This paper describes the design of four types of swirlers which produce different velocity profiles.The data of confined turbulent swirling flowfields are obtained from experiments and numerical calculations.The actua...This paper describes the design of four types of swirlers which produce different velocity profiles.The data of confined turbulent swirling flowfields are obtained from experiments and numerical calculations.The actual flow profiles at the swirler exit basically agree with the desired profiles. Two kinds of turbulence models,k-ε model and DDC model,are used to predict the flowfields produced by swirl augmentors.The results show that the DDC model,based on interaction between dissipation and dispersion,can overcome the defect of k-ε model and predict the swirling flowfields more accurately than k-ε model.展开更多
A novel variable geometry flame-holder(VGF) based on V-gutter was presented.The structural characteristics of the flame holder were introduced.Experimental study on drag characteristics of the VGF on un-burning and bu...A novel variable geometry flame-holder(VGF) based on V-gutter was presented.The structural characteristics of the flame holder were introduced.Experimental study on drag characteristics of the VGF on un-burning and burning states was conducted in a rectangular combustion test rig.The influence of the change of gutter trailing edge width w on pressure recovery in different operating conditions was analyzed emphatically.Furthermore,drag characteristics in different trailing edge width variation modes were discussed.Results show that:(1) Narrowing w can observably raise the total pressure recovery σ but the highest σ is not obtained at minimum w.(2) The relationship of drag coefficient ψ and w in the un-burning conditions can be well expressed in a form of exponential equation(w/d>0.4).(3) Drag characteristics are not sensitive to the variation modes and speeds of w.(4) In the burning condition,σ decreases with the increasing of w basically and the course can be divided into three stages.The results and experimental data presented in this paper would enhance the phenomenological understanding of this type of VGF,and would contribute to the next experimental study and numerical calculus of this novel VGF.展开更多
文摘This paper describes the design of four types of swirlers which produce different velocity profiles.The data of confined turbulent swirling flowfields are obtained from experiments and numerical calculations.The actual flow profiles at the swirler exit basically agree with the desired profiles. Two kinds of turbulence models,k-ε model and DDC model,are used to predict the flowfields produced by swirl augmentors.The results show that the DDC model,based on interaction between dissipation and dispersion,can overcome the defect of k-ε model and predict the swirling flowfields more accurately than k-ε model.
文摘A novel variable geometry flame-holder(VGF) based on V-gutter was presented.The structural characteristics of the flame holder were introduced.Experimental study on drag characteristics of the VGF on un-burning and burning states was conducted in a rectangular combustion test rig.The influence of the change of gutter trailing edge width w on pressure recovery in different operating conditions was analyzed emphatically.Furthermore,drag characteristics in different trailing edge width variation modes were discussed.Results show that:(1) Narrowing w can observably raise the total pressure recovery σ but the highest σ is not obtained at minimum w.(2) The relationship of drag coefficient ψ and w in the un-burning conditions can be well expressed in a form of exponential equation(w/d>0.4).(3) Drag characteristics are not sensitive to the variation modes and speeds of w.(4) In the burning condition,σ decreases with the increasing of w basically and the course can be divided into three stages.The results and experimental data presented in this paper would enhance the phenomenological understanding of this type of VGF,and would contribute to the next experimental study and numerical calculus of this novel VGF.
