HTR—10螺旋管式直流蒸法发生器的动态数学模型

为满足10MW高温气冷堆（HTR－10）控制系统分析设计的需要,分析了HTR－10螺旋管式直流蒸汽发生器内两相流动和传热的实际过程,根据建模的要求和可能获得的结构数据,选择四方程漂移模型来描述螺旋管内两相流现象;经过仿真试算与实验总结,确定了模型中关键的结构关系式和传热工 的判断逻辑,为此为基础,建立了可反映直流蒸汽发生器在正常功能运行范围内动态特性的动态数学模型,通过对典型工况的动静态仿真计算和研究分析,表明所得的结果与理论性分析和实验吻合,从而证明了该模型的正确性,所建立的动态数学模型还可以用于其他螺旋管式直流蒸汽发生器的研究设计。     

螺旋管蒸发器两相流动稳定性实验双向流量测量研究

10MW高温气冷堆螺旋管蒸汽发生器两相流体流动稳定性实验中,蒸发器冷却水为低流速双向流动的流体。通过理论分析,设计出一种结构简单可在低雷诺数小流量下测量双向流量的节流管,产成功的用于实验,从而提供了一种在低雷诺数小流量下测量单相双向流量的测量方法。     

压缩机制冷量测试系统量热器的动态分布模型的研究

提出了描述全封闭压缩机制冷量测试系统中量热器瞬态行为的数学模型。该模型应用热动力学、气液两相流体动力学的观点和方法，基于能量、质量和动量守恒，对控制体建立了一组动态的、分布参数的微分方程，然后通过边界条件在整个量热器范围内求该数学模型的数值解。该模型是优化测试系统测试量热器设计和研究测试工况控制策略的基础。实验证明：模型和实验结果具有一致的趋势     

Simulation and analysis of the emergency relief process of HTGR steam generator

研究了高温气冷堆( HTGR)蒸汽发生器事故排放过程的动态特性.把事故排放过程分为水排放和蒸汽排放两个阶段,对两个阶段分别建立了集总参数模型.在典型事故排放工况下,计算了蒸汽发生器排放温度、排放压力、排放比焓和排放流量随时间的变化.计算结果表明,事故排放系统可在6.175s内将HTGR蒸汽发生器二回路压力降低到一回路的压力水平,在事故排放结束时,蒸汽发生器仍然处于水排放阶段.计算得到的蒸汽发生器排放比焓和排放流量随时间变化的曲线为今后事故排放系统的排放罐内流动和传热的数值模拟提供了输入条件.     

正弦波纹翅片表冷器的传热及阻力特性实验研究

波纹式翅片具有良好的传热和阻力性能，应用于中央空调两器和末端设备中。以正弦波纹翅片换热器作为中央空调表面式冷却器进行了多种干、湿工况条件下的传热和阻力特性实验。对实验结果进行了分析处理，得出了正弦波纹翅片换热器的总传热系数关联式以及阻力特性的经验公式。实验结果对于中央空调两器和末端的设计具有重要的指导作用。     

液力惯容器特性研究

阐述了外置螺旋管式液力惯容器的基本结构及工作原理。考虑了液力惯容器的摩擦、流动压力损失、活塞惯性和流体的惯性,建立液力惯容器数学模型,并对该模型进行简化,同时对液力惯容器进行了摩擦力等准静态和动态力学特性试验,通过对其力学特性试验与仿真对比分析、阻尼力与惯性力量化关系分析,验证了螺旋管式液力惯容器数学模型的正确性,揭示了在较高频率激励下,液力惯容器可以等效为一个阻尼器与一个惯容器的并联结构,为后续研究液力惯容器特性参数影响规律以及在悬架中的应用奠定了基础。     

微通道蒸发器仿真计算模型与试验分析

分析了微通道蒸发器内制冷剂流动沸腾换热的经验关联式,建立了稳态分布参数和控制单元法的微通道蒸发器数学仿真模型。同时建立不同扁管宽度的微通道蒸发器样机并验证其在不同工况下的传热和压降性能。试验结果表明:微通道蒸发器工作时两相流制冷剂分配不均和冷凝水排除速度慢是造成微通道蒸发器在校核计算时计算值与试验值相差较大的主因。传热试验和修正的仿真模型为今后微通道蒸发器开发计算以及性能优化方面提供了参考。     

微通道平行流蒸发器流程布置研究与分析

微通道平行流蒸发器作为新一代汽车空调用蒸发器正在逐步取代传统的层叠式蒸发器,但是目前业界对微通道平行流蒸发器的流程排布对其性能的影响还不是十分清晰.针对微通道平行流蒸发器的双排结构,利用仿真和实验的方法对两组不同流程结构的蒸发器进行了性能分析,建立的模型仿真结果与实验结果误差在±10%以内.对于不同流程的微通道平行流蒸发器的仿真与实验结果表明,2流程设计比4流程设计具有更好的传热与压降特性.     

小型MRC天然气液化装置中板翅式换热器动态特性仿真研究

针对采用混合制冷剂液化流程(MRC)的小型天然气液化装置(LNG)中的板翅式换热器建立了动态特性仿真数学模型,基于气液两相流理论及气液相平衡理论,对多股流、多组分、有相变的板翅式换热器进行了动态仿真研究,并对该MRC-LNG装置中某换热器在非稳态工况下进行了仿真分析.结果表明:在小型MRC液化天然气装置设计和调试过程中,该模型对提高换热器设计效率、降低运行成本有指导意义.     

新型水暖式汽车暖风装置的开发与传热特性分析

 开发了一套应用于大、中型客车上的新型水暖式汽车暖风装置.介绍暖风装置的结构、工作原理和试验方案.对暖风装置中最重要的排气热能回收装置建立数学模型和动态特性仿真模型,通过MATLAB软件对该装置传热特性进行仿真分析.对发动机在一个连续的工作过程下该装置的传热特性进行试验,结果表明,试验分析和仿真分析结果比较吻合,回收的排气热能满足汽车的供暖要求且装置在工作过程中的排气背压低于4 kPa,有很好的应用前景.     

Numerical investigation of nanofluid heat transfer in helically coiled tubes using the four-equation model

Helical coils and nanofluids are among efficient methods for heat transfer augmentation. The present study numerically investigates convective heat transfer with nanofluids in helically coiled tubes. Two boundary conditions are applied to the coil walls; constant temperature and constant heat flux. Heat transfer in nanofluids are mainly investigated using either the homogeneous model or the two-phase model. However, in the present numerical solution, the four-equation model is applied, using slip mechanisms for the base fluid and nanoparticles. Considering that the proposed model is simplified compared to the two-phase model, it can be regarded as an efficient model for numerical solution of heat transfer in nanofluids. Governing equations are solved in the non-dimensional form using the projection algorithm of finite difference method. Water/CuO with a 0.2% volume fraction and water/Ag with a 0.03% volume fraction are examined for validation of numerical results in case of constant temperature and constant heat flux boundary conditions, respectively. The obtained results show a better agreement of this model with respect to experimental data, compared to the homogeneous model.     

中国先进研究堆备用柴油发电机组的抗震动力学分析

对10MW高温气冷堆(HTR-10)和中国先进研究堆(CARR)的SSE地震地表谱进行了比较,采用分析法与HTR-10备用柴油发电机组的抗震试验数据相结合的方法,对中国先进研究堆(CARR)的备用柴油发电机组进行了抗震动力学分析。由于两个堆所采用的备用柴油发电机组型号相同,HTR-10备用柴油发电机组的振动试验谱在局部不能包络CARR堆的地表谱,同时试验表明该柴油机组的非线性动力学特性较弱,因此首先建立了该柴油发电机组的复杂的有限元分析模型,通过对比模态分析的结果和试验的结果,保证了该模型的准确性,然后按照核安全规范要求,在该模型上施加CARR堆的地表谱,进行反应谱法抗震分析。这是国内首次独立用分析法完成的对这类设备的抗震检验,并得到了核安全部门的认可。同抗震试验法相比,本方法不但能够有效地验证CARR堆柴油发电机组的抗震性能,而且可以大大缩短工程进度、提高工程经济性。     

10MW高温气冷实验堆满功率下的动态特性研究

根据高温气冷实验堆HTR-10的运行特点和控制要求,利用清华大学核能与新能源技术研究院开发的用于仿真计算的系统——10MW HTR-10仿真控制支持系统,进行了HTR-10满功率下动态特性的仿真研究,研究了HTR-10满功率时在外加反应性、氦流量、给水流量变化下的动态特性规律,并将得出的系统动态响应的仿真结果与反应堆在3MW低功率运行时的试验结果作了比较,发现动态特性变化规律一致。验证了仿真控制支持系统的准确性,同时获得了HTR-10满功率下的主要动态特性：由于HTR-10具有很大的负温度反馈系数,只用控制棒很难调节堆功率;而氦流量的变化对堆功率影响很敏感,二者几乎成线性变化,适于负荷变化的功率调节;给水流量的变化对核功率和热氦温度等一回路的参数影响不大,但对蒸汽温度等二回路参数影响显著,适合于蒸汽温度的调节。     

Effect of the size of air bubbles on enhancement of heat transfer in an impinging liquid jet

The numerical modeling of heat transfer in a bubbly impinging jet is carried out. The axisymmetric system of RANS equations that take into account the two-phase nature of the flow is resolved based on the Euler approach. The turbulence of the liquid phase is described by the Reynolds stress transport model with taking into account the effect of bubbles on modification of the turbulence. The effect of the gas volumetric flow rate ratio and the bubble size on the flow structure and the heat transfer in a gas–liquid impact stream is studied. It is shown that the addition of the gas phase in a turbulent fluid causes an increase up to 1.5-fold in heat transfer. The comparison of the simulation results with experimental data showed that the developed model enables the simulation of turbulent bubbly impinging jet with heat transfer with the pipe wall in a wide range of gas fraction.     

LBB思想在HTR-10蒸汽发生器传热管上的应用

试图将LBB思想应用到高温气冷堆蒸汽发生器传热管上,按其中的若干原则规定,对蒸汽发生器传热管进行了LBB分析,初步结果表明传热管满是LBB和件,具有较大的安全裕度,对SG管束进行的LBB分析初步结果显示SG管束满足LBB准则。     

R22和R407C在水平微肋管内冷凝传热与压降的性能分析

根据两相流动换热理论，建立纯制冷剂和非共沸混合制冷剂R407C在微肋管内冷凝的稳态分布参数模型。在此基础上用分布参数法求解控制方程，得出在不同流量、不同干度下，R22和R407C在微肋管内的冷凝传热性能，同时还得出它们在微肋管内流动的压降。本模型可用于分析R22及R407C在系统中的整体换热性能，为冷凝器的优化设计、制冷系统的匹配提供依据。     

高温核动力厂核蒸汽供给系统的比值控制

结合１０ＭＷ高温气冷实验堆核蒸汽供给系统的控制系统设计，介绍了适合于高温核动力核蒸汽供给系统控制的一种新方法－－比值控制。仿真结果表明：比值控制使堆芯氦气出、入口温度变化在允许范围内，主蒸汽温度维持为给定值。     

Numerical analysis of unsteady behavior of cloud cavitation around a NACA0015 foil

Three-dimensional unsteady cavitating flow around a NACA0015 hydrofoil fixed between the sidewalls was simulated and the mechanism of U-shaped cloud cavity formation was clarified. A local homogeneous model was used for the modeling of the vapor–liquid two-phase medium. The compressible two-phase Navier–Stokes equations as the governing equations were solved. To describe the phase change between water and vapor, the mass transfer model based on the theory of evaporation/condensation on a plane interface was introduced. The cell-centered finite volume method was employed to discretize the governing equations. Assuming turbulent flow, the turbulent eddy viscosity coefficient was computed by using the Baldwin–Lomax model with the Degani–Schiff modification. As a result, even in the case of cavitating flow without sidewalls, the shed cloud cavities has slightly 3D structure, which was not so much large as extending across the whole spanwise direction. On the other hand, in the case of cavitating flow with sidewalls, the end of sheet cavities bows in the spanwise direction because of the development of boundary layer near both sidewalls. After that, due to the occurring of the reentrant jet towards the mid-span region, the sheet cavities breaks off from mid-span region near the leading edge of the hydrofoil, and became the vortical cloud cavities, which have the large-scale U-shaped structure.     

A simulation model of the transient performance of a heat pump

This paper describes a heat pump transient analysis computer program (TRPUMP). It is based upon component mathematical models in lumped parametric form. It uses first-order differential equations to describe single- and two-phase heat, mass and momentum transfer, and builds upon seven component sub-routines for the dynamic responses of electric motors, compressors, shafts, electric fans, air/refrigerant heat exchangers, accumulators, and thermostatic expansion valves. The model is capable of simulating dynamic responses of the air-to-air heat pump of the type commonly used in residential applications today. Confidence in the model's accuracy has been established by comparison of simulation results with test data taken at the NBS laboratories.     

A simulation model of the transient performance of a heat pumpSimulation de la performance transitoire d'une pompe à chaleur

This paper describes a heat pump transient analysis computer program (TRPUMP). It is based upon component mathematical models in lumped parametric form. It uses first-order differential equations to describe single- and two-phase heat, mass and momentum transfer, and builds upon seven component sub-routines for the dynamic responses of electric motors, compressors, shafts, electric fans, air/refrigerant heat exchangers, accumulators, and thermostatic expansion valves. The model is capable of simulating dynamic responses of the air-to-air heat pump of the type commonly used in residential applications today. Confidence in the model's accuracy has been established by comparison of simulation results with test data taken at the NBS laboratories.