摘要：Convection heat transfer coefficient and air pressure drop in sinter layer are important factors for the design of sinter cooling craft. Due to the lack of necessary data, the two parameters are studied by experimental method. The experimental results show that heat conduction of sinter impacts the measurement of convection heat transfer coefficient. Convection heat transfer increases with the increase of air volumetric flow rate. Sinter layer without small particles(sample I) gives higher convection heat transfer coefficient than that with small particles(sample II). Under the considered conditions, volumetric convection heat transfer coefficient is in the range of 400-1800 W/(m3·°C). Air pressure drop in sinter layer increases with the increase of normal superficial velocity, as well as with the rise of air temperature. Additionally, air pressure drop also depends on sinter particle size distribution. In considered experimental conditions, pressure drop in sinter sample II is 2-3 times that in sinter sample I, which resulted from 17% small scale particles in sinter sample II.

摘要：To aim at design requirements of high lift-to-drag ratio as well as high volumetric efficiency of next generation hypersonic airplanes,a body-wing-blending configuration with double flanking air inlets layout is ***,a novel forebody design methodology which by rotating and assembling two waverider-based surfaces is firstly introduced in this *** typical configurations are designed and their aerodynamic performances are evaluated by computational fluid *** results for forebodies analysis show that large volumetric efficiency,high lift-to-drag ratio,and uniformly distributed flowfield at the inlet cross section can be assured ***,results of numerical simulation of four integrated configurations with various leading edge shapes,including three power-law curves and a cosine curve clearly show the advantage of high lift-to-drag ***,the high pressure generated by the side wall of the airframe can be partly captured by the reasonably designed wings in the condition of small flight attack *** the order of lift-to-drag ratio of four configurations at 0 degree flight attack angle is completely different from the condition of 4-degree flight attack *** result demonstrates that the curve shape of the leading edge is very important for the lift-to-drag ratio of the aircraft,and it should be further optimized under the cruising attack angle in future work.

摘要：The optimization of 2D expansion lines and key parameters of three-dimensional configurations was carried out under simulated conditions of Mach 6.5 and a flight altitude of 25 km for an integrated configuration of the afterbody/nozzle of a hypersonic ***,the cubic B-spline method was applied to parameterize the expansion lines of the upper expansion *** optimization procedure was established based on computational fluid dynamics and the sequential quadratic programming *** local mesh reconstruction technique was applied to improve computational efficiency.A three-dimensional integrated configuration afterbody/nozzle was designed based on the two-dimensional optimized expansion *** influence rules incorporated certain key design parameters affecting the lift and thrust performance of the configuration,such as the ratio of the lengths of the lower expansion ramp to the afterbody (l/L),the dip angle of the lower expansion ramp ω,and the ratio of exit height to the length of afterbody (H/L).Under these conditions,we found that the integrated configuration has optimal performance when l/L=1/6,H/L=0.35 and =10°.We also showed that the presence of a side-board promotes lift and thrust performance,and effectively prevents the leakage of high pressure gas.

摘要：对于以吸气式推进为动力的高超声速飞行器来说,多重激波/激波干扰将在进气道唇口诱导极端气动载荷,对飞行器热防护系统的设计提出更高的要求.本研究对由两道入射斜激波与弓形激波干扰产生的多重激波干扰流场下的壁面气动载荷进行了详细的理论和数值研究.伴随射流流场和双射流流场是多重激波干扰流场的两种主要模式,分别对应两道入射斜激波诱导的超声速射流由滑移线或亚声速区分隔的情况.理论分析结果表明,在相同边界条件下,双射流流场诱导的壁面峰值压力近乎伴随射流流场的两倍.为了验证理论分析结果,开展了无黏瞬态数值计算.数值计算结果验证了理论分析给出的不同干扰模式下壁面峰值压力之间的大小关系.对比理论分析和数值计算结果发现,理论预测的壁面峰值压力略低于数值计算的值.同时,本文数值验证了由两个IV型超声速射流组成的双射流流场的存在.

摘要：When the variable geometry hypersonic inlet is sealed with ceramic wafers,the cavity flows inside the sealing chamber can be affected by the boundary layer near the side *** study the influence of the boundary layer thickness near the side wall on the flow and leakage characteristics in sealing chamber,the numerical calculation of the cavity flow in the sealing chamber under different inflow boundary layer thicknesses is carried *** results show that three-dimensional cavity flow structures are close to being asymmetric,and the entrance pressure of the leakage path can also be affected by asymmetry;with the increase of the thickness of the boundary layer,the pressure at the cavity floor and the seal entrance ***,the existing leakage prediction model is modified according to the distribution rule of the cavity floor and the flow properties in the leakage path.

摘要：A flow control method based on an active jet is developed to restart hypersonic inlets. The dynamic restarting process is numerically reproduced by unsteady Reynolds averaged Navier-Stokes(RANS) modeling to verify the effectiveness and reveal the influence of jet conditions. The active jet improves the inlet unstart status by drawing the high-pressure separation bubble from the internal compression duct and performing a full expansion to alleviate the adverse pressure gradient. Moreover, the favorable pressure gradient in the inlet caused by jet expansion allows for a successful restart after turning off the jet. The influence of the jet momentum ratio is then analyzed to guide the design of the active jet control method and choose the proper momentum ratios. A low jet momentum does not eliminate the high-pressure separation bubble, whereas an excessive jet momentum causes severe momentum loss due to the induced shock. The general rule in restarting the inlet using an active jet is to allow a full jet expansion downstream of the jet slot while avoiding excessive momentum loss upstream and preventing the thick low-speed layer.