Development Of Numerical Method And Investigation On Performances Of Supersonic Ejectors

High energy chemical laser weapon(HECL) is a kind of new concept high-techweapons, with some extraordinary advantage in comparison with other weapons. Pres-sure recovery system(PRS) is one of the important components of high energy chemicallaser weapons. Studies of High performance pressure recovery system are of great signif-icance for the integrative design of laser weapon system.There are three kinds of pressurerecovery systems used by high energy chemical laser weapon: vacuum machine and vac-uum tank PRS, ejector-type PRS, cryoadsorption pump PRS. The ejector-type PRS hasalready been successfully applied to high energy chemical laser weapon based on vari-ous battle carriers. It is re-usable with simple structure and needed by long-running highpower chemical laser weapon.The size of HECL weapon system depends on that of its battle carriersseverely.Particularly when working under high environment pressure,the helicopter-borneor mobile HECL weapon system needs to install a high efficiency, high credibility, smallsize PRS.It is very difficult to design the PRS like this. Supersonic ejector is a key com-ponent of the ejector-type PRS, and its efficiency and size decide whether the PRS willbe designed successfully or not.For long time, the design of supersonic ejectors relies ontheoretic computations and experiments.With the development of computer technology,CFD has been popular in the design and the performance research of supersonic ejectors.CFD can complete the analysis of ?ow parameters in relative short time, supply the detailcharacteristics of the ?ow field, and remedy the deficiency of theoretic computations andexperiments.This thesis focuses on the miniaturization of supersonic ejectors, develops numeri-cal simulation method of supersonic ejectors and builds a numerical software platform.Investigations on the in?uence of some important factors are performed for the miniatur-ization of supersonic ejectors. The performances of supersonic ejectors are emphaticallystudied when its ?ow and geometric parameters are changed. The ?ow structures andcharacteristics in supersonic ejectors with multiple nozzles or notched nozzle are alsoresearched.This thesis consists of seven chapters as follows:The first chapter introduces the background of supersonic ejectors research. Thedevelopment and current situation of supersonic ejectors and its related technologies arereviewed. The present research work of this thesis is also described brie?y in this chapter.The second chapter presents the details of numerical method used in this thesis,mainly including governing equations, turbulence models,numerical schemes,implicit so-lution techniques and treatment of boundary conditions etc.; Eight typical ?ows are sim- ulated to validate the credibility and accuracy of numerical method and software.The third chapter mainly introduces parallel computing method, including parallelcomputer, parallel programming, load balance method and parallel communication mech-anism, parallel implicit method.Two simple ?ows are simulated to validate the credibilityand accuracy of parallel computing method and software.The fourth chapter describes the basic concept and the one-dimensional theoriesmodel of supersonic ejectors, and studies the numerical method applied to supersonicejectors.Specific attention is paid to the use of turbulence models and compressibility cor-rections for simulating supersonic ejector ?ows. A comparison between computationaland experimental results is made in order to choose a suitable turbulence model withcompressibility correction.In this chapter,the performances of supersonic ejectors are alsostudied when its ?ow and geometric parameters are changed. Flow field structures and?ow phenomenon in supersonic ejectors are analyzed, and some important factors thatin?uence on the miniaturization of supersonic ejectors are found out.The fifth chapter analyzes ?ow field structures and ?ow phenomenon in supersonicejectors with multiple nozzles, and studies the performances of supersonic ejectors whenthe number of nozzles is changed. The performances of supersonic ejectors with one noz-zle,supersonic ejectors with multiple nozzles and multi-tube supersonic ejectors systemare compared. Based on these research works, the mechanism of supersonic ejectors withmultiple nozzles and its contribution to miniaturization are understood.The sixth chapter analyzes ?ow structures and ?ow phenomenon in supersonic ejec-tors with the notched nozzle, and studies the performances of supersonic ejectors whennotch depth and width is changed. These research works are done to understand theenhanced mixing performance of the notched nozzle. This chapter only presents basicresearch works of the notched nozzle that is applied to miniaturization of supersonicejectors.Finally the seventh chapter gives a summary of this work, its achievements andconclusions.Some recommendations for future work are also included in this chapter.