为了分析实际工况下高炉炉缸内流动与换热特性并对炭砖内侵蚀线进行预测,运用了计算流体力学(CFD)和二维快速反推算法的方法对炉底进行了数值仿真计算.研究结果表明,全尺寸炉底CFD模拟较好地展示了炉底流固区域的温度场和流场特征,测点温度与历史热电偶测温值小于5.2％,吻合效果较好;当炉体内存在气隙时,气隙左右分别形成极热区与极冷区,这与历史数据中热电偶温度骤变的现象吻合,且气隙厚度分别为10、20、30 mm时气隙左右温差相对于无气隙分别为原来的14.7、18.9、21.4倍;二维快反计算推演出了"象脚型"侵蚀的形状,最大侵蚀的位置在铁口下方1～3 m内,最小残余厚度与实际测值误差为13.5％,这与高炉实际侵蚀情况十分吻合.

为了更好地了解同轴离心喷嘴的工作特性,基于DDES模型研究了油气比分别为0.5、1、1.5下以煤油/氧气为推进剂的喷嘴的流体动力学特性与非预混燃烧特征.研究结果表明:由于旋流离心作用,在喷嘴出口轴心处和燃烧室顶部分别存在一个驻定涡和角涡,驻定涡径向分布在0.9 R～1.4 R,轴向尺寸在-1 R～14 R,随着燃料流量增大,驻定涡会向喷嘴内部推进,并且径向尺寸也会扩大.燃烧计算结果表明,随着燃料流量增大,推进剂的掺混拖曳区变长、掺混效果变好;而由于油气比的增加,燃烧室更加富油因此燃烧温度有所下降,同时火焰前锋向喷嘴内移.

针对因相变引起边界位置移动的二维Stefan反问题,提出了基于有限体积法(FVM)结合Powell法的求解算法.首先假设待定边界位置的初始猜测值,采用Stefan正问题的无量纲化焓法模型,通过FVM对Stefan正问题进行计算,得到各测温点处对应的温度估计值,计算测量值和估计值的方差,然后采用Powell算法,通过方向置换准则判断搜索正确边界问题的方向向量.通过数值仿真实验对提出的算法进行了验证,讨论了测量误差、测点位置、初值、测量时刻数目以及测点数量对反演精度的影响,并与共轭梯度法(CGM)的反演结果进行了对比.数值实验结果表明,该算法能够精确地识别各种不规则的边界形状,并且对误差和初值等影响因素不敏感,具有良好的稳定性.

为了掌握吸气式火箭发动机(SABRE)空气预冷器的流动换热特性,为设计相应类型的预冷器提供技术基础,针对SABRE预冷器最小周期性单元,以数值方法研究了管间距、管排数、空气入射角度及氦气/空气热容量比对预冷器流动换热的影响.研究结果表明:增大管排数和减小管间距,能够增大预冷器换热功率,降低空气出口温度,但会降低空气侧、氦气侧平均换热系数,减弱对流换热能力,增大空气侧总压损失.空气入射角度对空气侧、氦气侧换热影响微小,但对空气侧总压恢复系数影响显著.增大氦气/空气热容量比能够降低空气侧总压损失,增大空气侧、氦气侧平均换热系数,降低空气出口温度.

Taking a 300 MW unit boiler as the research object,the CFD software was used to simulate the gas-solid flow field after injecting activated carboninto the duct.The effects of different injector layout schemes on activated carbon particulates coverage ratio,residence time and the uniformity of particle concentration distribu-tion were investigated.The results indicate that the activated carbon particulates coverage ratio in the duct reaches 78.6%, and the residence time is longer than 2s when the scheme with 9 injectors is adopted.Moreover,the uni-formity of the particle concentration distribution is the best.The simulation results meet the requirement of high demercuration efficiency in the practical application of activated carbon injection.

To analyze the effect of vortex-reducers with bafflers,the influences of the rotational speed of cavity,the ratio of inlet pressure to outlet pressure and the number of bafflers is analyzed in the experiment.The study showed that firstly,under the working condition of a certain speed,with the increasing of the ratio of inlet pressure to outlet pressure,the mass flow rate going through cavity increased;secondly,with the rotational speed increasing,the mass flow rate decreased significantly in a linear trend basically;thirdly,compared with the simple cavity,because of the installation of the vortex-reducer with bafflers,the mass flow rate going through radially increased,with the change of the number of bafflers,the mass flow rate increased with the increase of the number of bafflers.

本文选用性能较好的设计点马赫6三楔压缩二维进气道为基准模型,精心设计了设计点马赫6性能与基准模型相当,采用等压力梯度曲面压缩的二维进气道.数值模拟分析了两进气道在非设计点和非均匀来流下的流场和性能.结果表明:非设计点,采用等压力梯度曲面压缩二维进气道,其流量系数、总压恢复和压比均高于三楔压缩二维进气道;在非均匀来流下,采用等压力梯度曲面压缩二维进气道比基准进气道性能要好,低马赫数下起动性能也较好,值得进一步研究.

The lifting-force characteristics of finger seal with flat lifting-pad were analyzed by numerical simulation,and the effects on pressure distribution of the lower surface of lifting-pads,lifting-force and lifting-force coefficient by the rotor speed,clearance of finger seal and pressure drop were investigated.The seal structure was consisted of two slice layers with 72 fingers per layer around its circumference,which were treated as the porous medium,and the three-dimensional (3-D)computation model included one lifting-pad and its nearby clearance.The research results indicate that the lifting-force is increased with the increase of pressure drop,and decreased with the increase of seal clearance,and increased slowly with the increase of rotor speed.The lifting-force coefficient is decreased with the increase of pressure drop,and decreased with the increase of seal clearance.Along with the increase of rotor speed,the lifting-force coefficient is de-creased,especially when the seal clearance is smaller.

本文采用加速的方法,数值模拟了侧压式进气道自起动现象.研究结果表明低马赫数不起动的侧压式进气道通过加速可以实现自起动,此时的侧压式进气道流场总体性能与直接起动的进气道流场总体性能存在差异,使得直接起动的进气道有较高的总压恢复.

The characteristics of air flow and heat transfer in finger seal structure was studied.The calculation model was built by the seal group area as porous media and heat source as frictional heat.The calculation results show that the maximum temperature of the seal area occurs in the contacting surface between finger-boots and rotor.The maximum temperature increases with the increased interference while differential pressure and speed;the maximum temperature decreased,while differ pressure increase in the interference and pressure.The results can be used to guide finger seal geometry design,contact-pair material selection and interference fit.

The leakage patterns and floating-lift of lifting-pads of finger seals are simulated in this essay,seal groups is treated as a porous region,the gap between seals and rotor is fixed in constant,and fluid-solid interaction is not considered.The research work indicates:seal gap is the primary factor affecting leakage;increasing layers of high pressure seals has influence on leakage;the rotor speeds hardly influences leakage;the floating-lift of lifting-pads increases when pressure differentials increases,while seal gap is invariable;the floating-lift of lifting-pads increases when seal gap decreases,while pressure differentials is unchanged;the higher the rotor speeds is,the smaller the floating-lift becomes.

This paper presents a numerical model to resolve the unidirectional non-linear inverse problem of heat conduction in transient state of buildings envelope.The temperature field is calculated with the control-volume-based numerical method and the heat conductivity is determined with the genetic algorithm.The result shows that the simulation method has high calculation accuracy and it can be applied to the identification of heat conductivity in different conditions.

本文研究了指式密封系统的泄漏特性及热变化特性,通过采用多孔介质模型进行数值模拟,得到了指式密封泄漏量与转速、结构参数等因素之间以及密封区域最高温度与安装过盈量、密封压差之间的影响关系,研究结果可为指式密封结构设计、接触副材料选择和安装方式提供参考。

The numerical model of one dimensional transient heat conduction inverse problem is established by a compound method of genetic algorithm and effective thermal conductivity to obtain the effective thermal conductivity.The model is applied in practical engineering cases and verified by the experimental data.The result shows that the model is of high accuracy and is very easy to be used for other thermo-physical parameter identification and other kinds of heat conduction inverse problems.

本文针对采用大庆3号航空煤油为冷却剂的冲压发动机燃烧室冷却面板进行了流动和传热的数值模拟研究,分析比较了在相同热流密度加热条件下,冷却面板中不同冷却剂流量、不同通道尺寸对再生冷却效果的影响。并对带有分、汇流室的冷却面板冷却效果的影响进行了研究。其模拟结果可为高超声速飞行条件下的冲压发动机再生冷却热防护设计提供参考。