Leaf vein bionic seal head plate heat exchanger

Abstract

The invention discloses a leaf vein bionic seal head plate heat exchanger which comprises a bionic inlet seal head, a heat exchange core body and an outlet seal head. The bionic inlet end socket comprises a main vein channel, an auxiliary vein channel and a transition section, the width of the main vein channel is gradually reduced in the flowing direction, the included angle between the side edge of the main vein channel and the horizontal line is theta 1, the auxiliary vein channel is connected with the main vein channel through the transition section, and the included angle between the tangent line of the transition section and the horizontal line is theta 2, fluid flows through the transition section through the bionic inlet end socket, enters the auxiliary vein channel and enters the heat exchange core body, the heat exchanger core body is composed of a single-layer or multi-layer flat plate and is affected by flowing media, each flat plate comprises a plurality of heat exchange channels or enhanced heat exchange surfaces, and the fluid flows into the heat exchange core body for heat exchange and finally flows out of the heat exchanger through the outlet end socket. By adjusting the cooperative relation between the auxiliary inclination angles and the main inclination angles of the heat exchange channels of the different auxiliary veins, fluid can be evenly distributed into the heat exchange channels, the volume utilization rate of the heat exchanger is increased, and the comprehensive performance of the heat exchanger is improved.

Description

Technical Field

[0001] The invention relates to the technical field of plate heat exchangers, and in particular to a leaf vein bionic head plate heat exchanger. Background Art

[0002] Plate heat exchangers are widely used in various industrial fields due to their compact structure, large heat exchange area per unit volume, good heat exchange performance and other advantages. The performance of the heat exchanger directly affects the efficiency of the thermal cycle. Plate heat exchangers are usually composed of inlet heads, heat exchange cores, outlet heads and cover plates. The fluid enters the inlet of the heat exchanger through the pipeline, and the inlet head distributes the future flow into the heat exchanger core. In this process, in order to reduce the volume of the heat exchanger and improve the volume utilization rate, the inlet cross-sectional area of ​​the head is much smaller than the flow cross-sectional area of ​​the heat exchanger core. There will be uneven flow distribution between the channels, and as the flow rate increases, the flow unevenness will seriously deteriorate, resulting in mismatched flows in each channel, affecting the comprehensive heat exchange performance of the heat exchanger, reducing the volume utilization rate of the heat exchanger, and even causing local overheating, which seriously affects the service life of the heat exchanger. In order to improve the head structure, the usual practice is to add or insert a secondary distribution structure inside the head and use a baffle to forcibly reduce the incoming flow velocity. This improves the uniformity of flow distribution under large flow conditions while bringing about huge pressure losses. Therefore, research on new structural heads that can achieve uniform flow distribution without increasing the pressure loss in the channel has become the key to further improving the overall performance of the heat exchanger. Summary of the invention

[0003] Purpose of the invention: The present invention provides a leaf vein bionic head plate heat exchanger, which can evenly distribute the fluid to each heat exchange channel by adjusting the coordinated relationship between the secondary inclination angle and the main inclination angle of different secondary leaf vein heat exchange channels.

[0004] Technical solution: The present invention describes a leaf vein bionic head plate heat exchanger, comprising: a bionic inlet head, a heat exchange core and an outlet head; the bionic inlet head comprises a main leaf vein channel, a secondary leaf vein channel and a transition section, the width of the main leaf vein channel gradually decreases along the flow direction, the angle between the side of the main leaf vein channel and the horizontal line is θ1, the secondary leaf vein channel is connected to the main leaf vein channel through a transition section, the angle between the tangent of the transition section and the horizontal line is θ2, the fluid passes through the inlet bionic inlet head, flows through the transition section, enters the secondary leaf vein channel, and enters the heat exchange core, the heat exchanger core is composed of a single-layer or multi-layer flat plate, affected by the flowing medium, each flat plate contains a number of heat exchange channels or enhanced heat exchange surfaces, the fluid enters the heat exchange core for heat exchange, and finally flows through the outlet head and flows out of the heat exchanger.

[0005] Furthermore, the cross-sectional area of ​​the main vein channel of the bionic inlet head gradually decreases along the flow direction, and the angle between the side of the main vein channel and the horizontal line is θ1, and the value range of θ1 is 60°<θ1<90°.

[0006] Furthermore, the secondary vein channel in the bionic inlet head is connected to the primary vein channel through a transition section, and the angle between the tangent line of the transition section and the horizontal line is θ2, and the value range of θ2 is 0°<θ2<90°.

[0007] Furthermore, the secondary vein channel in the bionic inlet head is connected to the main vein channel through a transition section, and the angle between the tangent of the transition section and the horizontal line is θ2. The angle θ between the tangent of the transition section connecting different secondary vein channels and the main vein channels and the horizontal line can be adjusted. By adjusting the angle θ between the tangent of different transition sections and the horizontal line, the optimal choice of flow uniformity distribution is achieved, and the value range of θ is 0°<θ<90°.

[0008] Furthermore, the transition section connecting the main vein channel and the secondary vein channel is a straight channel or a curved channel.

[0009] Furthermore, when the heat exchanger is composed of multiple layers of heat exchange plates, the working fluid of the heat exchanger is co-current or counter-current.

[0010] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The bionic head designed by the present invention combines the bionic concept with the design of the heat exchanger head. By using the vein characteristics of trees and leaves, a bionic head consisting of a main vein channel, a transition section and a secondary vein channel is designed. On the basis of not significantly increasing the pressure loss, the incoming flow can be evenly distributed to the sub-heat exchange channel, thereby significantly improving the volume utilization rate of the heat exchanger; (2) The main vein channel of the bionic head designed by the present invention has a structural feature of gradually decreasing cross-sectional area along the flow direction. The synergistic effect of the main inclination angle and the secondary inclination angle can drive the fluid into the secondary vein channel, thereby greatly reducing the pressure loss in the head; (3) The bionic head designed by the present invention utilizes the synergistic relationship between the main and secondary inclination angles to evenly arrange the fluid in different heat exchange channels. The main inclination angle, the secondary inclination angle and the width of different secondary vein channels can be adjusted, so that the flow can be evenly distributed under different working conditions, making the application of this bionic head extensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the heat exchanger structure of the present invention.

[0012] Figure 2 It is a schematic diagram of the head structure with different secondary inclination angles of the present invention.

[0013] Figure 3 Schematic diagram of the traditional head and bionic head structure of plate heat exchanger.

[0014] Figure 4 This is a speed distribution diagram for each channel of the present invention.

[0015] Figure 5 This is a mass flow distribution diagram for each channel of the present invention. DETAILED DESCRIPTION

[0016] like Figure 1 As shown, a leaf vein bionic head plate heat exchanger includes: a bionic inlet head, a heat exchange core and an outlet head; the bionic inlet head includes a main leaf vein channel, a secondary leaf vein channel and a transition section, the width of the main leaf vein channel gradually decreases along the flow direction, the angle between the side of the main leaf vein channel and the horizontal line is θ1, the secondary leaf vein channel is connected to the main leaf vein channel through the transition section, and the angle between the tangent of the transition section and the horizontal line is θ2. The heat exchanger core is composed of a single-layer or multi-layer flat plate, and the cold and hot fluids flow through different bionic inlet heads through the transition section and enter the secondary leaf vein channel. Affected by the design working conditions of the heat exchanger and the physical properties of the cold and hot fluids (fluid 1, fluid 2), each flat plate contains a number of heat exchange channels or enhanced heat exchange surfaces, and fluid 1 and fluid 2 enter different heat exchange plates for heat exchange respectively, and finally flow out of the heat exchanger through the outlet head.

[0017] like Figure 2 As shown, the heat exchanger core includes at least one heat exchange plate, and a single-layer heat exchange plate is used as an implementation example. The single-layer heat exchange plate includes 20 secondary vein channels, wherein the main inclination angle is θ1, and the 20 secondary vein channels are divided into 5 regions, and the secondary inclination angles in different regions are the same, namely θ2, θ3, θ4, θ5, and θ6, respectively. The secondary inclination angles in different regions can be adjusted to achieve uniform distribution of the fluid.

[0018] like Figure 3 The figure shows the structural comparison between the traditional head and the bionic head of a plate heat exchanger. The cross-sectional area of ​​the main channel of the traditional head of a plate heat exchanger remains unchanged along the flow direction, and the secondary channel is perpendicular to the main channel. The cross-sectional area of ​​the main channel of the bionic head gradually decreases along the flow direction, there is a transition section between the secondary channel and the main channel, and the angle between the transition section and the main channel is adjustable. By adjusting the main and secondary inclination angles, the flow unevenness can be reduced.

[0019] In order to verify the effect of the present invention, Fluent was used to perform numerical simulation of the flow, and numerical simulation was performed on the traditional head and bionic head of the plate heat exchanger, the flow channel height was 1mm, the plate thickness was 0.5mm; the inlet width of the traditional head and the bionic head of the heat exchanger was 6.25mm, the main inclination angle of the bionic head was set to 89° and 88° respectively, and the secondary inclination angles of all channels were kept the same and set to 60° and 75° respectively. RP-3 aviation kerosene was used as the flow medium, and the inlet flow rate was set to 0.1kg / s.

[0020] like Figure 4 and Figure 5The figure shows the distribution of flow velocity and flow rate in 20 channels. The standard deviation of velocity (MF) is used as the reference value of flow uniformity. Compared with the traditional head, when the main inclination angle is 89° and the secondary inclination angle is 60°, the pressure loss of the bionic head is reduced by 72%, and the flow uniformity is improved by 39%. When the main inclination angle is 88° and the secondary inclination angle is 75°, the pressure loss of the bionic head is improved by 82%, and the flow uniformity is also improved by 82%. It can be seen that when the same bionic head structure is used under different working conditions, the comprehensive performance of the heat exchanger is quite different. Therefore, the flow uniformity can be improved by optimizing the synergistic relationship between the main inclination angle and the secondary inclination angle.

[0021] The inlet bionic head of the present invention is composed of a main vein channel, a transition section and a secondary vein channel. The main vein channel presents a characteristic of gradually decreasing cross-sectional area along the flow direction. The fluid is dispersed into the secondary vein channels along the flow direction through the transition section. The synergistic effect of the main inclination angle and the secondary inclination angle can promote the fluid to enter the secondary vein channel. As the fluid decreases along the flow direction, the impact of the fluid and the wall is reduced, the backflow in the head is reduced, and the pressure loss is reduced. By adjusting the synergistic relationship between the secondary inclination angle and the main inclination angle of different secondary vein heat exchange channels, the fluid can be evenly distributed to each heat exchange channel, the fluid flows evenly through the heat exchanger core, and the sufficient heat exchange between the two fluids improves the volume utilization of the heat exchanger and improves the comprehensive performance of the heat exchanger.

Claims

1. A leaf vein bionic head plate heat exchanger, characterized in that: include: Bionic inlet head, heat exchange core and outlet head; the bionic inlet head includes a main vein channel, a secondary vein channel and a transition section. The width of the main vein channel gradually decreases along the flow direction. The angle between the side of the main vein channel and the horizontal line is θ1. The secondary vein channel is connected to the main vein channel through a transition section. The angle between the tangent of the transition section and the horizontal line is θ2. The fluid flows through the inlet bionic inlet head, flows through the transition section, enters the secondary vein channel, and enters the heat exchange core. The heat exchanger core is composed of a single layer or multiple layers of flat plates. Affected by the flowing medium, each flat plate contains a number of heat exchange channels or enhanced heat exchange surfaces. The fluid enters the heat exchange core for heat exchange and finally flows through the outlet head and out of the heat exchanger.

2. The vein bionic head plate heat exchanger according to claim 1, characterized in that: The cross-sectional area of ​​the main vein channel of the bionic inlet head gradually decreases along the flow direction, and the angle between the side of the main vein channel and the horizontal line is θ1, and the value range of θ1 is 60°<θ1<90°.

3. The vein bionic head plate heat exchanger according to claim 1, characterized in that: The secondary vein channel in the bionic inlet head is connected with the primary vein channel through a transition section, and the angle between the tangent line of the transition section and the horizontal line is θ2, and the value range of θ2 is 0°<θ2<90°.

4. The vein bionic head plate heat exchanger according to claim 1, characterized in that: The secondary vein channel in the bionic inlet head is connected to the main vein channel through a transition section. The angle between the tangent of the transition section and the horizontal line is θ2. The angle θ between the tangent of the transition section connecting different secondary vein channels and the main vein channel and the horizontal line can be adjusted. By adjusting the angle θ between the tangent of different transition sections and the horizontal line, the optimal choice of flow uniformity distribution is achieved. The value range of θ is 0°<θ<90°.

5. The vein bionic head plate heat exchanger according to claim 1, characterized in that: The transition section connecting the main vein channel and the secondary vein channel is a straight channel or a curved channel.

6. The vein bionic head plate heat exchanger according to claim 1, characterized in that: When the heat exchanger is composed of multiple layers of heat exchange plates, the working fluid of the heat exchanger is co-current or counter-current.

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