Lattice Boltzmann Study Of Two-Dimensional Non-Isothermal Impinging Flow Field And Temperature Field Structure

Impinging flow is a typical flow pattern in production practice.It is most common in coal gasification technology for synthesizing clean gas,and synthetic clean gas is beneficial to environmental protection.Therefore,studying impact flow can provide technical support for production practice.In the past,the study of impinging flow was mostly experimental,but in recent years,computer simulation has become an important means to study the impinging stream.In this paper,the two-dimensional non-isothermal impinging stream is numerically simulated using the two-dimensional thermal lattice model(TD2G9)in the lattice Boltzmann method(LBM).In the past,most studies on impinging flow fixed other parameters to discuss the influence of single parameters on the flow field and temperature field structure,while ignoring the changes of other parameters.Based on this paper,three parameters,the influence of the outlet and jet inlet ratio(H/W),Reynolds number(Re)and thermal buoyancy(Rit)on the flow field and temperature field structure of the impinging stream are studied.The research method is as follows:take two parameters A and B from three parameters,change another parameter C,and study the law D1 of the change of flow field and temperature field structure when parameter C changes.Then change one of A and B,observe the law of the change of flow field and temperature field structure when C changes,and finally compare the difference between D1 and D2.We classify the results of the calculation according to the size of the buoyancy and find that:1.The flow field structure exhibits an unsteady periodic deflection only in the absence of buoyancy,and a steady-state deflection occurs only in the presence of buoyancy,unsteady aperiodic deflection occurs in both buoyancy and no buoyancy.2.Larger H/W values and larger Rit values are necessary for the occurrence of a steady-state skew structure,and Re is not a necessary condition.3.At H/W=3,when buoyancy is large,the Re required for the first steady-state skew is smaller.In the past studies of impinging streams,some scholars have found that the impinging stream will have a cyclically changing skew structure.Some scholars have found a steady-state skew structure.This paper clarifies the parameter conditions for the two skew structures.