AbstractA simplified method is developed to calculate aerodynamic heating, ablation, and structur... more AbstractA simplified method is developed to calculate aerodynamic heating, ablation, and structural temperature response for a body traveling at high speeds. Mach number, altitude, and angle of att...
ABSTRACT CFD simulations of the reacting flow through an annular small turbojet combustor with pr... more ABSTRACT CFD simulations of the reacting flow through an annular small turbojet combustor with pre-filming air-blast atomizer were performed with two different spray modeling approaches: including wall film computations (film formation and break-up) and injecting fuel droplets directly downstream of the pre-filmer. In the former method, the whole multiphase phenomena, starting from primary break-up at the exit of the hollow cone simplex injector up to the evaporation of the droplets stripped or rebounded from the fuel film are simulated. In the latter method, which is widely used for practical purposes, droplets are injected at a location downstream of the air-blast atomizer with a presumed size and velocity distribution. Droplets are simulated within Lagrangian-Eulerian framework in both cases and flow of the wall film is computed with the shell approach. Counting in the film formation and breakup in the computations has shown that, some of the droplets didn’t join the fuel film, instead rebounded from the pre-filmer wall directly into the combustor. This led to larger droplet sizes inside the primary zone, thus delayed the evaporation process and consequently the reactions were shifted in the downstream direction. Related to this circumstance, a lower combustion efficiency (by ~1%) and a higher pattern factor (by 0.09) were observed at the combustor exit in the pre-filming case.
CFD, Computational Fluid Dynamics, tools have become an integral part of product design and analy... more CFD, Computational Fluid Dynamics, tools have become an integral part of product design and analysis of gas turbines, rocket engines and thrusters. In order to model the chemical reacting flow in the combustion chambers, a CFD solver dealing with combustion of multi species reactions is developed. The solver must also be able to cope with the three flow regimes, subsonic, transonic and supersonic flow that occur in many flow problems. This is namely called a solver for all flow speeds. This solver also utilizes all resources of computers by being CPU parallel and GPU accelerated. A third party Open Source matrix solver ViennaCL is integrated to the Solver to solve linear system of equations.
CFD simulations of the reacting flow through an annular small turbojet combustor with pre-filming... more CFD simulations of the reacting flow through an annular small turbojet combustor with pre-filming air-blast atomizer were performed with two different spray modeling approaches: including wall film computations (film formation and break-up) and injecting fuel droplets directly downstream of the pre-filmer. In the former method, the whole multiphase phenomena, starting from primary break-up at the exit of the hollow cone simplex injector up to the evaporation of the droplets stripped or rebounded from the fuel film are simulated. In the latter method, which is widely used for practical purposes, droplets are injected at a location downstream of the air-blast atomizer with a presumed size and velocity distribution. Droplets are simulated within Lagrangian-Eulerian framework in both cases and flow of the wall film is computed with the shell approach. Counting in the film formation and breakup in the computations has shown that, some of the droplets didn’t join the fuel film, instead re...
Because of different phenomena involved such as fluid dynamics, fuel atomization, complex chemica... more Because of different phenomena involved such as fluid dynamics, fuel atomization, complex chemical reaction mechanism and heat transfer; numerical simulation of a gas turbine combustor is still difficult and an uncertain part of aero engine design process. Therefore validation of the combustion chamber simulation results by rig tests is still a very vital step for a good product design. It is always possible and very likely to find some crucial problems during the testing phase that were not predicted by the 3D CFD computations. As a result of rig tests, the combustor is modified to comply with the requirements. However, the number of rig tests has to be well planned due to high costs of testing.
AbstractA simplified method is developed to calculate aerodynamic heating, ablation, and structur... more AbstractA simplified method is developed to calculate aerodynamic heating, ablation, and structural temperature response for a body traveling at high speeds. Mach number, altitude, and angle of att...
ABSTRACT CFD simulations of the reacting flow through an annular small turbojet combustor with pr... more ABSTRACT CFD simulations of the reacting flow through an annular small turbojet combustor with pre-filming air-blast atomizer were performed with two different spray modeling approaches: including wall film computations (film formation and break-up) and injecting fuel droplets directly downstream of the pre-filmer. In the former method, the whole multiphase phenomena, starting from primary break-up at the exit of the hollow cone simplex injector up to the evaporation of the droplets stripped or rebounded from the fuel film are simulated. In the latter method, which is widely used for practical purposes, droplets are injected at a location downstream of the air-blast atomizer with a presumed size and velocity distribution. Droplets are simulated within Lagrangian-Eulerian framework in both cases and flow of the wall film is computed with the shell approach. Counting in the film formation and breakup in the computations has shown that, some of the droplets didn’t join the fuel film, instead rebounded from the pre-filmer wall directly into the combustor. This led to larger droplet sizes inside the primary zone, thus delayed the evaporation process and consequently the reactions were shifted in the downstream direction. Related to this circumstance, a lower combustion efficiency (by ~1%) and a higher pattern factor (by 0.09) were observed at the combustor exit in the pre-filming case.
CFD, Computational Fluid Dynamics, tools have become an integral part of product design and analy... more CFD, Computational Fluid Dynamics, tools have become an integral part of product design and analysis of gas turbines, rocket engines and thrusters. In order to model the chemical reacting flow in the combustion chambers, a CFD solver dealing with combustion of multi species reactions is developed. The solver must also be able to cope with the three flow regimes, subsonic, transonic and supersonic flow that occur in many flow problems. This is namely called a solver for all flow speeds. This solver also utilizes all resources of computers by being CPU parallel and GPU accelerated. A third party Open Source matrix solver ViennaCL is integrated to the Solver to solve linear system of equations.
CFD simulations of the reacting flow through an annular small turbojet combustor with pre-filming... more CFD simulations of the reacting flow through an annular small turbojet combustor with pre-filming air-blast atomizer were performed with two different spray modeling approaches: including wall film computations (film formation and break-up) and injecting fuel droplets directly downstream of the pre-filmer. In the former method, the whole multiphase phenomena, starting from primary break-up at the exit of the hollow cone simplex injector up to the evaporation of the droplets stripped or rebounded from the fuel film are simulated. In the latter method, which is widely used for practical purposes, droplets are injected at a location downstream of the air-blast atomizer with a presumed size and velocity distribution. Droplets are simulated within Lagrangian-Eulerian framework in both cases and flow of the wall film is computed with the shell approach. Counting in the film formation and breakup in the computations has shown that, some of the droplets didn’t join the fuel film, instead re...
Because of different phenomena involved such as fluid dynamics, fuel atomization, complex chemica... more Because of different phenomena involved such as fluid dynamics, fuel atomization, complex chemical reaction mechanism and heat transfer; numerical simulation of a gas turbine combustor is still difficult and an uncertain part of aero engine design process. Therefore validation of the combustion chamber simulation results by rig tests is still a very vital step for a good product design. It is always possible and very likely to find some crucial problems during the testing phase that were not predicted by the 3D CFD computations. As a result of rig tests, the combustor is modified to comply with the requirements. However, the number of rig tests has to be well planned due to high costs of testing.
Uploads
Papers by Sitki UsLu