Heat exchanger

Abstract

A heat exchanger includes a housing having a first fluid inlet portion for introducing a first fluid, a body, and a first fluid outlet portion for discharging the first fluid. The first fluid inlet part and the first fluid outlet part are connected to the two ends of the body respectively. A distributor is arranged in the first fluid inlet part, is in a hollow ring shape with two open ends and is separated from the inner wall of the first fluid inlet part so as to allow the first fluid to flow through from the inner side and the outer side of the distributor at the same time. The inner diameter of the upstream end of the distributor is smaller than that of the downstream end of the distributor, and the inner diameter of the connecting port of the first fluid inlet part is smaller than that of the downstream end of the distributor.

Description

Technical Field

[0001] The present application relates to a heat exchanger, and in particular to a heat exchanger with improved fluid axial flow velocity distribution uniformity. Background Art

[0002] Heat exchangers (also called heat exchangers), such as shell and tube heat exchangers, are commonly used in chemical production processes to transfer part of the heat of a hotter fluid to a cooler fluid. In a heat exchanger, at least one fluid to be involved in heat exchange is introduced from a fluid inlet, and the fluid that has completed the heat exchange is removed from a fluid outlet accordingly.

[0003] Usually, the main body of the heat exchanger has a certain cross-sectional area in a direction generally perpendicular to the path of the fluid, and the cross-sectional area of ​​the main body is generally larger than the cross-sectional area of ​​the fluid inlet of the fluid. Therefore, the fluid entering from the fluid inlet usually undergoes a process in which the fluid passage expands from a smaller cross-sectional area of ​​the fluid inlet to a larger cross-sectional area of ​​the main body. However, in the process of expanding the cross-sectional area of ​​the fluid passage, it is often difficult to ensure that the axial flow velocity of the fluid distributed over the entire cross-sectional area of ​​the main body of the heat exchanger is uniform, and it is often the case that the intermediate axial flow velocity is larger and the peripheral axial flow velocity is smaller. Generally speaking, without any theoretical restrictions, the greater the flow velocity of the fluid in the heat exchanger, the greater its heat transfer coefficient. Therefore, a smaller peripheral axial flow velocity will lead to a lower peripheral heat transfer coefficient, thereby affecting the overall heat exchange efficiency of the heat exchanger.

[0004] It can be seen that there is still a need in the art for improved heat exchanger design, especially for improving the uniformity of fluid flow velocity distribution in the heat exchanger. Utility Model Content

[0005] In order to at least partially overcome the defects of the prior art heat exchanger, the present application proposes to set a distributor at the fluid inlet of the heat exchanger so that the axial flow velocity distribution of the fluid is more uniform. Specifically, the present application proposes a heat exchanger, including a shell, the shell having a first fluid inlet for introducing a first fluid, a main body, and a first fluid outlet for discharging the first fluid, the first fluid inlet and the first fluid outlet are respectively connected to the two ends of the main body. In some embodiments, a distributor is arranged in the first fluid inlet, the distributor is a hollow ring with openings at both ends and is spaced from the inner wall of the first fluid inlet to allow the first fluid to flow through the inside and outside of the distributor at the same time, the inner diameter of the upstream end of the distributor is smaller than the inner diameter of the downstream end of the distributor, and the inner diameter of the connecting port of the first fluid inlet is smaller than the inner diameter of the downstream end of the distributor. The distributor is arranged to change the flow path of the first fluid flowing in from the first fluid inlet so that the axial flow velocity distribution of the first fluid is more uniform.

[0006] In some embodiments, the first fluid inlet is located at the bottom of the housing and the downstream end of the distributor is located above the upstream end of the distributor, or the first fluid inlet is located at the top of the housing and the downstream end of the distributor is located below the upstream end of the distributor.

[0007] In some embodiments, the inner surface of the first fluid inlet portion is conical, and the shape of the distributor is also conical. The shape of the distributor can be the same or different from the cone angle of the inner surface of the first fluid inlet portion. In other words, the surface of the distributor is substantially parallel or non-parallel to the inner surface of the first fluid inlet portion.

[0008] In some embodiments, the distributor is fixed to the first fluid inlet portion, and the connection port is used to connect to the first fluid supply pipeline. In some embodiments, the ratio of the inner diameter of the upstream end of the distributor to the connection port is 0.3 to 0.9, and the ratio of the inner diameter of the downstream end of the distributor to the main body is 0.3 to 0.9. In some embodiments, the ratio of the inner diameter of the upstream end of the distributor to the connection port is 0.5 to 0.75, and the ratio of the inner diameter of the downstream end of the distributor to the main body is 0.5 to 0.75.

[0009] In some embodiments, the heat exchanger is a shell and tube heat exchanger, and the shell further includes a second fluid inlet for introducing a second fluid and a second fluid outlet for discharging the second fluid. In some embodiments, the second fluid inlet and the second fluid outlet are respectively arranged on both sides of the body. In some embodiments, the shell and tube heat exchanger further includes a first tube sheet separating the first fluid inlet from the body, a second tube sheet separating the first fluid outlet from the body, and a plurality of tubes connected between the first tube sheet and the second tube sheet, wherein the first fluid is a tube-side fluid and the second fluid is a shell-side fluid.

[0010] In some embodiments, the downstream end of the distributor is spaced apart from the first tube sheet in the axial direction of the heat exchanger.

[0011] In some embodiments, the ratio of the axial length of the first fluid inlet to the distributor is 1.2 to 4. In some embodiments, the ratio of the axial length of the first fluid inlet to the distributor is 2 to 3.

[0012] In some embodiments, multiple tubes are arranged symmetrically around the longitudinal axis of the main body, wherein the standard deviation of the axial flow velocity distribution of the first fluid entering each tube of the multiple tubes from the first fluid inlet portion in a cross section perpendicular to the longitudinal axis of the main body is no more than 85% of the average flow velocity of the first fluid in the cross section.

[0013] In some embodiments, the first fluid and the second fluid are respectively gas, liquid, gas-liquid mixture, gas-liquid-solid mixture or liquid-solid mixture. Accordingly, the above-mentioned dimensional ratios of the distributor relative to the first fluid inlet can be designed according to the density, viscosity, flow rate and other properties of the fluid to achieve the best axial flow velocity distribution uniformity effect of the first fluid.

[0014] The heat exchanger according to the present application improves the uniformity of axial flow velocity distribution when the fluid entering from the fluid inlet flows to the main body of the shell, thereby improving the overall heat exchange efficiency of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings schematically illustrate the arrangement of the heat exchanger according to the present application and its effects, wherein the sizes and positional relationships of various components and structures are not drawn to scale.

[0016] Figure 1 is a schematic cross-sectional view of a heat exchanger according to an embodiment of the present application.

[0017] Figure 2 It is a partial cross-sectional schematic diagram of a heat exchanger according to an embodiment of the present application.

[0018] Figure 3A is a cross-sectional view of flow velocity distribution of a heat exchanger according to an embodiment of the present application.

[0019] Figure 3B is a top view of the flow velocity distribution of a heat exchanger according to an embodiment of the present application.

[0020] Figure 4A It is a cross-sectional diagram of flow velocity distribution of a comparative heat exchanger.

[0021] Figure 4B It is a top view of the flow velocity distribution of a comparative heat exchanger.

[0022] Figure markings: 100-heat exchanger; 110-main body; 120-first fluid inlet; 122-connecting port; 130-distributor; 170-first fluid outlet; 152, 154, 156-tubes; 162-first tube sheet; 164-baffle; D1-inner diameter of connecting port 122; D2-inner diameter of main body 110; D3-inner diameter of the upstream end of distributor 130; D4-inner diameter of the downstream end of distributor 130; F-first fluid; L1-axial length of first fluid inlet 120; L2-axial length of distributor 130. DETAILED DESCRIPTION

[0023] A person skilled in the art can understand various embodiments of the heat exchanger according to the present application by reading the specification with reference to the drawings. In the context of the present application, axial direction refers to the direction of the overall path of travel of the first fluid of the heat exchanger (regardless of its possible circuitous path), that is, the direction parallel to the longitudinal axis of the heat exchanger, for example Figure 1 Accordingly, the axial velocity distribution of the first fluid refers to the velocity distribution in a cross section perpendicular to the axial direction, such as Figure 1 The flow velocity distribution in the cross section shown by the dotted line BB'.

[0024] refer to Figure 1 , which shows a cross-sectional schematic diagram of a heat exchanger 100 according to an embodiment of the present application. In order to avoid blurring the features of the present application, Figure 1 The common structure of the heat exchanger is omitted. The technicians of this application can combine it with the common structure of the heat exchanger based on reading this application. The heat exchanger 100 includes a shell, the shell having a first fluid inlet portion 120 for introducing a first fluid, a main body 110, and a first fluid outlet portion 170 for discharging the first fluid. The inner diameter of the main body 110 is D2. In some embodiments, the first fluid inlet portion 120 and the first fluid outlet portion 170 are respectively connected to the two ends of the main body 110. A distributor 130 is arranged in the first fluid inlet 120, and the distributor 130 is a hollow ring with openings at both ends, and is spaced apart from the inner wall of the first fluid inlet portion 120 to allow the first fluid to flow through the inside and outside of the distributor 130 at the same time. Similar to the conical shape of the first fluid inlet portion 120, the upstream end of the distributor 130 ( Figure 1 The inner diameter D3 of the downstream end ( Figure 1 The inner diameter D4 of the connection port 122 of the first fluid inlet portion 120 is smaller than the inner diameter D1 of the downstream end D4 of the distributor 130. The distributor 130 can guide the first fluid introduced from the connection port 122 to flow through the inside and outside of the hollow distributor 130 at the same time, and generate resistance to the fluid flow inside and outside.

[0025] Without being limited by any theory, the first fluid flow passing closely to the inner and outer sides of the distributor 130 generates a boundary layer and has a relatively low flow velocity. At the same time, the first fluid flowing closely to the inner side of the first fluid inlet 120 also generates a boundary layer and has a relatively low flow velocity. Therefore, the first fluid guided by the distributor 130 can have a relatively more uniform axial flow velocity in the cross section shown by the dotted line BB', thereby having a relatively uniform first fluid heat transfer coefficient in the entire cross section. Figure 3A and Figure 3B 1 shows the axial flow velocity distribution in a heat exchanger equipped with a distributor 130 according to an embodiment of the present application. For comparison, Figure 4Aand Figure 4B The axial flow velocity distribution in a heat exchanger without a distributor is shown. Figure 3A-Figure 4B In the table, the unit of digital scale is m / s.

[0026] In some embodiments, water at room temperature and pressure is used as the first fluid, and the ratio of the inner diameter D3 of the upstream end of the distributor 130 to the inner diameter D1 of the connecting port 122 is 0.7, the ratio of the inner diameter D3 of the downstream end of the distributor 130 to the inner diameter D1 of the connecting port 122 is also 0.7, and the ratio of the axial length L1 of the first fluid inlet 120 to the axial length L2 of the distributor 130 is 1.5. Figure 3A and Figure 3B As shown in FIG. 1 , when the average velocity of the first fluid in the section BB' is 0.18 m / s, the standard deviation of the velocity distribution in the section BB' is 0.15 m / s, and the axial velocity of the middle part and the peripheral part are relatively close. Figure 4A and Figure 4B As shown, in the comparative heat exchanger without a distributor, when other dimensional structures are the same, when the average flow velocity of the first fluid in section BB' is also 0.18 m / s, the standard deviation of the flow velocity distribution in section BB' is as high as 0.81 m / s, showing that the axial flow velocity in the middle part is much larger than the flow velocity distribution in the peripheral part.

[0027] It should be understood that the ratios among the inner diameter D3 of the upstream end of the distributor 130, the inner diameter D4 of the downstream end, the inner diameter D1 of the connection port 122, and the inner diameter D2 of the main body 110 in the above embodiment are only examples. According to actual operating parameters, including the viscosity, density, flow rate of the fluid, the smoothness of the material of the interior of the heat exchanger 100 and the distributor 130, and the overall size of the heat exchanger 100, the ratios among D1, D2, D3, and D4 and the ratios among L1 and L2 can be adjusted to obtain the most uniform axial flow velocity distribution of the first fluid. Through computer fluid simulation (for example, fluid finite element analysis), under different conditions of the above-mentioned operating parameters, when the ratio of the inner diameter D3 of the upstream end of the distributor 130 to the inner diameter D1 of the connecting port 122 is 0.3 to 0.9, the ratio of the inner diameter D3 of the downstream end of the distributor 130 to the inner diameter D1 of the connecting port 122 is 0.3 to 0.9, and the ratio of the axial length L1 of the first fluid inlet 120 to the axial length L2 of the distributor 130 is 1.2 to 4, the fluid can achieve a better effect of uniforming the axial flow velocity of the fluid. For common fluids with common viscosities and densities at temperatures, pressures and flow rates suitable for chemical production operations, the ratio of the inner diameter D3 of the upstream end of the distributor 130 to the inner diameter D1 of the connecting port 122 is 0.5 to 0.75, the ratio of the inner diameter D3 of the downstream end of the distributor 130 to the inner diameter D1 of the connecting port 122 is 0.5 to 0.75, and the ratio of the axial length L1 of the first fluid inlet 120 to the axial length L2 of the distributor 130 is 1.2 to 2, which can often achieve an excellent effect of uniforming the axial flow velocity of the fluid.

[0028] although Figure 1 and Figure 2 The first fluid inlet 120 and the distributor 130 are schematically shown as having the same taper, but in other embodiments, based on the properties of the fluid and the operating parameters of the heat exchanger, the taper angle of the distributor 130 may be greater than or less than the first fluid inlet 120 to optimize the effect of uniformizing the axial flow velocity of the fluid.

[0029] In some embodiments, the first fluid inlet 120 is located at the bottom of the housing, and the downstream end of the distributor 130 is located above the upstream end of the distributor 130. In other embodiments, the first fluid inlet 120 is located at the top of the housing, and the downstream end of the distributor 130 is located below the upstream end of the distributor 130. In these embodiments, the first fluid F entering from the first fluid inlet 120 contacts the upstream end of the distributor 130 with a smaller inner diameter first relative to the downstream end with a larger inner diameter.

[0030] In some embodiments, the inner surface of the first fluid inlet portion 120 is conical, and the shape of the distributor 130 is conical corresponding to the inner surface of the first fluid inlet portion 120 .

[0031] like Figure 2 As shown, in some embodiments, the heat exchanger 100 according to the present application can be a shell and tube heat exchanger, and the shell also includes a second fluid inlet 140 for introducing a second fluid and a second fluid outlet (not shown) for discharging the second fluid. In some embodiments, the second fluid inlet 140 and the second fluid outlet are respectively arranged on both sides of the main body 110, and the positions of the two can be interchanged according to the countercurrent or parallel flow operation mode of the heat exchanger 100. In some other embodiments, the second fluid inlet 140 and the second fluid outlet can also be arranged at both ends of the same side of the main body 110, or at other positions to increase the flow path length of the second fluid. The shell and tube heat exchanger includes a first tube sheet 162 separating the first fluid inlet 120 from the main body 110, a second tube sheet (not shown) separating the first fluid outlet from the main body 110, and a plurality of tubes 152, 154, 156 connected between the first tube sheet and the second tube sheet. Accordingly, the first fluid is a tube-side fluid and the second fluid is a shell-side fluid. In some embodiments, the downstream end of the distributor 130 is spaced apart from the first tube sheet 162 in the axial direction of the heat exchanger so that the first fluid can further diffuse radially after leaving the downstream end of the distributor 130. In some embodiments, one or more baffles 164 are further provided between the first tube sheet 162 and the second tube sheet to extend the flow path length of the second fluid in the shell side, thereby improving the heat exchange effect.

[0032] In the case of a shell and tube heat exchanger having a plurality of tubes 152, 154, 156, the heat exchanger 100 having the distributor 130 according to the present application can make the first fluid of the tube side in the cross section perpendicular to the longitudinal axis (such as Figure 1 The axial flow velocity distribution in the cross section BB' in the middle is more uniform. Accordingly, the flow velocity of the central tube 152 is closer to that of the peripheral tubes 154 and 156, thereby preventing the flow velocity of the first fluid in the peripheral tubes 154 and 156 from being too low, thereby improving the overall heat exchange effect.

[0033] In some embodiments, the plurality of tubes 152, 154, 156 are symmetrically arranged around the longitudinal axis of the body 110. The standard deviation of the axial flow velocity distribution of the first fluid entering each of the plurality of tubes 152, 154, 156 from the first fluid inlet portion 120 in a cross section perpendicular to the longitudinal axis of the body 110 is no greater than 85% of the average flow velocity of the first fluid in the cross section. More preferably, in some embodiments, the standard deviation is no greater than 50%.

[0034] In some embodiments, the first fluid and the second fluid are respectively gas, liquid, gas-liquid mixture, gas-liquid-solid mixture or liquid-solid mixture. It should be understood that the shape and various dimensional features of the distributor 130 can be designed and optimized according to the properties of the first fluid.

[0035] The above description of the disclosed embodiments enables those skilled in the art to implement or use the technical solutions of the present application. Those skilled in the art may make various modifications to these embodiments, and the general principles described herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments described or illustrated herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed in the present application.

Claims

1. A heat exchanger, comprising a shell, the shell having a first fluid inlet for introducing a first fluid, a main body, and a first fluid outlet for discharging the first fluid, the first fluid inlet and the first fluid outlet being connected to two ends of the main body, respectively, characterized in that: A distributor is arranged in the first fluid inlet portion, and the distributor is a hollow ring with openings at both ends and is spaced apart from the inner wall of the first fluid inlet portion to allow the first fluid to flow through the inside and outside of the distributor at the same time, the inner diameter of the upstream end of the distributor is smaller than the inner diameter of the downstream end of the distributor, and the inner diameter of the connecting port of the first fluid inlet portion is smaller than the inner diameter of the downstream end of the distributor.

2. The heat exchanger according to claim 1, characterized in that: The first fluid inlet is located at the bottom of the housing, and the downstream end of the distributor is located above the upstream end of the distributor, or The first fluid inlet portion is located at the top of the housing, and the downstream end of the distributor is located below the upstream end of the distributor.

3. The heat exchanger according to claim 1, characterized in that: The inner surface of the first fluid inlet portion is conical, and the shape of the distributor is also conical.

4. The heat exchanger according to claim 3, characterized in that: The distributor is fixed to the inner surface of the first fluid inlet portion, the connecting port is used to connect to the first fluid supply pipeline, the ratio of the inner diameter of the upstream end of the distributor to the connecting port is 0.3 to 0.9, and the ratio of the downstream end of the distributor to the inner diameter of the main body is 0.3 to 0.

9.

5. The heat exchanger according to claim 4, characterized in that: The ratio of the inner diameter of the upstream end of the distributor to the connecting port is 0.5 to 0.75, and the ratio of the inner diameter of the downstream end of the distributor to the main body is 0.5 to 0.

75.

6. The heat exchanger according to claim 1, characterized in that The heat exchanger is a shell and tube heat exchanger, the shell further includes a second fluid inlet for introducing a second fluid and a second fluid outlet for discharging the second fluid, the shell and tube heat exchanger includes a first tube sheet separating the first fluid inlet from the main body, a second tube sheet separating the first fluid outlet from the main body, and a plurality of tubes connected between the first tube sheet and the second tube sheet, wherein the first fluid is a tube-side fluid and the second fluid is a shell-side fluid.

7. The heat exchanger according to claim 6, characterized in that The downstream end of the distributor is spaced apart from the first tube sheet in the axial direction of the heat exchanger.

8. The heat exchanger according to claim 7, characterized in that The ratio of the axial length of the first fluid inlet to the axial length of the distributor is 1.2-4.

9. The heat exchanger according to claim 6, characterized in that The multiple tubes are arranged symmetrically around the longitudinal axis of the main body, wherein the standard deviation of the axial flow velocity distribution of the first fluid entering each of the multiple tubes from the first fluid inlet portion in a cross section perpendicular to the longitudinal axis of the main body is no more than 85% of the average flow velocity of the first fluid in the cross section.

10. The heat exchanger according to claim 6, characterized in that The first fluid and the second fluid are respectively gas, liquid, a gas-liquid mixture, a gas-liquid-solid mixture or a liquid-solid mixture.

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