【作者】 张登春；

【导师】 翁培奋；

【作者基本信息】 上海大学 ， 流体力学， 2010， 博士

【摘要】 旅客列车是我国中长途客运的主要交通工具之一。列车车厢内高度的密封性带来的热舒适和空气品质问题日益突出,已成为国内外学者关注的焦点和研究的热点。旅客列车车厢内热环境的特点是列车内外的热、湿扰量大,且不同的时段、不同的运行区间差别很大,热环境呈不稳定性。国内学者对旅客列车车厢内气流组织和热舒适的研究大多是基于空载条件下进行的,对车厢内气流分布特征和影响因素尚缺乏系统而全面的研究。本文以25K型旅客列车为研究背景,针对其热源和污染源复杂、多场耦合的特点,数值研究了车厢内气流分布特征,在此基础上对车厢内人体热舒适性和空气质量进行了研究。用三维不可压缩雷诺时均N-S方程描述旅客列车车厢内的空气流动,湍流模型采用标准k -ε模型,视人体为污染源和热源体,考虑太阳辐射和车体传热作用,自行编制计算程序,研究了不同工况下车厢内空气流场和温度场分布规律,以及人体作为污染源和热源体对车厢内流场、温度场和CO2浓度场的影响,讨论了不同送风方式和送风速度对车厢内气流分布参数的影响。将25K型硬座车厢内速度和温度实测数据与模拟结果进行对比,两者吻合良好,证实了所开发的数值计算程序的可靠性。针对旅客列车车厢内气流分布不均、人体热感觉差别较大的现状,成功实现了将热舒适评价指标PMV和吹风感指标PD应用于车厢内人体热舒适性的研究,研究了送风速度、送风温度和送风方式对车厢内热舒适性的影响。计算结果表明:硬座车厢内采用两侧条缝送风方式比较合适,车厢内送风速度不宜过大,较大的送风速度虽然能改善靠窗处乘客的热舒适性,但同时使过道处乘客有局部吹风感;硬卧车厢内为了保持各铺位乘客的热舒适性,宜采用条缝送风方式,且送风口应置于铺位区中央。在综合考虑人体热舒适性和空气品质的基础上,首次提出了全面评价旅客列车车厢内空气质量的指标AQI,利用该指标对车厢内空气质量进行了评价,得出了硬座车厢内两侧条缝送风的最佳送风速度为2.5m/s;对硬卧车厢送风方式进行了改进,得出了保持车厢内良好空气质量的送风方式和送风参数,硬卧车厢内应采用条缝送风,最佳送风速度为2.5m/s。该研究结论对指导列车车厢内通风系统设计有重要的参考价值。我国旅客列车空调系统通过控制空调机组的开停以实现车厢内的温度控制,该控制方法使车厢内温度波动大,车厢内环境不能满足热舒适性要求。以25K型旅客列车为研究对象,采用MATLAB/SIMULINK工具箱,设计了PID和FUZZY控制系统,以实现对车厢内的温度控制。针对旅客列车车厢内CO₂浓度偏高、车厢内空气质量较差这一状况,以车厢内CO₂浓度作为车厢内空气品质的控制标准,设计了PID控制系统并进行仿真,结果表明基于CO₂浓度变化控制车厢内的新风量,能有效改善车厢内的空气品质。更多还原

【Abstract】 Railway passenger car is one of the main vehicles in middle and long distance transportation in our country. The problem of comfort and air quality in the compartment induced by the good sealing is increasingly outstanding, which become the focus of attention and study by domestic and foreign scholars. The peculiarity in railway passenger car is that the heat flux and humidity internal and external has a big interference on thermal environment, and varies with different driving period and location, so the thermal environment in the compartment has a significant instability. Some relative studies on air organization and thermal comfort only in idle condition in train compartment have been carried out, but the airflow distribution characteristics and influencing factor are devoid of systematical and comprehensive research in our country. In this paper, aiming at the complexity of heat flux and contaminant source with multi-coupling in the 25K railway passenger car, the air distribution in the compartment is numerically simulated, and the thermal comfort and air quality is studied based on the anterior simulation result.The three-dimensional incompressible Reynolds time-average N-S equation is used to descript the air distribution. In the standard k-εturbulence model, the passenger body is regarded as contaminant and heat source, considering solar radiation and heat transfer of the compartment, and the calculation code is wholly compiled by the author successfully. The airflow and temperature distribution characteristics are studied in different conditions. The influence of body heat on turbulence airflow, temperature and CO2 concentration fields are analyzed, and the influence of supply air mode and air velocity on the air distribution parameters is discussed. The experimental measurement is carried out in the 25K railway passenger car. The data of experimental measurement are coinciding with the simulation results, which verify the reliability of the calculation code. Based on the state of uneven distribution of airflow and great difference of thermal sensation in the compartment, PMV and PD are successfully applied in the research of body thermal comfort. The influences of supply air velocity, temperature and supply air mode on thermal comfort are respectively studied. The results reveal that sew supply air at two sides of the ceiling is suitable for hard-seat car, and the supply air velocity should not be too large, because too large velocity easily produce local blowing feeling at the aisle while improving thermal comfort near the windows. Sew supply air mode is suitable for hard-berth sleeper to maintain the passengers’comfort, and the outlet should be located on the ceiling at the centre of the berth.On the basis of comprehensively considering thermal comfort and air quality,the index of AQI is first put forward to overall evaluate the air quality in the compartment. A conclusion that the optimal sew supply air velocity at two sides is 2.5m/s in hard-seat car is drawn. Supply air mode in hard-berth sleeper is improved, and the optimal supply air mode and supply air parameter simultaneously meeting the requirement of thermal comfort and good air quality are obtained. In hard-berth sleeper, the optimal supply air velocity is 2.5m/s with sew supply air. The research conclusion has an important reference value to guide the design of ventilation system in the compartment.In our country, the air-conditioning system in railway passenger car control the temperature through start-stop condition, so the temperature fluctuation is obvious, and the air environment can’t satisfy the passenger’s demand. In the study of 25K passenger car, PID and FUZZY control system are designed by simulink tool box of the Microsoft MATLAB to control the temperature in the compartment. Based on the condition that the CO₂ concentration is much high, and the air quality is bad in the compartment, the CO₂ concentration is regarded as control standard, and PID control system is designed and simulated. The results show that controlling fresh air volume based on CO₂ concentration can effectively implement improving the air quality in the compartment.更多还原