| In recent years,fluid topology optimization has gradually become a research hotspot in the field of optimization,and the current domestic research is still in the development stage.Most of the existing research is focused on the design of flow channel structure for the purpose of minimizing energy dissipation,and there is less research on control valve type engineering problems that need to meet the requirements of achieving high pressure drop.Therefore,it is very important to establish a reliable mathematical model for fluid topology optimization to solve practical engineering problems.The topology optimization analysis of high flow resistance microchannel is carried out based on the research ideas related to the topology optimization of Tesla microvalve,and the results of forward flow are studied by introducing reverse flow as an auxiliary variable,and the topology optimization method of high flow resistance flow channel with minimized pressure drop ratio as the objective function is proposed;the applicability of the method proposed in Chapter 3 is verified at the conventional flow channel scale by expanding the model scale,and the multi-stage pressure drop flow channel model is constructed by By comparing the flow field analysis with the industrial multi-turn angle labyrinth valve flow channel model,the engineering application value of the method is verified,and the topology optimization of the multi-stage reduced pressure flow channel is realized.First,the basic equations of fluid dynamics and the topology optimization theory involved in this paper are introduced.The assumed density is introduced in the design domain to represent the material distribution,the control equations are obtained by Darcy interpolation,and the study is carried out based on the microchannel scale with reference to the Tesla microvalve topology optimization case.The reverse flow is introduced as a reference to study the results of forward flow,and the topology optimization of the high flow resistance flow channel is finally determined by minimizing the pressure drop ratio as the objective function and combining with the MMA algorithm,and the feasibility and correctness of the method is verified by comparing with the straight microchannel.Secondly,the setting laws of key parameters in the topology optimization process are investigated.The optimization results with and without Helmholtz filtering and hyperbolic tangent projection are compared,and it is found that Helmholtz filtering can effectively solve the tessellation phenomenon and hyperbolic tangent projection can effectively solve the problem of grayscale region.The effects of different settings of Helmholtz filtration radius and hyperbolic tangent function projection slope on the optimization results are discussed,and the settings of relevant parameters for subsequent studies are determined.The influence of boundary conditions and constraints such as Reynolds number,fluid medium and flow channel volume fraction on the topology optimization results is investigated,and it is obtained that the smaller the set value of flow channel volume fraction,the better the high flow resistance characteristics of the flow channel,but too small will increase the volume and mass of the solid region,and even cause distortion of the calculation results;the larger the Reynolds number,the better the flow resistance characteristics of the flow channel,but the more complex the structure is,which is not conducive to industrial manufacturing;the method is applicable to different The method is applicable to different fluid media,and the fluid media has a certain influence on the topology of the optimized structure.Finally,the high flow resistance flow channel topology optimization method proposed in Chapter 3 of this paper is generalized to verify that the method is also applicable at the conventional flow channel scale.The topologically optimized flow channel is then used as a single-stage buckling flow channel to study the buckling performance of multi-stage buckling flow channels with different splicing methods,and the buckling performance is compared with that of multi-turn angle type labyrinth valve flow channel.It is concluded that reducing the angle of adjacent flow paths can help to improve the pressure reduction performance while ensuring the non-interference of structural splicing.In summary,this paper proposes a high flow resistance flow channel topology optimization method with minimized pressure drop ratio as the objective function,which can provide relevant references for engineering applications. |
