CN107944172B - Engine intake manifold design method based on fluid topology optimization - Google Patents
Engine intake manifold design method based on fluid topology optimization Download PDFInfo
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Abstract
The invention discloses an engine intake manifold design method based on fluid topology optimization, which utilizes a variable density method to carry out topology optimization on an intake manifold runner and comprises the following steps: (1) establishing a geometric model for intake manifold fluid topological optimization, and determining a design domain; (2) inputting medium attributes, and determining global and local variables; (3) establishing a mathematical model for intake manifold fluid topology optimization by taking minimum energy consumption as a target, and writing a program; (4) applying flow velocity, pressure boundary conditions and fluid loads to the design domain; (5) calculating the relative density of the units according to the RAMP model; (6) programming, performing fluid topology optimization calculation by using a moving progressive line method, updating design variables, judging whether iteration is terminated or not through residual errors, and outputting an optimal runner topological structure of an engine intake manifold. The optimal fluid topological structure can be obtained by adjusting the volume fraction, the Reynolds number and the interpolation function parameter q, the optimal fluid topological structure is suitable for different fluid media, and the result is reliable.
Description
Technical Field
The invention belongs to the field of mechanical optimization design in computer aided engineering, and particularly relates to a fluid topology optimization-based engine intake manifold design method.
Background
The structural optimization is a design method which aims at the problem of meeting certain control equations or rules, and solves the design method which meets all constraint conditions and enables an objective function to reach an optimal solution by controlling some variable design parameters. In the optimization, the quantity used to measure the structural features to be described in the design process is called a design variable, a performance equation or a geometric range to be satisfied is used as a constraint condition, and a performance function used to measure the optimal state is called an objective function. In practical engineering, structural optimization generally includes size optimization, shape optimization, topology optimization, and topography optimization. Among them, topology optimization is a hot research direction in the field of structural optimization design. By taking material distribution as an optimization object and through topological optimization, an optimal material distribution scheme can be found in a design space, and the defect that the related structure design is carried out only by depending on engineering practice experience in the past is overcome.
The engine intake manifold is one of the most critical components of the engine intake system and functions to distribute fresh air or fuel-air mixture to the individual cylinders. The performance of the intake manifold directly influences the size of the air input of the engine and directly influences the flowing mixing and combustion reaction process of gas in the cylinder of the engine, and the size, shape, arrangement and the like of the intake manifold of the engine greatly influence the intake resistance, intake uniformity and charging efficiency, so that the dynamic property, the economical efficiency and the emission characteristic of the engine are influenced. In the development of modern engines, the supply of fresh air or air-fuel mixture to each cylinder has an important influence on the performance index of the engine, so that the optimal design of the intake manifold structure of the engine is very important.
At present, in the traditional design process of an engine intake manifold, a designer generally adopts a steady flow experiment to evaluate the performance of the intake manifold and then performs structural optimization on the intake manifold through experience in consideration of the complexity of an intake passage of an intake manifold area. However, this method requires much experience for designers, and has a long design period and high cost, and only macroscopic characteristics such as a flow field and a differential pressure can be obtained by an experimental method, and detailed characteristics of the interior of the flow field cannot be reflected, so that structural optimization of the intake manifold cannot obtain sufficient useful information. To be able to obtain detailed information of each point in the intake manifold, the design of the engine intake manifold is now mainly obtained by Computational Fluid Dynamics-CFD (Computational Fluid Dynamics). The specific design method comprises the steps of preliminarily calculating the structural size of the intake manifold by given design parameters and arrangement forms of the engine, then carrying out CAD geometric modeling to form a preliminary model, deriving a calculation domain of internal airflow of the intake manifold, then obtaining the flow state of air or mixed gas in the intake manifold of the engine by CFD simulation calculation, providing a basis for the optimization design of an intake system, further obtaining the air flow state and influence factors of the intake manifold of the engine by experiments, providing structural optimization improvement suggestions, determining a design scheme of the intake manifold, and further obtaining a detailed structure of the intake manifold by shape optimization and size optimization.
Although the above methods can obtain the structure of the intake manifold, the methods still need to be repeated and tried, the period is long, the cost is high, and the design needs to be recalculated for different engine parameters, the flexibility and the adaptability are poor, and the finally obtained optimized structure of the intake manifold is not necessarily a global optimal solution.
In 1988, Bendsoe and Kikuchi put forward the basic theory of structural topology optimization design, and through decades of development, the structural topology optimization method and the application thereof have made great progress. At present, the results of topology optimization mainly focus on the aspects of structural solid mechanics and thermal structure optimization design. In 2003, Borrvall et al introduced topology optimization technology into the fluid field, and since then, foreign and domestic scholars performed some studies on fluid topology optimization from various aspects. At present, methods for fluid topology optimization include a boltzmann method, a phase field method, a level set method, and the like. The basic principle of the fluid topology optimization material distribution method is to replace the original discrete design problem with a continuous method, in which case the material density is allowed to vary continuously between solid and fluid spaces. Thus, assuming that the design field is filled with some desirable spatial variability of the porous material in the flow problem, the solid and open fluid channels correspond to the limits of low and high permeability, respectively. In an optimal topology optimization design, it is preferable that there are areas with no intermediate permeability that would otherwise not be interpreted as an optimal solution to the original discrete problem.
Nevertheless, the fluid topology optimization technology is still in the initial development stage in China, most of the existing related researches are directed to the design of a simple flow channel structure, and the optimization of the fluid topology structure for the practical problem of complex engineering is very little. Particularly, what is more about the optimization design of the engine intake manifold runner is that the calculation model of the engine intake system working process is established by using CAD/CAE/CFD simulation software, and then the engine intake manifold is subjected to size optimization and comparative analysis, or the comparative analysis of different intake manifold structures is obtained by shape optimization and auxiliary performance is further obtained, so that the final optimization design scheme is determined, and the design research of the engine intake manifold by directly using a fluid topology optimization method at the initial stage of design is not disclosed yet. Based on the method, the invention provides an engine intake manifold design method based on fluid topology optimization.
Disclosure of Invention
The invention aims to overcome the defects of repeated trial and error, long period, high cost, non-global optimal solution and the like of a traditional method for establishing a working process calculation model of an engine intake system by utilizing CAD/CAE/CFD simulation software and carrying out optimal calculation on an engine intake manifold or obtaining a structure of the engine intake manifold through shape optimization, provides a new thought for designing the engine intake manifold, and provides an engine intake manifold design method based on fluid topology optimization. Introducing a Material with variable hypothetical relative density between 0 and 1 according to a RAMP model (random application of Material Properties-RAMP), and selecting the relative density of each unit of a finite element method in a design domain as a design variable to construct a relative density field, wherein the design variable gamma takes a value between 0 and 1. Taking gamma as 0 corresponds to the solid phase material and taking gamma as 1 corresponds to the liquid phase material. The method comprises the steps of establishing a mathematical model for fluid topology optimization of an engine intake manifold by taking minimum energy consumption as an objective function of fluid topology optimization, taking the total volume of a structure as a constraint condition, taking an inlet speed boundary condition and an outlet pressure boundary condition, discussing the influences of different volume fractions theta, Reynolds numbers Re and parameters q in a RAMP interpolation model on the objective function and the optimal topological structure, and finally writing a calculation program of the mathematical topology optimization model by using MATLAB to obtain the optimal topological structure of the engine intake manifold.
The invention relates to a method for designing an engine intake manifold based on fluid topology optimization, which comprises the following steps:
(1) according to the purpose and the requirement of fluid topology optimization, a design domain geometric model of engine intake manifold fluid topology optimization is established, a fluid design domain of the engine intake manifold fluid topology optimization is determined, and fluid properties such as medium density, dynamic viscosity and the like are input;
(2) determining global variables, inputting Darcy number Da, inlet characteristic length l and maximum inflow speed umaxDesign domain volume V0Volume fraction theta, Reynolds number Re, and parameter q of the RAMP material interpolation function;
(3) setting local variable, local inverse permeability alpha of input mediummaxAnd alpha;
(4) according to the aim of minimum energy consumption, selecting appropriate design variables and performance constraint conditions, and calculating an objective function phi (u, p, gamma) of the engine intake manifold design method based on fluid topology optimization, thereby establishing a mathematical model of the engine intake manifold fluid topology optimization:
wherein rho is the density of the fluid, eta is the dynamic viscosity, the values are all 1, f is the physical force of the fluid,p is the pressure, u is the flow velocity of the fluid, V0The initial volume of the designed area is 0 & lttheta & lt & gt & lt 1 & gt, which is the volume fraction of the fluid area and represents the percentage of the volume of the engine intake manifold runner area in the volume of the designed area;
(5) giving an initial relative density, setting a constraint condition and a volume force of a design domain, inputting an integral objective function expression, and adding a design domain boundary condition;
(5.1) discretizing a fluid topology optimization mathematical model by using a finite element method, and writing an MATLAB program for optimizing the fluid topology;
(5.2) writing an MATLAB program of an objective function, a constraint condition, a boundary condition and a volume force;
(5.3) setting upper and lower limits of design variables in an MATLAB program, and giving initial relative density;
(6) partitioning a design domain and a non-design domain into quadrilateral grids with different densities, and setting an iteration termination condition of the engine intake manifold fluid topology optimization;
(7) the design variables were updated according to the Moving asymptotic line Method (Method of Moving asymptes — MMA): updating the relative density of the finite element unit according to an MMA method, solving the total volume of the updated design domain, judging whether the iteration of the new interpolation unit is terminated according to the relative tolerance before and after updating, if not, adopting the updated unit relative density and continuing the iteration according to the MMA method, and if the iteration is terminated, stopping the calculation and outputting the unit relative density;
(8) calculating the relative density difference of each corresponding unit during input and output in the step (7), solving the maximum relative density change value, comparing the maximum change value with the set total loop iteration termination condition, judging whether the termination condition is met, and if the termination condition is not met, feeding back the output unit relative density to re-iterate until the iteration termination condition is met;
(9) and outputting an optimal runner topological structure of the engine intake manifold based on fluid topological optimization, wherein a white area is an optimized engine intake manifold runner.
The invention has the beneficial effects that: the invention provides an engine intake manifold design method based on fluid topology optimization, which changes the defects of repeated trial and error, long period, high cost, non-global optimal solution and the like of the traditional method for establishing an engine intake system working process calculation model by utilizing CAD/CAE/CFD simulation software and carrying out optimization calculation on an engine intake manifold or obtaining the structure of the engine intake manifold through shape optimization, and provides a new thought for the design of the engine intake manifold; in the initial stage of design, the fluid topology optimization method is directly utilized to carry out design research on the engine intake manifold, the design domain can be more efficiently and more flexibly processed, and the optimized intake manifold fluid topology structure has higher reliability; the method utilizes a variable density method to carry out topology optimization on the flow channel of the intake manifold, and has the advantages of fast and stable convergence, weak dependence of the initial value of the design variable and suitability for processing multiple constraints; according to the invention, the optimal fluid topology optimization structure can be obtained by adjusting the volume fraction, the Reynolds number and the parameter q in the RAMP interpolation function, and the operability is high; the invention can optimize the structural topology of the flow channel aiming at different fluid media to obtain the optimal topological structure of the flow channel of the intake manifold matched with the media, and has good flexibility and adaptability.
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The present invention will be described in further detail with reference to the accompanying drawings and examples.
FIG. 1 is a flow chart of a fluid topology optimization design method of the present invention
FIG. 2 is a schematic diagram of an engine intake manifold design domain of an embodiment of the present invention
FIG. 3 is a graphical representation of engine intake manifold design domain meshing in accordance with an embodiment of the present invention
FIG. 4 shows the optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.1, the parameter q is 0.01, and the Reynolds number Re is 20
FIG. 5 is a diagram of an optimal channel topology structure for intake manifold fluid topology optimization according to an embodiment of the present invention when the volume fraction θ is 0.3, the parameter q is 0.01, and the Reynolds number Re is 20
FIG. 6 shows the optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.4, the parameter q is 0.01, and the Reynolds number Re is 20
FIG. 7 shows the optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.5, the parameter q is 0.01, and the Reynolds number Re is 20
FIG. 8 shows the optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.6, the parameter q is 0.01, and the Reynolds number Re is 20
FIG. 9 shows an optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.3, the parameter q is 0.01, and the Reynolds number Re is 50
FIG. 10 shows the optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.3, the parameter q is 0.01, and the Reynolds number Re is 100
FIG. 11 is an optimal flow channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when volume fraction θ is 0.5, parameter q is 0.01, and Reynolds number Re is 50
FIG. 12 shows the optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.5, the parameter q is 0.01, and the Reynolds number Re is 100
FIG. 13 is an optimal flow channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when volume fraction θ is 0.3, parameter q is 0.001, and Reynolds number Re is 20
FIG. 14 is an optimal flow channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.3, the parameter q is 1, and the Reynolds number Re is 20
FIG. 15 shows an optimal channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.5, the parameter q is 0.001, and the Reynolds number Re is 20
Fig. 16 shows the optimal flow channel topology for intake manifold fluid topology optimization of an embodiment of the present invention when the volume fraction θ is 0.5, the parameter q is 1, and the reynolds number Re is 20
Fig. 17 shows the influence of the volume fraction θ on the value of the objective function when the parameters q and Re are 0.01 and 20, respectively
FIG. 18 is a graph showing the influence of the volume fraction [ theta ] and the Reynolds number [ Re ] on the value of the objective function when the parameter q is 0.01
FIG. 19 is a graph showing the influence of the volume fraction [ theta ] and the parameter q on the value of the objective function when the Reynolds number Re is 20
Detailed Description
Referring to fig. 1, 2 and 3, the engine intake manifold design method based on fluid topology optimization mainly comprises the following steps:
(1) according to the purpose and the requirement of fluid topology optimization, a design domain geometric model of engine intake manifold fluid topology optimization is established, a fluid design domain of the engine intake manifold fluid topology optimization is determined, and fluid properties such as medium density, dynamic viscosity and the like are input;
(2) determining global variables, inputting Darcy number Da, inlet characteristic length l, volume fraction theta and maximum inflow speed umaxDesign domain volume V0Reynolds number Re and parameter q of the RAMP material interpolation function;
reynolds number Re describes the ratio of inertial and viscous forces, expressed as:
darcy number Da describes the ratio of viscous force to porous friction, expressed as:
the Darcy number represents the size of the permeability of the porous medium, and the larger the Darcy number is, the larger the permeability of the porous medium is, and the smaller the influence on the strength of the fluid zone is;
the RAMP material interpolation model is:
in the formula, alphamaxIs the inverse local permeability, alpha, of the maximum mediummaxThe larger the value, the larger the viscosity, and the penetrationThe smaller the rate; otherwise, αmaxThe smaller, the greater the permeability, the closer to reality the penetration is in principle, but since the densitometry algorithm in topological optimization relies on the penetration of the fluid, α ismaxIf not too large, otherwise, the numerical value is liable to be unstable, and the example takes alphamax＝1x104. The relative density γ is a design variable and takes a value between 0 and 1. Taking gamma as 0 corresponds to the solid phase material and taking gamma as 1 corresponds to the liquid phase material. q is positive real number, the concavity and convexity of the equation can be controlled by adjusting the value of q, when q tends to be positive and infinite, the interpolation function is a straight line, and when q tends to be 0, the method has good punishment effect on a certain area, is favorable for accelerating the fluid topology optimization convergence process, and enables the flow channel topology structure to be clearer;
(3) setting local variable, local inverse permeability alpha of input mediummaxAnd alpha;
(4) according to the aim of minimum energy consumption, selecting appropriate design variables and performance constraint conditions, and calculating an objective function phi (u, p, gamma) of the engine intake manifold design method based on fluid topology optimization, thereby establishing a mathematical model of the engine intake manifold fluid topology optimization:
in the formula, rho is the density of the fluid, eta is the dynamic viscosity, the values are all 1, f is the physical force of the fluid, p is the pressure, u is the flowing speed of the fluid, and V is0The initial volume of the designed area is 0 & lttheta & lt & gt & lt 1 & gt, which is the volume fraction of the fluid area and represents the percentage of the volume of the engine intake manifold runner area in the volume of the designed area;
(5) given the initial relative density, the constraints of the design domain are set:
∫ΩγdΩ-θ·V0≤0 (8)
volume force:
f＝-αu (9)
inputting an integral target expression, adding a design domain boundary condition, wherein an import is a Dirichlet boundary condition:
u＝uD,onD (10)
the exit is the Neumann boundary condition:
[-pI+η(▽u+▽uT)]n＝g,onN (11)
wherein g is a known stress distribution. For embodiments of the present invention where the entry boundary condition is a Dirichlet boundary condition with a known velocity, the entry flow rate is uinThe outlet boundary is Neumann boundary condition, g is 0, and other boundaries are no-slip boundaries;
(5.1) discretizing a fluid topology optimization mathematical model by using a finite element method, and writing an MATLAB program for optimizing the fluid topology;
(5.2) writing an MATLAB program of an objective function, a constraint condition, a boundary condition and a volume force;
(5.3) setting upper and lower limits of design variables in the MATLAB program and giving initial relative densities;
(6) partitioning a design domain and a non-design domain into quadrilateral grids with different densities, and setting an iteration termination condition of the engine intake manifold fluid topology optimization;
(7) updating design variables according to a moving progressive line method (MMA), and taking a relative density lower limit gamma min0 and an upper limit of γ max1, taking the relative tolerance as 1e-6, and specifically comprising the following steps:
(7.1) inputting the relative density of the current finite element, updating the relative density of the element according to an MMA method and solving the total volume of the updated design domain;
(7.2) solving the total product difference of the design domain before and after the unit relative density updating so as to set a new interpolation unit;
(7.3) judging whether iteration is terminated according to the new interpolation unit information, if not, adopting the updated relative density back substitution (7.1) to carry out iteration again, and if so, stopping calculating and outputting the updated unit relative density;
(8) calculating the relative density difference of each corresponding unit during input and output in the step (7), solving the maximum relative density change value, comparing the maximum change value with the set total loop iteration termination condition, judging whether the termination condition is met, and if the termination condition is not met, feeding back the output unit relative density to re-iterate until the iteration termination condition is met;
(9) and outputting an optimal runner topological structure of the engine intake manifold based on fluid topological optimization, wherein a white area is an optimized engine intake manifold runner.
The following is an example of the engine intake manifold optimization design for application of the method of the present invention in certain engineering practice:
referring to fig. 2, the present embodiment is a five-cylinder engine intake manifold, and the fluid medium flows in from the middle of the upper end and flows out from five outlets at the lower end, and enters five cylinders respectively. The design field is a middle 3x9 rectangular area and a section with an outlet length of 1, namely a black area in fig. 2, wherein the width of the inlet area and the width of the outlet area are both 1, and the length of the inlet area and the outlet area are both 2. The specific implementation steps of the invention for the example are as follows:
(a) according to the purpose and the requirement of fluid topology optimization, a design domain geometric model of engine intake manifold fluid topology optimization is established, a fluid design domain of the engine intake manifold fluid topology optimization is determined, and fluid attributes such as input medium density rho 1 and dynamic viscosity eta 1 are obtained;
(b) determining global variable, inputting Darcy number Da ═ 1x10-4The inlet characteristic length l is 1, the volume fraction θ (θ is 0.1, 0.2, 0.25, 0.3, 0.35, 0.4, 0.5 and 0.6, respectively), and the maximum inflow velocity umax(umaxRespectively taken as 20, 50, 100 and 200), design domain volume V032, reynolds number Re (Re takes 20, 50, 100 and 200, respectively), and parameter q of the RAMP material interpolation function (q takes 0.001, 0.005, 0.01, 0.05, 0.1, 0.5 and 1, respectively);
(c) setting local variable, local inverse permeability alpha of input mediummax＝1x104And alpha;
(d) according to the target of minimum energy consumption, calculating an objective function phi (u, p, gamma) of the engine intake manifold design method based on fluid topology optimization, and establishing a mathematical model of the fluid topology optimization of the engine intake manifold; discretizing the mathematical model by using a finite element method, and writing a key MATLAB program according to an algorithm and the mathematical model so as to carry out fluid topology optimization design on an engine intake manifold;
(e) given an initial relative density of 0.3, the constraints of the design domain are set:
∫ΩγdΩ-θ·V0≤0 (12)
setting the entrance boundary condition as Dirichlet boundary condition with known velocity and entrance flow velocity as uin＝-4umax(x-5) (6-x) n, exit boundary is Neumann boundary condition, and g is 0, other boundaries are no-slip boundaries;
(f) partitioning a design domain and a non-design domain into quadrilateral grids with different densities, wherein the complete grid comprises 3687 intra-domain units and 546 boundary units as shown in FIG. 3, and setting an iteration termination condition of the fluid topology optimization of the intake manifold of the engine;
(g) updating design variables according to a moving progressive line method (MMA), and taking a relative density lower limit gamma min0 and an upper limit of γ max1, and taking the relative tolerance of 1 e-6;
(h) calculating absolute difference values before and after updating of the relative density of the unit in the step (g), judging whether the maximum absolute difference value is smaller than 1e-6, if so, returning the updated relative density of the unit in the step (g) to re-iterate, and if not, terminating the iteration and outputting the updated relative density of the unit;
(i) calculating the relative density difference of each corresponding unit during input and output in the step (h), solving the maximum relative density change value, comparing the maximum change value with the set total loop iteration termination condition, judging whether the termination condition is met, and if the termination condition is not met, feeding back the output unit relative density to re-iterate until the iteration termination condition is met;
(j) and outputting an optimal runner topological structure of the engine intake manifold based on fluid topological optimization, wherein a white area is an optimized engine intake manifold runner.
Fig. 4 to 16 are structural diagrams of optimal flow channel topologies of an engine intake manifold based on fluid topology optimization according to the present embodiment, where fig. 4 to 8 are structural diagrams of optimal flow channel topologies of engine intake manifold fluid topology optimization when the volume fraction θ is 0.1, 0.3, 0.4, 0.5, and 0.6, and q is 0.01, and Re is 20, fig. 9 to 10 are structural diagrams of optimal flow channel topologies of engine intake manifold fluid topology optimization when the volume fraction θ is 0.3, q is 0.01, and Re is 50 and 100, fig. 11 to 12 are structural diagrams of optimal flow channel topologies of engine intake manifold fluid topology optimization when the volume fraction θ is 0.5, q is 0.01, and Re is 50 and 100, fig. 13 to 14 are structural diagrams of optimal flow channel topologies of engine intake manifold fluid topology optimization when the volume fraction θ is 0.3, and q is 0.001 and 1, and Re is 20, fig. 15 to 16 are diagrams of an optimal flow path topology for engine intake manifold fluid topology optimization when the volume fraction θ is 0.5, q is 0.001 and 1, and Re is 20, fig. 17 is a diagram of a relationship between the volume fraction θ and a target function value when the parameter q is 0.01 and the reynolds number Re is 20, fig. 18 is a diagram of a relationship between the volume fraction θ and the reynolds number Re and the target function value when the parameter q is 0.01, and fig. 19 is a diagram of a relationship between the volume fraction θ and the parameter q and the target function value when the reynolds number Re is 20, respectively. Through comparative analysis, it can be seen that the volume fraction θ, the reynolds number Re and the parameter q in the RAMP material interpolation function have a large influence on the optimal flow channel topology structure and the objective function value of the engine intake manifold fluid topology optimization, and the flow channel structures of the engine intake manifold shown in fig. 8, 11 and 15 are more in line with actual conditions; in order to obtain the optimal runner topological structure of an engine intake manifold, the volume fraction theta is recommended to be 0.4-0.7, the Reynolds number Re is recommended to be 20-200, and the parameter q is recommended to be 0.001-0.1. The optimal flow channel topological structure for engine intake manifold fluid topological optimization can be obtained by simultaneously controlling the volume fraction theta, the Reynolds number Re and the parameter q in the RAMP material interpolation function, and in order to obtain a reasonable engine intake manifold flow channel topological structure, the values of the three factors need to be reasonably matched.
Although the present invention has been described in detail with reference to the embodiment, the above description is not intended to limit the scope of the present invention, and any modification and improvement based on the concept of the present invention are considered as the scope of the present invention.
Claims (7)
1. The method for designing the engine intake manifold based on the fluid topology optimization is characterized by comprising the following steps of:
(1) according to the purpose and the requirement of fluid topology optimization, a design domain geometric model of the engine intake manifold fluid topology optimization is established, a fluid design domain of the engine intake manifold fluid topology optimization is determined, and medium density and dynamic viscosity fluid properties are input;
(2) determining global variables, inputting Darcy number Da, inlet characteristic length l, volume fraction theta and maximum inflow speed umaxThe volume of a design domain, the Reynolds number Re and a parameter q of an interpolation function of the RAMP material;
(3) setting local variable, local inverse permeability alpha of input mediummaxAnd alpha;
(4) according to the aim of minimum energy consumption, selecting appropriate design variables and performance constraint conditions, and calculating an objective function phi (u, p, gamma) of the engine intake manifold design method based on fluid topology optimization, thereby establishing a mathematical model of the engine intake manifold fluid topology optimization:
minΦ(u,p,γ)
u＝uD,onD
∫ΩγdΩ-θ·V0≤0
0≤γ≤1
where ρ is the fluid density, η is the dynamic viscosity, f is the fluid physical force, p is the pressure, u is the fluid flow velocity, γ is the relative density of the finite element, g is the known stress distribution, V0The initial volume of the design area is 0-theta, which is less than or equal to 1, and the volume fraction of the fluid area represents the percentage of the volume of the runner area of the engine intake manifold in the volume of the design area;
(5) giving an initial relative density, setting a constraint condition and a volume force of a design domain, inputting an integral target expression, and adding a design domain boundary condition;
(5.1) discretizing the fluid topology optimization mathematical model by using a finite element method, and writing an MATLAB program matched with an algorithm for optimizing the fluid topology of the intake manifold of the engine;
(5.2) writing an MATLAB program of an objective function, a constraint condition, a boundary condition and a volume force;
(5.3) setting upper and lower limits of design variables in an MATLAB program, and giving initial relative density;
(6) partitioning a design domain and a non-design domain into quadrilateral grids with different densities, and setting an iteration termination condition of the engine intake manifold fluid topology optimization;
(7) updating design variables according to a moving progressive line method: updating the relative density of the finite element unit according to an MMA method, solving the total volume of the updated design domain, judging whether the iteration of the new interpolation unit is terminated according to the relative tolerance before and after updating, if not, adopting the updated unit relative density and continuing the iteration according to the MMA method, and if the iteration is terminated, stopping the calculation and outputting the unit relative density;
(8) calculating the relative density difference of each corresponding unit during input and output in the step (7), solving the maximum relative density change value, comparing the maximum change value with the set total loop iteration termination condition, judging whether the termination condition is met, and if the termination condition is not met, feeding back the output unit relative density to re-iterate until the iteration termination condition is met;
(9) and outputting the optimal flow channel topology of the engine intake manifold based on the fluid topology optimization.
2. The engine intake manifold design method based on fluid topology optimization according to claim 1, characterized in that the relative density γ of finite element elements in the fluid design domain is selected as a design variable, and the relative density value of each element in the fluid design domain is calculated according to a RAMP material interpolation model; the interpolation model of RAMP material is
In the formula, alphamaxIs the inverse local permeability, alpha, of the maximum mediummaxThe larger the value is, the larger the viscosity is, the smaller the permeability is, and conversely, the alpha ismaxThe smaller, the greater the permeability, the closer to reality the penetration is in principle, but since the densitometry algorithm in topological optimization relies on the penetration of the fluid, α ismaxNot too large, otherwise the numerical value is liable to be unstable, and take alphamax＝1x104。
3. The engine intake manifold design method based on fluid topology optimization according to claim 1, characterized in that in steps (4) and (7), the relative density γ as the design variable takes a value between 0 and 1, γ takes 0 corresponding to solid phase material, γ takes 1 corresponding to liquid phase material; updating design variables according to a moving progressive line method, and taking a relative density lower limit gammamin0 and an upper limit of γmax1 and take relative tolerances 1 e-6.
4. The engine intake manifold design method based on fluid topology optimization according to claim 1, characterized in that the optimal flow channel topology structure of the fluid topology optimization of the engine intake manifold can be controlled by a volume fraction θ, and the volume fraction θ is in a range of 0.4-0.7 in order to obtain the optimal flow channel topology structure of the engine intake manifold.
5. The method for designing the engine intake manifold based on the fluid topology optimization according to claim 1, wherein the optimal flow channel topology structure of the fluid topology optimization of the engine intake manifold can be controlled by a Reynolds number Re, and the Reynolds number Re ranges from 20 to 200 in order to obtain the optimal flow channel topology structure of the engine intake manifold.
6. The engine intake manifold design method based on fluid topology optimization according to claim 1, characterized in that the optimal flow channel topology structure of the engine intake manifold fluid topology optimization can be controlled by a parameter q in a RAMP material interpolation function, and the parameter q ranges from 0.001 to 0.1 in order to obtain the optimal flow channel topology structure of the engine intake manifold.
7. The engine intake manifold design method based on fluid topology optimization according to claim 1, characterized in that the optimal flow channel topology structure of the engine intake manifold fluid topology optimization can be controlled by the volume fraction θ, the reynolds number Re and the parameter q in the RAMP material interpolation function at the same time, and the values of the three factors need to be reasonably matched in order to obtain a reasonable engine intake manifold flow channel topology structure.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106339522A (en) * | 2015-07-09 | 2017-01-18 | 科林工业技术有限责任公司 | Method for constructing member for passage of fluid |
| US9643251B2 (en) * | 2014-06-13 | 2017-05-09 | Zin Technologies, Inc. | Optimized additive manufacturing process |
| CN106777476A (en) * | 2016-11-17 | 2017-05-31 | 西安交通大学 | A kind of method of topological optimization design of electronic power integrated module cold drawing fluid course |
| CN106845021A (en) * | 2017-02-28 | 2017-06-13 | 湘潭大学 | Anisotropic material heat structure Topology Optimization Method based on mesh free RKPM |
| CN107122527A (en) * | 2017-04-10 | 2017-09-01 | 西安电子科技大学 | A kind of cold drawing flow passage design method based on topological optimization |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9576088B2 (en) * | 2013-01-23 | 2017-02-21 | Toyota Motor Engineering & Manufacturing North America, Inc. | Methods for orienting material physical properties using constraint transformation and isoparametric shape functions |
-
2017
- 2017-12-05 CN CN201711263844.5A patent/CN107944172B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9643251B2 (en) * | 2014-06-13 | 2017-05-09 | Zin Technologies, Inc. | Optimized additive manufacturing process |
| CN106339522A (en) * | 2015-07-09 | 2017-01-18 | 科林工业技术有限责任公司 | Method for constructing member for passage of fluid |
| CN106777476A (en) * | 2016-11-17 | 2017-05-31 | 西安交通大学 | A kind of method of topological optimization design of electronic power integrated module cold drawing fluid course |
| CN106845021A (en) * | 2017-02-28 | 2017-06-13 | 湘潭大学 | Anisotropic material heat structure Topology Optimization Method based on mesh free RKPM |
| CN107122527A (en) * | 2017-04-10 | 2017-09-01 | 西安电子科技大学 | A kind of cold drawing flow passage design method based on topological optimization |
Non-Patent Citations (3)
| Title |
|---|
| Structural Dynamic Topology Optimization and Sensitivity Analysis Based on RKPM;Zhang J P ET AL;《Advanced Materials Research》;20101231;全文 * |
| Topology optimization of fluid domains: kinetic theory approach;Evgrafov A ET AL;《Journal of Applied Mathematics & Mechanics》;20121231;全文 * |
| 水平集与灵敏度分析相结合的流体形状识别与优化方法;刘小民等;《西安交通大学学报》;20141231;全文 * |
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