| Design of gain generator is one of the most important techniques in study of continuous wave (CW) DF/HF CL (fluoride deuterium/fluoride hydrogen chemical lasers). In this paper,a three-dimensional(3D) program for the three-dimensional reactive flow fields of complicated geometric nozzle,which governed by the compressible full Navier-Stokes equations with realizable k - s turbulent model,has been upbuilt by using full implicit couple arithmetic and FVM (finite volume method) based on understanding and assimilation of a two-dimensional program group of CR(Chamber-Radon). The new program fulfils the urgent need of numerical tools for simulating three-dimensional reactive flow-fields of HYLTE (HYpersonic Low Temperature) and other latest nozzles,for which CR is out of action in simulation,and can be applied to simulate other chemical laser system,such as chemical oxygen iodine laser (COIL),overtone fluoride hydrogen,all-gas iodine laser,and so on. Furthermore,some related topics about nozzles design and engineering also have been discussed.As an example of 3D program with high quality mesh,proper boundary&initial conditions and ingenious simulation strategy,numerical analysis of flow-fields in HYLTE nozzle and cavity of DFCL running on fuel system of (NF3+H2+He)/D2 and experimental stagnation parameters,has been performed using vibration-state-unbalance & rotation-state-balance model,and a detailed kinetic model including 111 one-way primary reactions expressing by finite rate equations between thirteen species. The coefficients of transportation used in the analysis are calculated by employing the formulas of molecular kinetics. Characteristics of flow-field,total pressure loss/reduction,species distribution;parameters of reactive domain and mixing mechanism of reactant streams have been investigated. SSG(Small signal gain) coefficient,utilization of F atom and heat release in reaction have been computed. The result is directive to optimize parameters and understand the concept of HYLTE nozzles,also is one of few references including the report of DSMC(Direction Simulation Monte Carlo) program belonging to&used by TRW company of America.Using the 3D program,HYTEN (HYpersonic,Throat-Ejecting) Nozzle,which isone of the three latest nozzles first designed in this paper,has been simulated. The discussing emphases are structural and stagnation parameters of ejecting nozzles and secondary fuel nozzles. Characteristic of flow-fields at throat of oxidant nozzle,way to separate the equivalent three-nozzle,ejecting effect of different parameters and engineering situations have been demonstrated. Effect of distance between secondary flows,the jet angle and the total pressure on the status of flow-fields,has been studied. Reactive flow in a HYTEN nozzle with dimension that was primarily determined has been simulated. All these results have provided physical vision for engineering design,optimization and concept verification of HYTEN nozzle.To validate the outcome of the 3D program,numerical results of programs including 2D CR corresponding different chemical reaction kinetic models have been compared and analyzed,which is beneficial to determine the kinetics model and results analysis. Comparing numerical results with experimental results on the STL (Single Throat Laser) is another validated example. The results of experiment reveal the credibility of numerical results.Freezing efficiency of F atom in oxidant nozzle of different contour walls,mixing mechanism of reactants in 2SLOT (two-dimensional,plane symmetry nozzle) nozzle and comparison of flow-fields&SSG between 2SLOT and 3SLOT (3-Slit Jet plane Nozzle) have been studied by using 2D CR program. The conclusion is significant to understand the requirement of reactant flows and to generate ideas for nozzles design. The dependence of CW DF/HF CL performance on the flow-field parameters in F&D2/H2 reacting zone,which act as criterion to nozzles design,has been inversely educed on the light of original formula of gain coefficient,output power and laser eff...
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