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胸部送风非均匀环境下的人体热舒适研究

Study on Thermal Comfort under Non-uniform Environment with Chest Exposing to the Local Airflow

【作者】 王月梅

【导师】 连之伟;

【作者基本信息】 上海交通大学 , 制冷及低温工程, 2013, 博士

【摘要】 由于目前节能的迫切要求以及对室内环境质量要求的提高,工位空调被提出并越来越受到关注。然而,工位空调为非均匀的热环境,与以往的均匀环境存在很大差异,其在热舒适方面有很多基础性的问题有待解决,如工位空调型式的优化,背景温度的可接受范围以及局部送风参数的设置范围等。这些问题决定着工位空调的节能潜力和提高舒适性等性能是否能够得到充分发挥。再者,由于在工位空调下人体处于非均匀的热环境中,已有的标准和规范中被采用的PMV-PPD等热感觉和热舒适的预测和评价方法并不适用,因此需要建立工位空调环境下热感觉及热舒适的评价方法。此外,工位空调环境下的吹风感问题也是影响其性能发挥的主要问题,对于工位空调环境下吹风感的预测和评价也有待解决。针对上述问题,本文的主要研究内容及结果如下:1.提出了胸部送风的工位空调形式,并开展了胸部送风非均匀环境下人体热舒适的基础性实验研究。研究发现28°C的背景环境下可以通过胸部工位送风来改善人体的热舒适,并得到了工位送风温度、风速及风口面积组合的适宜范围。2.通过系统地研究和比较工位送风参数对整体热舒适、整体热感觉及局部热感觉、局部热舒适及吹风感的影响之间的规律,阐明了非均匀环境下整体热舒适与整体热感觉的关系与均匀环境下的“一一对应”不同而出现“分离”的原因。工位空调环境下的整体热舒适不仅与整体热感觉偏离中性的程度有关系,还与局部热舒适及吹风感有关系。据此提出了胸部送风非均匀环境下的整体热舒适的预测关联式。3.提出非均匀环境下考虑局部送风作用和各部位生理差异的平均皮温计算方法的思想。并建立了适用于胸部送风非均匀环境下的的人体平均皮肤温度的计算方法—14点法。4.在本文研究范围内,稳态情况下整体热感觉与平均皮温之间存在线性关系。非稳态情况下,整体热感觉与平均皮温及其变化率之间呈线性关系。并得到了上述关系的经验关联式。此外,得到了基于胸中部位皮肤温度的整体热感觉的预测经验关系式。5.在非均匀环境下,当整体热感觉在中性区附近时,得到如下结论:稳态情况下,局部皮肤温度与局部热感觉之间呈线性关系,局部热感觉与局部热舒适之间呈二次方关系。并得到了胸中部位、上臂前侧、前臂前侧及颈部前侧的热感觉及热舒适的预测关联式。非稳态情况下,得到胸中部位热感觉与胸中部位皮温及其变化率的线性经验关联式。6.通过不同紊流度下的吹风感实验,对紊流度影响吹风感的原因进行了探讨。研究结果表明紊流度影响吹风感是由于其影响了人体的局部皮肤温度。证明了采用皮肤温度预测吹风感的思路是可行的。进而,在胸部送风非均匀环境下建立了胸部吹风感投票值与胸中部位皮温、胸中部位热感觉及热舒适之间的关系式。该关系式可用于胸部暴露情况下的吹风感预测。7.建立了包含暴露时间、气流温度、风速和紊流度四个因素的吹风不满意率预测模型。并建立了吹风感投票值与吹风不满意率之间转化的经验关系式。本研究中得到的背景和胸部工位送风的参数范围,以及热感觉、热舒适和吹风感的预测关系式可以为工位空调系统的开发和设计标准的制定提供基础性的依据。

【Abstract】 Task ambient air conditioning has potentials to save energy and improve air qualityand thermal comfort. However, there are many knowledge gap needed to be solved beforeit can be used. Thermal comfort characteristic is one of the important issues which affectthe performance of the task ambient air conditioning. Many questions needs to beanswered, e.g. the optimization of the type, the acceptable range of the ambient airtemperature, the suitable local supply air temperature, velocity et al. Besides, the theoriesand principles built under the uniform environment are not applicable to the task ambientair conditioning environment, which is non-uniform and transient. For example, thePMV-PPD model, which is widely used in mixing ventilation environment, needs to bereevaluated. The evaluation and prediction on draft under the task ambient airconditioning was also an important issue. Therefore, the basic researches on thermalcomfort in task ambient air conditioning are needed.Based on the above questions, the main contents and results of this study include:1. Experimental study on thermal comfort under the non-uniform environment withchest exposing to the local airflow was carried out. Under the ambient temperature of28°C, overall thermal comfort can be improved by local cooling. The range of the local supplyair temperature, velocity and the size of the vent was suggested.2. The correlation between the overall thermal sensation and overall thermal comfortunder non-uniform environment was different from that under uniform environments. Thephenomenon was explained by analyzing the relationship between the local supply airflowparameters, the local thermal sensation and comfort, and overall thermal sensation and comfort. Overall thermal comfort was not only related to overall thermal sensation, but alsorelated to the local thermal sensation, thermal comfort and draft.3. Mean skin temperature calculation method was suggested considering the effect ofthe local airflow and the physiological difference between the different body parts. Basedon this principle,14points method was built to calculate the mean skin temperature undernon-uniform environment with chest exposure to the local airflow.4. The overall thermal sensation was linearly related to the mean skin temperatureunder the steady state under the present research condition. Overall thermal sensation waslinearly related to the mean skin temperature and its change rate. The correlations of theabove relationships were regressed. Besides, correlations between the overall thermalsensation and the skin temperature on the middle of the chest and its change rate wasobtained to predict overall thermal sensation under the non-uniform envieonment withchest exposing to the local airflow.5. A serious of correlations were built to predict the local thermal sensation and thelocal thermal comfort when the overall thermal sensation was nearly thermal neutral. Thecorrelation between the local thermal sensation and the local skin temperature was linear.The correlation between the local thermal comfort and the local thermal sensation wasquadratic. The correlations were obtained to predict the thermal sensation and the thermalcomfort at the middle of the chest, anterior upper arm, anterior forearm and anterior neck,respectively.6. The effect of turbulence intensity on draft was studied by experiments. Turbulenceintensity affects draft because it affects the local skin temperature. Skin temperature canbe considered as a parameter to predict draft rate. Furthermore, the draft rate at the chestwas correlated to the local skin temperature, the local thermal sensation and the localthermal comfort, in order to predict human’s responses to draft when the chest exposed tothe local airflow.7. A model to predict draft rate was built considering exposure time, airflowtemperature, velocity and turbulence intensity. Besides, a correlation between draft voteand draft rate was proposed. The suggested range of the local supply airflow parameters and the correlationspredicting the thermal sensation, comfort and draft can be referenced by the designer ofthe task ambient air conditioning.

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