Study On The Control Of Spray Molding Process Based On Sodium Alginate Composite Drive

Microdroplet injection manufacturing technology is a kind of non-impact printing technology,which can drop dozens of picolitres of microdroplet from the nozzle mouth to the designated position of the substrate,which is a kind of printing method well adapted to various coupling processes.In tissue engineering,simultaneous printing of cells and biological materials based on this method enables cells or proteins to be accurately placed in three-dimensional hydrogel structures,which not only increases the possibility of spatial control of scaffold structures,but also increases the possibility of the construction of viable tissue types in scaffolds.Therefore,the study of microdroplet jet printing technology with biological materials can provide a strong theoretical basis for tissue engineering and guidance for biological application.In this Dissertation,the characteristics of materials suitable for micro-droplet injection were studied,the corresponding mathematical model and simulation model of each process were established in the micro-droplet injection process,and the parameters affecting the micro-droplet forming were analyzed in detail,and the main research work in this Dissertation was as follows:1.The Dissertation provides a basis for distinguishing the flow type of the material used in micro-droplet jet printing(hydrogel with sodium alginate),studies its shear viscosity and thinning phenomenon,analyzes its inherent characteristic viscosity,and expounds the influence of calcium ion concentration and crosslinking temperature value in the crosslinking reaction.The selection basis of concentration value of hydrogel prepared with sodium alginate in microdroplet injection under different parameters was determined.2.In the Dissertation,the process from the formation of microdroplets to the wetting and spreading of the substrate is theoretically studied,and the corresponding theoretical mathematical model is established to solve the dynamic relation equation of the formation of microdroplets,given the coupling equation of wetting and spreading on the substrate,the equilibrium equation of mutual disturbance of microdroplets is proposed.Mathematica was used to numerically calculate the established model,and the variation rules of parameters such as the size of two-phase antenna and disturbance coefficient of the droplet were obtained,which provided amacroscopic judgment method for the smooth progress of the experiment.3.Based on the theoretical analysis of mathematical model,the formation process of microdroplets and the wetting and spreading process on the substrate were simulated by using FLUENT's VOF method.The key parameters affecting droplet forming,such as velocity boundary peak material viscosity and micronozzle aperture,were analyzed.The results showed that the maximum wetting spreading radius of the droplet,the final wetting spreading radius and the equilibrium time of the droplet were related to the roughness degree on the surface of two-phase antenna substrate with initial velocity.By means of numerical simulation,the parameters affecting the final state of the droplet can be controlled and the corresponding droplet can be obtained.4.According to the principle of micro droplet on-demand(DOD)injection structures,test bench,the experiments of micro droplet forming experiments in the process of a series of conditions were analyzed,and the micro droplet pinch off location estimation is given,and the experiments of micro droplet forming a retention and sums up the factors influencing drag wires and presents a reference basis,the study found that is mainly due to the insufficient material dissolved in the process of configuration and voltage amplitude of the bubble,it also analysis the main pair of micro droplet formation and micro-droplet bias problem Platform through the experiment research of physical factors on the influence of sodium alginate gel micro droplet forming,this Dissertation analyzes the driving signal waveform parameters(including time and frequency of the pulse waveform amplitude)of the generated micro nozzle diameter and the influence of the size of droplet diameter and velocity,and through the analysis of the micro droplet generation in the experiment to discuss the changing rule of the sedimentary state.