飞行器上层大气层空气动力特性探讨

针对近地轨道飞行器所面临的上层大气层(100～300 km)空气动力学问题,对几类典型航天器构型的上层大气层气动力特性进行了分析,给出了典型气动布局在该空域的气动力基本规律,取得了对上层大气层气动力关键影响因素的初步认识.在上层大气层,飞行器的绕流属于自由分子流状态.研究发现,气体分子与不同材质物面的相互作用反映出截然...     

三电极共面介质阻挡放电的放电特性及诱导气流实验研究

等离子体流动控制激励器由于其响应速度快、激励频带宽、能量损耗低、可靠性强的优势,在航空航天领域的主动流动控制等方面得到了广泛应用.文章提出了一种新型的等离子体气动激励器——三电极共面介质阻挡放电激励器,研究了该激励器电极结构对放电特性和诱导气流速度的影响,并与传统共面介质阻挡放电和沿面介质阻挡放电激励器进行了比较.结果表明:（1）随着激励电压的提高,高压电极和地电极之间先出现了丝状放电并逐渐延伸到第三电极;（2）随着第三电极与高压电极之间的距离增大,诱导气流速率从2.4 m/s下降到0 m/s,而第三电极宽度的变动对诱导气流速度影响可忽略不计;（3）相同外部条件下,该激励器诱导的气流速度小于沿面介质阻挡放电激励器,但高于共面介质阻挡放电激励器.      

Phase Transitions Induced by Top-Priority of Randomization

We study the characteristics of phase transition to take the top-priority of randomization in the rules of NaSch model (i.e.noise-first model) into account via computing the relaxation time and the order parameter.The scaling exponents of the relaxation time and the scaling relation of order parameter,respectively,axe obtained.     

Global Stability to Steady Supersonic Rayleigh Flows in One-Dimensional Duct∗

Heat exchange plays an important role in hydrodynamical systems, which is an interesting topic in theory and application. In this paper, the authors consider the global stability of steady supersonic Rayleigh flows for the one-dimensional compressible Euler equations with heat exchange, under the small perturbations of initial and boundary conditions in a finite rectilinear duct.     

凹槽叶顶冷气射流对涡轮叶尖泄漏流动的影响

涡轮叶尖泄漏流动对涡轮通道内流动损失有着显著影响,叶顶冷气射流对控制叶尖泄漏流动和改善涡轮叶尖气热性能有重要意义.本文利用数值模拟方法,研究了叶顶冷气喷射位置和喷射流量对高压涡轮凹槽叶顶间隙泄漏流动控制的影响.文中重点分析了泄漏流动结构及涡轮气动效率的变化,探讨了冷气对刮削涡这一间隙内主控流动结构演化的影响.研究表明,...     

流动注射化学发光抑制法测定尼群地平

基于尼群地平在碱性条件下对铁氰化钾鲁米诺化学发光体系有较强的抑制作用,联用流动注射技术建立了测定尼群地平的新方法.本法的线形范围为0.1～100.0 μg/mL,检出限0.02 μg/mL ,此法用于尼群地平片剂含量测量和药典法对照结果满意.     

气泡流纳米流体的太阳能蒸腾特性研究

太阳能驱动水蒸发是光热利用的重要途径,光-热-蒸汽转化可通过纳米流体吸收太阳能生成蒸汽.本文提出光散射气泡耦合光吸收纳米颗粒强化光能转换的新思路,在太阳能纳米流体蒸发体系中引入气泡群,这些动态气泡作为光能散射与传递中心,延长了入射光路径并倍增了光通量;同时提供了极大的气液界面完成气泡吸湿,以及破水而出的炸裂扰动加速蒸汽...     

CHAOTIC MOTIONS AND LIMIT CYCLE FLUTTER OF TWO-DIMENSIONAL WING IN SUPERSONIC FLOW

Based on the piston theory of supersonic flow and the energy method, the flutter motion equations of a two-dimensional wing with cubic stiffness in the pitching direction are established. The aeroelastic system contains both structural and aerodynamic nonlinearities. Hopf bifurcation theory is used to analyze the flutter speed of the system. The effects of system parameters on the flutter speed are studied. The 4th order Runge-Kutta method is used to calculate the stable limit cycle responses and chaotic motions of the aeroelastic system. Results show that the number and the stability of equilibrium points of the system vary with the increase of flow speed. Besides the simple limit cycle response of period 1, there are also period-doubling responses and chaotic motions in the flutter system. The route leading to chaos in the aeroelastic model used here is the period-doubling bifurcation. The chaotic motions in the system occur only when the flow speed is higher than the linear divergent speed and the initial condition is very small. Moreover, the flow speed regions in which the system behaves chaos axe very narrow.     

长光程比色池-流动注射测定水中微量挥发酚

利用长光程比色池 流动注射系统快速测定水样中的微量挥发酚.该方法的检出限为0.232 μg·L^-1,相对标准偏差小于0.553%,相对误差小于0.185%,样品加标回收率在91.0%~99.8%,且标准曲线具有良好线性（r =0.999 9）.与传统国标方法（《水质挥发酚的测定4-氨基安替比林分光光度法》,HJ503-2009）相比,样品浓度测定偏差为2.59%~8.25%,在分析速率上,传统的国标方法约为5个·h^-1,而该方法分析速率达24个·h^-1,能满足大批量样品连续准确测定的要求,特别适合事故性的应急监测.     

管内插新型自旋转子的流阻及抑垢特性

提出了一种新型自旋转子,并通过数值及实验方法研究了其流动阻力及抑垢特性.实验结果表明,在流速为0.76 m/s时转子转速仍可达100r/min,内插该转子的流动阻力比光管增加2倍左右,正反旋向转子组(每组4个转子)相问布置可防止沿流向转子转速递减,使转子转速基本恒定.数值分析表明,通过减小转子的旋转轴套外径并加前端导流...