Aiming at improving efficiency in combustion systems, the study on droplet behavior and its trajectory is of crucialimportance. Vortex engine is a kind of internal combustion engine which uses swirl flow to achieve hi...Aiming at improving efficiency in combustion systems, the study on droplet behavior and its trajectory is of crucialimportance. Vortex engine is a kind of internal combustion engine which uses swirl flow to achieve highercombustion efficiency. One of the important advantages of designing vortex engine is to reduce the temperatureof walls by confining the combustion products in the inner vortex. The scopes of this investigation are to studyvortex engine flow field as well as effective parameters on fuel droplet behavior such as droplet diameter, dropletinitial velocity and inlet velocity of the flow field. The flow field is simulated using Reynolds Stress TransportModel (RSM). The Eulerian-Lagrangian method and the one-way coupling approach are employed to simulatetwo phase flow and dispersed phase in the chamber, respectively. A new method, based on computing pressureforce exerted on the droplet surface, is introduced to determine the distinction between using one-way andtwo-way coupling approaches. The results showed that the droplets with smaller diameter are more likely to followthe flow stream lines than bigger droplets, thus evaporate completely in the chamber. Moreover, droplets withgreater initial velocity have higher evaporation rate, yielding the existence of evaporation and combustion in theinner vortex. Additionally, the higher inlet velocity of continuous phase results in higher centrifugal force, leadsdroplets in question to deviate towards the wall faster.展开更多
The inlet/isolator is one of the important parts to the SCRAMjet engine. In the present paper, the flow fields within an inlet and isolator of a SCRAMjet engine have been simulated by the Reynolds-Averaged Navier-Stok...The inlet/isolator is one of the important parts to the SCRAMjet engine. In the present paper, the flow fields within an inlet and isolator of a SCRAMjet engine have been simulated by the Reynolds-Averaged Navier-Stokes equations with the Baldwin-Lomax algebraic turbulence model. The second order H. C. Yee TVD scheme is used for the inviscid flux terms and a central difference considering the character of flow is used for the diffusion terms. The code was used to simulate the flow field of three types of the inlet/isolator models. The results show that the configuration of the internal compression surface of the inlet and the divergent angle of the isolator have a great important effect on the characteristics of the inlet/isolator.展开更多
文摘Aiming at improving efficiency in combustion systems, the study on droplet behavior and its trajectory is of crucialimportance. Vortex engine is a kind of internal combustion engine which uses swirl flow to achieve highercombustion efficiency. One of the important advantages of designing vortex engine is to reduce the temperatureof walls by confining the combustion products in the inner vortex. The scopes of this investigation are to studyvortex engine flow field as well as effective parameters on fuel droplet behavior such as droplet diameter, dropletinitial velocity and inlet velocity of the flow field. The flow field is simulated using Reynolds Stress TransportModel (RSM). The Eulerian-Lagrangian method and the one-way coupling approach are employed to simulatetwo phase flow and dispersed phase in the chamber, respectively. A new method, based on computing pressureforce exerted on the droplet surface, is introduced to determine the distinction between using one-way andtwo-way coupling approaches. The results showed that the droplets with smaller diameter are more likely to followthe flow stream lines than bigger droplets, thus evaporate completely in the chamber. Moreover, droplets withgreater initial velocity have higher evaporation rate, yielding the existence of evaporation and combustion in theinner vortex. Additionally, the higher inlet velocity of continuous phase results in higher centrifugal force, leadsdroplets in question to deviate towards the wall faster.
文摘The inlet/isolator is one of the important parts to the SCRAMjet engine. In the present paper, the flow fields within an inlet and isolator of a SCRAMjet engine have been simulated by the Reynolds-Averaged Navier-Stokes equations with the Baldwin-Lomax algebraic turbulence model. The second order H. C. Yee TVD scheme is used for the inviscid flux terms and a central difference considering the character of flow is used for the diffusion terms. The code was used to simulate the flow field of three types of the inlet/isolator models. The results show that the configuration of the internal compression surface of the inlet and the divergent angle of the isolator have a great important effect on the characteristics of the inlet/isolator.
