An efficient multi-stage air compressor interpass shell-and-tube cooler

Abstract

The application discloses a high-efficiency multi-stage air compressor intermediate shell-and-tube cooler. In the application, an air inlet pipe and an air outlet pipe are fixed at two ends of a shell, the air inlet pipe is communicated with an air inlet passage in the shell, and the air outlet pipe is communicated with an air outlet passage in the shell; a plurality of U-shaped tube bundle groups arranged equidistantly in the up-down direction are arranged in the shell, the U-shaped tube bundle group is composed of a plurality of U-shaped tube bundles nested from outside to inside, the U-shaped tube bundle is composed of U-shaped tubes horizontally arranged with water inlets and water outlets, the U-shaped tube is in the shape of an ellipse, the long axis, the short axis and the inclination angle of the long axis of each U-shaped tube section are different, and the inclination directions of the long axes of the U-shaped tubes are also not completely the same; a plurality of fins arranged equidistantly are arranged along the water inlet direction of the U-shaped tube bundle, and each fin is fixed with the U-shaped tubes; and the air inlet passage and the air outlet passage are communicated through the gaps between the adjacent fins. The application has good heat exchange effect and high heat exchange efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of shell-and-tube coolers, specifically relating to a high-efficiency intermediate shell-and-tube cooler for a multi-stage air compressor. Background Technology

[0002] Air compressors are essential general-purpose equipment in modern industry, widely used in machinery manufacturing, metallurgy, automotive, cement, power, electronics, textiles and other industrial fields. Screw compressors, with their advantages of stable performance, fewer vulnerable parts, high energy efficiency, low environmental pollution, and low noise, are gradually replacing piston compressors in large-scale industrial applications. Miniature piston compressors, with their small size and low price, are being applied to household applications, automotive repair and other fields. Centrifugal air compressors are oil-free compressors, offering advantages in safety and hygiene, and can be used in industries with high requirements for the working environment, such as food, pharmaceuticals, mining, and air separation.

[0003] Multistage air compressors are widely used in industrial production. By incorporating intercoolers between stages, the compressed gas undergoes isobaric cooling after each stage of compression to lower its temperature before entering the next stage cylinder. This further cooling and density increase facilitates further compression, significantly reducing power consumption compared to single-stage compression. Therefore, under the same pressure, multistage compression requires less work area than single-stage compression. The more stages, the greater the power savings and the closer the performance is to isothermal compression. The design of the intercooler significantly impacts the compressor's efficiency and stability; however, existing intercooler designs suffer from insufficient cooling efficiency. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose a high-efficiency multi-stage air compressor intermediate shell-and-tube cooler.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention discloses a high-efficiency multi-stage air compressor intermediate shell-and-tube cooler, comprising a shell, tube sheet, inlet pipe, outlet pipe, U-shaped tube bundles, and fins. The shell is open at one end and hollow internally; the tube sheet is fixed to the opening and seals it. The tube sheet is divided into a water inlet area and a drainage area in half. The inlet pipe and outlet pipe are fixed to both ends of the shell, with the inlet pipe closer to the tube sheet than the outlet pipe. The inlet pipe communicates with an inlet channel in the shell cavity located on the water inlet side of the tube sheet, and the outlet pipe communicates with an outlet channel in the shell cavity located on the drainage side of the tube sheet. The shell contains multiple U-shaped tube bundles arranged equidistantly, each U-shaped tube bundle consisting of multiple nested U-shaped tube bundles from the outside in. Each U-shaped tube bundle consists of nine horizontally arranged U-shaped tubes with both inlet and outlet ports in a 3×3 array. The cross-sectional area of ​​each U-shaped tube is... The tubes are elliptical, and the major axis, minor axis, and the angle of inclination of the major axis relative to the vertical direction are all different for each U-shaped tube section. The direction of inclination of the major axis of the ellipse relative to the vertical direction is also not exactly the same for each U-shaped tube section. The water inlet of each U-shaped tube is fixed and connected to a water inlet in the water inlet area of ​​the tube sheet, and the water outlet is fixed and connected to a water outlet in the drainage area of ​​the tube sheet. The outer shell is provided with multiple fins equidistantly arranged along the water inlet direction of the U-shaped tube bundle. The cross-section of the fins parallel to the water inlet direction of the U-shaped tube bundle is corrugated. Each fin is fixed to each U-shaped tube covered along the fluid direction. The air inlet channel and the air outlet channel are connected through the gap between each adjacent fin.

[0007] Preferably, the ratio of the major and minor axes of the ellipse of each U-shaped tube section in the U-shaped tube bundle is in the range of 1.341 to 1.657.

[0008] Preferably, the ratio of the inclination angles of the elliptical major axis of the three U-shaped tube sections in the outermost column of the U-shaped tube bundle relative to the vertical direction is 1:1~1.235:-0.266~-0.217, the ratio of the inclination angles of the elliptical major axis of the three U-shaped tube sections in the middle column relative to the vertical direction is 1:1~4.559:-0.36~-1.642, and the ratio of the inclination angles of the elliptical major axis of the three U-shaped tube sections in the innermost column relative to the vertical direction is 1:-1~-0.785:-0.815~-0.630, where "-" indicates that the top of the elliptical major axis of the U-shaped tube bundle section is inclined outward.

[0009] Preferably, in the U-shaped tube bundle, the height of the middle row of U-shaped tubes is lower than the height of the other two rows of U-shaped tubes.

[0010] Preferably, the ratio of the center distance in the row direction of each U-shaped tube inlet to the height of the tube sheet is 0.0681, and the ratio of the center distance in the column direction to the length of the water inlet area of ​​the tube sheet is 0.0992.

[0011] The present invention has the following beneficial effects:

[0012] This invention offers excellent heat exchange performance and high efficiency. Specifically, the U-shaped tubes used in this invention have elliptical cross-sections with different ratios of their major and minor axes and different inclination angles of their major axes relative to the vertical direction. Furthermore, the U-shaped tubes in each adjacent row are arranged in an alternating pattern, which enhances the turbulence of the heat flow after it enters the inner cavity of the outer shell from the air inlet pipe, thereby improving the mixing effect of the heat flow. At the same time, the use of corrugated fins increases the heat exchange area and further enhances the turbulence of the heat flow. The combination of these two factors enhances the heat exchange effect and improves the heat exchange efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0014] Figure 2 This is a cross-sectional view along the water inlet direction of the U-shaped tube bundle after removing the air inlet and outlet pipes of the present invention.

[0015] Figure 3 A diagram showing the layout of the U-shaped tube bundle after removing the inlet and outlet pipes from an existing intermediate shell-and-tube cooler.

[0016] Figure 4 This is a diagram showing the arrangement of the U-shaped tube bundle after removing the inlet and outlet pipes according to the present invention.

[0017] Figure 5 for Figure 3 Enlarged view of part A in the middle.

[0018] Figure 6 for Figure 4 Enlarged view of section B. Detailed Implementation

[0019] The present invention will now be further described with reference to the accompanying drawings.

[0020] like Figure 1 , Figure 2 , Figure 4 and Figure 6 As shown, a high-efficiency multi-stage air compressor intermediate shell-and-tube cooler includes a shell 1, a tube sheet, an inlet pipe, an outlet pipe, a U-shaped tube bundle assembly, and fins 3.

[0021] The outer shell 1 is open at one end and hollow inside; the tube sheet is fixed to the opening and seals the opening; the tube sheet is divided into a water inlet area and a drainage area in half; the air inlet pipe and the air outlet pipe are fixed to both ends of the outer shell 1, with the air inlet pipe closer to the tube sheet than the air outlet pipe; the air inlet pipe is connected to the air inlet channel on the side of the tube sheet in the inner cavity of the outer shell 1 located in the water inlet area, and the air outlet pipe is connected to the air outlet channel on the side of the tube sheet in the inner cavity of the outer shell 1 located in the drainage area; the outer shell 1 is provided with multiple U-shaped tube bundles arranged vertically and vertically at equal intervals. Each U-shaped tube bundle is composed of multiple nested U-shaped tube bundles from the outside to the inside. Each U-shaped tube bundle consists of 9 horizontally arranged U-shaped tubes 2 with both the inlet and outlet arranged in a 3×3 array. The cross-sectional surface of the U-shaped tube 2 is elliptical. The U-shaped tubes 2 are circular, and the major and minor axes of the ellipse, as well as the angle of inclination of the major axis relative to the vertical direction, are different for each U-shaped tube 2 section. The direction of inclination of the major axis of the ellipse relative to the vertical direction is also not exactly the same for each U-shaped tube 2 section. The water inlet of each U-shaped tube 2 is fixed and connected to a water inlet in the water inlet area of ​​the tube sheet, and the water outlet is fixed and connected to a water outlet in the drainage area of ​​the tube sheet. The outer shell 1 is provided with multiple fins 3 equidistantly arranged along the water inlet direction of the U-shaped tube bundle. The cross-section of the fins 3 parallel to the water inlet direction of the U-shaped tube bundle is corrugated, and each fin 3 is fixed to each U-shaped tube 2. The air inlet channel and the air outlet channel are connected through the gap between each adjacent fin 3.

[0022] Preferably, the ratio of the major to minor axis of the ellipse of each U-shaped tube segment in the U-shaped tube bundle ranges from 1.341 to 1.657. The ratio of the inclination angles of the major axis of the ellipse relative to the vertical direction for the three U-shaped tube segments in the outer row of the U-shaped tube bundle is 1:1 to 1.235: -0.266 to -0.217, respectively. The ratio of the inclination angles of the major axis of the ellipse relative to the vertical direction for the three U-shaped tube segments in the middle row is 1:1, respectively. ~4.559: -0.36~-1.642, the ratios of the inclination angles of the elliptical major axis of the three U-shaped tube sections in the inner row relative to the vertical direction are 1: -1~-0.785: -0.815~-0.630, where "-" indicates that when viewed from the perspective of the tube sheet along the water inlet direction of the U-shaped tube bundle, the top of the elliptical major axis is tilted to the left relative to the vertical direction (i.e., the top of the elliptical major axis of the U-shaped tube section is tilted outward). In the U-shaped tube bundle, the height of the middle row of U-shaped tubes 2 is lower than that of the other two rows of U-shaped tubes 2. The ratio of the center distance of the row direction of each U-shaped tube 2 inlet to the height of the tube sheet is 0.0681, and the ratio of the center distance of the column direction to the length of the water inlet area of ​​the tube sheet is 0.0992.

[0023] This invention is based on, for example Figure 3 and Figure 5In the existing intermediate shell-and-tube cooler, where the U-tubes in the U-tube bundle are equidistant and have circular cross-sections, the cross-sections of each U-tube are changed to elliptical shapes. A neural network optimization algorithm is then used to optimize the parameters (a, b, θ) of each U-tube in the U-tube bundle, ultimately yielding a more optimal parameter embodiment for the U-tube bundle, as shown below. Figure 4 and Figure 6 As shown; In this embodiment, based on the existing intermediate shell-and-tube cooler shell, the tube sheet height h = 1468 mm, the tube sheet water inlet length k = 1008 mm, and there are 5 groups of U-shaped tube bundles, each group of U-shaped tube bundles has 3 U-shaped tube bundles, and the center distance between the rows and columns of each U-shaped tube in the U-shaped tube bundle is 100 mm. During optimization, the major axis and minor axis of the ellipse of the U-shaped tube section are set as a and b respectively, and the center coordinates are (x, y). The major axis of the ellipse of the U-shaped tube section is... The vertical tilt angle is θ, and the initial value of θ for each U-tube in the U-tube bundle before optimization is 0. The initial values ​​of a and b before optimization are both 50mm. The center coordinates of the U-tube section in the first row and first column are (0,0). The centers of the inlets of each U-tube in each row are aligned before optimization. After optimization, the relevant parameters in the U-tube bundle are shown in Table 1. The height of the center of the inlet of the middle column of U-tube 2 in the U-tube bundle group is 52mm lower than the height of the center of the inlet of the other two columns of U-tube 2. In this embodiment, the Nusselt number of the intermediate shell-and-tube cooler is increased by 26.2% compared with the existing intermediate shell-and-tube cooler.

[0024] Table 1. Relevant parameters of the optimized U-shaped tube bundle

[0025]

[0026] The working principle of this invention is as follows:

[0027] Coolant enters from the inlet of each U-tube and flows out from the outlet of each U-tube, cooling each fin 3. Heat from the air compressor enters the inner cavity of the outer casing through the intake pipe, exchanges heat with each fin 3, and then flows out through the outlet pipe to the next stage air compressor or load, where the fins 3 cool the heat flow. Because the cross-sectional surfaces of each U-tube in the optimized U-tube bundle of this invention are elliptical with different aspect ratios and different inclination angles of the major axis relative to the vertical direction, and the U-tubes 2 in each adjacent row are arranged in a staggered manner, the turbulence of the heat flow is enhanced after entering the inner cavity of the outer casing through the intake pipe. Simultaneously, the corrugated fins increase the heat exchange area and further enhance the turbulence. The combination of these two factors enhances the heat exchange effect and improves the heat exchange efficiency.

Claims

1. A high efficiency multi-stage air compressor interpass shell-and-tube cooler comprising a shell, a tube sheet, an inlet pipe and an outlet pipe, the shell having an open end and being hollow inside, the tube sheet being fixed to the open end and sealing the open end; characterized in that: Also include U-shaped tube bundle group and fin; The tube plate is provided with water inlet area and drainage area; The gas inlet pipe and the gas outlet pipe are fixed at both ends of the shell, and the gas inlet pipe is closer to the tube plate than the gas outlet pipe; The gas inlet pipe is communicated with the gas inlet passage on the water inlet area side of the tube plate in the inner cavity of the shell, and the gas outlet pipe is communicated with the gas outlet passage on the drainage area side of the tube plate in the inner cavity of the shell; A plurality of U-shaped tube bundle groups are arranged equidistantly in the shell, the U-shaped tube bundle group is composed of a plurality of U-shaped tube bundles nested from outside to inside, the U-shaped tube bundle is composed of 9 U-shaped tubes arranged in a 3*3 array, the section surface of the U-shaped tube is elliptical, the inclination angle of the major axis and the minor axis of the elliptical section surface of each U-shaped tube is different, and the inclination direction of the major axis of the elliptical section surface of each U-shaped tube is also not completely the same; The water inlet of each U-shaped tube is fixed and communicated with a water inlet opening in the water inlet area of the tube plate, and the water outlet is fixed and communicated with a drainage opening in the drainage area of the tube plate; A plurality of fins are arranged equidistantly along the water inlet direction of the U-shaped tube bundle in the shell, the fin is corrugated along the section surface parallel to the water inlet direction of the U-shaped tube bundle, and each fin is fixed with each U-shaped tube covered in the fluid direction; The gas inlet passage and the gas outlet passage are communicated through the gap between each adjacent fin.

2. A high efficiency multi-stage air compressor inter-bundle cooler as claimed in claim 1, wherein: The ratio of the major axis and the minor axis of the elliptical section surface of each U-shaped tube in the U-shaped tube bundle is 1.341-1.

657.

3. A high efficiency multi-stage air compressor inter-bundle cooler as claimed in claim 1, wherein: The inclination angle of the major axis of the elliptical section surface of the three U-shaped tubes in the outer column of the U-shaped tube bundle relative to the vertical direction is 1:(1-1.235):(-0.266--0.217) in turn, the inclination angle of the major axis of the elliptical section surface of the three U-shaped tubes in the middle column of the U-shaped tube bundle relative to the vertical direction is 1:(1-4.559):(-0.36--1.642) in turn, and the inclination angle of the major axis of the elliptical section surface of the three U-shaped tubes in the inner column of the U-shaped tube bundle relative to the vertical direction is 1:(-1--0.785):(-0.815--0.630) in turn, wherein "-" represents that the top of the major axis of the elliptical section surface of the U-shaped tube bundle is inclined outward.

4. A high efficiency multi-stage air compressor inter-bundle cooler as claimed in claim 1, wherein: In the U-shaped tube bundle, the height of the U-shaped tubes in the middle column is lower than that of the U-shaped tubes in the other two columns.

5. A high efficiency multi-stage air compressor inter-bundle cooler according to any one of claims 1 to 4, characterized in that: The ratio of the row direction center distance of the water inlet of each U-shaped tube in the U-shaped tube bundle group to the height of the tube plate is 0.0681, and the ratio of the column direction center distance to the length of the water inlet area of the tube plate is 0.0992.

Images