Application of novel welding seam shape in pillow type heat exchanger plate

Abstract

The invention relates to the technical field of heat exchange equipment, and discloses application of a novel weld shape in a pillow type heat exchanger sheet, the application comprises novel weld shape design and CFD simulation, the novel weld shape design comprises a design concept and a specific shape design, and the CFD simulation comprises a simulation purpose and a simulation method. The design concept is based on a streamline body structure of a sword fish in the nature, the scheme aims to design a more streamline welding seam shape to reduce the resistance of fluid at the welding seam so as to reduce the pressure loss and improve the heat exchange efficiency, and the novel welding seam shape is applied to the pillow type heat exchanger plate, so that the heat exchange efficiency is improved. By simulating a streamline body structure of a sword fish in the nature, the resistance of fluid at the weld joint is obviously reduced, the pressure loss is further reduced, the heat exchange efficiency is effectively improved, and in the specific shape design, a non-uniform rational B spline (NURBS) curve is adopted to describe the streamline outline of the weld joint.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchange equipment, and in particular to application of a new type of weld shape in a pillow type heat exchanger plate. Background Art

[0002] Pillow plate heat exchanger (PPHE) is an efficient and compact heat exchange equipment that plays an important role in many industries such as food, pharmaceuticals, and refrigeration. Its core features lie in its structure consisting of two stacked steel plates and its wavy surface design. These features give PPHE excellent heat exchange performance and broad application prospects.

[0003] In the design process of PPHE, the weld shape is a crucial parameter. The weld not only affects the structural strength of the heat exchanger, but is also directly related to core performance indicators such as heat transfer efficiency and pressure loss. However, traditional weld shape designs are often elliptical or other simpler geometric shapes, which have certain disadvantages in practical applications.

[0004] The disadvantages of traditional weld shape design are mainly reflected in two aspects: first, the resistance of the fluid at the weld is large, resulting in increased pressure loss, affecting the overall performance of the heat exchanger; second, the optimization of the weld shape is not sufficient, and the heat exchange efficiency still has room for improvement. These problems limit the application potential of pillow heat exchangers in terms of higher efficiency and lower energy consumption, so a new type of weld shape is proposed for the application of pillow heat exchanger plates to solve the above problems. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the shortcomings of the prior art, the present invention provides an application of a new weld shape in pillow-type heat exchanger plates, which has the advantages of improving heat exchange efficiency and reducing unit pressure drop, thereby solving the problems of low heat exchange efficiency and large pressure loss caused by traditional weld shapes.

[0007] (II) Technical solution

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A new type of weld shape is applied to pillow-type heat exchanger plates, including new weld shape design and CFD simulation. The new weld shape design includes design concept and specific shape design, and the CFD simulation includes simulation purpose and simulation method.

[0010] As a preferred technical solution of the present invention, the design concept is based on the streamlined body structure of swordfish in nature. This solution aims to design a more streamlined weld shape to reduce the resistance of the fluid at the weld, thereby reducing pressure loss and improving heat exchange efficiency.

[0011] As a preferred technical solution of the present invention, the specific shape design includes a streamlined weld profile, optimization of weld width and height, and optimization of weld spacing. The streamlined weld profile is described by the weld shape using a non-uniform rational B-spline (NURBS) curve to ensure a smooth transition and streamlined characteristics of the weld.

[0012] As a preferred technical solution of the present invention, the optimized weld width further reduces the resistance of the fluid at the weld by reducing the width and height ratio of the weld while ensuring the strength of the weld. The optimization of the weld spacing adjusts the transverse and longitudinal spacing of the weld according to the CFD simulation results to optimize the flow state of the fluid inside the heat exchanger and improve the heat exchange efficiency.

[0013] As a preferred technical solution of the present invention, the simulation purpose is to verify the influence of the new weld shape on the heat transfer efficiency and pressure loss of the pillow heat exchanger through CFD simulation, and to optimize parameters such as the weld shape and spacing to obtain the best performance.

[0014] As a preferred technical solution of the present invention, the simulation method includes physical models and assumptions, mathematical models and equations, numerical methods and grid division, and model verification and optimization.

[0015] As a preferred technical solution of the present invention, the physical model and assumptions include fluid properties, boundary conditions and computational domains. The fluid properties are achieved by using water with constant physical properties as the heat transfer fluid in the simulation, assuming that it is single-phase, turbulent, incompressible, stationary and three-dimensional. The boundary conditions adopt the assumptions of uniform inlet velocity, constant outlet atmospheric pressure (0.0Pa gauge) and symmetrical pillow sides. The computational domain consists of five segments of basic periodic symmetric units on the pillow surface so as to capture the inlet area and the steady-state area.

[0016] As a preferred technical solution of the present invention, the mathematical model and equations include a continuity equation, a momentum equation and an energy equation. The continuity equation ensures the conservation of mass and describes the mass change of the fluid during the flow process. The momentum equation describes the change of the velocity and force of the fluid during the flow process, taking into account the influence of the friction inside the fluid and the external pressure. The energy equation describes the energy change of the fluid during the flow process, including heat transfer and temperature distribution.

[0017] As a preferred technical solution of the present invention, the heat transfer coefficient needs to be used in the heat transfer. The heat transfer coefficient is calculated using the LMTD method. However, in this simulation, we are more concerned about the relative intensity of fluid heat exchange, so it is expressed by Nusselt Number (Nu), and its calculation formula is:

[0018]

[0019] Where α is the heat transfer coefficient, d is the size of the channel that determines the movement of the coolant, λ is the thermal conductivity, C, n, and m are coefficients selected according to the movement of the coolant and the plate surface, Re is the Reynolds number, and Pr is the Prandtl number;

[0020] The Reynolds number (Re) is defined as:

[0021]

[0022] Where ρ is the density of the coolant, w is the linear velocity of the coolant in the channel, d is the channel size, and μ is the dynamic viscosity of the coolant;

[0023] The Prandtl number (Pr) is calculated as:

[0024]

[0025] In the formula, c p is the specific heat capacity of the coolant;

[0026] The calculation of friction coefficient and pressure loss will be expressed using dimensionless parameters such as Darcy friction coefficient to evaluate the effect of different weld shapes on flow resistance.

[0027] As a preferred technical solution of the present invention, the numerical method and grid division include grid division and numerical method, the grid division adopts a scanning grid division scheme, and uses finer grid division near the edge to capture boundary layer physics and physical phenomena in the entire 3D domain. The numerical method uses a finite volume method for fluid CFD simulation modeling and simulation, and turbulence is studied using an achievable k-ε model. All spatial discretization schemes are second-order upwind to obtain good accuracy at a relatively low computational cost.

[0028] As a preferred technical solution of the present invention, the model verification and optimization adopts the grid convergence index (GC) method to verify the CFD model to ensure that the grid resolution provides the minimum inaccuracy in the simulation results, and optimizes the new weld shape based on the simulation results to further improve the heat exchange efficiency and reduce the pressure loss.

[0029] (III) Beneficial effects

[0030] Compared with the prior art, the present invention provides a new type of weld shape for application in pillow type heat exchanger plates, which has the following beneficial effects:

[0031] The application of this new weld shape in pillow-type heat exchanger plates, by imitating the streamlined body structure of swordfish in nature, not only significantly reduces the resistance of the fluid at the weld, thereby reducing the pressure loss, but also effectively improves the heat transfer efficiency. In the specific shape design, the non-uniform rational B-spline (NURBS) curve is used to describe the streamlined contour of the weld, ensuring the smooth transition and streamlined characteristics of the weld, while optimizing the width, height and spacing of the weld, further enhancing the flow efficiency and heat transfer performance of the fluid. Through the use of CFD simulation technology, the influence of the new weld shape on the heat transfer efficiency and pressure loss is verified, and the parameters such as the weld shape and spacing are optimized according to the simulation results, and finally the output of the best performance is achieved. In addition, high-precision numerical methods and meshing techniques are used to ensure the accuracy and reliability of the simulation results, providing strong technical support for the optimization of the new weld shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the coordinate diagram of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] See also Figure 1 ,

[0037] Application of a new weld shape in pillow heat exchanger plates includes new weld shape design and CFD simulation. The new weld shape design includes design concept and specific shape design. The CFD simulation includes simulation purpose and simulation method.

[0038] In this embodiment, the design concept is based on the streamlined body structure of swordfish in nature. This solution aims to design a more streamlined weld shape to reduce the resistance of the fluid at the weld, thereby reducing pressure loss and improving heat exchange efficiency.

[0039] In this embodiment, the specific shape design includes a streamlined weld profile, optimization of weld width and height, and optimization of weld spacing. The streamlined weld profile is described by the weld shape using a non-uniform rational B-spline (NURBS) curve to ensure a smooth transition and streamlined characteristics of the weld.

[0040] In this embodiment, the weld width is optimized by reducing the ratio of the weld width to the height, thereby further reducing the resistance of the fluid at the weld while ensuring the weld strength. The weld spacing is optimized by adjusting the lateral and longitudinal spacing of the weld according to the CFD simulation results to optimize the flow state of the fluid inside the heat exchanger and improve the heat exchange efficiency.

[0041] In this embodiment, the purpose of the simulation is to verify the influence of the new weld shape on the heat transfer efficiency and pressure loss of the pillow heat exchanger through CFD simulation, and to optimize parameters such as the weld shape and spacing to obtain the best performance.

[0042] In this embodiment, the simulation method includes physical models and assumptions, mathematical models and equations, numerical methods and grid division, and model verification and optimization.

[0043] In this embodiment, the physical model and assumptions include fluid properties, boundary conditions and computational domain. The fluid properties are obtained by using water with constant physical properties as the heat transfer fluid in the simulation, assuming it to be single-phase, turbulent, incompressible, stationary and three-dimensional. The boundary conditions adopt the assumptions of uniform inlet velocity, constant outlet atmospheric pressure (0.0Pa gauge) and symmetrical pillow sides. The computational domain consists of five segments of the basic periodic symmetric units on the pillow surface to capture the inlet area and the steady-state area.

[0044] In this embodiment, the mathematical model and equations include the continuity equation, the momentum equation and the energy equation. The continuity equation ensures the conservation of mass and describes the change in mass of the fluid during the flow process. The momentum equation describes the change in velocity and force of the fluid during the flow process, taking into account the influence of internal friction and external pressure of the fluid. The energy equation describes the change in energy of the fluid during the flow process, including heat transfer and temperature distribution.

[0045] In this embodiment, the heat transfer coefficient is required for heat transfer. The heat transfer coefficient is calculated using the LMTD method. However, in this simulation, we are more concerned about the relative intensity of fluid heat transfer, so it is expressed by Nusset Number (Nu), and its calculation formula is:

[0046]

[0047] Where α is the heat transfer coefficient, d is the size of the channel that determines the movement of the coolant, λ is the thermal conductivity, C, n, and m are coefficients selected according to the movement of the coolant and the plate surface, Re is the Reynolds number, and Pr is the Prandtl number;

[0048] The Reynolds number (Re) is defined as:

[0049]

[0050] Where ρ is the density of the coolant, w is the linear velocity of the coolant in the channel, d is the channel size, and μ is the dynamic viscosity of the coolant;

[0051] The Prandtl number (Pr) is calculated as:

[0052]

[0053] In the formula, c p is the specific heat capacity of the coolant;

[0054] The calculation of friction coefficient and pressure loss will be expressed using dimensionless parameters such as Darcy friction coefficient to evaluate the effect of different weld shapes on flow resistance.

[0055] In this embodiment, the numerical method and grid division include grid division and numerical methods. The grid division adopts a scanning grid division scheme, and a finer grid division is used near the edge to capture the boundary layer physics and the physical phenomena in the entire 3D domain. The numerical method adopts the finite volume method for fluid CFD simulation modeling and simulation. The turbulence is studied using an achievable k-ε model. All spatial discretization schemes are second-order upwind to obtain good accuracy at a relatively low computational cost.

[0056] In this embodiment, the model verification and optimization adopts the grid convergence index (GC) method to verify the CFD model to ensure that the grid resolution provides the minimum inaccuracy in the simulation results, and according to the simulation results, the new weld shape is optimized to further improve the heat transfer efficiency and reduce the pressure loss.

[0057] Beneficial effects:

[0058] The application of this new weld shape in pillow-type heat exchanger plates, by imitating the streamlined body structure of swordfish in nature, not only significantly reduces the resistance of the fluid at the weld, thereby reducing the pressure loss, but also effectively improves the heat transfer efficiency. In the specific shape design, the non-uniform rational B-spline (NURBS) curve is used to describe the streamlined contour of the weld, ensuring the smooth transition and streamlined characteristics of the weld, while optimizing the width, height and spacing of the weld, further enhancing the flow efficiency and heat transfer performance of the fluid. Through the use of CFD simulation technology, the influence of the new weld shape on the heat transfer efficiency and pressure loss is verified, and the parameters such as the weld shape and spacing are optimized according to the simulation results, and finally the output of the best performance is achieved. In addition, high-precision numerical methods and meshing techniques are used to ensure the accuracy and reliability of the simulation results, providing strong technical support for the optimization of the new weld shape.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Application of a new weld shape in pillow heat exchanger plates, including new weld shape design and CFD simulation, characterized in that: The novel weld shape design includes design concept and specific shape design, and the CFD simulation includes simulation purpose and simulation method.

2. The application of a novel weld shape in pillow heat exchanger plates according to claim 1 is characterized in that: The design concept is based on the streamlined body structure of swordfish in nature. This scheme aims to design a more streamlined weld shape to reduce the resistance of the fluid at the weld, thereby reducing pressure loss and improving heat exchange efficiency.

3. The application of a novel weld shape in pillow type heat exchanger plates according to claim 1 is characterized in that: The specific shape design includes a streamlined weld profile, optimization of weld width and height, and optimization of weld spacing. The streamlined weld profile is described by a non-uniform rational B-spline (NURBS) curve through the weld shape to ensure a smooth transition and streamlined characteristics of the weld.

4. The application of a new type of weld shape in pillow type heat exchanger plates according to claim 3 is characterized by: The optimization of the weld width reduces the ratio of the weld width to the height, thereby further reducing the resistance of the fluid at the weld while ensuring the weld strength. The optimization of the weld spacing adjusts the transverse and longitudinal spacing of the weld according to the CFD simulation results to optimize the flow state of the fluid inside the heat exchanger and improve the heat exchange efficiency.

5. The application of a novel weld shape in pillow heat exchanger plates according to claim 1 is characterized in that: The purpose of the simulation is to verify the influence of the new weld shape on the heat transfer efficiency and pressure loss of the pillow heat exchanger through CFD simulation, and to optimize parameters such as the weld shape and spacing to obtain the best performance.

6. The application of a novel weld shape in pillow heat exchanger plates according to claim 1 is characterized in that: The simulation method includes physical models and assumptions, mathematical models and equations, numerical methods and grid division, and model verification and optimization.

7. The application of a new type of weld shape in pillow heat exchanger plates according to claim 6 is characterized in that: The physical model and assumptions include fluid properties, boundary conditions and computational domains. The fluid properties are achieved by using water with constant physical properties as the heat transfer fluid in the simulation, assuming it to be single-phase, turbulent, incompressible, stationary and three-dimensional. The boundary conditions adopt the assumptions of uniform inlet velocity, constant outlet atmospheric pressure (0.0Pa gauge) and symmetrical pillow sides. The computational domain consists of five segments of basic periodic symmetric units on the pillow surface to capture the inlet area and the steady-state area.

8. The application of a new type of weld shape in pillow heat exchanger plates according to claim 6 is characterized in that: The mathematical model and equations include the continuity equation, momentum equation and energy equation. The continuity equation ensures the conservation of mass and describes the mass change of the fluid during the flow process. The momentum equation describes the change of the velocity and force of the fluid during the flow process, taking into account the influence of the friction inside the fluid and the external pressure. The energy equation describes the energy change of the fluid during the flow process, including heat transfer and temperature distribution.

9. The application of a new type of weld shape in pillow heat exchanger plates according to claim 7 is characterized in that: The heat transfer requires the use of heat transfer coefficients, which are calculated using the LMTD method. However, in this simulation, we are more concerned with the relative intensity of fluid heat transfer, so we use Nusselt Number (Nu) to represent it. The calculation formula is: Where α is the heat transfer coefficient, d is the size of the channel that determines the movement of the coolant, λ is the thermal conductivity, C, n, and m are coefficients selected according to the movement of the coolant and the plate surface, Re is the Reynolds number, and Pr is the Prandtl number; The Reynolds number (Re) is defined as: Where ρ is the density of the coolant, w is the linear velocity of the coolant in the channel, d is the channel size, and μ is the dynamic viscosity of the coolant; The calculation formula of Prandtl number (Pr) is: In the formula, c p is the specific heat capacity of the coolant; The calculation of friction coefficient and pressure loss will be expressed using dimensionless parameters such as Darcy friction coefficient to evaluate the effect of different weld shapes on flow resistance.

10. The application of a new type of weld shape in pillow heat exchanger plates according to claim 6 is characterized in that: The numerical method and grid division include grid division and numerical methods. The grid division adopts a scanning grid division scheme, and uses finer grid division near the edge to capture boundary layer physics and physical phenomena in the entire 3D domain. The numerical method adopts a finite volume method for fluid CFD simulation modeling and simulation. Turbulence is studied using an achievable k-ε model. All spatial discretization schemes are second-order upwind to obtain good accuracy at a relatively low computational cost.

11. The application of a novel weld shape in pillow heat exchanger plates according to claim 6 is characterized in that: The model verification and optimization uses the grid convergence index (GC) method to verify the CFD model to ensure that the grid resolution provides minimal inaccuracy in the simulation results, and based on the simulation results, the new weld shape is optimized to further improve the heat transfer efficiency and reduce the pressure loss.

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