Numerical Simulation Of Ignition And Combustion Process In Solid Fuel Scramjet Combustor

Solid fuel scramjet has broad application prospects in aspirated hypersonic vehicles.The combustor is the core component of scramjet,the flow,ignition and combustion in it are complex strong transient processes.The relevant research in China started late.Although some progress has been made in experimental research and numerical simulation,it is still in the exploratory stage.In order to further understand the working mechanism of combustor,it is necessary to carry out transient research on ignition and combustion process in combustor.According to the classical solid fuel scramjet combustor configuration,the fuel surface pyrolysis reaction and gas-phase combustion reaction rate are set according to Arrhenius formula.Based on FLUENT software,the numerical calculation models of flow,pyrolysis,combustion and charge surface retreat are established,and the turbulence model suitable for this paper is selected.The combustion model in this paper is verified to be feasible according to steady-state calculation,Finally,the ignition and combustion process of combustor are studied by transient simulation method.According to the characteristics of flow and combustion,the ignition process is divided into three stages: heat accumulation,gas phase ignition and flame propagation.In the heat accumulation stage,the combustion chamber is heated by the incoming hot air,accompanied by micro pyrolysis and gas phase reaction.In the gas phase ignition stage,a gas phase flare appears at the junction of large and small reflux areas.In the flame propagation stage,all the fuel surfaces are ignited and the combustion chamber enters a choked state.The results show that the boundary movement can be realized by using unstructured grid and hybrid grid,but the simulation effect is different.In the process of stable combustion,the cavity is rich in combustion.With the retreat of solid fuel surface,the choking state gradually disappears,and the flame surface position,temperature and component distribution change.This paper provides a new implementation method for the working process simulation of solid fuel scramjet combustor,but there is room for improvement.