Dynamic Simulation and Performance Investigation of No-Frost Refrigerator: Part Ⅱ System Simulation and Performance Analysis

The methodology for modeling no-frost refrigerator is described based on the component models de-veloped in Part I, and then, system simulation is applied to a BCD-235W refrigerator-freezer (RF). Experiments are carried out to study "pull-down" and steady-state performance of the RF, and to determine how the exper-iment and simulation temperature stack up against each other. Good match is found between simulated and measured results for the "pull-down" period. For the steady-state period, the simulation results are also found to agree well with experiment ones except for the temperature profiles of the refrigerator compartment (RC) and freezer compartment (FC). The average temperature and the energy consumption errors between measurement and simulation are less than 10%. Although the model can not reflect the non-uniform air temperature fields in the RC and FC, the variation range and periodicities of the temperature correlate well between the simulation and experiment. We conclude that such a model is valid for investigating the performance of no-frost refrigerator.     

Dynamic Simulation and Performance Investigation of No-frost Refrigerator: Part Ⅰ Mathematical Model

A dynamic approach for the modeling, simulation and analysis of no-frost Refrigerator (RF) is dis-cussed. In Part Ⅰ, the complex interactions among the components in the cooling system are analyzed in detail, based on which the modeling simplifications are proposed. Then, the mathematical models for the evaporator, cabinet and duct-fan are presented. The whole system is divided into two subsystems-refrigerant cycling system and air cycling system. In order to simplify the model, two closed-loop systems are broken into the compressor component and the evaporator component, respectively. A general distributed parameter model is employed for evaporator with homogeneous flow to simplify the two-phase evaporating flow region. The z-transfer function model is used to describe the cabinet load. Computational fluid dynamics (CFD) method is employed to obtain the pressure drop and flow rate curve of the duct-fan model.     

Dynamic simulation and performance investigation of no-frost refrigerator: Part I mathematical model

A dynamic approach for the modeling, simulation and analysis of no-frost Refrigerator (RF) is discussed. In Part I, the complex interactions among the components in the cooling system are analyzed in detail, based on which the modeling simplifications are proposed. Then, the mathematical models for the evaporator, cabinet and duct-fan are presented. The whole system is divided into two subsystems—refrigerant cycling system and air cycling system. In order to simplify the model, two closed-loop systems are broken into the compressor component and the evaporator component, respectively. A general distributed parameter model is employed for evaporator with homogeneous flow to simplify the two-phase evaporating flow region. The z-transfer function model is used to describe the cabinet load. Computational fluid dynamics (CFD) method is employed to obtain the pressure drop and flow rate curve of the duct-fan model.

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轨距不平顺激励下高速列车动力响应研究

为分析轨距不平顺对车辆动力响应的影响,建立了直线和曲线上不同工况的轨距不平顺,仿真计算了列车以不同速度通过轨距不平顺下动力响应,并对各项指标进行了对比分析。     

轨面短波不平顺对轮轨力影响的研究

轨面短波不平顺是轮轨作用力的主要影响因素。通过分析实测轨面短波不平顺数据,利用仿真计算研究不同轨面不平顺、不同运行条件下的车辆动力响应,比较分析动力响应计算结果有利于了解短波不平顺对运行列车的安全性和稳定性的影响。最后的结果分析为现场轨面短波不平顺的维修养护控制值提供一定的理论依据,并建议了轨面不平顺的控制值。     

基于ADAMS的齿轮减速器动力学仿真

基于三维造型设计软件Solidworks,构建了单级齿轮减速器的三维参数化模型,并将其导入机械系统动力学仿真软件ADAMS中,在ADAMS中建立减速器的虚拟样机模型,对此样机模型进行仿真,得到转速、轮齿啮合力等参数特性曲线,对其进行分析,为动态特性优化提供理论指导。     

拱桥施工可视化动态仿真研究

计算机模拟拱桥施工是在3DS.MAX6.0软件平台下的Motion和Video.P0st模块相结合进行的桥梁施工动态研究.研究成果演示了吊装施工过程,比较真实地反映了拱桥施工技术的特点,可对施工方案的可行研究和预案提供比较确切的数据分析,对桥梁施工有一定的应用价值.     

轻轨列车用缓冲器动态阻抗特性研究

目前国内是参考铁道客车的标准提出轻轨用列车缓冲器的性能指标,并据此选择轻轨列车缓冲器容量和动态阻抗特性。由于城轨车辆采用动力分散的模式,且编组很少,在正常工况下所受车钩力很小,所以参照铁道客车标准选择的缓冲器容量和动态阻抗力往往过高。采用动力学的分析方法确定了动态阻抗特性改变前后的列车纵向冲动量,提出在满足性能和安全要求的前提下,可以降低缓冲器的动态阻抗力和容量,不仅可以改善列车的纵向冲动、提高缓冲器的使用寿命,而且能够降低制造成本。     

舰载蒸汽弹射系统建模与仿真研究

针对舰用蒸汽弹射器的基本工作原理,在一定的假设条件下建立其动态仿真数学模型.通过模型对舰用蒸汽弹射系统的动力学和热力过程特性进行了研究,给出了其在各种运行工况下的仿真结果,并进行了仿真试验,得到了不同条件下活塞速度、加速度、位移以及汽缸压力的变化规律;分析了漏汽对弹射系统的影响,获得了不同漏汽情况下弹射末速度和过载的变化.     

联合工况的车辆动力学仿真

建立了整车的模型,用Matlab软件对车辆在不同车轮转角、不同车速及不同制动力矩情况下的动力学进行了仿真。仿真结果表明:随着车轮转角及车速的增大,车辆横摆角速度峰值、横向速度峰值增大;过大的制动力矩将使车辆横向侧滑加剧及使横摆角速度峰值变大,车辆在联合工况下的稳定性变差。仿真为车辆在联合工况下的建模和控制提供了参考。