Mechanism of Unsteady Aerodynamic Heating With a Sudden Change in Surface Temperature
-
摘要: 研究了高超声速平板边界层因壁温时变引发的非定常气动热环境特征及机理.通过近似解析和数值模拟两种手段,得到了壁面热流随时间变化的完整过程.解析手段求解非定常可压缩边界层方程,将非定常响应表达成稳态解加上摄动级数的形式,在初始和最终稳态邻域分别求解,在适当的位置进行拼接,从而得到整个时间域上的解.在满足解析解假设的区域,数值结果与解析结果吻合较好,证明了所使用方法的可靠性.结果表明,非定常响应有两点显著特征:在壁温突然增加后短时间内,壁面热流方向改变,热边界层剖面在壁面附近出现了另一个拐点,这种新的剖面形状是典型的非定常特征.但是,高超声速情况下此种非定常响应存在的时间却很短,在考虑长时间气动加热的情况下,若只存在壁面温度时变的诱因,可以忽略流动中的非定常过程,当作准定常情况来处理.Abstract: The chazacteiistics and mechanism of the unsteady aerodynamic heating of a transient hypersonic borurdary layer caused by sudden change in surface temperature was studied, the complete time history of wall heat flax was presented by both analytical and numerical approaches. With analytical methods, the unsteady compressible boundary layer equation was solved. In the neighborhoods of initial and final steady state, the transient response can be expressed by a steady-state solution plus a perturbation series, respectively.By patching these two solutions, the complete solution in the elrtire time domain wag achieved. In the region where the assumptions of analytical approach are satisfied, the numerical and analytical results were matched well, proving the reliability of the methods. The result showed two distinct features of the unsteady response. In the short period just after a sudden increase in the wall temperature, the direction of the wall heat flux reverted, a new inflexion near the wall arose in the profile of the thermal boundary layer, which is a typical unsteady characteristic. However, these unsteady responses only exist in a very short period in hypersonic flows, which means that, in a long-term aerodynamic heating process concidering only rinsready surface temperature, the unsteady characteristics of the flow can be ignored and the traditional quasi-steady aerodynamic heating prediction methods are still valid.
-
[1] Kolodziej P. Aerothermal performance constraints for hypervelocity small radius unswept leading edges and nosetips, NASA-TM-11204[R]. NASA, 1997. [2] Kontinos D. A coupled fluid-, structural-heating analysis method for metallic thermal protection panels, AIAA-1996-1808[R]. AIAA, 1996. [3] Quinn R D, Gong L. A method for calculating transient surface temperatures and surface heating rates for high-speed aircraft, NASA-TP-2000-209034[R]. NASA, 2000. [4] Riley N. Unsteady heat transfer for flow over a flat plate[J].J Fluid Mech,1963,17(1): 97-104. doi: 10.1017/S0022112063001130 [5] Chao B T, Cheema L S. Unsteady heat transfer in laminar boundary layer over a flat plate[J]. Internat J Heat Mass Transfer,1968,11(9):1311-1324. doi: 10.1016/0017-9310(68)90177-4 [6] Rebay M, Padet J. Laminar boundary-layer flow over a semi-infinite plate impulsively heated or cooled[J].Eur Phys J AP,1999,7(3):263-269. doi: 10.1051/epjap:1999104 [7] Polidori G, Padet J. Transient laminar forced convection with arbitrary variation in the wall heat flux[J].Heat and Mass Transfer,2002,38(4/5):301-307. doi: 10.1007/s002310100273 [8] Cheng W T, Lin H T. Non-similarity solution and correlation of transient heat transfer in laminar boundary layer flow over a wedge[J].International Journal of Engineering Science,2002,40(5): 531-548. doi: 10.1016/S0020-7225(01)00081-7 [9] Rebay M, Padet J. Transient laminar forced convection from a wedge flow[J].Internat Comm Heat Mass Transfer,2004,31(4): 537-548. doi: 10.1016/S0735-1933(04)00034-X [10] Padet J. Transient convective heat transfer[J].J Braz Soc Mech Sci & Eng,2005,27(1): 74-96. [11] Harris S D, Ingham D B, Pop I.Transient boundary-layer heat transfer from a flat plate subjected to a sudden change in heat flux[J].Eur J Mech B-Fluids,2001,20(2):187-204. doi: 10.1016/S0997-7546(00)01112-2 [12] Kumari M, Nath G. Transient laminar compressible boundary layers over a permeable circular cone near a plane of symmetry[J].Internat J Heat Mass Transfer,2005,48(13):2771-2778. doi: 10.1016/j.ijheatmasstransfer.2005.01.031 [13] Van Dyke M. Computer extension of perturbation series in fluid mechanics[J].SIAM Journal on Applied Mathematics,1975,28(3):720-734. doi: 10.1137/0128060 [14] Bijl H, Carpenter M H, Vasta V N,et al.Implicit time integration schemes for the unsteady compressible Navier-Stokes equations: laminar flow[J].Journal of Computational Physics,2002,179(1):313-329. doi: 10.1006/jcph.2002.7059 [15] 张涵信. 求解气动方程的高阶精度格式及其相关问题[A].见:全国计算流体力学会议组委会、北京空气动力研究所 编.计算流体力学研究进展: 第七届全国计算流体力学会议论文集[C]. 1994, 1-8. [16] 周伟江, 姜贵庆. 迎风TVD格式在粘性流计算中的应用研究与改进[J].计算物理, 1999,16(4):401-408. [17] Liou M S. A sequel to AUSM, part Ⅱ: AUSM+-up for all speeds[J].Journal of Computational Physics,2006,214(1): 137-170. doi: 10.1016/j.jcp.2005.09.020
点击查看大图
计量
- 文章访问数: 3288
- HTML全文浏览量: 70
- PDF下载量: 800
- 被引次数: 0