A pipe structure for uniform heating of a gas

Abstract

The present application belongs to the technical field of gas heating pipeline, and particularly relates to a pipeline structure for uniformly heating gas. The pipeline structure is provided with a turbulence structure in the pipeline, and a heating layer is coated outside the pipeline to heat the internal transported gas. The turbulence structure comprises ball shell structures symmetrically and alternately arranged along the pipe axis direction and conical baffles with edge holes, so that the flow direction of the transported gas in the pipeline is changed, the heat exchange between the gases is promoted, and the temperature homogenization of the gases at the outlet section is realized. Experiments show that, compared with the case without the turbulence structure, the turbulence structure greatly improves the cross-section temperature uniformity of the transported gas flow.

Description

Technical Field

[0001] This invention belongs to the field of gas heating pipeline technology, specifically relating to a pipeline structure for uniformly heating gas inside a pipeline. Background Technology

[0002] Gas transport pipelines are widely used in chemical, biological, pharmaceutical, semiconductor, and other processing and manufacturing fields, as well as scientific research. In some cases, pipelines need to simultaneously fulfill the functions of transport and heating. Industrially, external heating sources such as heating jackets or heating coils are often used to heat the gas flow inside the pipeline. However, this method has limitations: the heat transfer efficiency between gas streams is low, making it difficult to achieve uniform heating within a limited heating path. The outlet gas often exhibits a low temperature at the center and a high temperature at the periphery. In environments where high uniformity of the transported gas cross-section temperature is required, this limitation will affect the quality of subsequent production. Furthermore, when measuring the internal temperature of the pipeline using sensors, most sensors can only detect the temperature at a specific location in space. When there are significant differences in temperature distribution across the pipeline cross-section, a single sensor cannot accurately obtain the overall temperature situation across the cross-section, thus affecting the normal operation of the heating control system. Summary of the Invention

[0003] The purpose of this invention is to provide a pipe structure for uniform heating of gas inside a pipe, so as to achieve uniform temperature at the gas outlet section.

[0004] The present invention provides a pipe structure for uniformly heating gas, wherein a flow-turbulence structure is provided inside the pipe, and a heating layer is wrapped around the outside of the pipe for heating the gas transported inside. The flow-turbulence structure includes spherical shell structures arranged symmetrically and alternately along the pipe axis and conical baffle structures with edge holes. The alternating spherical shell structures form a spherical shell structure region, and the apex of the conical baffle is located at the end of the spherical shell structure region. That is, when the fluid is transported in the pipe, it first passes through the spherical shell structure region, causing the fluid to be disturbed, and then passes through the conical baffle. The fluid is diverted by the conical surface and flows out from the edge holes, thereby changing the flow direction of the transported fluid in the pipe, thereby promoting heat exchange between gases and achieving temperature homogenization of the gas at the outlet section. See the structural description below. Figure 1 , Figure 2 , Figure 3 .

[0005] The spherical shell structure is arranged symmetrically and alternately along the pipe axis. The diameter of the sphere is between 1 / 4 and 1 / 2 of the inner diameter of the pipe. The center of the sphere falls on the inner wall of the pipe (that is, a single sphere is attached to the inner wall of the pipe and appears as a hemispherical protrusion). The distance between the centers of two adjacent spherical shells in the axial direction is greater than twice the diameter of the sphere.

[0006] The conical baffle includes a conical wall and a bottom annular area with circular holes. Airflow can pass through the holes. The size of the holes is smaller than the width of the annular area. The holes are evenly distributed and can have various numbers of holes, such as 8, 12, or 24.

[0007] Optionally, the conical wall inside the pipe forms an angle between 30° and 60° with the horizontal direction.

[0008] Optionally, the spherical shell structure area is located in the region of the pipeline near the gas inlet; the conical baffle is located at the gas outlet of the pipeline, and the distance between the bottom annular area and the pipeline outlet is controlled within a certain range to ensure stable outlet flow.

[0009] Optionally, the conical baffle and the pipe wall can be a rigid fixed connection structure or a sliding and detachable composite structure.

[0010] Optionally, the pipe base, spherical shell structure, and conical baffle are made of the same material and can be manufactured using integrated methods such as CNC or 3D printing.

[0011] Pipes can be made of metal, plastic, or other materials.

[0012] This invention designs a pipeline structure in which the transported gas changes its flow direction under the action of the turbulence structure, realizing heat exchange between the relatively high temperature gas around the perimeter and the relatively low temperature gas in the center, reducing the temperature difference of the gas at the pipeline outlet section, and greatly improving the temperature uniformity of the transported gas flow across the cross section. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a cross-section of a gas uniform heating pipe.

[0014] Figure 2 This is a schematic diagram of the spherical shell structure region inside the pipe.

[0015] Figure 3 This is a schematic diagram of a conical baffle inside a pipe.

[0016] Figure 4 This is a schematic diagram of the calculation model containing the turbulent structure.

[0017] Figure 5 This is a schematic diagram of the heating layer and insulation layer structure.

[0018] Figure 6 This is a schematic diagram of the computational model without any turbulence.

[0019] The diagram is labeled as follows: 1 is the tube body, 2 is the heating layer, 3 is the spherical shell (showing several spherical shells arranged symmetrically and alternately), 4 is the conical plate, 5 is the circular airflow hole, and 6 is the bottom annular area. Detailed Implementation

[0020] To better understand the technical principles and application effects of the present invention, detailed descriptions are provided below through specific embodiments.

[0021] The COMSOL finite element software was used for simulation to draw the pipeline model, establish the coupled physical field of heat transfer and fluid flow, set reasonable boundary conditions and mesh accuracy, and judge the temperature uniformity of the heated gas in the pipeline by the physical quantities in the simulation results.

[0022] The present invention will be described below through different embodiments.

[0023] Example 1: The pipe has a flow-disrupting structure.

[0024] The pipe model is drawn in COMSOL finite element software, and the model profile is as follows. Figure 4 As shown, the pipe is made of copper and transports air. The air flow rate is 800 SCCM, the inlet gas temperature is 293.15 K, the inlet gas velocity is 0.1 m / s, and a pressure of 1000 W / m is applied to the outer wall of the pipe. 2 A constant heat source is provided, and an insulation structure is installed. The cross-sectional structure of the insulation layer is as follows: Figure 5 As shown, the pipe is 500mm long, 20mm in inner diameter, and 1mm thick. The spherical shells have a radius of 8mm and an alternation period of 40mm, with a total of 36 spherical shells inside. The conical plate is 50mm high, and there are 24 circular airflow holes in the bottom annular region, each with a diameter of 2mm. There is convective heat flux between the pipe and the outside air, with a heat transfer coefficient of 5W / (m²). 2 (K), the research method is steady state, and the temperature distribution at the outlet is analyzed after calculation. See [link / reference]. Figure 4 , Figure 5 .

[0025] Comparative Example 1: No turbulence-causing structure inside the pipe.

[0026] The pipe model is drawn in COMSOL finite element software, and the model profile is as follows. Figure 6 As shown, the pipe is made of copper and transports air. The air flow rate is 800 SCCM, the inlet gas temperature is 293.15 K, the inlet gas velocity is 0.1 m / s, and a pressure of 1000 W / m is applied to the outer wall of the pipe. 2 A constant heat source is provided, and an insulation structure is installed, with a cross-sectional structure as follows: Figure 5 As shown, the pipe is 500mm long, 20mm in inner diameter, and 1mm thick, with no turbulence-causing structures inside. There is convective heat flux between the pipe and the outside air, with a heat transfer coefficient of 5W / (m²). 2 (K), the research method is steady state, and the temperature distribution at the outlet is analyzed after calculation. See [link / reference]. Figure 5 , Figure 6

[0027] Example 2: The pipe has a turbulence-inducing structure.

[0028] The pipe model is drawn in COMSOL finite element software, and the model profile is as follows. Figure 4 As shown, the specific structural dimensions are the same as in Example 1. The pipe is made of copper and the gas being transported is air. The air flow rate is 3000 SCCM, the inlet gas temperature is 293.15 K, the inlet gas velocity is 0.55 m / s, and a pressure of 1000 W / m is applied to the outer wall of the pipe. 2 A constant heat source is provided, and an insulation structure is installed. There is convective heat flux between the pipes and the outside air, with a heat transfer coefficient of 5 W / (m²). 2 (K), the research method is steady state, and the temperature distribution at the outlet is analyzed after calculation. See [link / reference]. Figure 4 , Figure 5 .

[0029] Comparative Example 2, no turbulence-causing structure inside the pipe

[0030] The pipe model is drawn in COMSOL finite element software, and the model profile is as follows. Figure 6 As shown, the structure is the same as Comparative Example 1, but the pipe is made of metallic copper and the gas being transported is air. The air flow rate is 3000 SCCM, the inlet gas temperature is 293.15 K, the inlet gas velocity is 0.55 m / s, and a pressure of 1000 W / m is applied to the outer wall of the pipe. 2 A constant heat source is provided, and an insulation structure is installed. There is convective heat flux between the pipes and the outside air, with a heat transfer coefficient of 5 W / (m²). 2 (K), the research method is steady state, and the temperature distribution at the outlet is analyzed after calculation. See [link / reference]. Figure 5 , Figure 6 .

[0031] The outlet temperature distribution results of the embodiments and comparative examples are shown below. The inlet gas flow rate (flow rate) was controlled consistently in both embodiments and comparative examples to control variables. Embodiment 1 and Comparative Example 1 show that after adding the turbulence structure, the average outlet temperature decreased by 8.9 K. The main reason for the temperature decrease is that the turbulence structure itself absorbed some heat. The outlet temperature difference decreased from 13.8 K to 3.5 K, a decrease of approximately 74.6%. Embodiment 2 and Comparative Example 2 show that increasing the inlet gas flow rate shortened the effective heating time. After adding the turbulence structure, the average outlet temperature increased by 14.3 K. The main reason is that the increased heating contact area promoted heat exchange. The outlet temperature difference decreased from 70.4 K to 8.6 K, a decrease of approximately 87.8%. The turbulence structure design in both embodiments effectively reduced the temperature difference at the outlet, achieving the effect of improving the temperature uniformity of the conveyed airflow across the cross-section.

[0032]

Claims

1. A pipe structure for uniformly heating gas, characterized in that, The pipeline is equipped with a flow-disrupting structure and is covered with a heating layer to heat the transported gas. The flow-disrupting structure includes spherical shell structures arranged symmetrically and alternately along the pipeline axis and conical baffles with edge holes. The alternating spherical shell structures form a spherical shell structure region, and the apex of the conical baffle is located at the end of the spherical shell structure region. That is, when the gas is transported in the pipeline, it first passes through the spherical shell structure region, causing the gas to be disturbed. Then, it passes through the conical baffle, where the fluid is diverted by the conical surface and flows out from the edge holes, thereby changing the flow direction of the transported fluid in the pipeline. This promotes the exchange of heat between the gases and achieves temperature homogenization of the gas at the outlet section. The spherical shell structure has a diameter between 1 / 4 and 1 / 2 of the inner diameter of the pipe. The center of the spherical shell is located on the inner wall of the pipe, that is, a single spherical shell is attached to the inner wall of the pipe and presents as a hemispherical protrusion. The distance between the centers of two adjacent spherical shells in the axial direction is greater than twice the diameter of the spherical shell. The conical baffle includes a conical wall and a bottom annular area with circular holes. Airflow passes through the holes, and the size of the holes is smaller than the width of the annular area. The holes are evenly distributed. The conical baffle has a conical surface that forms an angle between the conical surface and the horizontal direction, which is between 30° and 60°.

2. The pipe structure for uniform gas heating according to claim 1, characterized in that, The spherical shell structure area is located in the region of the pipeline near the gas inlet; the conical baffle is located at the gas outlet of the pipeline, and the distance between the bottom annular area of ​​the conical baffle and the pipeline outlet is controlled within a certain range to ensure stable outlet flow.

3. The pipe structure for uniform gas heating according to claim 1, characterized in that, The conical baffle is rigidly fixed to the pipe wall.

4. The pipe structure for uniform gas heating according to claim 1, characterized in that, The pipe base, spherical shell structure, and conical baffle are made of uniform material and are manufactured using an integrated CNC or 3D printing method.

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