A current collecting structure with uniform flow distribution

Abstract

The application provides a flow uniform distribution collecting structure, which comprises a working medium inlet and an inlet distribution section, and the working medium inlet is communicated with the inlet distribution section, and is characterized in that the distribution section is designed as a curve, wherein L is the length of the distribution section, W 分流段_max is the width of the widest part of the flow channel of the distribution section, l is the distance from a certain position in the distribution section to the working medium inlet, and w is the width of the flow channel of the distribution section at the position l away from the working medium inlet. Compared with the common conical distribution section design, the working medium flow path is better optimized, the temperature uniformity is improved, and the local hot spot is avoided. Meanwhile, the calculation is easy, and the application has certain engineering practical significance.

Description

Technical Field

[0001] This invention relates to heat exchanger technology, and more particularly to a flow distribution manifold structure with uniform flow distribution. Background Technology

[0002] Heat exchangers are widely used in industries such as chemical, petroleum, refrigeration, nuclear power, and power. Due to the global energy crisis, the demand for heat exchangers in industrial production is increasing, and the quality requirements for heat exchangers are also becoming more stringent. In recent decades, compact heat exchangers (plate, plate-fin, and welded plate heat exchangers, etc.), heat pipe heat exchangers, and direct contact heat exchangers have developed rapidly. Heat exchangers are widely used in many fields. In fields such as electronics, petrochemicals, communications, and aerospace, due to their special working environments, there are special requirements for the size and weight of heat exchangers, as well as a need for stronger heat exchange capacity. In 1981, some scholars proposed using microchannels for heat dissipation, which can reduce the size of the heat exchanger and significantly improve its heat exchange capacity by utilizing the high specific surface area of ​​the microchannels. However, although the heat exchange capacity is strong, the overall pressure loss is also high due to the small hydraulic diameter of the microchannels.

[0003] Numerous studies have found that microchannel heat exchangers also suffer from uneven flow distribution. In 1991, researchers proposed a manifold microchannel heat exchanger based on existing microchannel heat exchangers, significantly reducing its overall pressure loss. However, extensive research indicates that the fluid distribution within the manifold microchannel is not uniform, resulting in uneven flow distribution.

[0004] Patent CN202111291436.7 discloses a manifold shell-and-tube heat exchanger, a microchannel heat exchanger capable of exchanging heat between hot and cold fluids. It reduces overall pressure loss while also possessing the advantages of manifold impinging jets, enhancing fluid turbulence and heat exchange. Simultaneously, it ensures uniform fluid distribution and counter-current flow of hot and cold fluids, improving heat exchange efficiency. However, its flow distribution structure uses a conical channel, which still suffers from uneven fluid distribution; the design of the flow distribution section requires further optimization. It also exhibits problems such as low heat exchange efficiency and excessive flow resistance. Most existing evaporator structures are flat, making it difficult to dissipate heat from curved surfaces such as hydraulic cylinders and motors.

[0005] However, in actual operation, due to changes in operating conditions or improper selection of the distributor, uneven flow rates occur in different tubes. Some tubes have low flow rates and evaporate prematurely, while others have excessive flow rates, resulting in very low superheat at the outlet or even the presence of some liquid. Both situations prevent the heat exchange area from being fully utilized, thus seriously affecting system performance.

[0006] To address the aforementioned shortcomings, this invention improves upon existing heat exchangers by proposing a novel flow collection structure. Summary of the Invention

[0007] This invention provides a novel flow collection structure that improves the evaporator structure, thereby solving the aforementioned technical problems.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] A flow distribution collection structure, comprising a working fluid inlet and an inlet branching section, wherein the working fluid inlet is connected to the inlet branching section, characterized in that the branching section is designed with a curve...

[0010]

[0011] In the formula, L is the length of the split section, and W 分流段_max denoted as the width of the widest part of the flow channel in the flow branch section, l is the distance from a certain point in the flow branch section to the working medium inlet, and w is the width of the flow channel in the flow branch section at a distance l from the working medium inlet.

[0012] A flow collection structure with uniform flow distribution, the flow collection structure including a working fluid outlet and an outlet confluence section, characterized in that the confluence section is designed with a curve...

[0013]

[0014] In the formula, L is the length of the recirculation section, and W 分流段_max denoted as the width of the widest part of the confluence channel, l is the distance from a certain point in the confluence channel to the working medium inlet, and w is the width of the confluence channel at a distance l from the working medium inlet.

[0015] Preferably, the current collection structure is arc-shaped with an arc angle r of 60°-80°.

[0016] An arc-shaped flow-equalizing manifold evaporator includes an arc-shaped cover plate and an arc-shaped base plate. Microchannels are machined on the base plate. The cover plate includes a working fluid inlet, an inlet branching section, a manifold guide plate, an outlet confluence section, and a working fluid outlet. The microchannels are located in the middle of the base plate, with their length direction perpendicular to the length direction of the manifold guide plate. The manifold guide plate is located in the middle of the cover plate, its position corresponding to the position of the microchannels on the base plate. After the base plate and cover plate are installed together, the manifold guide plate is installed above the microchannels. A working fluid inlet and outlet are located diagonally at the top of the base plate, and the branching section is located between the manifold guide plate and the working fluid inlet and outlet.

[0017] An improvement is that the top of the cover plate is provided with a working fluid inlet 1-1 and a working fluid outlet 1-2, with the inlet and outlet located diagonally opposite each other on the cover plate.

[0018] One improvement is that the manifold deflector is located in the middle of the bottom of the cover plate, and the deflector is obtained by a U-shaped periodic structure array.

[0019] One improvement is that the manifold guide plate has eight manifold inlets and manifold outlets, located at the openings of the U-shaped periodic units.

[0020] An improvement is the inclusion of an inlet diversion section between the manifold inlet and the working fluid inlet, and an outlet confluence section between the manifold outlet and the working fluid outlet, ensuring uniform distribution of the working fluid.

[0021] One improvement is that the flow resistance of each segment of the flow divider on the cover plate is calculated by constructing an equivalent flow resistance network model 5. The widths of the midpoints of each segment of the flow divider are 9.5mm, 6.8mm, 4.3mm, 3.3mm, 2.6mm, 2.3mm, and 2.15mm.

[0022] An improved equivalent flow resistance network model has 7 individual loops. Analyzing at the diagonal nodes of each loop, the voltage drop across the two paths between nodes should be equal, satisfying the formula: [Formula omitted for brevity]

[0023] Formula 1

[0024] (8-i)R_inlet_i=i×R_outlet_i (i=1,2,3...8)

[0025] R_inlet_i = R_outlet_i

[0026] In the formula, R_in_i represents the flow resistance of the i-th branch segment. The flow resistance of each segment is shown in 2-5. The number of the flow segment closer to the working medium inlet and outlet is small, and the number of the flow segment farther away from the working medium inlet and outlet is large. Similarly, R_out_i represents the flow resistance of the i-th confluence segment, that is, the flow resistance of the confluence segment sandwiched by the i-th manifold inlet and the (i+1)-th manifold inlet that are close to the working medium outlet.

[0027] Preferably, the base plate has a microchannel structure, a thickness of 3.25 mm, a length of 80 mm, a width of 53.42 mm, and a bending angle of 60°.

[0028] Preferably, the evaporator bottom plate has 27 microchannels, each channel is 50.22mm long, 1mm wide, and 2mm high; the spacing between the microchannels is 1mm.

[0029] R134A is preferred as the working fluid.

[0030] Preferably, the working fluid flows into the evaporator working fluid inlet 1-1 through the pipeline and is evenly distributed into the 8 manifold inlets under the action of the inlet diversion section. The flow direction of the manifold guide plate is perpendicular to the extension direction of the microchannel. After the working fluid flows into the guide plate, it will flow into the microchannel below. The bottom of the microchannel is the heat source. The manifold microchannel structure increases the working fluid jet effect, enhances heat exchange, shortens the flow path of the working fluid in the microchannel, and reduces pressure loss.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] (1) Flow distribution is a critical issue in manifold microchannel structures, largely determining their heat transfer performance. The flow-equalizing evaporator proposed in this invention is equipped with a flow-dividing section and a flow-merging section, and provides a design optimization method for the flow-dividing section. This method constructs an equivalent flow resistance network model, uses nonlinear programming to calculate the width of the flow channels at each point in the flow-dividing section, and obtains the design curve of the flow-dividing section (flow-merging section).

[0033]

[0034] In the formula, L is the length of the flow branch section 2-2 (the length is along the arc length of the evaporator), W 分流段_max Let 2-1 be the width of the widest part of the flow channel in the flow segment, l be the distance from a certain point in the flow segment to the working medium inlet, and w be the width of the flow channel in the flow segment at a distance l from the working medium inlet, 2-4.

[0035] Compared to the conventional conical flow divider design, this method optimizes the working fluid flow path, improves temperature uniformity, and avoids local hot spots. It is also easy to calculate and has practical engineering significance.

[0036] (2) The present invention is provided with an arc-shaped cover plate and an arc-shaped bottom plate. By setting the arc structure, the working fluid flow time is extended, the heat exchange area is increased, and the heat transfer capacity is improved.

[0037] (3) The arc-shaped structure can be directly fitted with motors, actuators, hydraulic cylinders, circular pipes, etc., reducing thermal resistance. The invention integrates a manifold microchannel with an arc-shaped structure, resulting in an arc-shaped evaporator with an arc radius r, arc length L, and radius of curvature R, and a microchannel width d in the manifold microchannel. 微通道 Microchannel spacing d 微通道间距 Manifold guide vane height H 导流板 Microchannel height h 微通道高度 , deflector plate bending plate L 弯折板 and longboard L 导流板 The optimization formula for the length is proposed, and design specifications for different curvatures are put forward, which can guide the design of manifold microchannels under different curvature conditions.

[0038]

[0039] d 微通道 = (0.05~0.2)Rcos 2 r

[0040]

[0041] h 微通道高度 = (0.8~1.5)H 底板厚度 Rcos2 r Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the pump-driven two-phase circuit structure of the present invention.

[0043] Figure 2 This is a schematic diagram of a preferred evaporator cover structure of the present invention.

[0044] Figure 3 This is a schematic diagram of the preferred evaporator cover flow divider structure of the present invention.

[0045] Figure 4 This is a schematic diagram of the preferred evaporator base plate structure of the present invention.

[0046] Figure 5 This is a preferred equivalent flow resistance network model diagram of the present invention.

[0047] Figure 6 This is a preferred structural diagram of the evaporator unit of the present invention. Detailed Implementation

[0048] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0049] Unless otherwise specified, in this article, " / " represents division, and "×" and "*" represent multiplication.

[0050] This invention improves the flow collection structure to achieve uniform flow distribution. For example... Figure 1-3 As shown, the main technical solution adopted is as follows: a flow collection structure with uniform flow distribution, the flow collection structure including a working fluid inlet and an inlet branching section, the working fluid inlet being connected to the inlet branching section, characterized in that the branching section is designed with a curve

[0051]

[0052] In the formula, L is the length of the split section, and W 分流段_max denoted as the width of the widest part of the flow channel in the flow branch section, l is the distance from a certain point in the flow branch section to the working medium inlet, and w is the width of the flow channel in the flow branch section at a distance l from the working medium inlet.

[0053] A flow collection structure with uniform flow distribution, the flow collection structure including a working fluid outlet and an outlet confluence section, characterized in that the confluence section is designed with a curve...

[0054]

[0055] In the formula, L is the length of the recirculation section, and W 分流段_max denoted as the width of the widest part of the confluence channel, l is the distance from a certain point in the confluence channel to the working medium inlet, and w is the width of the confluence channel at a distance l from the working medium inlet.

[0056] The current collection structure is arc-shaped, with an arc angle r of 60°-80°.

[0057] This application applies to a mechanical pump-driven two-phase fluid circuit, such as... Figure 1 As shown, the pump-driven two-phase circuit includes a mechanical pump 1, an evaporator 2, a condenser 3, a liquid receiver 4, a regenerator 5, a preheater 6, a sensor 7, and fuel oil 8. During operation, the subcooled single-phase working fluid, driven by the mechanical pump 1, is preheated by the regenerator 5 and preheater 6 until it reaches saturation temperature, then flows into the evaporator 2. The saturated working fluid undergoes a phase change in the evaporator 2, absorbing heat from the heat source. Subsequently, the two phases flow through the regenerator 5 again, exchanging heat with the subcooled working fluid, and then flow into the condenser 3, where heat is exchanged again and the heat is discharged. The condensed subcooled working fluid then enters the next working cycle. During system operation, the liquid receiver 4 can compensate for the working fluid in the main pipeline in real time, buffering system pressure fluctuations. The evaporator is the core heat transfer component of the pump-driven two-phase flow system. Currently, most pump-driven two-phase evaporators adopt a straight microchannel or ordinary manifold structure, and their heat transfer capacity, drag reduction effect, and temperature uniformity performance need to be improved.

[0058] As an improvement, such as Figure 2 , 3 As shown, the evaporator includes an arc-shaped cover plate and an arc-shaped base plate. Microchannels are machined on the base plate. The cover plate includes a working fluid inlet 1-1, an inlet branch section 1-6, a manifold guide plate, an outlet confluence section 1-7, and a working fluid outlet 1-2. The working fluid inlet connects to the inlet branch section, and the outlet confluence section connects to the working fluid outlet. The manifold guide plate includes a long plate and a bent plate, with the bent plate connecting adjacent long plates. The microchannels are located in the middle of the base plate, with their length direction perpendicular to the direction of the long plate of the manifold guide plate. The manifold guide plate is located in the middle of the cover plate, its position corresponding to the position of the microchannels on the base plate. After the base plate and cover plate are installed together, the manifold guide plate is installed above the microchannels. A working fluid outlet and a working fluid inlet are located diagonally at the top of the base plate. The inlet branch section and the outlet confluence section are respectively located between the manifold guide plate and the working fluid outlet and inlet.

[0059] This invention provides an arc-shaped flow equalization manifold evaporator. The invention is equipped with an arc-shaped cover plate and an arc-shaped bottom plate. By setting the arc structure, the flow time of the working fluid is extended, the heat exchange area is increased, and the heat transfer capacity is improved.

[0060] Preferably, the top of the cover plate is provided with a working fluid inlet 1-1 and a working fluid outlet 1-2, with the inlet and outlet located diagonally opposite each other on the top of the cover plate. Providing the inlet and outlet at the top eliminates the limitation imposed by thickness on the size of the inlet and outlet, buffers the working fluid flow rate, and improves flow uniformity.

[0061] The arc-shaped structure of this invention can directly fit with motors, actuators, hydraulic cylinders, circular pipes, etc., reducing thermal resistance. This invention integrates a manifold microchannel with an arc-shaped structure, obtaining optimized formulas for the arc radius of the arc-shaped evaporator and the width of the microchannel, the height of the manifold guide plate, and the lengths of the bent and long plates of the guide plate. Design specifications for different arc radii are proposed, guiding the design of manifold microchannels under various arc conditions. Simultaneously, a method for optimizing the design of the evaporator flow segment is proposed, and a formula for the flow channel width of the flow segment design is given. This solves the problem of uneven flow in arc-shaped manifold microchannel evaporators; the arc-shaped manifold microchannel can further increase the heat exchange area and extend the flow heat exchange time.

[0062] Preferably, the manifold guide vanes 1-3 are located in the middle of the bottom of the cover plate, and the guide vanes are formed by a U-shaped periodic structure array. Based on a series of simulation analyses, the length L of the guide vane bending plates 1-9 is... 弯折板 , Deflector plate length 1-10 L 长板 and the height H of the deflector 导流板 The following relationship should be satisfied with: Evaporator arc length L and evaporator curvature r

[0063] L 导流板 = (0.5~2)×(0.9L-1.3Ltan 2 r)H 导流板 = (1~3)L 弯折板

[0064] Through the above optimizations, the problem of uneven flow in the arc-shaped manifold microchannel evaporator has been solved. The arc-shaped manifold microchannel can further increase the heat exchange area and extend the flow heat exchange time.

[0065] Preferably, the evaporator curvature r is 60°-80°, and the evaporator radius of curvature is consistent with the radius of curvature of the heat dissipation surface. This is preferred, as it makes the arc-shaped manifold microchannel evaporator have stronger heat dissipation performance.

[0066] Further optimization yielded a manifold guide plate with a width of 0.8-1.2 mm, a length of 50-60 mm (preferably 56 mm), and a height of 1.8-2.2 mm. This size and structure satisfy the preferred dimensions for a manifold-type microchannel unit structure. This size also optimizes the working fluid flow path and reduces flow resistance.

[0067] Further optimization shows that the manifold guide plate has a width of 1mm, a length of 56mm, and a height of 2mm.

[0068] Preferably, the manifold guide plate has eight manifold inlets 1-4 and manifold outlets 1-5, located at the openings of the periodic units. Based on a series of simulation analyses, the widths of the manifold inlets and outlets 1-8 should satisfy the following relationship:

[0069] W 歧管入口 = (1.7~3.5)L 弯折板

[0070] At this size, the optimization of the working fluid flow path is effective, and the flow resistance is lower.

[0071] As a preferred option, an inlet diversion section 1-6 is designed between the manifold inlet 1-4 and the working fluid inlet 1-1, and an outlet confluence section 1-7 is provided between the manifold outlet 1-5 and the working fluid outlet 1-2 to ensure uniform distribution of the working fluid.

[0072] As a preferred embodiment, the flow diversion section on the cover plate is constructed by building an equivalent flow resistance network model. Figure 5 The flow resistance of each segment of the split section is calculated, and the split section is divided into 7 segments by 8 manifold inlets 1-5. The i-th segment is the flow segment sandwiched between the i-th manifold inlet closest to the working fluid inlet 1-1 and the (i+1)-th manifold inlet, and the width at the midpoint of the i-th segment is W. 分流段_i The width direction is along the length direction of the manifold guide vane.

[0073] As a preferred option, the equivalent flow resistance network model has 8 loops. Analyzing at the diagonal nodes of each loop, the pressure drop of the two paths between the nodes should be equal and satisfy the formula:

[0074] (8-i)R_in_i=i×R_out_i(i=1,2,3...8)

[0075] In the formula, R_in_i represents the flow resistance of the i-th branch segment, that is, the flow resistance of the branch segment sandwiched between the i-th manifold inlet and the (i+1)-th manifold inlet near the working fluid inlet 1-1. Similarly, R_out_i represents the flow resistance of the i-th confluence segment, that is, the flow resistance of the confluence segment sandwiched between the i-th manifold inlet and the (i+1)-th manifold inlet near the working fluid outlet 1-2.

[0076] As a preferred approach, R_in_i (i = 2, 3, 4) is solved using nonlinear programming to ensure that the flow segment satisfies the following conditions: monotonic rate of change of flow resistance, minimum magnitude of flow resistance change, and minimum overall average flow resistance. This ultimately establishes...

[0077] R_in_2=1.4R_in_1R_in_3=2.2R_in_1R_in_4=2.9R_in_1.

[0078] As a preferred option, according to the flow resistance calculation formula

[0079]

[0080] The width at the midpoint of each segment of the flow divider is calculated. In the formula, μ is the dynamic viscosity, L is the channel length, H is the channel height, and W is the channel width.

[0081] The calculated width at the midpoint of the i-th branch segment is...

[0082] W 分流段_i =X i ·W 分流段_1

[0083] In the formula, X represents the ratio of flow resistance. i =R_in_1 / R_in_i.

[0084] Design curve of the branch section (merging section)

[0085]

[0086] In the formula, L is the length of the flow branch section 2-2 (the length is along the arc length of the evaporator), W 分流段_max Let 2-1 be the width of the widest part of the flow channel in the flow segment, l be the distance from a certain point in the flow segment to the working medium inlet, and w be the width of the flow channel in the flow segment at a distance l from the working medium inlet, 2-4.

[0087] Theoretically, this ensures that the working fluid is evenly distributed to the inlet of each manifold guide plate after it flows in.

[0088] Further optimization revealed that the channel widths at the midpoints of each segment (2-4) were 9.5mm, 6.8mm, 4.3mm, 3.3mm, 2.6mm, 2.3mm, and 2.15mm, respectively.

[0089] Preferably, the base plate is a microchannel structure with a thickness of 2.5–3.5 mm, a length of 80 mm, a width of 52–54 mm, and a bending angle of 60°. This size and structure meet the preferred dimensions for a manifold-type microchannel unit structure. This size optimizes the working fluid flow path and reduces flow resistance.

[0090] This structural dimension satisfies the following formula, representing the preferred dimensions for an arc-shaped manifold microchannel unit structure. It effectively increases the effective heat transfer area of ​​the arc-shaped manifold microchannel structure, prolongs the heat transfer time of the working fluid flow, enhances the jet impact effect, and improves heat transfer. It also avoids the occurrence of localized hot spots in traditional arc-shaped heat dissipation structures used in manifold microchannel applications.

[0091] d 微通道 = (0.05~0.2)Rcos 2 r

[0092]

[0093] h 微通道高度 = (0.8~1.5)H 底板厚度 Rcos 2 r

[0094] In the formula d 微通道d is the width of the microchannel. 微通道间距 R is the microchannel spacing, R is the radius of curvature of the arc-shaped evaporator, r is the radius in radians, and h is the radius of curvature. 微通道高度 H represents the height of the microchannel. 底板厚度 This refers to the thickness of the base plate.

[0095] R134A is preferred as the working fluid. R134A has a high latent heat of vaporization, low dynamic viscosity, a suitable operating temperature range, and is non-toxic, harmless, safe, and stable, making it a commonly used two-phase working fluid.

[0096] Further optimization shows that the number of microchannels 3-1 on the evaporator bottom plate is 27, with each channel being 50.22 mm long, 1 mm wide, and 2 mm high; the spacing between microchannels 3-2 is 1 mm, and the radius of curvature is 50.75 mm.

[0097] Preferably, the working fluid flows into the evaporator working fluid inlet 1-1 through the pipeline and is evenly distributed into the 8 manifold inlets under the action of the inlet diversion section. The flow direction of the manifold guide plate is perpendicular to the extension direction of the microchannel. After the working fluid flows into the guide plate, it will flow into the microchannel below. The bottom of the microchannel is the heat source. The manifold microchannel structure increases the working fluid jet effect, enhances heat exchange, shortens the flow path of the working fluid in the microchannel, and reduces pressure loss.

[0098] This patent provides a novel evaporator for pump-driven two-phase systems, with the following innovations:

[0099] (1) An innovative design was implemented for the evaporator inlet branching section and outlet confluence section. By constructing an equivalent flow resistance network model, and assuming that the flow rates at the inlet and outlet of each manifold are the same, the flow resistance of each corresponding flow segment at each inlet is calculated, thereby obtaining the width of each branching section at its midpoint. The calculation process is achieved through nonlinear programming, ensuring uniform flow resistance variation and a small overall flow resistance.

[0100] (2) An innovative manifold microchannel structure was designed. The evaporator consists of a base plate and a cover plate. Microchannels are provided on the base plate, and manifold guide plates are provided on the cover plate. When the base plate and cover plate are installed, a manifold microchannel structure is formed. Through two-phase heat and mass transfer finite element analysis, the optimal microchannel width, thickness, spacing, and manifold guide plate width and height were selected to improve the heat transfer enhancement and flow resistance reduction effects of the manifold microchannel. The optimal dimensions are as follows:

[0101]

[0102] d 微通道 = (0.05~0.2)Rcos 2 r

[0103]

[0104] h 微通道高度 = (0.8~1.5)H底板厚度 Rcos 2 r

[0105] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An evaporator, comprising an arc-shaped cover plate and an arc-shaped base plate, wherein microchannels are machined on the base plate, and the bottom of the cover plate includes a working fluid inlet, an inlet branch section, a manifold guide plate, an outlet confluence section, and a working fluid outlet; the working fluid inlet is connected to the inlet branch section, and the outlet confluence section is connected to the working fluid outlet; the manifold guide plate includes a long plate and a bent plate, the bent plate connecting adjacent long plates to form a U-shaped periodic structure array; the microchannels are disposed in the middle of the base plate, and their length direction is perpendicular to the direction of the long plate of the manifold guide plate; the manifold guide plate is disposed in the middle of the cover plate, and its position corresponds to the position of the microchannels on the base plate; after the base plate and the cover plate are combined and installed, the manifold guide plate is installed above the microchannels; the manifold guide plate is provided with a manifold inlet and a manifold outlet, the positions of which are at the openings of the U-shaped periodic units; a design curve is designed in the inlet branch section between the manifold inlet and the working fluid inlet. In the formula The length of the diversion section, This refers to the width at the widest point of the flow channel in the branch section. This refers to the distance from a point in the diversion section to the inlet of the working medium. The distance between the working fluid inlet and the flow diversion section. The width of the flow channel in the branch section at that location.

2. The evaporator as described in claim 1, characterized in that, The evaporator's arc r is 60°-80°.

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