冬季大空间室内两种典型气流组织的试验研究

试验研究并分析了喷口单侧送风和柱状下送风2种典型气流组织的5个工况下冬季室内的垂直温度分布、居住域温度场、速度场、PMV以及供热量等试验结果。试验A、B、C、D、E 5个工况依次为:喷口下调30°、15°侧上送侧下回风2个工况,柱状下送上回方式,分设计送风面积、削减下部送风面积40%、削减上部送风面积60%3个工况。试验风量为7275~8506 m3/h,室外空气综合温度为9.0~9.3℃。试验结果表明:A、B、C、D、E 5个工况的单位室内外温差供热量依次为1832、1673、2210、2016和1836 W/℃时,居住域的平均温度相应可达23.1、23.1,18.7,19.7和21.3℃,其PMV均值分别为0.48,0.33,0.02,0.03和0.34。试验和理论研究结果表明,在同样的舒适度的条件下,冬季喷口送风节能性、稳定时间要好于柱状送风气流组织,从居住域的热环境均匀性、局部吹风感角度出发,柱状送风要好于喷口送风。     

Experimental study on occupant’s thermal responses under the non-uniform conditions in vehicle cabin during the heating period

The existing investigations on thermal comfort mostly focus on the thermal environment conditions, especially of the air-flow field and the temperature distributions in vehicle cabin. Less attention appears to direct to the thermal comfort or thermal sensation of occupants, even to the relationship between thermal conditions and thermal sensation. In this paper, a series of experiments were designed and conducted for understanding the non-uniform conditions and the occupant＇s thermal responses in vehicle cabin during the heating period. To accurately assess the transient temperature distribution in cabin in common daily condition, the air temperature at a number of positions is measured in a full size vehicle cabin under natural winter environment in South China by using a discrete thermocouples network. The occupant body is divided into nine segments, the skin temperature at each segment and the occupant＇s local thermal sensation at the head, body, upper limb and lower limb are monitored continuously. The skin temperature is observed by using a discrete thermocouples network, and the local thermal sensation is evaluated by using a seven-point thermal comfort survey questionnaire proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc（ASHRAE） Standard. The relationship between the skin temperature and the thermal sensation is discussed and regressed by statistics method. The results show that the interior air temperature is highly non-uniform over the vehicle cabin. The locations where the occupants sit have a significant effect on the occupant＇s thermal responses, including the skin temperature and the thermal sensation. The skin temperaWa-e and thermal sensation are quite different between body segments due to the effect of non-uniform conditions, clothing resistance, and the human thermal regulating system. A quantitative relationship between the thermal sensation and the skin temperature at each body segment of occupant in real life traffic is presented. The investigation result indicates that the skin temperature is a robust index to evaluate the thermal sensation. Applying the skin temperature to designing and controlling parameters of the heating, ventilation and air conditioning（HVAC） system may benefit the thermal comfort and reducing energy consumption.     

基于集中质量的铰接式自卸车平顺性仿真研究

根据振动力学以及多刚体系统动力学原理,分析了某铰接式自卸车的振动模型,同时进行合理的简化,建立了集中质量的虚拟样机模型,并在虚拟样机软件ADAMS上进行仿真。通过与试验的对比,也验证了仿真方法可行,仿真模型可靠。因此可用该模型计算随机激励下铰接式自卸车的响应,并进行整车动力学分析和悬架系统参数优化设计。     

一种基于支持向量回归的驾驶座椅舒适度评价方法

提出一种基于支持向量回归的预测驾驶座椅主观舒适度的方法.预测的输入变量为14个体压分布变量以及3个人体变量,输出变量为整体舒适度指数.通过12名被试对5辆不同汽车进行实际驾驶来获取座椅压力数据.在利用支持向量回归建立的舒适度预测方法进行预测时,均方误差为0.0018,相关系数为0.869,这一结果优于人工神经网络预测模型的预测结果.研究结果有助于汽车制造企业在提高汽车座椅舒适性的过程中降低成本并缩短制造时间.     

基于参数辨识的矿用自卸车平顺性优化

矿用自卸车行驶路况非常恶劣,为改善某型矿用自卸车的平顺性,需要得到油气悬架非线性刚度阻尼特性。利用具有紧支撑正交特性的Daubechies小波和最小二乘法原理辨识油气悬架物理参数,将时变刚度阻尼离散为正交尺度函数下的线性组合,从而把辨识时变物理参数的"黑箱"问题转化为已知尺度函数序列和系统的输入输出来估计线性组合中的时不变系数问题。为验证辨识的刚度阻尼值,在Adams/view中建立整车多体动力学模型,得知辨识参数下的加速度时域响应和功率谱密度与试验结果相差无几,从而验证了该方法的有效性。借助遗传算法优化油气悬架的物理参数,将辨识结果作为优化变量的初始条件,以座椅垂直方向加速度方均根值为目标,优化后目标值下降了51.84%,达到了改善平顺性的目的。     

A study on the dynamic performance of the 200km/h Korean tilting train by means of roller rig test

The dynamic performances of newly developed railway vehicles should be carefully verified step by step, from computer simulation through the laboratory-based roller rig test to the main line trial running test. The laboratory-based roller rig test is an effective and safe way to evaluate the dynamic characteristics such as high speed, ride comfort and dynamic behaviors. This experimental research was performed to evaluate the dynamic performances of the 200 km/h Korean tilting train, ‘Hanvit200’, by means of a full scale roller rig test. The newly developed tilting mechanism and stabilizer were included in the tilting bogie to satisfy both the conflicting requirements of higher stability and higher curving performance. This paper shows the roller rig test results and the effectiveness of tilting bogie design. Included are the roller rig test results of various kinds of conditions such as tare and fully laden load case, normal and failed case of important bogie components, linear and non-linear critical speed. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Nam-Po Kim received a B.S. degree in Mechanical Engineering from Ajou University in 1985. He then went on to receive his M.S. and Ph.D. degrees from Ajou University in 1992 and 2008, respectively. Dr. Kim is currently a principal researcher at the department of vehicle dynamics and propulsion system at Korea Rail Road Research Institute in Uiwang, Korea. His research interests are in the area of railway vehicle dynamics, active control of running gear for railway vehicle and vehicle system engineering.     

基于虚拟试验的摩托车平顺性仿真研究

利用三维建模软件建立摩托车三维实体模型,导入多体动力学软件ADAMS,在各零部件之间设置相互约束,编制路面文件,形成适合平顺性分析的摩托车多体动力学模型.通过对摩托车多体动力学模型进行虚拟试验,提取对驾乘舒适性显著影响部位的振动加速度值,对摩托车的平顺性进行评价分析.     

Evaluation of comfort level in desks equipped with two personalized ventilation systems in slightly warm environments

In this work the comfort level, namely the thermal comfort, local thermal discomfort and air quality levels, in a classroom with desks equipped with two personalized ventilation systems, in slightly warm environments, is evaluated. A manikin, a ventilated classroom desk, two indoor climate analyzers, a multi-nodal human thermal comfort numerical model and a computational fluid dynamic numerical model, are used.     

Evaluation of thermal comfort conditions in a localized radiant system placed in front and behind two students seated nearby warmed curtains

In this work the evaluation of thermal comfort conditions, that two students are subjected, in a classroom desk equipped with a localized radiant system placed in front and behind the occupants seated nearby windows equipped with curtains subjected to solar radiation, in Winter conditions, is made. In the simulation, performed in a 2.7 × 2.4 × 2.4 m³ virtual chamber, two occupants seated in a classroom desk, equipped with two localized radiant surfaces placed in front and two localized radiant surfaces placed behind them, a window subjected to solar radiation and an internal curtain are considered.     

Improved indoor thermal comfort during defrost with a novel reverse-cycle defrosting method for air source heat pumps

When an air-source heat pump (ASHP) unit is used for space heating at a low ambient temperature in winter, frost may be formed on its outdoor coil surface. Frosting affects its operational performance and energy efficiency, and therefore periodic defrosting is necessary. Currently, the most widely used standard defrosting method for ASHP units is reverse-cycle defrost. During a standard reverse-cycle defrosting process, the indoor coil in an ASHP unit actually acts as an evaporator, therefore, no heating is provided and hence indoor air temperature in a heated space can drop. Furthermore, a longer period of time is needed before space heating can become available immediately after the completion of defrosting. Consequently, occupants’ thermal comfort may be adversely affected. To improve the indoor thermal comfort for occupants during reverse-cycle defrosting, a novel thermal energy storage (TES) based reverse-cycle defrosting method has been developed and the improvement to occupants’ thermal comfort experimentally evaluated and is reported in this paper. Comparative experiments using both the novel TES based reverse-cycle defrosting method and the standard reverse-cycle defrosting method were carried out. Experimental results and the evaluated indoor thermal comfort indexes clearly suggested that when compared to the use of standard reverse-cycle defrost, the use of the novel reverse-cycle defrosting method can help achieve improved indoor thermal comfort, with a shorter defrosting period and a higher indoor supply air temperature during defrosting.