高超声速飞行器异型气膜孔无喷流热增量研究

目的获取高超声速飞行器气膜孔不喷流时的热负荷增量。方法通过计算流体力学(CFD)方法针对典型高超声速飞行器50km、飞行马赫数为15条件下的无开孔、有开孔气膜冷、有开孔无喷流3种工况开展壁面热流分布研究。结果无开孔的最大热流分布在头部滞止点附近,约为2.2 MW/m~2,有气膜冷却的工况热流最高值在侧面气膜孔没有覆盖到的部位,约为1.4 MW/m~2,有异型孔但是不喷流的工况,热流密度最大值主要分布在开孔附近,最大值大于3.3 MW/m~2。结论对于在高超声速飞行器表面开孔采用气膜冷却方式冷却时,如果由于某种原因气膜孔不喷流,那么在孔的附近乃至整个滞止区域附近的热流负荷将会大幅度升高。     

高超声速飞行器多物理场耦合及热防护技术研究综述

主要对国内外近年来在解决流热固多场耦合以及热防护问题方面所做的研究和所采用的分析方法进行论述和总结,对各类研究方法的优缺点和适用范围进行分析和评价,为从事多场耦合问题及热防护技术的研究人员提供一定理论支持。     

变温环境下结构高频瞬态能量响应预示

目的解决变温环境下结构的高频瞬态能量响应预示问题。方法基于统计能量分析方法,通过考虑时变参数对结构能量的影响和热效应引起的材料力学性能变化和热应力对统计能量分析参数的影响,提出了一种变温环境下结构高频瞬态能量响应预示方法。以双振子模型为例,通过与Newmark-beta法的对比验证数值方法的准确性。结果该能够较好地捕捉结构高频能量响应的周期性变化规律,其峰值时间和峰值能量与精确数值解基本吻合。以L型折板系统为例,研究了20～300℃变温环境下结构的瞬态能量响应变化规律,子系统1和子系统2之间的能量交换远小于两子系统中因阻尼引起的能量消耗,子系统2瞬态能量响应的峰值时间为4.3ms、峰值能量为0.09J。结论该方法具有较高的计算精度和计算效率,能够较好地适用于结构高频瞬态能量响应预示。     

HTPB推进剂自然环境加速老化试验方法研究

目的建立一种HTPB推进剂自然环境加速老化试验方法。方法研发一套户外热循环自然环境加速试验装置,可以模拟和强化太阳辐射对HTPB推进剂的热效应和昼夜温差冲击效应,并保持环境温度日夜温差循环、季节温差循环的特点。利用该装置,在海南万宁试验站户外暴露场开展HTPB推进剂自然环境加速老化试验及其验证试验,设定试验最高温度不超过70℃,并同期开展HTPB推进剂库房贮存试验。从模拟性、加速性、重现性评价自然环境加速老化试验方法的可信度。结果随着老化时间的延长,最大拉伸强度保留率波动下降,可作为HTPB推进剂敏感力学参数。与该推进剂在库房贮存不同时间的最大拉伸强度保留率相比,在置信度为99%,两种试验方法的Spearman秩相关系数为0.93时,自然环境加速老化试验方法对于库房贮存试验方法的加速倍率为5倍,自然环境加速老化试验重现性良好。结论建立了一种适用于HTPB推进剂的简单易行、模拟性强、加速倍率高的自然环境加速老化试验方法,能再现HTPB推进剂在实际库房贮存的力学性能变化规律。     

Transport and Diffusion of Ozone in the Nocturnal and Morning Planetary Boundary Layer of the Phoenix Valley

The evolution of ozone (O ₃) in the nocturnal and morning-transitional planetary boundary layer (PBL) of the Phoenix valley was measured as a part of the `Phoenix Sunrise Experiment 2001' of the U.S. Department of Energy conducted in June 2001. The goal of the field program was to study the transport, distribution and storage of ozone and its precursors in the urban boundary layer over a diurnal cycle. The ground level O <sub>3</sub> as well as mean meteorological variables and turbulence were measured over the entire period, and vertical profiling (using a tethered balloon) was made during the morning transition period. Approximately half of the observational days showed the usual diurnal cycle of high O <sub>3</sub> during the day and low O <sub>3</sub> at night, with nitrogen oxides (NO <sub>x</sub> = NO <sub>2</sub> + NO) showing an out of phase relationship with O <sub>3</sub>. The rest of the days were signified by an anomalous increase of O <sub>3</sub> in the late evening ( 2200 LST), concomitant with a sudden drop of temperature, an enhancement of wind speed and Reynolds stresses, a positive heat flux and a change of wind direction. NO <sub>x</sub> measurements indicated the simultaneous arrival of an `aged' air mass, which was corroborated by the wind predictions of a mesoscale numerical model. In all, the results indicate that the recirculation of O ₃ rich air masses is responsible for the said high-O ₃ events. Such air masses are produced during the transport of O ₃ precursors by the upslope flow toward mountainous suburbs during the day, and they return back to the city at night via downslope winds (i.e. mountain breeze). The corresponding flow patterns, and hence the high-O ₃ events, are determined by background meteorological conditions. The vertical profiling of O ₃ and flow variables during the morning transition points to a myriad of transport, mixing and chemical processes that determine the fate of tropospheric O ₃. How well such processes are incorporated and resolved in predictive O ₃ models should determine the accuracy of their predictions.     

城市地表覆盖材料的热反应

本文对几种地表覆盖材料在具有“火炉”之称的山城重庆典型夏季气候条件下的热反应进行了实测研究，以期为生态城市设计提供有益的参考数据。     

A Numerical Study of the Dynamics of the Riverine Thermal Bar in a Deep Lake

A numerical model based on a Finite Volume formulation of the Navier–Stokes equations is used to simulate a range of scenarios leading to a thermal bar formed by a river inflow to an idealised deep lake. The results presented here show that small riverine salinity increases have a profound effect on the dynamics of the thermal bar, suppressing horizontal propagation of the plume and raising the possibility of a thermal bar which is capable of sinking to great depths. This finding is particularly relevant to Lake Baikal in Siberia, where the vigorous deep-water renewal is still not fully understood. An analysis of the buoyancy forces governing the depth of penetration of the thermal bar plume shows that realistic salinity gradients are an important factor in determining the circulation of Baikal waters. Observations of the saline curtailment of the thermal bar's horizontal propagation also reveal a potential for reduced productivity in the ecosystem of any temperate river delta during the Spring renewal period.     

A Model of the Thermal Bar in the Rotating Frame Including Vertically Non-Uniform Heating

Small bottom slope, inviscid solutions are found for a model of the temperature and circulation structure of the thermal bar system. This model includes Coriolis effects, a vertically non-uniform heat input and is axisymmetric. The model also includes general topography and time dependent heating. These solutions include inertial oscillations that have a significant effect on the circulation, especially for the case when the heating is instantaneously applied.     

城市热岛的遥感研究

随着城市建设事业的发展以及人为热释放的增多，城市热岛效应呈现不断增强趋势。将遥感技术与常规城市热岛监测方法结合起来，才能深入进行城市热岛监测研究。通过回归分析建立一定模式，将遥感手段获得的辐射温度（亮温）转换为常规方法所用的空气温度（气温）是城市热岛遥感研究的主要思路和方法。以武汉市城市热岛分析为例，本文探讨了城市覆盖层与边界层的热岛形成因子，城市热岛效应直接或间接对城市其他气候要素产生多种影响，并对城市居民生产生活和健康带来有利和不利的因素。     

应用热分析法研究多环芳烃的催化深度氧化

应用热分析技术对多环芳烃化合物催化氧化反应过程中催化剂初活性进行评价。比较了两种样品前处理方法,测定结果基本一致。分别测定了六种不同组分的过渡金属氧化物催化剂的初活性。考察了多环芳烃结构对其催化氧化难易的关系。实验结果表明,热分析可作为评价高沸点有机化合物深度氧化催化活性的可靠方法,且简便易行。