure for physical tempering of ultra-thin glass is disclosed, specifically a small-gap impact jet array structure with return orifices, comprising a jet orifice plate with return orifices and a jet target plate. The jet orifice plate is a jet plate with return orifices, wherein the jet orifice plate is made of heat-resistant stainless steel. The small gap is defined as the ratio of the distance H from the jet orifice plate to the jet target plate to the equivalent diameter D of the jet orifice being 0.2. The jet orifice plate consists of staggered jet orifices and return orifices, with the jet orifices arranged in a 6×6 square array. The jet orifice plate has return orifices arranged in a 5×5 array.

[0027] Figure 3 , Figure 4 The diagram shows the flow field structure around the jet orifice and return orifice under a small gap. High-temperature air enters from the jet orifice and undergoes a very small jet deflection at the inlet. A pipe flow similar to that flowing along a wall is formed in the confined jet channel under the small gap. The high-temperature gas formed by the injection, which resembles a pipe flowing along a wall, is then discharged from the return orifice and enters the high-temperature gas waste heat recovery device for heat recovery, thereby reducing the industrial energy consumption in the physical tempering of glass manufacturing.

[0028] The above structure is also applicable to jet impingement cooling, and it can also achieve good heat transfer effect in jet impingement cooling.

[0029] The implementation process of a high-efficiency heat transfer impact jet array structure for physical tempering of large-size ultrathin glass is further explained below:

[0030] like Figure 4 , Figure 5 As shown, the jet nozzle is triangular in shape, with an equivalent diameter D of 5 mm. The ratio of the jet nozzle spacing S to the jet nozzle diameter D is 4, the return orifice diameter is 2D, and the ratio of the return orifice spacing S1 to the return orifice diameter D1 is 2. In this embodiment, the heating jet medium is high-temperature air at 943K-963K, and the high-temperature air jet mass flow rate is 18.98 g / s. Results show that under the same inlet temperature, mass flow rate, and pressure, compared to the traditional large-spacing circular nozzle jet (H / D = 2), the heat transfer rate is increased by 23.5%. Compared to the small-gap circular nozzle array jet without return orifices, the inclusion of return orifices reduces the influence of crossflow and return vortex within the confined cavity, resulting in a 19.1% increase in heat transfer rate.

[0031] like Figure 6 As shown, in the later stage of heating, compared with the large-pitch triangular array jet without return holes, the standard deviation of the impact surface temperature under the high-efficiency heat transfer impact jet array structure of the present invention is significantly reduced, the temperature dispersion of the glass surface is small, and the heat transfer uniformity is improved by 49.5%; compared with the small-pitch triangular array jet without return holes, the heat transfer uniformity is improved by 31.4%; compared with the small-pitch circular array jet with return holes, the triangular nozzle jet has stronger three-dimensional development and the heat transfer uniformity is improved by 13.4%.

[0032] The above description is merely a preferred embodiment of the specific thermal processing ultrathin glass physical tempering process of the present invention, and is not intended to limit the present invention. It is applicable to other jet thermal processing or jet cooling processes. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass, characterized in that, The structure is a small gap array jet impact structure with backflow holes, comprising a jet hole plate with backflow holes and a jet target plate; the ratio of the distance H between the jet hole plate and the jet target plate and the equivalent diameter D of the jet hole is only 0.1-0.2, and the jet holes and the backflow holes are distributed in staggered manner on the jet hole plate. 2.The high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass according to claim 1, wherein The jet holes on the jet hole plate are arranged in a 6×6 square array in a periodic distribution. 3.The high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass according to claim 1, wherein The cross section of the jet hole is triangular, and the equivalent diameter of the jet hole is 3-5 mm. 4.The high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass according to claim 1, wherein A single backflow hole is located at the center of each 2×2 jet hole array, and the cross section of the backflow hole is circular or square, and the backflow holes are arranged in a 5×5 square array. 5.The high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass according to claim 1, wherein The ratio of the spacing S between the jet holes and the equivalent diameter D of the jet hole is in the range of 3-5. 6.The high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass according to claim 1, wherein, The ratio of the diameter D1 of the backflow hole on the jet hole plate to the equivalent diameter D of the jet hole is in the range of 2-3, and the ratio of the spacing S1 between the backflow holes to the diameter D1 of the backflow hole is in the range of 1-2.

5. 7.The high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass according to claim 1, wherein, The high-temperature gas discharged from the backflow holes enters a heat circulation system for recycling. 8.The high-efficiency heat transfer impinging jet array structure for physical toughening of ultra-thin glass according to claim 1, wherein, The material of the jet hole plate is heat-resistant stainless steel plate.

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