婴儿睡眠环境的个性化通风设计

发布时间：2018-07-13 18:07

【摘要】：婴儿猝死综合症(SIDS)是1-12个月婴儿的第一致死原因。根据流行病学研究结果，热不舒适性、新风供给不足和空气污染暴露是诱发SIDS的主要环境因素。由于婴儿睡眠期间是SIDS的高发期，因此采用切实可靠的通风策略来调控婴儿睡眠环境，确保婴儿呼吸到足够的温度适宜的干净空气，对预防SIDS具有重要的实践意义。本研究首先通过现场实测评估婴儿的睡眠环境质量，考察针对婴儿睡眠环境采用个性化通风的必要性。在此基础上，提出了两种个性化送风方式即覆盖式个性化通风(WCPV)和置换式个性化通风(DPV)，以便在避免因吹风感而引起婴儿热不舒适的同时，直接将处理过的干净适温的空气送入婴儿呼吸域。采用WCPV时，冷空气被斜吹向婴儿上方后在重力作用下落向婴儿头部周围空间，将婴儿头部覆盖于其影响范围内；采用DPV时，冷空气被低速吹向婴儿头部，逐步置换头部附近空气，渗透进入婴儿呼吸域。采用经过验证的基于计算流体力学(CFD)的数值模拟方法，本研究考察了上述两种个性化通风方式的应用效果。在室内环境的数值模型中，婴儿仰卧于位于室内中间位置的床上；设置在床背后墙上的壁挂式空调将24oC的空气以0.4m/s的速度吹向45°斜下方，室内换气次数为5ACH；立在离床沿0.1m的个性化通风装置以0.5L/s的流量将18oC的干净空气吹向婴儿头部。根据计算结果，WCPV和DPV均能将婴儿头部周边的风速控制在0.2m/s以下，温度控制在18~22oC之间，以满足婴儿的热舒适要求；另一方面，采用WCPV和DPV能分别将婴儿呼吸域的空气龄降低39%和86%；DPV能比WCPV快4.6倍将干净空气送入婴儿呼吸域，并使送风可及性提高24%。此外，本研究考察了源于一个站立于个性化通风装置对面床沿边的成年人的三手烟和流感对婴儿的影响。结果显示，采用WCPV和DPV分别将婴儿吸入空气中的三手烟浓度降低了67%和86%，将婴儿感染流感的概率降低了68%和92%。本研究进一步考察了个性化通风的送风量及婴儿睡眠姿势对WCPV和DPV应用效果的影响。计算结果显示，当个性化通风送风量减少至0.25L/s，婴儿呼吸域的换气效率显著降低，婴儿对室内污染的暴露大幅增加。当婴儿将脸朝向个性化通风装置相反一侧时，WCPV的应用效果虽然略有改善但仍然不如DPV的应用效果。综上所述，与WCPV相比，，DPV具有更好的个性化通风应用效果，能更好地控制婴儿的呼吸空气质量。
[Abstract]:Sudden infant death syndrome (SIDS) is the first cause of death in infants aged 1-12 months. According to the results of epidemiological studies, thermal discomfort, lack of fresh air supply and air pollution exposure are the main environmental factors that induce SIDS. Since SIDS is a high incidence period during infant sleep, it is of great practical significance to prevent SIDS by adopting reliable ventilation strategies to regulate the sleeping environment of infants and to ensure that infants breathe enough clean air with adequate temperature. In this study, the quality of infant's sleep environment was evaluated by field measurement, and the necessity of individualized ventilation for infant's sleep environment was investigated. On this basis, two individualized ventilation modes, namely overlay individualized ventilation (WCPV) and displacement individualized ventilation (DPV), are proposed in order to avoid the thermal discomfort caused by blowing air. Send clean and warm air directly into the infant's respiratory tract. With WCPV, cold air is deflected to the top of the baby and then falls into the space around the baby's head by gravity, covering the baby's head in the area of influence; when using DPV, the cold air is blown to the baby's head at a low speed. Step by step replace the air near the head and penetrate into the infant's respiratory region. Based on the proven numerical simulation method based on computational fluid dynamics (CFD), the effects of the two individual ventilation methods mentioned above are investigated in this study. In the numerical model of indoor environment, the infant lies on the bed located in the middle of the room, and the wall mounted air conditioner on the back wall of the bed blows the air from 24oC to 45 掳at the speed of 0.4m/s, and the number of indoor air exchange is 5ACH; A personalized ventilator standing 0.1 m from the edge of the bed blows 18 oC of clean air to the baby's head at a flow rate of 0.5 L / s. According to the calculation results, both WCPVs and DPVs can control the wind speed around the baby's head below 0.2m/s and the temperature between 182oC to satisfy the thermal comfort requirement of the baby. WCPV and DPV can reduce the air age of infant respiratory region by 39% and 86% respectively. DPV can send clean air into infant respiratory region 4.6 times faster than WCPV, and increase the air supply accessibility by 24%. In addition, the study examined the effects of three-hand smoke and influenza on infants from an adult standing on the edge of a bed opposite a personalized ventilation device. The results showed that WCPV and DPV reduced the concentration of three-hand smoke in air by 67% and 86%, respectively, and reduced the probability of infantile infection by 68% and 92%, respectively. The effects of individualized ventilation and infant sleep posture on the application of WCPV and DPV were investigated. The results show that when the ventilation volume of individualized ventilation is reduced to 0.25 L / s, the air exchange efficiency in the respiratory region of infants decreases significantly, and the exposure of infants to indoor pollution increases significantly. The application effect of WCPV is not as good as that of DPV, although the application effect of WCPV is slightly improved when the baby faces toward the opposite side of the ventilation device. In conclusion, compared with WCPV, DPV has better application effect of individualized ventilation and can better control the air quality of infants.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU834

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