Numerical Simulation Of Temperature Field,Flow Field And Mass Deposition In Polysilicon Reduction Furnace

Traditional energy reserves are diminishing,and the large amount of CO₂ generated in the process of traditional energy use causes the"greenhouse effect",leading to global warming and causing serious adverse effects on the ecological environment,based on this,China proposed the Goal of“Peak Carbon Dioxide Emission and Carbon Neutrality”in 2020,and promulgated policies to implement the goal in 2022.The new energy industry is booming,among which the photovoltaic industry is developing rapidly due to its high availability,and the demand for polysilicon as a basic material for the photovoltaic industry is soaring,but now the polysilicon production process still has high energy consumption and long production time.Because of the complexity of the polysilicon production process,if the experimental study is conducted,there are many uncontrollable conditions and high cost,and the theoretical study is very complicated,while the current CFD numerical simulation method can complete the analysis of the impact of each factor under the condition of ensuring the accuracy.In this paper,we mainly use the radiation Do model,the turbulent Realizable k-εmodel and the component transport EDC model in Fluent to verify the reasonableness of the three-dimensional numerical simulation by comparing the simulation results with the experimental data of silicon growth in the polysilicon reduction furnace,and to prove the reasonableness of the two-dimensional numerical simulation by means of citation.Four evaluation indexes,namely silicon deposition rate,temperature field uniformity,flow field uniformity,and energy consumption,were used to analyze the effects of structurally correlated and structurally uncorrelated parameters on yield and product quality and energy consumption.The influence of the structurally irrelevant parameters on the silicon deposition rate was analyzed by CHEMKIN software using a two-dimensional model,and the influence of the structurally irrelevant parameters on the silicon deposition rate,temperature field uniformity,flow field uniformity and energy consumption was analyzed by Fluent software using a three-dimensional model.The following conclusions were drawn:（1）Influencing factors of silicon deposition rate.Structurally uncorrelated parameters:silicon deposition rate is positively correlated with the reaction pressure;silicon deposition rate increases with the molar fraction of hydrogen inlet and then decreases,reaching a peak of 34μm/min at a molar fraction of 0.55;silicon deposition rate is negatively correlated with the inlet gas temperature.Structural correlation parameters:the inlet velocity is positively correlated with the silicon deposition rate;the minimal silicon deposition rate is 0.00138 kg/（m²·s）for an inlet/outlet area ratio of 1.4.（2）Temperature field uniformity influencing factors:the highest temperature field uniformity is 0.993 at an inlet velocity of 60 m/s;the highest temperature field uniformity is0.993 at a silicon rod diameter of 15 mm;the temperature field uniformity is 0.001 lower in the center outlet plus surrounding outlet arrangement than in the surrounding outlet arrangement;the highest flow field uniformity is 0.99 at an inlet/outlet area ratio of 1.（3）Influence of flow field uniformity:the lowest flow field uniformity is 0.55 when the inlet speed is 15m/s;the flow field uniformity is negatively correlated with the diameter of the silicon rod;the flow field uniformity is 0.015 higher in the form of center outlet plus surrounding outlet arrangement than in the form of surrounding outlet arrangement;the highest flow field uniformity is 0.85 when the inlet/outlet area ratio is 1.（4）Influence factors of energy consumption:the total energy consumption increases by4000k W for every 15m/s increase in inlet speed;the total energy consumption increases gradually with the increase in diameter of the silicon rod but decreases;the total energy consumption of the surrounding exit form is 1.13 times higher than that of the center plus surrounding exit form.