论文标题:矢量喷管非定常流场计算与动态数学模型研究
Study on the Unsteady Flow Calculation & Transient Mathematical Model of Vectoring Nozzle
论文作者 马会民
论文导师 樊思齐,论文学位 博士,论文专业 航空宇航推进理论与工程
论文单位 西北工业大学,点击次数 264,论文页数 148页File Size5355k
2003-02-01论文网 http://www.lw23.com/lunwen_373382/ 推力矢量;数学模型;有限体积;非定常流动;B样条;函数逼近;矢通量分裂;人工粘性;发动机
Thrust Vectoring;Mathematical Model;Finite Volume Method;Unsteady Flow;B-Spline;Function Approximation;Flux Vector Splitting;Artificial viscosity;Aero-engine
推力矢量技术是现代战机具有敏捷性、过失速机动能力、良好的飞行品质的关键技术，其已成为第四代战斗机的必备技术和第三代战斗机改型的热门技术，得到了越来越多的重视。矢量喷管是实现推力矢量的关键部件，建立其数学模型是推力矢量技术尤其是开展带矢量喷管的发动机研究以及飞／推一体化综合控制研究的基础，具有十分重要的意义。 本文的研究就是针对矢量喷管数学模型的建立开展的。由于气流在喷管流动中具有复杂的三维非定常的特征，因此，建立其动态数学模型有着更为重要的工程及理论价值。本文通过CFD计算获得矢量喷管的性能参数，如流量系数、推力系数以及有效推力矢量角等与矢量喷管压比、面积比以及几何偏转角之间的关系数据，并利用函数逼近理论建立了矢量喷管的动态数学模型。本文的主要工作和贡献如下： 1．研究了Jamson提出了中心型有限体积法，并改进了其在边界上的处理，通过验证计算验证了本文发展的矢量喷管三维有粘流动计算程序的正确性。 2．利用该程序计算了某矢量喷管在不同的压比、面积比和几何偏转角下的200多种三维有粘流场，获得了矢量喷管的性能数据。 3．研究了影响矢量喷管性能的因素，研究了压比、面积比以及几何偏角对矢量喷管性能的影响。 4．研究了喷管流动分离现象和流动分离对喷管性能的影响，以及导致分离流动的宏观因素。 5．研究了矢量喷管动态偏转过程中气流的非定常流动和矢量喷管非定常流动计算方法，计算了矢量喷管在发动机某中间状态和加力状态下的非定常流场。 6．分析比较了定常流动计算结果和非定常流动计算结果，得出了定常流动计算结果和非定常计算结果的基本一致性，从而为工程通过定常计算或试验来研究矢量喷管以及建立其数学模型提供了依据。 7．研究了基于矢通量分裂的高分辨率迎风型有限体积法，重点研究了Sieger Warming、Vn Leer、Roe以及 AUSM”分裂格式。 8．研究了B样条参数拟合方法，提出了三元B样条参数拟合方法。以此为基础，建立了轴对称矢量喷管的三自由参数动态数学模型。
Thrust Vectoring is the key technique for the modem fighter with agility and post-stall maneuver ability and good flight quality. And now it is the necessary technique for the fourth generation fighter and hot technique for the performance improvement for the third generation fighter. Therefore, more and more attention is paid to this technique recently. Vectoring nozzle is the main component for generating vectoring thrust. And establishing the model of the thrust vectoring nozzle is the base for researching thrust vectoring technique and engine performance with vectoring nozzle, especially the integration of flight and propulsion system control (IFPSC). So thrust vector modeling is very important and meaningful.This paper is focused on how to establish mathematical model of vectoring nozzle on the basis of flow field calculation. In order to obtain transient mathematical model as vectoring deflection which is very important in engineering and valuable in theory, three-dimensional and unsteady flow fields must be researched. In our study computational fluid dynamic(CFD) is used to calculate the performance parameters such as the coefficients of mass rate and thrust and efficient deflected angle of the thrust vectoring nozzle. CFD is also used to get the data of performance parameters of the nozzle at different nozzle pressure ratio, different nozzle area ratio and different geometric defected angle. The theory of function approximation is used to establish the transient model of thrust vectoring with the data calculated. The main works and contribution of this paper are as follows:1.Central type finite volume method proposed by Jameson A. is investigated and the boundary condition of the method is improved. Compared with the testing data it is proved that the program for 3D viscosity steady flow in thrust vectoring nozzle developed is correct and reasonable.2. More than 200 different condition 3D viscosity steady flow fields in the thrust vectoring nozzle at different nozzle pressure ratio and different nozzle arearatio and different geometric defected angle is calculated by the program developed. And the related performance parameters are acquired by numerical simulation.3. The affecting factors of the performance parameters of the thrust vectoring nozzle are investigated. And the affect of nozzle pressure ratio, nozzle area ratio and geometric defected angle on the performance parameters is also investigated.4. The affect of flow separation on the nozzle is investigated and the macroscopical factor that leads to flow separation is also analyzed.5. The unsteady flow as thrust vectoring nozzle deflecting dynamically is investigated. The method of calculating the unsteady flow in the nozzle is given and the flow of the nozzle in the maximum power setting and maximum A/B power setting of the engine is calculated.6. The calculating results of steady flow and unsteady flow in the nozzle are compared. And it proves that both the results of the steady flow and the results of the unsteady .flow are uniform basically. This is very valuable because it is convenient to study the flow in the vectoring nozzle by steady hypothesis or steady test.7. The upwind finite volume method based on flux vector splitting is investigated, especially the splitting scheme of Steger-Warming, Van Leer, Roe and AUSM+.8.The method of the parameter fitting based B-spline is investigated. And the method of the parameter fitting which has three free variables is proposed. Based on this method the transient mathematical model of the thrust vectoring nozzle which has three free variables is established.
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